EM Lect 8 ID tox

Emergency MedicineLecture 8Infectious DiseaseImmunologyToxicologyEnvironmental Injuries: 

Emergency Medicine Lecture 8 Infectious Disease Immunology Toxicology Environmental Injuries Tom Lynn, PA-C

Florida moves out of hurricane zone: 

Florida moves out of hurricane zone

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1. All of the following statements concerning decontamination of the poisoned patient are TRUE EXCEPT (A)ipecac syrup continues to be a front-line tool in home management of poisoning (B)gastric lavage is of limited utility except in selected overdoses when the airway has been adequately protected (C)current superactivated charcoal has very limited effectiveness in overdose patients (D)cathartics may cause electrolyte derangements and dehydration (E)whole bowel irrigation is a highly effective method for dealing with body "packers" or "stuffers" and overdoses with enteric-coated or sustained release medications

The answer is C: 

The answer is C Current superactivated charcoal has three times the absorptive area of older preparations, or 3000 m²/kg. The dose is 1 mg/kg, and it may reduce absorption of ingested toxins by 50 percent. Cathartics may be dangerous, especially in pediatric patients and when given in multiple doses to poorly hydrated patients.

Slide9: 

2. What is the antidote for acetaminophen toxicity? (A) flumazenil (B) Narcan (C) vitamin K (D) N-acetylcysteine (E) ethanol

Answer D: 

Answer D Treatment priorities of acetaminophen toxicity consist of supportive care, gastrointestinal decontamination, and the use of the antidote N-acetylcysteine (NAC or Muco-myst). If given early (less than 8 hours after ingestion), NAC can prevent toxicity by inhibiting the binding of the toxic metabolite N-acetyl-p-benzoquinoneimine to hepatic proteins. In acetaminophen toxicity, more than 24 hours after ingestion, NAC diminishes hepatic necrosis by nonspecific mechanisms. The standard 72-hour oral NAC regimen used in the United States is a loading dose of 140 mg/kg followed by maintenance doses of 70 mg/kg every 4 hours for 17 doses.

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3. Which of the following statements is true regarding button battery ingestion? (A) A button battery lodged in the esophagus is a true emergency because of the extremely rapid action of the alkaline substance on the mucosa. (B) Button battery ingestion is essentially a benign ingestion because of the unlikelihood of the battery dissolving. (C) Button battery ingestion is a minor emergency that can often be treated with a Foley balloon technique extraction. (D) Most button batteries, even if symptomatic, can be left to pass through the GI tract naturally by peristalsis. (E) Surgical removal of the button battery is always indicated, even if the patient is asymptomatic.

Answer A: 

Answer A A button battery ingestion may cause significant complications in as little as 4 to 6 hours due to the rapid action of alkaline in the battery. Severe burns of the esophagus or perforation may occur. A plain radiograph of the abdomen should be obtained first to localize the battery. A battery lodged in the esophagus should be removed emergently with endoscopy. A surgical consult may be indicated for symptomatic ingestions past the esophagus.

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4. A patient presents to the emergency department with a dislocated shoulder. Nitrous oxide is the drug selected for sedation and analgesia during reduction. Which of the following is true with regard to the administration of nitrous oxide for short-term painful procedures in the emergency department? (A) A 50:50 concentration of nitrous and oxygen should be used. (B) Never administer oxygen with nitrous oxide. (C) Nitrous oxide concentrations should always be <30%. (D) Higher altitudes require lower concentrations of nitrous oxide. (E) Nitrous oxide is not approved for emergency department use.

Answer A: 

Answer A Nitrous oxide may be used for both sedation and analgesia in the emergency room, as long as it is mixed with at least 30% oxygen to prevent hypoxia. Therapeutic concentrations of nitrous oxide include those in the 30% to 50% range (maximum 70%). Concentrations below 30% may not be effective in this setting. Younger children (below 8 years old) may not gain therapeutic effect from nitrous oxide.

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5. A 30-year-old male patient presents to the emergency department with an acute change in mental status. The examination reveals a patient who is sleepy but arousable to loud verbal stimuli. His airway is intact and the vital signs are stable. Investigative studies indicate an alcohol level 150 mg/dL, an anion gap of 30, a metabolic acidosis, an osmolar gap of 20, and calcium oxalate crystalluria. What is the most likely diagnosis? (A) methanol poisoning (B) ethanol poisoning (C) ethylene glycol poisoning (D) isopropanol poisoning (E) buspirone poisoning

Answer C: 

Answer C Patients with ethylene glycol ingestion usually present with an acute change in mental status, high anion gap metabolic acidosis, osmolar gap, and calcium oxalate crystals in the urine. Ethylene glycol is commercially available as preservatives, glycerine substitutes, and antifreeze. Ethylene glycol may be ingested in suicide attempts, accidentally by children, and by alcoholics as an alcohol substitute. The toxic metabolites formed by ethylene glycol metabolism are primarily formaldehyde, formic acid, and oxalic acid. (Tintinalli, pp. 1103-1107)

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6. All of the following are signs and symptoms of acute altitude mountain sickness EXCEPT (A)headache (B)ataxia (C)vomiting (D)fatigue (E)peripheral edema

The answer is B: 

The answer is B Acute mountain sickness can occur at altitudes as low as 6900 ft (2100 m). Susceptibility differs by individual and is also influenced by rate of ascent, altitude of usual residence, and sleeping altitude. Signs and symptoms resemble those of an alcohol hangover and include headache, nausea, and fatigue or weakness. Patients may exhibit fluid retention and mild peripheral edema. The presence of ataxia suggests a more serious condition, high altitude cerebral edema (HACE).

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7. Which of the following is the most important treatment option in a patient with moderate acute mountain sickness? (A) oxygen therapy (B) dexamethasone (C) hyperbaric therapy (D) acetazolamide (E) immediate descent

Answer E: 

Answer E The three principles of treatment regarding acute mountain sickness (AMS) are (1) to stop the ascent, (2) to descend to lower altitude, and (3) to treat immediately in the presence of change in normal mental status, ataxia, or pulmonary edema. Emergent treatments include oxygen, acetazolamide, nifedipine, dexamethasone, hyperbaric therapy, and continuous positive airway pressure. HACE may progress to coma and death if the patient does not descend quickly to a lower altitude. (Tintinalli, pp. 1263-1267)

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8. A patient presents to the emergency department after being bitten by an unknown "insect" while camping. The pain began as a pinprick sensation at the bite site and spread quickly to include the entire bitten extremity. The bite wound became erythematous 45 minutes after the bite. The bite wound eventually evolved into a target lesion. The patient complains of muscle cramp-like spasms in the large muscle groups. Which of the following is the most likely cause? (A) black widow spider (B) hobo spider (C) brown recluse spider (D) tarantula (E) scorpion

Answer A: 

Answer A The black widow spider (Latrodectus) is found in many areas of the United States. Its bite produces immediate pain and pinprick sensations that soon encompass the entire extremity. Erythema of the bite area develops usually within 1 hour and in about half of the cases quickly evolves into a target pattern. Patients frequently complain of cramp-like spasms in the large muscle groups. The physical examination rarely exhibits muscle rigidity, and serum creatine kinase concentrations usually are not elevated significantly.

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9. Arthropod bites that typically reveal a central blue color of impending necrosis with a surrounding white area of vasospasm and a peripheral red halo of inflammation are associated with (A) scabies (B) black widow spiders (C) brown recluse spiders (D) deer ticks

Answer C: 

Answer C Brown recluse (Loxoscelidae recluses) spider bites in fatty areas such as thighs and buttocks can become necrotic within 4 hours, with a rapidly expanding blue-gray halo around the puncture site surrounded by a white area of vasospasm and a peripheral red halo of inflammation. Scabies (Sarcoptes scabiei) lesions are pleomorphic and often vesicular, pustular, or excoriated with linear, curved, or S-shaped burrows. Black widow (Latrodectus mactans) bites result in slight swelling with small red fang marks. Deer tick (Ixodes dammini) lesions can present as a small papule with a slowly enlarging ring (erythema migrans), a bluish-red nodule (Borrelia lymphocytoma), or an atrophic plaque (acrodermatitis chronica atrophicans). (Fitzpatrick and Aeling, p. 229)

Slide26: 

The brown recluse (Loxosceles) spider bites are difficult to identify. The bite lesion is usually mildly erythematous and may become firm and heal with little scarring over several days to weeks. Occasionally, the lesion may become necrotic over 3 to 4 days with subsequent eschar formation. The hobo spider (Tegenaria) usually causes a painless local reaction similar to that of the brown recluse spider. Blisters eventually develop that rupture, leaving an encrusted cratered wound. A tarantula bite typically causes pain and local swelling at the site. Treatment consists of local wound care. Scorpions (Scorpionida) present with a multitude of local and systemic manifestations. Some of these manifestations include pain, paresthesia, cranial nerve and somatic motor dysfunction, uncontrolled jerking, restlessness, pharyngeal incoordination, and respiratory compromise. (Tintinalli, pp. 1244-1250)

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10. What is the MOST common finding in a patient with a brown recluse spider bite? (A)Severe itching (B)Severe muscle cramps (C)Anaphylaxis (D)Local tissue necrosis (E)Respiratory failure

The answer is D: 

The answer is D The brown recluse species (Loxosceles reclusa) is one of the most common types of spider in the United States. A necrotic wound that may take weeks or months to heal often follows a bite. Wounds may be resistant to treatment and result in long-term disability. Severe muscle cramping, particularly of the abdominal musculature, is the hallmark of black widow spider envenomation. Anaphylaxis may result from insect stings, the most common being from yellow jackets. Respiratory failure may result from anaphylaxis and rarely from black widow spider envenomation, but it is not common after brown recluse spider bite.

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Brown Recluse Spider Bite

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11. A 25-year-old man complains of pain and swelling in the hand and forearm, perioral numbness, and vomiting after trying to catch a rattlesnake. Blood pressure is 90/60 mm Hg. All of the following are appropriate therapies EXCEPT (A)fluid resuscitation (B)administration of 10 vials of antivenin (C)measurement of coagulation factors and platelets (D)immediate fasciotomy of the arm (E)pain medication

The answer is D: 

The answer is D The mainstay of treatment after rattlesnake bites is neutralization of the venom with antivenin. Large amounts of antivenin may be required. Coagulation factors and platelets should be checked in all snake-bite victims to help determine the severity of envenomation. Supportive care, including fluid resuscitation, is important for all patients with pit viper envenomation. If compartment syndrome is suspected, pressures should be measured. Fasciotomy should only be performed when compartment pressures remain above 30 mm Hg after medical treatment.

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12. The most immediate management priority in a patient with septic shock is (A) empiric antimicrobial therapy (B) inotropic support (C) oxygenation and ventilation (D) fluid therapy (E) acid-base status

Answer C: 

Answer C The first priority in the management of septic shock is assessment of the airway, oxygenation, and ventilation. Oxygen should be administered at 100% via mask or endotracheal tube. Fluid resuscitation is the second priority in the patient with septic shock. Tissue and organ perfusion can be assessed by parameters such as the patient's mental status, blood pressure, respiratory rate, pulse rate, skin color and temperature, central venous pressure, and urine output greater than 30 mL/hour (1 mL/kg/hour in pediatric patients). Other important areas of assessment and management include acid-base status and antimicrobial therapy. (Tintinalli, pp. 234-236)

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13. The antidotal agent for benzodiazepine overdose is (A) naloxone (B) Narcan (C) ketamine (D) flumazenil (E) flutamide

Answer D: 

Answer D Flumazenil competitively blocks the effects of benzodiazepines on GABAergic pathway-mediated inhibitors in the central nervous system. Naloxone HCl (Narcan) is a narcotic antagonist. Ketamine is a rapid-acting general anesthetic. Flutamide is a nonsteriodal, antiandrogenic agent used for prostate carcinoma. (Drug Facts and Comparisons, pp. 1802, 3383, 3638)

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14. Which of the following medications is responsible for the most drug-related deaths? (A) benzodiazepines (B) tricyclic antidepressants (C) stimulants (D) monoamine oxidase inhibitors (E) lithium

Answer B: 

Answer B The class of prescription medications responsible for the most drug-related deaths is tricyclic antidepressants (TCAs). The clinical toxicity is due to the complex pharmacologic activity, low therapeutic index, and general availability. The clinical toxicity is quite variable, ranging from mild antimuscarinic activity to severe cardiotoxicity. (Tintinalli, pp. 1063-1066)

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15. A 22-year-old female presents to the ED comatose after a seizure, with a blood pressure of 80/40 and a pulse of 148. QRS duration is 280 ms. She has been depressed and began taking nortriptyline 2 weeks ago. What is the MOST appropriate initial therapeutic intervention? (A)Intravenous access and sodium bicarbonate (B)Intravenous access, gastric lavage, and diazepam to control seizures (C)Airway control, intravenous access, and activated charcoal per nasogastric tube (D)Airway control and mechanical ventilation, intravenous access, and sodium bicarbonate (E)Physostigmine, intravenously

The answer is D: 

The answer is D This patient is severely intoxicated due to TCA overdose. She is at high risk of further cardiopulmonary decompensation and aspiration unless immediate airway control and ventilation are initiated. After ensuring an adequate airway, intravenous access and bicarbonate therapy are the treatment priorities. Gastric lavage (if soon after the ingestion) and activated charcoal are then indicated to prevent continuing absorption of the drug. Use of physostigmine in this case may show transient improvement in level of consciousness but is contraindicated because of the risk of death. Lidocaine is the second-line agent of choice in TCA overdose after sodium bicarbonate for treatment of ventricular dysrhythmias

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16. All of the following statements concerning serotonin syndrome are TRUE EXCEPT (A)it is characterized by alterations in cognitive-behavioral ability, autonomic nervous function, and neuromuscular activity (B)it is usually seen when monoamine oxidase inhibitors or selective serotonin reuptake inhibitors are combined with other serotonergic drugs (C)morphine and fentanyl are contraindicated for treatment (D)neuromuscular symptoms are greatest in the lower extremities (E)mandatory treatment includes discontinuation of all serotonergic medications

The answer is C: 

The answer is C Paroxetine (Prozac) is the most potent of the SSRIs. The most serious side effect of this class of antidepressants is serotonin syndrome. it is characterized by alterations in cognitive-behavioral ability, autonomic nervous function, and neuromuscular activity Extrapyramidal symptoms, hyponatremia, hypoglycemia, and sexual dysfunction are also associated with SSRI medications. Morphine and fentanyl are considered safe treatments for serotonin syndrome. The syndrome is usually seen after increasing the dose of a potent serotonin agonist or adding a second serotonergic agent (such as lithium) to a patient's regimen. Electroconvulsive therapy, cocaine, meperidine, levodopa, L-tryptophan, and other drugs may predispose patients to serotonin syndrome.

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17. Which of the following drugs can be safely used in patients taking monoamine oxidase inhibitors (MAOIs)? (A)Codeine (B)Dextromethorphan (C)Ketamine (D)Meperidine (E)Morphine

The answer is E: 

The answer is E Drugs that are safe to use with MAOIs include aspirin, acetaminophen, ibuprofen, morphine, albuterol, epinephrine, norepinephrine, and isoproterenol. Drugs that are contraindicated if the patient is taking MAOIs include bretylium, pseudoephedrine, caffeine, levodopa, theophylline, and TCAs. MAOIs result in three basic types of drug interactions: pharmacodynamic, pharmacokinetic, and idiosyncratic. Indirect-acting sympathomimetics are the most common cause of pharmacodynamic drug interactions for the MAOI patient. The indirect-acting sympathomimetics can result in a tyramine-like hyperadrenergic state when consumed in conjunction with MAOIs. Pharmacokinetic drug interactions from MAOIs are due to inhibition of usual drug metabolism by cytochrome oxidase. Opiates and sedative-hypnotics are especially susceptible to this phenomenon.

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18. Which of the following factors increases the risk of lithium toxicity at standard doses? (A)Diabetes mellitus (B)Renal failure (C)Advanced age (D)Concurrent use of nonsteroidal antiinflammatory drugs (NSAIDs) (E)All of the above

The answer is E: 

The answer is E Any factor that decreases the efficiency of the kidney to deal with chronic lithium exposure increases the risk of lithium toxicity. Pathophysiologic factors that deplete the body of water or total body sodium increase lithium toxicity. Risk factors for lithium toxicity include diabetes mellitus, hypertension, renal failure, old age, a low sodium diet, and coingestion of diuretics or NSAIDs.

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19. Which of the following statements regarding barbiturates is FALSE? (A)Barbituric acid has no central nervous system activity (B)In a pure barbiturate overdose, the patient's pupils will be small (C)Barbiturates may be used to treat seizures, induce anesthesia, or manage elevated intracranial pressure (D)A severe overdose may result in a flat- line EEG (E)Charcoal administration and alkalinization of the urine are beneficial treatments for barbiturate overdose

The answer is B: 

The answer is B A general rule of thumb is that 10 times the therapeutic dose of barbiturates causes severe toxicity. Overdose results in progressive central nervous system depression similar to that seen with ethanol ingestion. Hypothermia is common, skin bullae occur in 6 percent of patients, and pupils may be either constricted or dilated. Flat-line electroencephalogram (EEG) is not uncommon in severe overdose. Hence, brain death cannot be declared until the effects of the acute ingestion have resolved.

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20. Flumazenil is a selective antagonist of benzodiazepines. Which of the following is TRUE regarding its use in a patient with an altered level of consciousness? (A)Flumazenil can be safely used if there is a reliable history of pure benzodiazepine overdose (B)Benzodiazepine overdoses are usually isolated overdoses and flumazenil can be freely used with diagnostic and therapeutic benefit (C)Administration of a trial of flumazenil has very low risk of adverse effect (D)Few patients who overdose on benzodiazepines are physically dependent on these drugs (E)In the ED, flumazenil is most useful for reversing effects of benzodiazepines given for diagnostic and therapeutic procedures

The answer is E: 

The answer is E Benzodiazepine overdose is usually a mixed overdose. If the patient is prone to seizures (e.g., when TCAs are coingested), flumazenil is contraindicated. Even if the history is reliable for a pure benzodiazepine overdose, the patient may be benzodiazepine-dependent and thus at risk for intractable seizures if flumazenil is administered. Because supportive care and charcoal lead to good outcomes after most benzodiazepine overdoses, blind use of flumazenil in the ED patient with an altered level of consciousness is unwarranted.

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21. Which of the following statements regarding alcohol toxicity is TRUE? (A)Cocaethylene has 40 times higher affinity for cocaine receptors than cocaine (B)Methanol causes a severe anion gap acidosis and is directly toxic to the optic nerve (C)Isopropanol is strongly associated with hemorrhagic gastritis and produces a profound anion gap acidosis (D)Ethylene glycol is commonly found in antifreeze and causes a severe nonanion gap acidosis (E)Isopropanol is less intoxicating than ethanol

The answer is A: 

The answer is A The combination of ethanol with cocaine produces a dangerous metabolite, cocaethylene. Risk of sudden death in coingesters is about 20 times that with cocaine alone. Toxicity from methanol and ethylene glycol results from their metabolites, formaldehyde and formic acid, not direct toxicity. Isopropanol causes hemorrhagic gastritis, and it produces an osmolal gap but not an anion gap. Both methanol and ethylene glycol cause a severe anion gap metabolic acidosis. Isospropanol is commonly used as rubbing alcohol and is approximately twice as potent as ethanol.

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22. Which of the following drugs is the MOST efficacious for the treatment of opiate withdrawal in an intravenous drug user? (A)Methadone (B)Compazine (C)Clonidine (D)Ativan (E)Naloxone The answer is A Methadone is an oral opiate that relieves all symptoms of opiate withdrawal except the desire to use a needle or "shoot up." Compazine, clonidine, and benzodiazepines provide partial relief of symptoms and are useful for treatment of opiate withdrawal in outpatients. Naloxone induces opiate withdrawal.

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23. Which of the following statements regarding cocaine is TRUE? (A)Cocaine is both a local anesthetic and a central nervous system stimulant (B)Cocaine has a quinidine-like effect on myocardial conduction causing QRS widening and QT prolongation (C)Cocaine inhibits presynaptic reuptake of norepinephrine, dopamine, and serotonin (D)Overdose on cocaine predisposes to dysrhythmias, seizures, hyperthermia, and rhabdomyolysis (E)All of the above

The answer is E: 

The answer is E The parent compound of cocaine exists naturally in the plant Erythroxylon coca and is indigenous to South America. In large doses, cocaine may exert a direct negative effect on the myocardium because of its quinidine-like activity. Plasma cholinesterase converts cocaine to ecgonine methyl ester. Benzoylecgonine, the other major metabolite, is excreted in urine and assayed in most toxicology screens. It is present in the urine for 24 to 72 h after an isolated use but may persist for up to 2 weeks in chronic users.

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24. Which of the following is NOT associated with toxic doses of amphetamines? (A)Cerebral vasculitis and choreoathetosis (B)Cardiomyopathy and polyarteritis nodosa (C)Urinary incontinence and dysuria (D)Nausea, vomiting, and diarrhea (E)Elevated thyroxine level and leukocytosis

The answer is C: 

The answer is C Amphetamine intoxication causes urinary retention but not incontinence. Patients may complain of dysuria and urinary hesitancy. The other listed effects have all been reported. In addition, flushing, tachycardia, hypertension, dysrhythmias, and myocardial infarction can be caused by amphetamine ingestion. Aggressive cooling measures and even paralysis are sometimes needed to control severe hyperthermia and prevent rhabdomyolysis.

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25. Which of the following statements regarding hallucinogens is TRUE? (A)Phencyclidine (PCP) is strongly associated with synesthesias (B)Flashbacks are common with PCP use (C)Patients who have ingested lysergic acid diethylamide (LSD) are prone to anxiety-induced paranoia and auditory hallucinations (D)Complications are common with nutmeg, marijuana, mescaline, and peyote (E)Hallucinogenic amphetamines are associated with vasculitis

The answer is E: 

The answer is E Synesthesias are common with LSD and are manifested by the "hearing of colors" and "seeing of sounds." This phenomenon is not described with PCP. Flashbacks are common with LSD but not with PCP. Patients who have ingested LSD are prone to anxiety-induced paranoia and visual, not auditory, hallucinations. Complications are rare with nutmeg, marijuana, mescaline, and peyote. Chronic use of hallucinogenic amphetamines can lead to vasculitis.

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26. Which of the following are side effects of NSAIDs? (A)Nausea, vomiting, and abdominal pain (B)Headache, behavioral and cognitive problems, and aseptic meningitis (C)Seizures (D)Metabolic acidosis and acute renal insufficiency (E)All of the above

The answer is E: 

The answer is E NSAIDs include salicylates and nonsalicylates. There are five chemical classes of nonsalicylate NSAIDs: acetic acids, propionic acids, fenamic acids, oxicams, and pyrazolones. Mefenamic acid ingestion can lead to seizures. Aseptic meningitis has been reported with NSAID use and is most often found in patients suffering from autoimmune disorders. NSAID-induced aseptic meningitis is thought to be due to drug hypersensitivity.

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27. Which of the following statements regarding chronic digitalis toxicity is FALSE? (A)It is most often seen in elderly patients taking digoxin and diuretics (B)Chronic digitalis toxicity may mimic common diseases such as influenza or gastroenteritis (C)This toxicity may manifest as mental status changes or psychiatric symptoms (D)Serum potassium is usually decreased or normal (E)The serum digoxin level is markedly elevated

The answer is E: 

The answer is E A high index of clinical suspicion is necessary to make the diagnosis of chronic digoxin toxicity. Chronic toxicity is usually associated with a normal or mildly elevated digoxin level. Acute, but not chronic, digoxin overdose is associated with hyperkalemia. Hypomagnesemia is a common feature of chronic overdose.

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28. All of the following are consistent with lead poisoning EXCEPT (A) profound anemia (B) vague complaints of mild and persistent muscle weakness (C) difficulty concentrating, progressively worsening (D) basophilic stippling (E) lead level >40 mcg/dL

Answer A: 

Answer A Lead poisoning is a common occurrence, usually resulting in a mild anemia. Patients often have vague complaints including fatigue, abdominal pain, difficulties with concentration, and muscle weakness. The most common severe complication of the disease is the development of episodic paralytic ileus. Mild anemia and the presence of basophilic stippling are often seen. Lead levels should be checked in anyone presenting with these complaints and at risk, including children and adults with an occupational/environmental exposure. Routine screening is often recommended in children.

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29. Which of the following is FALSE regarding toxic iron ingestions? (A)Iron poisoning can be divided into four stages based on clinical signs and symptoms (B)A child with nausea and vomiting, WBC >15,000/µL, and serum glucose > 150 mg/dL is likely to have a serum iron level > 300 µg/dL (C)A negative deferoxamine challenge test is unreliable in ruling out significant iron ingestion (D)Deferoxamine is best administered intravenously at a rate of at least 15 mg/kg/h (E)Total iron binding capacity (TIBC) assays are unaffected by the presence of acute iron overdose

The answer is E: 

The answer is E Iron poisoning can be divided into four stages based on clinical signs and symptoms. Nausea and vomiting, white blood cell (WBC) count > 15,000/µL, and serum glucose > 150 mg/dL are all highly predictive of a serum iron level > 300 µg/dL in acute iron overdose. A single negative deferoxamine challenge test should not be used to rule out significant iron ingestion in the presence of a strong history or significant signs or symptoms. TIBC assays may be falsely elevated in the setting of acute iron overdose. If the patient survives an acute ingestion, the fourth stage of toxicity may develop days to weeks later; this stage is characterized by gastric outlet or small bowel obstruction.

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30. Which statement about hydrocarbon toxicity is TRUE? (A)Hydrocarbon ingestion accounts for up to 10 percent of childhood accidental ingestions in the United States and 20 percent in less developed nations (B)Persons ingesting hydrocarbons with viscosities of < 30 Saybolt Seconds Universal (SSU) are at much lower risk of aspiration than those ingesting agents with SSU ratings of > 60 (C)Highly volatile hydrocarbons such as diesel oil have a high toxic potential when inhaled (D)Volatile hydrocarbon inhalational solvent abuse may cause chronic encephalopathy and cerebellar ataxia (E)All of the above

The answer is D: 

The answer is D Hydrocarbon ingestion accounts for up to 10 percent of childhood accidental ingestions in the United States and between 33 and 59 percent in less developed nations. Persons ingesting hydrocarbons with viscosities of < 60 SSU are at much higher risk of aspiration than those ingesting agents with SSU ratings of > 100. Highly volatile hydrocarbons have a high toxic potential when inhaled, but diesel oil is not highly volatile.

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31. Which of the following is true regarding sepsis and septic shock? (A) Positive blood cultures are required to make the diagnosis. (B) They may result from non-infectious causes. (C) They rarely are accompanied by organ dysfunction. (D) Antibiotics should be started as soon as culture results are available. (E) Cancer patients are at increased risk of the disease.

Answer E: 

Answer E Sepsis is the systemic inflammatory response to an infection. The diagnosis is made with the presence of a confirmed infection plus at least two of the following: hyper- or hypothermia, tachycardia, tachypnea, and evidence of shock. Septic shock occurs when sepsis leads to hypotension and/or organ dysfunction caused by poor perfusion. Septic shock results in high mortality, especially if treatment is delayed.

Slide73: 

As soon as sepsis is suspected, cultures should be obtained and broad-spectrum antibiotics initiated. Although commonly associated with bacteremia, sepsis may occur with local infections because of the release of cytokines into the bloodstream. In these cases, blood culture will be negative. Although a similar systemic response may be seen in other settings, the terms sepsis and septic shock are reserved for patients with documented infections. Patients at increased risk for sepsis include those with indwelling catheters, prolonged hospitalizations, and impaired immune systems (such as cancer patients).

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32. What is an antidote for organophosphates poisoning? (A) atropine sulfate (B) hyperbaric oxygen (C) methylene blue (D) N-acetylcysteine (E) naloxone

Answer A: 

Answer A Organophosphates and carbamate insecticides are widely used for control of vector-borne disease; in food production, transport, and storage; and for domestic insect control. These compounds can be found throughout the world in urban, suburban, and rural environments. Pediatric exposures to these insecticides account for more than 8000 events per year in the United States alone. Atropine alone may be sufficient therapy in carbamate poisoning or in mild to moderate organophosphate poisonings when there are no significant central nervous system signs, muscular effects, or respiratory insufficiencies.

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33. All of the following are signs of acetylcholinesterase inhibitor toxicity EXCEPT (A)miosis (B)salivation (C)diarrhea (D)muscle fasciculations (E)anhydrosis

The answer is E: 

The answer is E Acetylcholinesterase inhibitor toxicity due to organophosphate or carbamate poisoning is characterized by diaphoresis, not by anhydrosis. Signs and symptoms of these poisonings may be classified as muscarinic, nicotinic, and central. Miosis is the most specific muscarinic finding and muscular fasciculations is the most specific finding for nicotinic receptors. The acronym SLUDGE (salivation, lacrimation, urination, diarrhea, gastrointestinal, emesis) describes the clinical presentation. Organophosphate binding to acetylcholinesterase becomes covalent and irreversible if not treated with pralidoxime within 24 to 36 h. Carbamate binding to acetylcholinesterase is reversible.

Cholinergic Toxidrome: 

Cholinergic Toxidrome SLUDGE/BBB mnemonic S = Salivation L = Lacrimation U = Urination D = Defecation G = GI symptoms E = Emesis B = Bronchorrhea B = Bronchospasm B = Bradycardia

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34. Which of the following plants may cause anticholinergic toxicity? (A)Datura stramonium (B)Deadly nightshade (C)Henbane (D)Mandrake (E)All of the above

The answer is E: 

The answer is E Datura stramonium is the scientific name for the plant commonly known as jimsonweed. It is a weed that is widely distributed throughout the United States, grows 3 to 6 feet high, and has large, jagged, white or purple trumpet-shaped flowers. All parts of the plant are toxic and contain atropine, hyoscyamine, and scopolamine. Mydriasis from jimsonweed may persist for up to 1 week and can result from systemic or ocular exposure ("cornpicker's" eye). The classic description of a patient with anticholinergic syndrome is: "hot as a hare, blind as a bat, dry as a bone, red as a beet, and mad as a hatter."

Anticholinergic syndrome: 

Anticholinergic syndrome "hot as a hare, blind as a bat, dry as a bone, red as a beet, and mad as a hatter.“ The mnemonic refers to the symptoms of flushing, dry skin and mucous membranes, mydriasis with loss of accommodation, altered mental status (AMS), and fever, respectively. Additional manifestations include sinus tachycardia, decreased bowel sounds, functional ileus, urinary retention, hypertension, tremulousness, and myoclonic jerking. Patients with central ACS may present with ataxia, disorientation, short-term memory loss, confusion, hallucinations (visual, auditory), psychosis, agitated delirium, seizures (rare), coma, respiratory failure, and cardiovascular collapse.

Agents c Anticholinergic properties: 

Agents c Anticholinergic properties Anticholinergics Antihistamines (Benadryl, Meclizine) Antipsychotics Antispasmotics Cyclic Antidepressants Mydriatics Certain Plants

Slide83: 

35. Which of the following is NOT a central nervous system finding in cyanide toxicity? (A)Arterialization of retinal veins (B)Headache (C)Agitated delirium (D)Coma (E)Seizures

The answer is C: 

The answer is C Agitated delirium is not a feature of acute cyanide toxicity. Cyanide results in progressive central nervous system dysfunction, with coma and death being the end result. Local effects of cyanide include oropharyngeal burns and the odor of almonds. Cardiopulmonary effects are divided into early and late stages. The early stage includes dyspnea, hypertension, tachycardia, and dysrhythmias. The late cardiopulmonary effects are bradycardia, hypotension, and cardiopulmonary arrest.

Slide85: 

36. What is an antidote for narcotics poisoning? (A) atropine sulfate (B) hyperbaric oxygen (C) methylene blue (D) N-acetylcysteine (E) naloxone

Answer E: 

Answer E Narcotic overdose can cause significant respiratory depression. Administration of naloxone (narcan), a competitive antagonist, should be performed intravenously to restore ventilation, antagonize coma, and reverse hypotension.

Slide87: 

37. What is an antidote for methemoglobin (nitrates) poisoning? (A) atropine sulfate (B) hyperbaric oxygen (C) methylene blue (D) N-acetylcysteine (E) naloxone

Answer C: 

Answer C Methemoglobin is an oxidized form of hemoglobin that is incapable of carrying oxygen. It may be formed by a variety of oxidizing agents, including nitrate-containing well water, as well as many medications, dyes, and industrial chemicals. Its presence produces a functional anemia. Also, it may interfere with oxygen delivery at the tissues by causing a leftward shift in the oxygen-hemoglobin dissociation curve. Methylene blue is a specific antidote and is the treatment of choice for significant methemoglobinemia

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38. Which of the following toxin-antidote pairs is correct? (A)Arsenic and British antilewisite (BAL) (B)Lead and calcium disodium edetate or dimercaptosuccinic acid (C)Mercury and BAL (D)Nitrites and methylene blue (E)All of the above

The answer is E: 

The answer is E Arsenic, mercury, and gold poisoning are treated with BAL. Each milliliter of BAL in oil has 100 mg of dimercaprol in 210 mg of 21 percent benzyl benzoate and 680 mg of peanut oil. Dimercaptosuccinic acid is an oral, water-soluble preparation of BAL that can be used to treat lead poisoning.

Alternative to spanking: 

Alternative to spanking

Slide92: 

39. A 16-year-old high school male presents to the ER 4 hours after sustaining an abrasion to his knee after a fall while roller blading on the school playground. His school immunization record reveals that his last diphtheria, tetanus, and pertussis (DPT) booster was at 4 years of age. In this situation, which of the following is the MOST appropriate plan? (A) administer tetanus toxoid (B) administer adult tetanus and diphtheria toxoid (Td) (C) administer diphtheria, tetanus, and acellular pertussis (DTaP) booster (D) administer tetanus immune globulin (TIG) (E) administer no immunizations

Answer B: 

Answer B Generalized tetanus (lockjaw) is a neurologic disease caused by Clostridium tetani. Although any open wound is a potential source for contamination with C. tetani, those with dirt, soil, feces, or saliva are at increased risk. Tetanus-prone wounds contain devitalized tissue, especially those caused by punctures, frostbite, crush injury, or burns. Recommendations for tetanus prophylaxis in a child with a laceration or abrasion depend upon the number of previous vaccinations, occurrence of last booster, type of wound (clean or tetanus-prone), and age of child. In this case, the patient is older than 7 years of age and had all of his previous immunizations; however, his most recent booster was greater than 10 years ago. Thus, he should receive an adult-type diphtheria and tetanus toxoid (Td).

Slide94: 

In most cases, when tetanus toxoid is required for wound prophylaxis in a child older than 7 years of age, the Td instead of tetanus toxoid alone is recommended so that diphtheria immunity is maintained. If tetanus immunization is not up to date at the time of wound treatment, then the immunization series should be completed according to the primary immunization schedule. If a child is less than 7 years of age, then the diphtheria, tetanus, acellular pertussis (DTaP) booster is indicated, unless there is a contraindication for pertussis, in which case the diphtheria and tetanus (DT) booster should be administered. Tetanus immune globulin (TIG) is recommended for treatment of tetanus. Under special circumstances a patient infected with the human immuno-deficiency virus (HIV) with a tetanus-prone wound should also receive TIG in addition to the prophylactic vaccine.

Slide95: 

40. A patient who fell down a cliff while backpacking is brought to the ED after a prolonged rescue 8 h after falling. The patient sustained multiple lacerations and abrasions that are covered by dirt and grass. The patient is a 45-year-old U.S. native who cannot remember the last time she received tetanus prophylaxis. Which of the following represents the BEST management? (A)Adult tetanus toxoid (Td) 0.5 mL intramuscularly (B)Human tetanus immune globulin (TIG) 250 U intramuscularly (C)Td 0.5 mL intramuscularly and TIG 250 U intramuscularly in the opposite extremity (D)No prophylaxis is necessary because the patient is a U.S. native who received primary immunization as a child (E)Td 0.5 mL intramuscularly and TIG 250 U intramuscularly, followed by additional doses of Td at 1 month and 6 months

The answer is C: 

The answer is C This patient should receive Td because she cannot remember the last time she received tetanus prophylaxis. In addition, she should receive TIG because the wounds are more than 6 h old and are contaminated with dirt. Tetanus prophylaxis in the ED is especially important in elderly Americans (>70 years of age), the majority of whom lack adequate immunity to tetanus. Intravenous drug users and immigrants are also at disproportionate risk of contracting tetanus.

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41. Clostridium tetani is the organism responsible for causing tetanus. All of the following statements regarding tetanus are TRUE EXCEPT (A)tetanospasmin, an exotoxin produced by C. tetani, is responsible for the clinical manifestations of tetanus (B)tetanospasmin is released into the CNS after C. tetani crosses the blood-brain barrier (C)clinical manifestations of tetanus include generalized muscular rigidity, violent muscular contractions, and instability of the autonomic nervous system (D)the most common presenting complaint of patients with generalized tetanus is pain and stiffness in the masseter muscle (E)tetanospasmin prevents the release of GABA and glycine from presynaptic nerve terminals

The answer is B: 

The answer is B Tetanospasmin, an exotoxin produced by C. tetani, is responsible for the clinical manifestations of tetanus. These manifestations include muscular rigidity, violent muscular contractions, and autonomic nervous system instability. The most common presenting complaint for patients with generalized tetanus is pain and stiffness in the masseter muscle “Lock-Jaw”. Tetanospasmin produces these effects by preventing release of GAMMA-aminobutyric acid (GABA) and glycine from presynaptic terminals thus preventing the normal inhibitory control in the CNS. Clostridium tetani remains localized to the site of the injury. The exotoxin tetanospasmin reaches the CNS by retrograde intraneuronal transport from the peripheral nervous system.

Slide99: 

42. Which of the following animals is NOT a potential carrier of rabies? (A)Dogs (B)Bats (C)Skunks (D)Squirrels (E)Cows

The answer is D: 

The answer is D In developing countries, the most common reservoir of rabies virus is the dog. However, in the United States, new human rabies cases are most commonly associated with exposure to wild carnivores. Rabid wildlife species recorded by the CDC include skunks, racoons, bats, and foxes. Domestic species found to be rabid include cats, cows, dogs, and other livestock. Rodents (e.g., squirrels, chipmunks, hamsters, rats, and mice) and lagomorphs (e.g., rabbits and hares) are NOT rabies carriers.

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43. A 16-year-old girl is brought to the ER by ambulance after reportedly ingesting "a bottle of aspirin". Vital signs are Temperature 37.8ºC oral Pulse 94/minute Respiration 30/minute Blood pressure 100/68 mm Hg What would you expect the blood gases to show that would confirm she had swallowed the aspirin? (A) metabolic acidosis with respiratory acidosis (B) metabolic acidosis with respiratory alkalosis (C) metabolic alkalosis with respiratory acidosis (D) metabolic alkalosis with respiratory alkalosis

Answer B: 

Answer B An acute salicylate overdose (greater than 150 mg/kg) will produce symptoms of salicylate intoxication. Chronic salicylate intoxication occurs with ingestion of greater than 100 mg/kg/day for at least 2 days. Salicylates affect most organ systems, leading to various metabolic abnormalities. Because salicylates are a gastric irritant, symptoms of vomiting and diarrhea occur soon after the overdose, which may contribute to the development of dehydration. Salicylates stimulate the respiratory center leading to hyperventilation and hyperpnea resulting in respiratory alkalosis and compensatory alkaluria. A characteristic feature of salicylate intoxication is the coexistence of a respiratory alkalosis with a widened anion gap metabolic acidosis.

Slide104: 

44. What is an antidote for Carbon monoxide poisoning? (A) atropine sulfate (B) hyperbaric oxygen (C) methylene blue (D) N-acetylcysteine (E) naloxone

Answer B: 

Answer B Carbon monoxide has an affinity for hemoglobin approximately 250 times that of oxygen. Thus, at a carbon monoxide air concentration of only 0.1% (1000 parts per million), about one half of hemoglobin binding sites are occupied by the toxin. The half-life of the carboxyhemoglobin complex is 4 to 5 hours in room air, but can be shortened to about 40 minutes by administration of 100% oxygen.

Slide106: 

45. Which of the following is LEAST important in the initial evaluation of a near-drowning victim? (A)Arterial blood gas (ABG) (B)Core temperature (C)Chest x-ray (CXR) (D)C-spine precautions (E)Electrolytes

The answer is E: 

The answer is E Near-drowning victims require aggressive resuscitation and evaluation. A core temperature must be obtained because near-drowning patients are frequently hypothermic and require rewarming. Furthermore, hypothermic patients in cardiac arrest should continue to be resusucitated until the core temperature reaches at least 30°C. CXR may demonstrate pulmonary edema but may be initially normal. Patients with a normal CXR may still be hypoxic, and oxygenation should be measured by ABG or pulse oximetry. Because many near-drownings occur secondary to trauma, all victims need their C-spines evaluated for injury. Electrolytes are rarely abnormal in near-drowning victims unless a large amount of salt-water has been aspirated.

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46. A patient presents to the emergency department hypothermic after an environmental exposure to the cold and snow. The patient's core temperature is 85.5ºF. Which of the following is the most accurate statement regarding this patient? (A) Shivering is common. (B) An Osborne (J) wave is pathognomic for hypothermia. (C) Rough handling can produce serious dysrhythmias. (D) A nasogastric tube should be inserted to protect the airway from regurgitation. (E) The patient is in an excitation phase of hypothermia.

Answer C: 

Answer C Mild hypothermia is defined as a temperature from 32 to 35ºC (89.6 to 95ºF). In mild hypothermia, the body responds by increasing metabolic activity to produce heat. This is known as the excitation or responsive phase. When the temperature drops below 32ºC (89.6ºF), bodily functions slow down, giving way to the adynamic phase. As metabolism slows, there is a decrease in both oxygen utilization and carbon dioxide production. As the body temperature falls below 30 to 32ºC (86 to 89.6ºF), shivering will cease. Hypothermia may induce life-threatening dysrhythmias and ECG changes. A characteristic, but not pathognomonic, ECG finding in hypothermia is the Osborne (J) wave. This abnormal wave is a slow, positive deflection at the end of the QRS complex. (Tintinalli, pp. 1231-1233)

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47. All of the following are predisposing factors for hypothermia EXCEPT (A)Wernicke's disease (B)alcoholism (C)hyperglycemia (D)severe burns (E)extremes of age

The answer is C: 

The answer is C Hypoglycemia and Wernicke's disease may lead to hypothermia secondary to hypothalamic dysfunction. Other endocrine disorders such as hypothyroidism and hypoadrenalism predispose to hypothermia because of decreased metabolic rate. Severe burns and other dermal diseases may impair the ability of the skin to thermoregulate or prevent vasoconstriction. Patients at the extremes of age are more vulnerable to hypothermia. The use of any drug, including alcohol, that causes altered sensorium places a patient at higher risk for hypothermia.

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48. All of the following statements are true regarding cold-related injury EXCEPT (A)chilbains (pernio) is more common in women (B)dry heat is the best method for rewarming frostbite (C)early surgical intervention is indicated for severe frostbite (D)body parts affected by cold injury are more sensitive to reinjury (E)trench foot may result in irreversible damage

The answer is B: 

The answer is B Rapid rewarming is the primary therapy for frostbite. The injured part should be immersed in warm water (40-42°C). Dry heat from fires or car exhaust should be avoided because it may cause thermal damage in addition to the cold injury. Early surgical intervention is not indicated because the extent of injury is difficult to assess initially and areas of eschar may be protective to underlying healing tissue. Once affected by chilbains, frostnip, or other cold injury, the body part involved becomes more susceptible to reinjury. Trench foot develops from exposure to wet, cold, but nonfreezing conditions over hours to days. Early on, tissue damage is reversible but can become permanent if the foot is not removed from the cold environment.

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49. Which of the following statements regarding heat-related illness is FALSE? (A)Adult patients with a core temperature of 40°C (104°F) require aggressive cooling measures (B)Salicylate ingestion may induce hyperpyrexia (C)Elderly and psychiatric patients are at increased risk for heat stroke (D)The body acclimatizes to heat exposure by gradually decreasing the sodium and chloride concentration in sweat (E)Oral rehydration adequately compensates for fluid losses

The answer is A: 

The answer is A Heat stroke is defined as a body temperature of greater than 40°C (104°F) accompanied by altered mental status and anhidrosis. Patients with heat stroke should be aggressively cooled to a temperature of 40°C (104°F), at which point cooling measures should stop to avoid overshoot hypothermia. Prognosis is related to the rate of cooling rather than to the initial temperature. Salicylates cause uncoupling of oxidative phosphorylation, which leads to increased heat production. Elderly and psychiatric patients are at increased risk for heat stroke because they are less likely to remove themselves from hot environments. Ingestion of psychiatric medications also increases susceptibility to heat stroke. The body is able to acclimatize to hot temperatures over time by various mechanisms including decreasing the concentration of sodium and chloride in sweat. In the acute situation however, the body is not accurately able to assess fluid losses and cannot compensate by oral rehydration. Athletes given free access to water when exercising in the heat will only drink 50 percent of their fluid losses.

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50. Which of the following patients require admission to a burn-care facility? (A)A 35-year-old man with extensive partial-thickness burns on the back, shoulders, and buttocks (B)A 60-year-old diabetic with a full-thickness burn of the entire forearm (C)A 25-year-old woman with full-thickness burns of both hands and lower arms (D)A 40-year-old house-fire victim with multiple, small partial-thickness burns and wheezing (E)All of the above

The answer is E: 

The answer is E Burn-center admission criteria include: patients 10 to 50 years old with partial-thickness burns over an area greater than 15 percent of total body surface area (TBSA) or full-thickness burns greater than 5 percent TBSA; any patient younger than 10 years or older than 50 years with partial-thickness burns greater than 10 percent TBSA or full-thickness burns greater than 3 percent TBSA; any patient with partial- or full-thickness burns to the face, hands, feet or perineum, or circumferential limb burns; a patient with burns and inhalation injury; and any patient with burns and underlying medical problems. Percentage of TBSA can be calculated in adults by the rule of nines by using the size of the back of the patient's hand as 1 percent. Children have a relatively larger head size and smaller legs.

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51. All of the following are true of chemical burns EXCEPT (A)acids cause deeper tissue injury than do alkalis (B)most chemical burns should be copiously irrigated with water (C)calcium gluconate is a specific antidote for hydrofluoric acid burns (D)Neosporin ointment is useful for removing tar from skin (E)time of exposure is the most important factor in determining the extent of tissue damage

The answer is A: 

The answer is A Acids generally cause protein denaturation and coagulation necrosis that create a tough eschar, limiting the spread of the toxic compound. Alkalis cause liquifaction necrosis, allowing the agent to penetrate more deeply into the tissue and cause more extensive damage. The mainstay of therapy for all chemical burns is reducing the length of time of exposure to the compound by immediate copious irrigation with water. In addition, hydrofluoric acid burns should be treated with calcium gluconate. Neosporin contains plyuoxylene sorbitan, an emulsifying agent that is useful for removing tar.

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52. Which of the following types of electrical injury is correctly paired with its resultant complication? (A)Low-voltage alternating current (AC) and ventricular fibrillation (B)lightning and ventricular fibrillation (C)high-voltage AC and superficial burns (D)lightning and compartment syndrome (E)high-voltage AC and tetanic contraction

The answer is A: 

The answer is A The type of injury pattern from an electrical burn depends on the source: high-voltage AC, low-voltage AC, or lightning. The most common initial rhythm in cardiac arrest is asystole from lightning strikes and ventricular fibrillation from low-voltage AC. Low-voltage AC causes tetanic contraction of muscle and may cause victims to pull themselves closer to the source secondary by flexor muscle contraction. The immediate cause of death from high-voltage AC and lightning is apnea. Lightning causes superficial burns and a ferning pattern, whereas AC results in deep tissue burns and injury. Although minimal external signs of damage are present after this deep tissue injury, compartment syndrome requiring fasciotomy may develop. High-voltage AC is usually a single blast that throws the victim from the source. Lightning can also cause a blast effect.

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53. A 55-year-old male scuba diver begins complaining of back pain and urinary retention 1 h after a dive. What is the MOST likely diagnosis? (A)Barotrauma to the bladder (B)Lumbar strain (C)Neurotoxin from a marine envenomation (D)Nitrogen narcosis (E)Decompression sickness

The answer is E: 

The answer is E Barotrauma is the most common affliction of divers and usually affects the ears, sinuses, lungs, and, rarely, the gastrointestinal tract. The bladder is not involved. Decompression sickness (DCS) is caused by formation of gas bubbles in tissues after ascent from a dive and results in vascular occlusion, usually in the venous circulation. DCS may have cutaneous manifestations including rash and pruritus. DCS classically causes joint and back pain and may be associated with neurologic symptoms secondary to spinal cord involvement. Patients with neurologic or other severe forms of DCS should be referred for hyperbaric oxygen therapy. Nitrogen narcosis is due to the anesthetic effects of breathing nitrogen at high partial pressures and causes divers to become altered on deep dives.

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54. All of the following are useful in determining the severity of radiation exposure EXCEPT (A)time to development of nausea and vomiting (B)lymphocyte count (C)type of radiation exposure (e.g., GAMMA vs. ß) (D)presence of skin erythema (E)severity of symptoms

The answer is E: 

The answer is E Although severity of symptoms does not correlate with dose of radiation received, time to onset of symptoms does. Skin erythema indicates skin exposure greater than 300 rem (3 Sv); seizures occur with central nervous system exposure greater than 2000 rem (20 Sv). Lymphocyte counts greater than 1200/µL 48 h after exposure suggest good prognosis, counts between 300 and 1200 indicate fair prognosis, and counts less than 300 indicate poor prognosis. The type of radiation exposure is important in determining the severity of injury. GAMMA Rays readily penetrate body tissues. ALPHA Particles do not penetrate skin, and ß particles only barely penetrate the skin. Both ALPHA and ß particles can cause damage if inhaled or ingested.

Slide128: 

55. A 35-year-old man presents complaining of headache, weakness, nausea, and vomiting after working with paint remover in an enclosed space. Which of the following statements regarding management of this patient's problem is TRUE? (A)A special antidote kit is required (B)Carboxyhemoglobin level is not helpful in this case (C)Treatment must continue longer in patients with this exposure than from other sources (D)The patient's oxygen-hemoglobin dissociation curve is shifted to the right (E)Severe metabolic acidosis may be present

The answer is C: 

The answer is C Carbon monoxide (CO) exposure occurs from many sources including fires, engines, home furnaces, and heaters. Methylene chloride, a chemical found in many paint removers, is inhaled and then converted to CO when metabolized by the liver. The elimination half-life of CO from methylene chloride is about twice that of inhaled CO because it is stored in tissues and gradually released. Carboxyhemoglobin levels guide therapy and may indicate severity of exposure. CO binds hemoglobin with a 250 times greater affinity than does oxygen. Therefore, all patients should be treated with 100 percent oxygen therapy.

Slide130: 

Once bound, CO causes the hemoglobin molecule to hold more tightly to oxygen at the other binding sites, thus shifting the oxygen-hemoglobin dissociation curve to the left. The presence of a high carboxyhemoglobin level and a severe metabolic acidosis should suggest concomitant intoxication with cyanide, as can commonly occur in house or industrial fires. CO alone does not cause a severe metabolic acidosis

Slide131: 

56. A 25-year-old male with a history of recent unprotected sexual intercourse presents with a complaint of urethritis. Gram stain of a urethral smear shows intracellular gram-negative diplococci. All of the following actions are recommended EXCEPT (A)administering a single oral dose of cefixime 400 mg (B)administering a single oral dose of azithromycin 1 g (C)obtaining a serologic test for syphilis (D)advising the patient to obtain HIV testing (E)administering a single oral dose of metronidazole 2g

The answer is E: 

The answer is E Although this patient's gram stain suggests gonococcal infection, there is a high incidence of concomitant chlamydial infection. Therefore, he should be treated for both gonorrhea and chlamydia. In addition, a serum test for syphilis and counseling regarding testing for human immunodeficiency virus (HIV) are warranted. This patient should also be educated about condom use and advised to have his sexual partners checked for sexually transmitted diseases (STDs). Metronidazole is not routinely administered unless trichomonas is seen on microscopic urinalysis.

Slide133: 

57. Which of the following characteristics or findings are suggestive of the secondary stage of syphilis? (A)Painless chancre with indurated borders on the penis, vulva, or other areas of sexual contact (B)Red papular rash on the trunk and flexor surfaces that spreads to the palms and soles (C)Findings that develop about 21 days after initial infection (D)Involvement of the cardiovascular and nervous systems (E)Symptoms that develop years after initial infection

The answer is B: 

The answer is B There are three stages of syphilis. The primary stage usually occurs about 21 days after initial infection and is characterized by a painless chancre on the penis, vulva, or other area of sexual contact. These typical lesions usually resolve within 3 to 6 weeks. The second stage of syphilis occurs 3 to 6 weeks after the end of the primary stage. Stage II includes nonspecific symptoms (headache, sore throat, fever, malaise), diffuse lymphadenopathy, and rash. The rash is usually dull red and papular, first occurring on the trunk and flexor surfaces and then spreading to the palms and soles. The tertiary stage of syphilis may occur years after inital infection and is characterized by cardiovascular and nervous system involvement. Findings can include tabes dorsalis, acute meningitis, dementia, and thoracic aneurysm. HIV-positive patients may have an accelerated course.

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58. The diagnosis of toxic shock syndrome requires a temperature above 38.9°C (102°F), a systolic blood pressure (BP) below 90 mm Hg, an orthostatic decrease of systolic BP by 15 mm Hg or syncope, a rash with subsequent desquamation, and involvement of at least three organ systems. Which of the following systems is NOT considered in the diagnosis? (A)Hematologic: thrombocytopenia < 100,000 platelets/µL (B)Renal: increase in BUN and creatinine two times normal level; pyuria without evidence of infection (C)CNS: disorientation without focal neurologic signs (D)Respiratory: respiratory rate > 28 breaths per minute, evidence of bilateral alveolar infiltrates on chest x-ray (E)Gastrointestinal: vomiting, profuse diarrhea

The answer is D: 

The answer is D The CDC formulated a case definition of toxic shock syndrome (TSS) In addition to the findings of a fever, hypotension, and rash, at least three of the following organ systems must be involved: gastrointestinal: vomiting, profuse diarrhea; musculoskeletal: severe myalgias or twofold increase in CPK; renal: increase in blood urea nitrogen (BUN) and creatinine two times normal level, pyuria without evidence of infection; mucosal inflammation: vaginal, conjunctival, or pharyngeal hyperemia; hepatic involvement: hepatitis (twofold elevation of bilirubin, AST, ALT); hematologic: thrombocytopenia < 100,000 platelets/µL; central nervous system (CNS): disorientation without focal neurologic signs. Although not included in the case definition, involvement of the respiratory system, and development of adult respiratory distress syndrome (ARDS) and refractory hypotension are late manifestations of TSS that represent end-organ damage

Slide137: 

59. All of the following statements regarding TSS and toxic shock-like syndrome (TSLS) are TRUE EXCEPT (A)the majority of cases of TSS are associated with menstruation (B)Staphylococcus aureus and Streptococcus pyogenes are the most common organisms isolated from patients with TSS and TSLS (C)TSST-1, an exotoxin implicated in the production of many TSS symptoms, has been isolated from 20 percent of randomly tested S. aureus isolates (D)up to 60 percent of patients relapse if they are not treated with ß-lactamase-stable antimicrobial drugs (E)residual neurologic deficits, including memory deficits, decreased concentration, and diffuse electroencephalographic abnormalities, are seen in 50 percent of TSS survivors

Slide138: 

The answer is A TSS was initially a disease of young, healthy, menstruating women Changes in tampon composition and a heightened public and professional awareness of the risks of tampon use are credited for a change in epidemiology. At present, men comprise one-third of patients with TSS, and another 25 percent of cases have been associated with postpartum and S. aureus vaginal infections in nonmenstruating women. In addition, TSS has been associated with nasal packing (nasal tampons) and has been reported after influenza and influenza-like illnesses. Staphylococcus aureus and S. pyogenes are associated with TSS and TSLS, respectively. The TSST-1 exotoxin is a significant factor in the development of many TSS symptoms. Sequelae of TSS are numerous and include a high rate of neurologic deficits. Up to 60 percent of patients who do not receive ß-lactamase-stable antibiotics have recurrence of the disease, usually within 2 months of the initial episode, but sometimes up to 1 year later. This second episode is usually less severe than the first, but deaths have resulted from recurrences of mild cases.

Slide139: 

60. The CDC publishes a list of reportable communicable diseases that is updated and revised routinely. A 20-year-old patient is found to have a sexually transmitted disease. Which of the following is NOT included on the CDC list of reportable diseases? (A)Chancroid (B)Gonorrhea (C)HIV (D)Syphilis (E)Chlamydia

The answer is C: 

The answer is C All of the STDs listed except HIV are reportable communicable diseases according to the CDC guidelines. HIV is reportable in the pediatric population (< 13 years old). In patients older than 13 years, HIV disease is not reportable until the disease has progressed to AIDS. The current CDC definition of AIDS requires an HIV-infected adult to have: (1) a CD4 T lymphocyte count of less than 200, (2) a CD4 T lymphocyte count less than 14 percent of total lymphocytes, or (3) any of the following: pulmonary tuberculosis, recurrent pneumonia, invasive cervical cancer, or 23 other clinical conditions that are listed on www.cdc.gov/epo/mmwr/mmwr.html.

Slide141: 

61. An HIV-positive patient presents to the ED complaining of shortness of breath and nonproductive cough. Chest x-ray shows diffuse interstitial infiltrates, and O2 saturation is 85 percent on room air. All of the following statements regarding this patient's probable diagnosis are TRUE EXCEPT (A)Pneumocystis jiroveci pneumonia (PCP) is the most common opportunistic infection in AIDS patients (B)pentamidine isothionate is an effective alternate therapy to TMP-SMX (C)a normal chest x-ray rules out acute PCP infection (D)65 percent of patients relapse within 18 months (E)oral steroid therapy should be started in patients with a Pao2 < 70 mm Hg, or an alveolar-arterial gradient > 35

The answer is C: 

The answer is C PCP is the most common opportunistic infection in AIDS patients, and more than 80 percent of patients acquire PCP at some time during their illness. Common symptoms include nonproductive cough, shortness of breath, and exertional dyspnea. Chest x-ray findings often demonstrate bilateral alveolar infiltrates, but 5 to 10 percent of patients have a negative chest film. PCP is often the presumptive diagnosis in HIV-positive patients with unexplained hypoxia. Initial therapy for PCP is trimethoprim-sulfamethoxazole (TMP-SMX) orally or intravenously; pentamidine isothionate is an acceptable alternative. An ABG should be obtained and results used to determine the need for initiation of steroid therapy. Reinfection is common, and prophylactic therapy with TMP-SMX, inhaled pentamidine, or dapsone is recommended.

Slide143: 

62. CNS disease occurs in 75 to 90 percent of patients with AIDS. Which of the following is the MOST common cause of opportunistic infection of the CNS in AIDS patients? (A)Cryptococcal meningitis (B)Bacterial meningitis (C)HSV encephalitis (D)Toxoplasmosis (E)AIDS dementia

The answer is D: 

The answer is D Common etiologies of neurologic symptoms in AIDS patients include AIDS dementia, Toxoplasma gondii, and Cryptococcus neoformans. Of these, toxoplasmosis is most likely to cause focal encephalopathy. It may present with headache, fever, focal neurologic deficits, altered mental status, or seizures. Computed tomographic (CT) findings of ring-enhancing lesions are suggestive of toxoplasmosis; however, lymphoma, fungal infections, and cerebral tuberculosis may present with similar findings. Other infections such as HSV encephalitis, bacterial meningitis, brain abscess, cytomegalovirus (CMV) encephalitis, and neurosyphilis should be considered in the differential diagnosis of neurological symptoms in AIDS patients.

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63. A patient presents to the ED with symptoms of Bell's palsy. Which of the following signs or symptoms are atypical and suggest a more worrisome diagnosis? (A)Facial hemiparesis (B)Taste disturbance (C)Decreased blinking (D)Sparing of the forehead muscles on the affected side (E)Hearing increased on the affected side

The answer is D: 

The answer is D Herpes simplex virus 1 is a frequent cause of cranial nerve (CN) VII (Bell's) palsy. All of the signs or symptoms described can be found with a simple peripheral CN VII palsy, except sparing of the forehead musculature on the affected side. Central CN VII lesions spare the forehead musculature because of cross-inervation from the opposite side. However, a peripheral lesion should cause the patient to be unable to wrinkle the brow on the ipsilateral side. If the forehead is spared, additional investigations such as head CT or magnetic resonance imaging are warranted. The differential diagnosis of Bell's palsy includes tumor, stroke, Guillain-Barré syndrome, Lyme disease, and Ramsay Hunt syndrome. In addition, if a Bell's palsy is found with an otitis media, mastoiditis, or parotitis, an ENT specialist should be consulted.

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64. Which of the following laboratory studies or pieces of historical information is LEAST helpful when evaluating a patient for suspected bacterial diarrhea? (A)A 3- to 4-day history of food and water exposure (B)Information regarding frequent restaurant meals, consumption of raw foods and meats, overseas travel, exposure to day-care centers, and ingestion of stream or lake water (C)Stool studies for fecal leukocytes (D)Information regarding immunocompetence and recent use of antibiotics, antacids, H2 blockers, and proton pump inhibitors (E)A history of other contacts who have developed similar symptoms

The answer is C: 

The answer is C Information regarding ill contacts, recent food and water exposure, and host susceptibility are important factors in making a diagnosis of food-borne illness. Most infectious diarrhea is self-limiting, and routine studies for ova and parasites and stool cultures are not cost effective. If symptoms persist for more than 3 or 4 days, especially when accompanied by dehydration or fever, laboratory studies may be indicated. Fecal leukocytes in stool samples suggest a bacterial pathogen, but the absence of fecal leukocytes does not exclude a bacterial etiology; therefore, the test has limited diagnostic efficacy.

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65. Which of the following organisms is the major cause of most travelers' diarrhea? (A)E. coli (B)Campylobacter (C)Vibrio (D)Giardia (E)Shigella

The answer is A: 

The answer is A Viral infections are the most common overall cause of diarrheal disease, but travelers' diarrhea is most likely of bacterial etiology. Enterotoxigenic E. coli is the major cause of travelers' diarrhea. Other strains associated with travel include enterohemorrhagic and enteroinvasive E. coli. All of the organisms listed are also travel-related pathogens, mostly seen after international travel by U.S. citizens. Additional etiologies of travelers' diarrhea include Salmonella, Brucella, Cryptosporidium, and hepatitis A.

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66. A 37-year-old male arrives at the ED at 9:00 a.m. complaining of diarrhea that began at 5:00 a.m. The patient felt fine the night before after eating dinner at 8:00 p.m. at a local seafood restaurant. His dinner companion reportedly also developed copious diarrhea the same morning and is going to meet the patient at the ED. Which of the following organisms is MOST likely responsible for the food-borne illness? (A)S. aureus (B)A Norwalk virus (C)Enterotoxigenic E. coli (D)Vibrio parahaemolyticus (E)Campylobacter

The answer is D: 

The answer is D Vibrio poisoning is commonly associated with ingestion of seafood. The patient's symptoms developed 9 h after the ingestion of the suspected contaminated food. Of the organisms listed, only V. parahaemolyticus has an incubation period of 6 to 24 h. Staphylococcus aureus and Norwalk viruses usually produce symptoms 1 to 6 h after exposure. Enterotoxigenic E. coli produces symptoms 24 to 48 h after exposure, and Campylobacter produces symptoms 2 to 6 days after ingestion of contaminated food.

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67. Etiologic agents in tick-borne infections include bacterial, rickettsial, viral, and protozoal organisms. All of the following infections can be acquired from a tick bite EXCEPT (A)Rocky Mountain spotted fever (B)Q fever (C)relapsing fever (D)tularemia (E)babesiosis

The answer is B: 

The answer is B All of the diseases listed except Q fever may be contracted by a tick bite. Rocky Mountain spotted fever is caused by a rickettsial organism, Rickettsia rickettsia. Relapsing fever is caused by a spirochete, Borrelia burgdorferi. Tularemia is caused by a gram-negative nonmotile coccobacillus, Francisella tularemia. The protozoan parasites, Babesia microti and B. equi, cause babesiosis. Q fever is unique in that it is the only rickettsial infection acquired by aerosol inhalation rather than by an arthropod vector. Q fever is common among domesticated farm animals in the United States and is shed in urine, feces, and afterbirth. The rickettsial organism responsible for causing Q fever is Coxiella burnetti.

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68. Gas-forming soft tissue infections are life threatening and must be diagnosed early and treated aggressively. Which one of the following symptoms or findings is LEAST likely to be seen with these infections? (A)Increasing symptoms over 7 to 10 days (B)Pain out of proportion to physical findings (C)Brawny edema with crepitance on palpation (D)Bullae or malodorous serosanguinous discharge (E)Low-grade fever, with tachycardia out of proportion to the fever

The answer is A: 

The answer is A Gas-forming soft tissue infections are rapidly progressive. The incubation period is short, with symptoms occurring fewer than 3 days after inoculation. Patients frequently describe pain out of proportion to physical findings and a sensation of "heaviness" of the affected part. On examination, the skin is often bronze-colored with brawny edema and crepitance. Bullae and a malodorous serosanguinous discharge may be seen. Patients are often irritable or confused and have low-grade fevers with tachycardia out of proportion to the fever. Common laboratory findings include leukocytosis, anemia, metabolic acidosis, thrombocytopenia, coagulopathy, myoglobinemia, and myoglobinuria and abnormalities of kidney or liver function tests. Radiologic studies may demonstrate gas within soft tissue planes and within the peritoneal or retroperitoneal spaces.

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69. Which of the following patients is MOST likely to benefit from antibiotic therapy in addition to abscess incision and drainage? (A)A previously healthy female with a Bartholin's gland abscess and no history suggesting a high risk for STD (B)A healthy 25-year-old male with recurrence of a pilonidal abscess that first occurred 2 years previously (C)A febrile 50-year-old female with NIDDM and recurrence of axillary hydradenitis suppurativa (D)A 35-year-old male with a sebaceous gland cyst that has been present for 2 years and has now become infected (E)An intravenous drug user without fever or tachycardia presenting with a 2-cm² deltoid abscess that developed 7 days after "skin popping"

The answer is C: 

The answer is C Cutaneous abscesses represent 1 to 2 percent of all presenting complaints to EDs. Most patients can be treated with incision and drainage of the abscess and discharged from the ED with follow-up in 2 to 3 days. Antibiotic use is controversial. The risk of systemic infection after local incision and drainage appears to be low. In patients with diabetes, alcoholism, or other underlying immunocompromised states, the threshold for antibiotic use should be lower. In addition, patients with signs of systemic disease such as fever, chills, or cellulitis extending beyond the abscess borders should be strongly considered for antibiotic therapy.

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70. Universal precautions were recommended by the CDC to protect healthcare workers from the potential hazards of exposure to blood and other body fluids. All of the following practices are part of the recommended universal precautions EXCEPT (A)wear puncture-proof gloves when handling needles or sharp instruments with the potential for puncturing skin (B)mask and eye protection are indicated if mucous membranes of the mouth, nose, and eyes may be exposed to drops of blood or other body fluids (C)do not recap or bend needles (D)use a bag-valve mask to prevent the need for mouth-to-mouth resuscitation (E)healthcare workers with weeping dermatitis should avoid direct patient care until the condition resolves

The answer is A: 

The answer is A The CDC instituted six basic universal precautions, including all of the listed recommendations, except the recommendation regarding puncture-proof gloves. Gloves should be worn routinely when contact with blood or other body fluids is anticipated. However, to date, no acceptable puncture-proof glove is available. Needles should never be recapped, and they should be disposed of in special "sharps" containers. Pregnant healthcare workers should be aware of the risk of perinatal HIV transmission.

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71. The etiologic agent _____________ is associated with the disease, syphilis. (A) group A Streptococcus spp. (B) Borrelia burgdorferi (C) Pityrosporum orbiculare (D) Treponema pallidum (E) Propionibacterium acnes Answer D Treponema pallidum is the spirochete responsible for syphilis.

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72. The etiologic agent _____________ is associated with the disease, tinea versicolor. (A) group A Streptococcus spp. (B) Borrelia burgdorferi (C) Pityrosporum orbiculare (D) Treponema pallidum (E) Propionibacterium acnes Answer C Pityrosporum orbiculare, (also known as Malassezia furfur) thought to be part of the normal skin flora, is responsible for this common cutaneous infection.

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