Specific Toxins

Specific Toxins : 

Specific Toxins Part II

Infectious Agents : 

Infectious Agents

Bacterial Food Infection/Poisoning : 

Bacterial Food Infection/Poisoning Signs/Symptoms Nausea, vomiting Abdominal cramps Diarrhea History of eating same foods in same place as others with similar symptoms

Bacterial Food Infection/Poisoning : 

Bacterial Food Infection/Poisoning Management Prevention Cook thoroughly Keep hot foods hot Keep cold foods cold Replace lost fluids, electrolytes Antiemetic agents

Botulism : 

Botulism Pathophysiology Neurotoxin from Clostridium botulinum Produced in anaerobic environment at pH >4.6 Boiling will destroy toxin Toxin binds to cholinergic nerve terminals; Blocks acetylcholine release

Botulism : 

Botulism Signs/Symptoms GI upset Dry mouth Double vision (diplopia) Drooping eyelids Slurred speech Descending paralysis - respiratory arrest

Botulism : 

Botulism Management Support ABC’s Antitoxin

Common Cardiac Medications : 

Common Cardiac Medications

Beta Blockers : 

Beta Blockers Signs/Symptoms Bradycardia Hypotension, shock AV blocks Prolonged QRS complex Heart failure Bronchospasms

Beta Blockers : 

Beta Blockers Management ABC’s Oxygen Bronchospasms Inhaled 2 agents

Beta Blockers : 

Beta Blockers Management Bradycardia Atropine 0.5 - 1.0 mg Glucagon 5mg every 30’ Cardiac pacing Hypotension Glucagon 5mg every 30’ Dopamine 5mcg/kg/min

Calcium Channel Blockers : 

Calcium Channel Blockers Signs/Symptoms Bradycardia Hypotension, shock AV blocks Heart failure QRS prolongation does NOT occur

Calcium Channel Blockers : 

Calcium Channel Blockers Management Calcium reverses decrease in contractility Fluid infusion increases BP

Digitalis : 

Digitalis Signs/Symptoms Central Nervous System Headache Irritability Psychosis Yellow-green vision Gastrointestinal Anorexia Nausea, vomiting

Digitalis : 

Digitalis Signs/Symptoms Cardiac Atrial tachycardia with block Non-paroxysmal junctional tachycardia PACs, PJCs, PVCs Tachyarrhythmias + Blocks =>Digitalis toxicity

Digitalis : 

Digitalis Management ABC’s, oxygen Check electrolytes, correct hypo/hyperkalemia Atropine: bradycardia with hypotension Dilantin: ectopy Lidocaine/magnesium sulfate: ventricular ectopy Digtalis immune Fab Fragments (Digibind)

Digitalis : 

Digitalis Precautions Cardioversion, pacing attempts may cause VF Vagal stimulation may cause bradycardia, AV blocks Calcium may worsen ventricular arrhythmias

Theophylline : 

Theophylline

Theophylline : 

Theophylline Actions Relaxes bronchial smooth muscle Stimulates respiration Stimulates cardiovascular constriction Stimulates gastric acid secretion Augments cardiac inotrophy Relax uterine smooth muscle Diuresis (Stronger than caffeine but shorter duration)

Theophylline : 

Theophylline Narrow therapeutic index Leading cause of drug induced seizures Seizures can occur with levels slightly over 20 mcg/ml. Common causes of toxicity Large single dose Accidental accumulation secondary to inadvertent overmedication.

Theophylline : 

Theophylline Mild Toxicity (20-40 mcg/ml) Gastrointestinal discomfort, vomiting, diarrhea Most common sign of toxicity 60-100% of patients experience vomiting Restlessness, irritability

Theophylline : 

Theophylline Moderate Toxicity (40 - 100mcg/ml) Wakefulness Mild Sinus Tachycardia Tachydysrhythmias Increased Blood Pressure Decreased blood pressure Hyperthermia Albuminuria Dehydration Hematemesis Manic behavior Hallucinations

Theophylline : 

Theophylline Dysrhythmias VF threshold reduction Seizures Mechanism unknown Indicate poor outcome May lead to rhabdomyolysis, renal failure, permanent neurologic sequelae On EEG seizure is continuous Severe Toxicity (>100mcg/ml) Dehydration Metabolic abnormalities Hyperthermia Coma DEATH

Theophylline : 

Theophylline Management ABCs Provide O2 Intubate, if necessary Support vital signs Control seizures, arrhythmias

Theophylline : 

Theophylline Management Decontamination Lavage, activated charcoal Due to possible rapid onset of seizures, emesis NOT recommended. Whole bowel irrigation may be necessary if Theophylline levels continue to rise secondary to sustained release preparations. Endoscopic removal of bezoar may be necessary if levels continue to rise, patient’s condition deteriorates

Theophylline : 

Theophylline Management Sinus tachycardia Rarely requires treatment Supraventricular tachycardia Verapamil Cardiospecific beta blockers Ventricular ectopy Lidocaine

Theophylline : 

Theophylline Management Hypotension Correct SVT, if present Fluids Dopamine Norepinephrine Seizures Valium Phenytoin Phenobarbitol General anesthesia for status seizures

Tricyclic Antidepressants : 

Tricyclic Antidepressants

TCAs : 

TCAs Examples Elavil Tofranil Sinequan Surmontil Vivactil

TCAs : 

TCAs Mechanism of Toxicity: Cardiovascular Alpha-adrenergic blockade: vasodilation Anticholinergic effects: tachycardia, mild hypertension Quinidine-like effects: myocardial depression Inhibition of sodium channels: conduction defects Metabolic or respiratory acidosis may contribute to cardiotoxicity by inhibition of fast sodium channels

TCAs : 

TCAs Mechanism of Toxicity: CNS Anticholinergic effects: sedation, coma Inhibition of NE, serotonin re-uptake: seizures

TCAs : 

TCAs Three major toxic syndromes Anticholinergic effects Cardiovascular effects Seizures

Anticholinergic Effects : 

Anticholinergic Effects Sedation, coma, delirium Dilated pupils Dry skin, mucous membranes Tachycardia Decreased bowel sounds Urinary retention Myoclonic jerking (often mistaken for seizures)

Cardiovascular Effects : 

Cardiovascular Effects Arrhythmias, abnormal conduction, hypotension Prolongation of PR, QRS, QT intervals (QRS > 0.12 is a good predictor of toxicity) Various degrees of AV block Hypotension caused by vasodilatation Cardiogenic shock Pulmonary edema

Seizures : 

Seizures Common with TCA toxicity Recurrent or persistent Combined with diminished sweating can lead to Severe hyperthermia, Rhabdomyolysis Brain damage Multisystem failure DEATH

Death : 

Death Usually occurs within hours due to : Ventricular fibrillation Intractable cardiogenic shock Status epilepticus with hyperthermia

TCAs : 

TCAs The three C’s Coma Convulsions Cardiac arrhythmias

TCAs : 

TCAs Overdose Evaluation Most have narrow therapeutic index Doses <10x therapeutic daily dose may produce severe poisoning 10-20 mg/kg can be life threatening In children one tablet can cause death

TCAs : 

TCAs Management of Toxicity ABCs Decontamination (Lavage even up to 4-6 hours post ingestion may be useful due to decreased GI motility) Activated charcoal

TCAs : 

TCAs Management of Toxicity Sodium Bicarbonate (1-2 mEq/kg) Maintain pH of 7.45 to 7.55 Protects cardiac membrane, corrects acidosis Hyperventilation to induce respiratory alkalosis can work for short time

TCAs : 

TCAs Management of Toxicity Pacing for bradyarrhythmias, high-degree AV block Overdrive pacing for Torsades des pointes Do NOT use type 1a or 1c antiarrhythmic agents for V-tach; can aggravate cardiotoxicity

TCAs : 

TCAs Management of Toxicity Hypotension Fluids Vasopressors Seizures Diazepam, phenobarbital. If these do not work, paralyze patient

Iron : 

Iron

Iron : 

Iron Incidence (1995 AAPCC Annual Report) 28,039 Exposures 378 moderate, major effects 3 deaths

Iron : 

Iron Overdose Evaluation How much elemental Fe could have been ingested (mg/kg)? < 20mg/kg: not considered toxic, can be left at home 20-60mg/kg: mild to moderate toxicity, some treatment required > 60mg/kg: high toxicity; hospitalization required

Iron : 

Iron Signs and Symptoms Occur in five stages

Stage I : 

Stage I 30 minutes-6 hours post ingestion GI irritation, due to iron’s corrosive effects Nausea, vomiting Epigastric pain GI bleeding Drowsiness Hypotension Metabolic acidosis Leukocytosis Hyperglycemia

Stage II : 

Stage II 6-24 hours post ingestion Sometimes absent in severely poisoned patients Patient seem to improve; feels, looks better

Stage III : 

Stage III 6-48 hours post ingestion Metabolic, systemic derangement Cardiovascular collapse Coma Seizures Coagulopathy Pulmonary edema

Stage IV : 

Stage IV 2-7 days post ingestion Hepatotoxicity (jaundice) Coagulopathy Metabolic acidosis Renal insufficiency

Stage V : 

Stage V 1-8 weeks post ingestion Primarily delayed GI complications Gastric/duodenal fibrosis Scarring of pylorus Intestinal obstruction

Iron : 

Iron Overdose Treatment Decontamination Lavage useful if done within first 60 minutes post ingestion Iron does NOT bind to activated charcoal Whole bowel irrigation

Iron : 

Iron Overdose Treatment Desferal ( desferoximine ) Chelating agent Binds free iron, complex is excreted renally “Vin rose’” urine color depending on urine pH

Isoniazid : 

Isoniazid

Isoniazid : 

Isoniazid Drug of Choice for Tuberculosis treatment Tuberculosis prophylaxis Used in prevention of opportunistic Infections in HIV infected patients

Isoniazid : 

Isoniazid Mechanisms of Toxicity: Acute Neurological Competes with pyridoxal 5-phosphate (vitamin B6) for enzyme glutamic acid decarboxylase Results in decreased GABA levels Causes seizures Hepatic Inhibits hepatic conversion of lactate to pyruvate Produces lactic acidosis.

Isoniazid : 

Isoniazid Mechanisms of Toxicity: Chronic Peripheral neuritis (thought to be related to competition with pyridoxine) Systemic Lupus Erythematosus Hepatic Injury

Isoniazid : 

Isoniazid Toxic Doses Acute Ingestion: As little as 1.5 gms Chronic Use: 10-20% incidence of hepatic toxicity when dose is 10mg/kg/day

Isoniazid : 

Isoniazid Acute Overdose Slurred Speech Ataxia Coma Seizures (within 30 - 60 minutes) Profound anion gap metabolic acidosis

Isoniazid : 

Isoniazid Management ABCs Treat coma, seizures, metabolic acidosis accordingly. Pyridoxine ( vitamin B6 ) One gram for each gram of isoniazid ingested If amount unknown give at least 5gm IV If amount on hand is insufficient, give what is available and then give diazepam

Carbon Monoxide : 

Carbon Monoxide Produced by incomplete combustion (autos, home heaters) Colorless, odorless, tasteless Binds to hemoglobin - blocks oxygen carrying capacity

Carbon Monoxide : 

Carbon Monoxide Signs/Symptoms Headache, N/V, ringing in ears, incontinence, seizures, coma, pulmonary edema Cherry-red skin - usually a terminal event Suspect with a lot of “sick” patients at one location

Organophosphates : 

Organophosphates Pathophysiology Block cholinesterase. Cause build-up of acetylcholine in synapses. Produce cholinergic crisis.

Organophosphates : 

Organophosphates Signs and Symptoms Salivation Lacrimation Urination Defecation Gl Cramping Emesis Pin-point pupils Bradycardia Bronchospasms Muscle twitching Weakness Ventilatory failure

Organophosphates : 

Organophosphates Management 100% oxygen, assist ventilations IV tko Monitor ECG Atropine 1mg IV, 2mg IM. Repeat until atropinized Pulmonary edema is non-cardiogenic in origin; avoid lasix, morphine

Anhydrous Ammonia : 

Anhydrous Ammonia Signs/Symptoms Acute pulmonary edema Laryngeal edema Ventricular arrhythmias/hypotension Ocular necrosis - blindness Partial and full thickness skin burns

Anhydrous Ammonia : 

Anhydrous Ammonia Management SCBA/Protective equipment required! Delay entry until equipment available Wash patient with large amounts of H2O ABC’s, O2, assist ventilations Intubate/suction lower airway PRN Assist ventilation/consider PEEP Irrigate eyes Admit/observe for delayed effects