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Acute Gastroenteritis in Children:

Acute Gastroenteritis in Children


infections of the gastrointestinal tract caused by bacterial, viral, or parasitic pathogens Many of these infections are foodborne illnesses The most common manifestations are diarrhea and vomiting, which can also be associated with systemic features such as abdominal pain and fever. Diarrheal disorders in childhood account for a large proportion (9%) of childhood deaths, with an estimated 0.71 million deaths per year globally,


ETIOLOGY OF DIARRHEA Gastroenteritis is the result of infection acquired through the fecal–oral route or by ingestion of contaminated food or water Gastroenteritis is associated with poverty, poor environmental hygiene, and development indices. rotavirus and the noroviruses (small round viruses such as Norwalk-like virus and caliciviruses ) are the most common viral agents, followed by sapoviruses , enteric adenoviruses and astroviruses Shigella , Salmonella, E. coli, Campylobacter are examples of bacterial causes Giardia and Entamoeba histolytica are examples of paracytic causes


PATHOGENESIS OF INFECTIOUS DIARRHEA 1- noninflammatory diarrhea through enterotoxin production by some bacteria, destruction of villus (surface) cells by viruses, adherence by parasites, and adherence and/or translocation by bacteria 2- Inflammatory diarrhea is usually caused by bacteria that directly invade the intestine or produce cytotoxins

Risk factors for diarrhea:

Risk factors for diarrhea Lack of exclusive breastfeeding (0-5 mo) No breastfeeding (6-23 mo ) Underweight,stunted,wasted Vitamin A deficiency Zinc deficiency Crowding (>8 persons/kitchen) Indoor air pollution Unwashed hands Poor water quality Inappropriate excreta disposal


Acute diarrhea is defined as the abrupt onset of 3 or more loose stools per day and lasts no longer than 14 days Consider the following to determine the source/cause of the patient’s diarrhea :


Stool characteristics ( eg , consistency, color, volume, frequency) Presence of associated enteric symptoms ( eg , nausea/vomiting, fever, abdominal pain) Use of child daycare (common pathogens: rotavirus, astrovirus , calicivirus; Campylobacter ,  Shigella ,  Giardia , and  Cryptosporidium  species [ spp ]) Food ingestion history ( eg , raw/contaminated foods, food poisoning) Water exposure ( eg , swimming pools, marine environment) Camping history (possible exposure to contaminated water sources) Travel history (common pathogens affect specific regions; also consider rotavirus and  Shigella , Salmonella, and Campylobacter   spp regardless of specific travel history, as these organisms are prevalent worldwide) Animal exposure ( eg , young dogs/cats:  Campylobacter   spp ; turtles: Salmonella   spp ) Predisposing conditions ( eg , hospitalization, antibiotic use, immunocompromised state)

Rotavirus infection:

Rotavirus infection typically begins after an incubation period of <48 hr with mild to moderate fever as well as vomiting, followed by the onset of frequent, watery stools. All 3 symptoms are present in about 50-60% of cases. Vomiting and fever typically abate during the 2nd day of illness, but diarrhea often continues for 5-7 days. The stool is without gross blood or white blood cells. Dehydration may develop and progress rapidly, particularly in infants. The most severe disease typically occurs among children 4-36 mo of age. Malnourished children and children with underlying intestinal disease, are particularly likely to acquire severe rotavirus diarrhea

Clinical Evaluation of Diarrhea:

Clinical Evaluation of Diarrhea The most common manifestations of gastrointestinal tract infection in children are diarrhea, abdominal cramps, and vomiting. Systemic manifestations are varied and associated with a variety of causes. The evaluation of a child with acute diarrhea includes : 1- Assessing the degree of dehydration and acidosis and provide rapid resuscitation and rehydration with oral or intravenous fluids as required 2- Obtaining appropriate contact, travel, or exposure history. This includes information on exposure to contacts with similar symptoms , intake of contaminated foods or water, child-care center attendance, recent travel of patient or contact with a person who traveled to a diarrhea-endemic area, and use of antimicrobial agents .


3- Clinically determining the etiology of diarrhea for institution of prompt antibiotic therapy, if indicated Although nausea and vomiting are nonspecific symptoms, they indicate infection in the upper intestine. Fever suggests an inflammatory process(inflammatory diarrhea) but also occurs as a result of dehydration or coinfection (e.g ., urinary tract infection, otitis media)called also parenteral diarrhea(etiology outside the G.I system) Severe abdominal pain, tenesmus and bloody diarrhoea indicate involvement of the large intestine and rectum . Features such as nausea and vomiting and absent or low-grade fever with mild to moderate periumbilical pain and watery diarrhea indicate small intestine involvement and also reduce the likelihood of a serious bacterial infection.


InvestigationS 1-Stool Examination A-Microscopic examination of the stool: Fecal leukocytes and RBC indicate bacterial invasion of colonic mucosa, stool microscopy must include examination for parasites causing diarrhea, such as G. lamblia and E. histolytica B- Stool culture is required if the child appears septic, if there is blood or mucus in the stools or the child is immunocompromised.It may be indicated following recent foreign travel, if the diarrhoea has not improved by day 7 or the diagnosis is uncertain


3- Plasma electrolytes, urea, creatinine and glucose should be checked if intravenous fluids are required or there are features suggestive of hypernatraemia. 4- If antibiotics are started, a blood culture should be taken. 5- urinalysis to exclude UTI (parenteral diarrhea) 6- XTAG GPP is an FDA-approved gastrointestinal pathogen panel using multiplexed nucleic acid technology that detects Campylobacter, C. difficile, toxin A/B, E. coli 0157, enterotoxigenic E. coli, Salmonella, Shigella, Shiga-like toxin E. coli, norovirus, rotavirus A, Giardia, and Cryptosporidium


7- Enzyme immunoassay for rotavirus or adenovirus antigens


BLOODY DIARRHEA Causes of bloody diarrhoea (real or apparent) in infants and children Infants aged <1 year 1- Intestinal infection( shigella,salmonella,E-coli,campylobacter,Yersinia ) And Entamoeba histolytica 2- Infant colitis( Cow’s milk colitis)—non specific allergic colitis 3- rare causes like Intussusception, Malrotation and volvulus


Infants aged >1 year 1- Intestinal infection 2- Inflammatory bowel disease 3- Juvenile polyp 4- rare causes Intussusception , Malrotation and volvulus and Henoch-Schönlein purpura  Recent antibiotic use raises suspicion for antibiotic-associated colitis and  Clostridium difficile  colitis.




ORS The low-osmolality World Health Organization (WHO) oral rehydration solution (ORS) containing 75 mEq of sodium, 64 mEq of chloride, 20 mEq of potassium, and 75 mmol of glucose per liter, with total osmolarity of 245 mOsm/L, is now the global standard of care and more effective than home fluids, including decarbonated soda beverages, fruit juices, and tea. These are not suitable for rehydration or maintenance therapy because they have inappropriately high osmolalities and low sodium concentrations.


Oral rehydration should be given to infants and children slowly, especially if they have emesis. It can be given initially by a dropper, teaspoon, or syringe, beginning with as little as 5 mL at a time .The volume is increased as tolerated. Oral rehydration can also be given by a nasogastric tube if needed; this is not the usual route. Limitations to oral rehydration therapy include shock, an ileus, intussusception, carbohydrate intolerance (rare), severe emesis, and high stool output (>10 mL/kg/hr)

DEHYDRATION (total body deficit of sodium and water):

DEHYDRATION (total body deficit of sodium and water) The following children are at increased risk of dehydration: Infants, particularly those under 6 months of age or those born with low birthweight. • If they have passed ≥6 diarrhoeal stools in the previous 24 h • If they have vomited three or more times in the previous 24 h • If they have been unable to tolerate (or not been offered ) extra fluids • If they have malnutrition


Infants are at particular risk of dehydration because they have a greater surface area to weight ratio than older children, leading to greater insensible water losses (300 ml/m2 per day, equivalent in infants to 15–17 ml/kg per day). They have higher basal fluid requirements (100–120 ml/kg per day, i.e. 10–12% of bodyweight) and immature renal tubular reabsorption. In addition, they are unable to obtain fluids for themselves when thirsty.

Hypernatraemic dehydration ( sodium concentration >150 mEq/L):

Hypernatraemic dehydration ( sodium concentration >150 mEq/L) Infrequently, water loss exceeds the relative sodium loss and plasma sodium concentration increases (hypernatraemic dehydration). This usually results from high insensible water losses (high fever or hot, dry environment)or from profuse, low-sodium diarrhea. The extracellular fluid becomes hypertonic with respect to the intracellular fluid, which leads to a shift of water into the extracellular space from the intracellular compartment. Signs of extracellular fluid depletion are therefore less per unit of fluid loss, and depression of the fontanelle, reduced tissue elasticity and sunken eyes are less obvious. This makes this form of dehydration more difficult to recognise clinically , particularly in an obese infant.


It is a particularly dangerous form of dehydration as water is drawn out of the brain and cerebral shrinkage within a rigid skull may lead to jittery movements, increased muscle tone with hyper reflexia, altered consciousness, seizures and multiple, small cerebral haemorrhages. If the serum sodium concentration is lowered rapidly, there is movement of water from the serum into the brain cells to equalize the osmolality in the 2 compartments . The resultant brain swelling manifests as seizures or coma.


Because of the associated dangers, hypernatremia should not be corrected rapidly. The goal is to decrease the serum sodium by <12 mEq/L every 24 hr-- The fluid deficit should be replaced over at least 48 h and the plasma sodium measured regularly

Isonatraemic dehydration (sodium 135-150 meq/l):

Isonatraemic dehydration (sodium 135-150 meq/l) the losses of sodium and water are proportional and plasma sodium remains within the normal range Most common type

hyponatraemic dehydration: (serum sodium level <135 mEq/L):

hyponatraemic dehydration: ( serum sodium level <135 mEq/L) When children with diarrhoea drink large quantities of water or other hypotonic solutions, there is a greater net loss of sodium than water, leading to a fall in plasma sodium (hyponatraemic dehydration). This leads to a shift of water from extra- to intracellular compartments. The increase in intracellular volume leads to an increase in brain volume, which may result in convulsions, whereas the marked extracellular depletion leads to a greater degree of shock per unit of water loss. This form of dehydration is more common in poorly nourished infants in developing countries.

Severe dehydration(TREATMENT) :

Severe dehydration(TREATMENT) Phase 1 : focuses on emergency management. Severe dehydration is characterized by a state of hypovolemic shock requiring rapid treatment. Initial management includes placement of an intravenous or intraosseous line and rapid administration of 20 mL/kg of an isotonic crystalloid ( eg , lactated Ringer solution, 0.9% sodium chloride). Additional fluid boluses may be required depending on the severity of the dehydration. The child should be frequently reassessed to determine the response to treatment. As intravascular volume is replenished, tachycardia, capillary refill, urine output, and mental status all should improve. If improvement is not observed after 60 mL/kg of fluid administration, other etiologies of shock ( eg , cardiac, anaphylactic, septic) should be considered. Hemodynamic monitoring and inotropic support may be indicated.


Phase 2: focuses on deficit replacement, provision of maintenance fluids, and replacement of ongoing losses. Maintenance fluid requirements are equal to measured fluid losses (urine, stool) plus insensible fluid losses. Normal insensible fluid loss is approximately 400-500 mL/m 2  body surface area and may be increased by factors such as fever and tachypnea. Alternatively, daily fluid requirements may be roughly estimated as follows: Less than 10 kg = 100 mL/kg 10-20 kg = 1000 + 50 mL/kg for each kg over 10 kg Greater than 20 kg = 1500 + 20 mL/kg for each kg over 20 kg


Severe dehydration by clinical examination suggests a fluid deficit of 10-15% of body weight in infants and 6-9% of body weight in older children. The daily maintenance fluid is added to the fluid deficit. In general, the recommended administration is one half of this volume administered over 8 hours and administration of the remainder over the following 16 hours. Continued losses (eg, emesis, diarrhea) must be promptly replaced.


If the child is isonatremic (130-150 mEq/L), the sodium deficit incurred can generally be corrected by administering the fluid deficit plus maintenance as 5% dextrose in 0.45-0.9% sodium chloride. Potassium (20 mEq/L potassium chloride) may be added to maintenance fluid once urine output is established and serum potassium levels are within a safe range.

Enteral Feeding and Diet Selection:

Enteral Feeding and Diet Selection Continued enteral feeding in diarrhea aids in recovery from the episode , and a continued age-appropriate diet after rehydration is the norm. Once rehydration is complete, food should be reintroduced while oral rehydration is continued to replace ongoing losses from emesis or stools and for maintenance. Breastfeeding or non diluted regular formula should be resumed as soon as possible. Foods with complex carbohydrates (rice, wheat, potatoes, bread, and cereals ), lean meats, yogurt, fruits, and vegetables are also tolerated Fatty foods or foods high in simple sugars (juices, carbonated sodas ) should be avoided

Zinc Supplementation:

Zinc Supplementation Zinc administration for diarrhea management can significantly reduce all cause mortality by 46% and hospital admission by 23%. Also reduce duration and severity of diarrhea All children older than 6 mo of age with acute diarrhea in at-risk areas should receive oral zinc (20 mg/day) in some form for 10-14 days during and continued after diarrhea

Additional Therapies:

Additional Therapies The use of probiotic nonpathogenic bacteria for prevention and therapy of diarrhea has been successful in some settings Saccharomyces boulardii is effective in antibiotic-associated and in C. difficile diarrhea, and there is some evidence that it might prevent diarrhea in daycare centers. Lactobacillus rhamnosus GG is associated with reduced diarrheal duration and severity, which reduction is more evident in cases of childhood rotavirus diarrhea


Antimotility agents (loperamide) are contraindicated in children with dysentery and probably have no role in the management of acute watery diarrhea in otherwise healthy children. Because persistent vomiting can limit oral rehydration therapy, a single sublingual dose of an oral dissolvable tablet of ondansetron (4 mg 4-11 yr and 8 mg for children older than 11 yr [generally 0.2 mg/kg]) may be given.However, most children do not require specific antiemetic therapy;careful oral rehydration therapy is usually sufficient.

Antibiotic Therapy:

Antibiotic Therapy antibiotic therapy in select cases of diarrhea related to bacterial infections can reduce the duration and severity of illness and prevent complications Although these agents are important to use in specific cases, their widespread and indiscriminate use leads to the development of antimicrobial resistance.


PREVENTION 1- Promotion of Exclusive Breastfeeding (administration of no other fluids or foods for the 1st 6 mo of life) 2- Improved Complementary Feeding Practices 3- Rotavirus Immunization 4- Improved Water and Sanitary Facilities and Promotion of Personal and Domestic Hygiene 5- Improved Case Management of Diarrhea

Complications(Extraintestinal Manifestations of Enteric Infections):

Complications(Extraintestinal Manifestations of Enteric Infections) 1- Focal infections from systemic spread of bacterial pathogens, includingvulvovaginitis, urinary tract infection,endocarditis, osteomyelitis, meningitis,pneumonia, hepatitis, peritonitis,chorioamnionitis, soft-tissue infection,and septic thrombophlebitis 2- Reactive arthritis 3- Guillain-Barré syndrome 4- Glomerulonephritis


5- Immunoglobulin A (IgA) nephropathy 6- Erythema nodosum 7- Hemolytic uremic syndrome: Escherichia coli O157:H7 8- Hemolytic anemia


CHRONIC DIARRHOEA chronic or persistent diarrhea is defined as an episode that lasts longer than 14 days . four principle pathophysiologic mechanisms: osmotic, secretory, dysmotility associated, and inflammatory 1- Osmotic diarrhea is caused by a failure to absorb a luminal solute, resulting in secretion of fluids and net water retention across an osmotic gradient(best exemplified by the common disorder of lactose malabsorption) , either because of dissacharidase deficiencies or because the absorptive capacity of the intestine for that sugar may be overwhelmed by excessive consumption, eg , fructose and sorbitol. Such excessive intake may be seen in young children drinking fruit juices


2- Secretory diarrhea occurs when there is a net secretion of electrolyte and fluid from the intestine without compensatory absorption, Children with a pure secretory diarrhea will therefore continue to experience diarrhea even while fasting. (Congenital chloride diarrhea) 3- Chronic diarrhea associated with intestinal dysmotility typically occurs in the setting of intact absorptive abilities. Intestinal transit time is decreased, the time allowed for absorption is minimized, and fluid is retained within the lumen(diarrhea-predominant irritable bowel syndrome (IBS))


4- Inflammatory diarrhea (may encompass all of the pathophysiologic mechanisms) . Inflammation with resultant injury to the intestine may lead to malabsorption of dietary macronutrients which, in turn, creates a luminal osmotic gradient. Additionally, particular infectious agents may induce secretion of fluid into the lumen, and blood in the gut may alter intestinal motility. Diseases such as inflammatory bowel disease (IBD) and celiac disease


AETIOLOGY 1- Enteric infections are by far the most frequent cause of chronic diarrhea, both in developing and industrialized countries


2- Lactose intolerance or carbohydrate malabsorption may be caused by a brush-border enzyme defect in lactase or other enzymes--More commonly, lactose intolerance is secondary to lactase deficiency caused by intestinal mucosal damage. 3- Allergy to cow’s milk protein and other food proteins also may present during infancy with chronic diarrhea 4- Chronic diarrhea may be the manifestation of maldigestion caused by exocrine pancreatic disorders. In most patients with cystic fibrosis , exocrine pancreatic insufficiency results in steatorrhea and protein malabsorption


5- The most benign etiology of chronic diarrhea is nonspecific diarrhea that encompasses functional diarrhea (or toddler’s diarrhea ) in children younger than 4 yr of age and irritable bowel syndrome in those 5 yr of age and older. The diseases fall under the umbrella of functional disorders , in that in older children abdominal pain is often associated with diarrhea alternating with constipation and growth and weight gain are normal


6- In older children and adolescents, inflammatory bowel diseases, including Crohn disease, ulcerative colitis cause chronic diarrhea that is often associated with abdominal pain, elevated inflammatory markers 7- Diarrhea may be the result from an excessive intake of fluid and carbohydrate (fruit juice). If the child’s fluid intake were >150 mL/kg/24 hr, fluid intake should be reduced not to exceed 90 mL/kg/24 hr


8- A reduction of intestinal absorptive surface is responsible for diarrhea in celiac disease, a genetically determined permanent gluten intolerance that affects as many as 1 in 100 individuals, depending on geographic origin. In the genetically susceptible host, gliadin, the major protein of gluten, reacts with the immune system to cause villous atrophy. The reduction of functional absorptive surface area is reversible upon restriction of gluten from the diet.


DIAGNOSIS The diagnosis of celiac disease is based on a combination of symptoms,antibodies , HLA, and duodenal histology TREATMENT The only treatment for celiac disease is lifelong strict adherence to a gluten-free diet .This requires a wheat-, barley-, and rye-free diet


Malabsorption Disorders affecting the digestion or absorption of nutrients manifest as: • abnormal stools(The true malabsorption stool is difficult to flush down the toilet and has an odor which pervades the whole house,pale,bulky) • failure to thrive or poor growth in most but not all cases • specific nutrient deficiencies, either singly or in combination.

Inflammatory bowel disease:

Inflammatory bowel disease Approximately a quarter of patients present in childhood or adolescence. Crohn disease can affect any part of the gastrointestinal tract from mouth to anus, whereas in ulcerative colitis the inflammation is confined to the colon

Ulcerative colitis:

Ulcerative colitis Diagnosis: made on endoscopy (upper and ileocolonoscopy) and on the histological features, after exclusion of infective causes of colitis In contrast to adults, in whom the colitis is usually confined to the distal colon, 90% of children have a pancolitis


TREATMENT In mild disease, aminosalicylates (balsalazide and mesalazine) are used for induction and maintenance therapy. Disease confined to the rectum and sigmoid colon may be managed with topical steroids More aggressive or extensive disease requires systemic steroids for acute exacerbations and immunomodulatory therapy, e.g. azathioprine to maintain remission alone or in combination with low-dose corticosteroid therapy.


CRONH DIASEASE Diagnosis is based on endoscopic and histological findings on biopsy. Upper gastrointestinal endoscopy, ileocolonoscopy and small bowel imaging are required. TREATMENT : Remission is induced with nutritional therapy, when the normal diet is replaced by whole protein modular feeds (polymeric diet) for 6–8 weeks. This is effective in 75% of cases. Systemic steroids are required if ineffective.


Constipation Parents may use the term to describe decreased frequency of defecation; the degree of hardness of the stool and painful defecation Infants have an average of four stools per day in the first week of life, but this falls to an average of two per day by 1 year of age. Breast-fed infants may not pass stools for several days and be entirely healthy. By 4 years of age, children usually have a stool pattern similar to adults, in whom the normal range varies from three stools per day to three stools per week.


Constipation may be precipitated by dehydration or reduced fluid intake or an anal fissure causing pain. In older children, it may relate toproblems with toilet training, unpleasant toilets or stress

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