Acute Infectious Diarrhea An overview By Professor Dr Intekhab Alam Faculty of Medicine Khyber Medical University PGMI, Lady Reading Hospital, Peshawar.

Introduction Food poisoning (Acute Infectious Diarrhea) denotes gastrointestinal diseases caused by micro-organism transmitted in food or by microbial toxins preformed in the food. Worldwide impact of food poisoning is great, responsible for increasing childhood mortality and their physical and mental growth retardation. The commonest bacterial pathogens responsible for bacterial gastroenteritis in the world are Enterobacteriaceae (E.coli, Salmonella and Shigella) in underdeveloped and Compylobacter in the industrialized world.

Epidemiology of Acute Infectious Diarrhea Etiologic Agent%ageComments Enterotoxigenic Escherichia coli 15–50Single most important agent, particularly in summertime in semitropical areas; percentage of cases ranges from 15% in Asia to 50% in Latin America Enteroaggregative E. coli 20–35Emerging enteric pathogen of worldwide distribution Shigella and enteroinvasive E. coli 10–25Major causes of fever and dysentery Salmonella 5–10Causes fever and dysentery Campylobacter jejuni 3–15More common in winter in semitropical areas; more common in Asia Aeromonas 5Important in Thailand Plesiomonas 5Related to tropical travel and seafood consumption Vibrio cholerae 0–10Most common in India and Asia; also common in Central and South America Rotavirus and norovirus10–40Latin America, Asia, and Africa; norovirus associated with seafood ingestion on cruise ships Entamoeba histolytica 5Particularly important in Mexico and Thailand Giardia lamblia <2Zoonotic reservoirs in northern United States; affects hikers and campers who drink from freshwater streams; contaminates water supplies in Russia Cryptosporidium 2Affects travelers to Russia, Mexico, and Africa; causes large-scale urban outbreaks in United States Cyclospora <1Affects travelers to Nepal, Haiti, and Peru; contaminates water or food Unknown20Illness improves with antibacterial therapy, implicating bacterial diarrhea

GI Pathogens and the pathogenesis of acute Diarrhea MechanismLocationIllnessStool FindingsExamples of Pathogens Involved Non inflammatory (enterotoxin) Proximal small bowelWatery diarrhea No fecal leukocytes; mild or no increase in fecal lactoferrin Vibrio cholerae, enterotoxigenic Escherichia coli (LT and/or ST), enteroaggregative E. coli, Clostridium perfringens, Bacillus cereus, Staphylococcus aureus, Aeromonas hydrophila, Plesiomonas shigelloides, rotavirus, norovirus, enteric adenoviruses, Giardia lamblia, Protozoa: Cryptosporidium spp., Cyclospora spp., microsporidia and isospora. Inflammatory (invasion or cytotoxin) Colon or distal small bowel Dysentery or inflammatory diarrhea Fecal polymorphonuclear leukocytes; substantial increase in fecal lactoferrin Shigella spp., Salmonella spp., Campylobacter jejuni, enterohemorrhagic E. coli, enteroinvasive E. coli, Yersinia enterocolitica, Vibrio parahaemolyticus, Clostridium difficile, ?A. hydrophila, ?P. shigelloides, Entamoeba histolytica PenetratingDistal small bowelEnteric fever Fecal mononuclear leukocytes Salmonella typhi, Y. enterocolitica, ?Campylobacter fetus

Bacterial Food Poisoning Incubation Period, OrganismSymptomsCommon Food Sources Staphylococcus aureus (1-6 hrs) Nausea, vomiting, diarrheaPoultry, potato or egg salad, mayonnaise, cream pastries B. cereus(Gm+ive saprophyte) Nausea, vomiting, diarrheaFried rice Clostridium perfringens (8–16 hrs) Abdominal cramps, diarrhea (vomiting rare) Beef, poultry, legumes, gravies B. cereus (Gm+ive saprophyte)Abdominal cramps, diarrhea (vomiting rare) Meats, vegetables, dried beans, cereals Vibrio cholerae (>16 H)Watery diarrheaShellfish Enterotoxigenic Escherichia coli Watery diarrheaSalads, cheese, meats, water Enterohemorrhagic E. coli (EHEC), E.coli O157:H7 Bloody diarrhea HUS in 15% of children <10 yrs. Ground beef, roast beef, salami, raw milk, raw vegetables, apple juice Salmonella spp. Inflammatory diarrheaBeef, poultry, eggs, dairy products Campylobacter jejuni Inflammatory diarrheaPoultry, raw milk Shigella spp. DysenteryPotato or egg salad, lettuce, raw vegetables Vibrio parahaemolyticus DysenteryMollusks, crustaceans

Management Take history: recent fast food or dining in a restaurant. onset, frequency, consistency of stools, colic, tenemus, vomiting and fever. Examine and assess: Conscious state, Hydration status, postural drop, icterus and abdominal tenderness. collect stool sample for physical examination and if indicated send for C/S. Secure two wide bored IV lines and send blood for S.Electrolytesa and S. Creatinine and keep strict intake-output record and commence IV hydration. Pass CV line if pt is in shock and peripheral IV access is difficult. Keep hourly BP/Pulse record.

Treatment of Acute Infectious Diarrhea on the Basis of Clinical Features Clinical syndrome Suggested therapy Watery diarrhea (no blood in stool, no fever), 1 or 2 unformed stools per day without distressing enteric symptoms Oral fluids (Pedialyte, ORS, or flavored mineral water) and saltine crackers Watery diarrhea (no blood in stool, no fever), 1 or 2 unformed stools per day with distressing enteric symptoms Bismuth subsalicylate (for adults): 30 mL or 2 tablets (262 mg/tablet) every 30 min for 8 doses; or loperamide: 4 mg initially followed by 2 mg after passage of each unformed stool, not to exceed 8 tablets (16 mg) per day (prescription dose) or 4 caplets (8 mg) per day (over-the-counter dose); drugs can be taken for 2 days Watery diarrhea (no blood in stool, no distressing abdominal pain, no fever), >2 unformed stools per day Antibacterial drug plus (for adults) loperamide a (see dose above) Dysentery (passage of bloody stools) or fever (>37.8°C) Antibacterial drug Vomiting, minimal diarrheaBismuth subsalicylate (for adults; see dose above) Diarrhea in infants (<2 y old)Fluids and electrolytes (Pedialyte, ORS); continue feeding, especially with breast milk; seek medical attention for moderate dehydration, fever lasting >24 h, bloody stools, or diarrhea lasting more than several days Diarrhea in pregnant womenFluids and electrolytes; can consider attapulgite, 3 g initially, with dose repeated after passage of each unformed stool or every 2 h (whichever is earlier), for a total dosage of 9 g/d; seek medical attention for persistent or severe symptoms Diarrhea despite trimethoprim-sulfamethoxazole prophylaxis Fluoroquinolone—with loperamide (see dose above) if no fever and no blood in stool, alone in cases of fever/dysentery Diarrhea despite fluoroquinolone prophylaxisBismuth subsalicylate (see dose above) for mild to moderate disease; consult physician for moderate to severe disease or if disease persists

Post-Diarrhea Complications of Acute Infectious Diarrheal Illness ComplicationComments Chronic diarrheaOccurs in ~1% of travelers with acute diarrhea Lactase deficiency Small-bowel bacterial overgrowth Protozoa account for ~⅓ of cases Malabsorption syndromes (tropical and celiac sprue) Initial presentation or exacerbation of inflammatory bowel disease (IBD) May be precipitated by traveler's diarrhea I rritable bowel syndrome (IBS)Occurs in ~10% of travelers with traveler's diarrhea Reiter's syndrome (reactive arthritis)Particularly likely after infection with invasive organisms (Shigella, Salmonella, Campylobacter) Hemolytic-uremic syndrome (hemolytic anemia, thrombocytopenia, and renal failure) Follows infection with Shiga toxin–producing bacteria (Shigella dysenteriae type 1 and enterohemorrhagic Escherichia coli)

Differential Diagnosis of Acute Diarrhea 1.Food intolerance e.g. Lactose intolerance, 2.Inorganic agents like Sodium nitrite, 3.Organic substances like Mushrooms and shellfish, 4.Drugs e.g. Laxatives and Antibiotics, 5.Emotional stress. finally 1.Infectious agents including Bacteria, Viruses and Protozoal agents.

Prevention 1.All agents responsible for food poisonings are transmitteed through oro-fecal route. 2.First principal is personal hygiene and handwashing before handling food, eating and attending the toilet provides 80-90% safety against the transmission of these agents. 3.It is of paramount importance to wash the food with plenty of fresh and clean water before consumption, especially the raw food consumption like lettuce and salad. 4.Production of safe food rests on evidence based practical technologies and management systems; HACCP (Hazard Analysis and Critical Control Points). This system identifies the Hazards and the points in a process whwere and when they can occur and decides which points are critical to control to ensure consumers’ safety, e.g. Pasteurization of the milk in which critical points are, a)Temperatures reeached during heating, b)its duration and c)to prevent subsequent contamination 5.Good sanitation and sewerage system and safe water supply

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