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Gastroenteritis – “stomach flu” but is not related to influenza at all Irritation or inflammation of the stomach and intestines N/V/D and abdominal pain – metabolic acidosis (bicarb wasting) Most cases are acute, benign and self-limited Pts do not always seek medical attention Diarrhea Acute diarrhea (<3wks) = INFX Chronic diarrhea (>1 month) = disease process COMPLICATIONS: dehydration, orthostasis, tachycardia, hypotension, lethargy, electrolytes, AMS Risk Factors: 1. Contagious – meal preparers and healthcare providers 2. Abx – alter normal bowel flora 3. Mes (antacids, H2 blockers) and surgery – alter normal acidic pH 4. Hypomobility 5. Immunocompromised states 6. Untreated drinking water PE Hydration, nutrition, blood/mucus/impaction, acute abdomen, bowel sounds, tenderness, masses Pathophysiology: Viral, bacterial, protozoa Agents invade GI mucosa, produce cytotoxins and enterotoxins (alter the permeability of GI wall leading to increased fluid secretion, decreased absorption by GI mucosa). Causes dehydration, loss of electrolytes and nutrients Diarrhea o Osmotic – excessive intake and diminished absorption o Inflamed mucosa o Secretory – increased secretions o Motile – increased motility Enterotoxins – act on secretory mechanisms producing large amounts of watery (rice water) diarrhea Cytotoxins – result in mucosal cell destruction leading to bloody diarrhea with inflammatory cells Why vomiting? Role of serotonin? Neurotoxins produced by S. aureus and Bacillus cereus HISTORY: travel, camping, Abx, daycare, ingestion of raw seafood, similar illness in contacts (contag) Viral Most common etiology (50-70%) Prodrome Sx, N/V/D, malaise, HA, fatigue, Transmission: fecal-oral; contagious via food handlers; fomites o Norwalk virus is the leading cause of viral gastroenteritis in US o Rotavirus Oct – April –most common in children <5 (vaccine aval – intussception) o Adenovirus throughout year o Calicivirus, Astrovirus, parvovirus, coronavirus Common in developed and nondeveloped – transmitted thru humans Low infx dose Incubation 1-3 days Fever not common except Rotavirus and Norwalk No bloody diarrhea Vomiting common Dx via exclusion Tx: supportive and hydration Bacterial Areas of poor hygiene, summer/rainy months – transmitted thru animals and humans High infx dose Incubation 1-7 days; if bacterial toxins – hrs Fever common if cause inflammatory diarrhea (Salmonella, Shingella) Frequent bloody diarrhea Vomiting not common unless preformed toxins (S. aureus and bacillus cereus) Dx: leukocytes, blood/stool cultures to identify pathogens Tx: supportive, hydration and ABx “I think bloody diarrhea is SECSY” Salmonella, Enterohemoragic E. coli, Camplyobacter, Shingella, Yersinia Enterocyte invasion – secretory mechanisms 1. Campylobacter Jejuni a. G- rod b. Contaminated food/water, birds and other animals c. Erythromycin or fluoroquinolones d. Complications: toxic megacolon; colonic hemorrhage 2. Salmonella a. G- rod b. Food does not appear/smell spoiled c. Poultry, contaminated water, eggs, dairy, reptiles d. Only Tx Salmonella if immunocompromised: Ciprofloxacin or Bactrim (sulfamethoxazole/TMP) e. Complication = Reiter’s syndrome (can’t see, can’t see, can’t dance with me) i. TYPHOID FEVER – salmonella typhi = unremitting fever, rose spots, splenomegaly and bradycardia. Bacteria spreads to organs and blood = bacteremia (in blood) 1. Tx: Ceftriaxone of Cephalosporins 2. Vaccine available 3. Yersinia Entercolitica a. G- Bacillus b. Transmitted thru contaminated pork, milk, water c. Lymphoid rxn in terminal ilieum = mucosal ulceration spread to mesenteric L.N. = bacteremia d. May mimic appendicitis e. Tx: supportive but Bactrim, Ciprofloxacin if immunocompromised Bacterial Toxins 1. Enterotoxic Escherichia Coli a. Aerobic bacteria b. Major cause of traveler’s diarrhea c. Food, water, contaminated feces, undercooked meat d. Tx: self-limited; can five fluoroquinolones or Bactrim x3 days 2. Vibrio Cholera a. G - rod b. Ingestion of food or water contaminated by feces c. Rice water diarrhea d. Can be fatal (QUICK) – dehydration and electrolyte imbalances e. Tx: Tetracycline, IV fluids Cytotoxins – mucosal destruction and bloody diarrhea 1. Enterohemorrhagic E. coli [o157:H7] a. Fecal-oral route b. Progression watery diarrhea bloody diarrhea c. Hemolytic uremic syndrome (HUS) triad: i. Anemia (hemolytic) ii. Renal failure iii. Thrombocytopenia 1. Can lead to thrombo thrombocytopenic purpura (TTP) a. Fever and neurologic Sx d. Tx: RBCs destroyed and kidney fails = transfusions and kidney dialysis e. INFX DZ CONSULT FOR ABX 2. Clostridium difficile aka “psuedomembrane colitis” a. Fecal-oral; common nosocomial b. Onset with ABx: ampicillin and clindamycin – disrupted normal flora c. Dx: C. diff toxin assays, acute abdomen, pseudomembranous adherent yellowish-whitish plaques 3. Shingella dysenteriae a. Swimming in pools with out chlorine, raw veg, dairy, poutry b. Fecal-oral c. Tenesmus and dysentery d. Tx: ampicillin, Bactrim or fluoroquinolones AVOID ANTIDIARRHEAL TX 4. Vibrio parahaemolyticus a. Undercooked seafood b. Tx: tetracycline or doxycycline Food-Borne 1. Staphylococcus aureus a. MC toxin induced gastroenteritis b. Custard, processed meats, mayonnaise c. Tx: supportive; hospitalization 2. Bacillus cereus a. Enterotoxin- cell wall – secretions b. Fried rice or bean sprouts left on steam tables c. Supportive 3. Clostridium perfringes a. Enterotoxin – cell wall secretions b. High protein foods (meat, poultry, potato salads) c. Watery diarrhea d. supprotive 4. Clostridium Botulinum a. Neurotoxin – from gut to peripheral nervous synapses where it blocks the release of ACH. i. Dysphagia, diplopia, dysarthria, weakness, dyspnea ii. Symmetric descending extremity paralysis (w/in 12-36 hrs) iii. Dx: serum Botulinum toxin assay iv. Tx: trivalent botulism anti-toxin 1. No effect on neurotoxin already bound to neuromuscular junction b. Spores in meats and vegetables; canned foods and honey Parasitic Gastroenteritis (10-15%) 1. Giardia lamblia a. Protozoa + ova b. Most common parasitic gastroenteritis in US c. Explosive watery foul-smelling diarrhea w bloating and flatulence d. Contaminated food/water e. Travelers drank untreated Mt. water, daycare, homosexual men f. Tx Metronidazole of Furazolidone for 10 days 2. Entamoeba histolytica aka “amebiasis” aka “traveler’s dysentery” a. Fecal contamination of food/water b. Develop liver abscess – sepsis, seizures and kidney failure c. Tx: Metronidazole 3. Cryptosporidium parvum a. Commonly in AIDs pts b. Contaminated water or rodents c. Acid-fast stain of stool d. Tx: no effective Tx (HIV) spiramycin = temporary relief Non-bacterial food poisoning: FISH POISONING 1. Cinguatera poisoning a. Bottom dwelling fish of tropics b. Paresthesia lips, tongue, limbs c. supportive 2. Scombroid poisoning a. Tuna, mackerel, bluefish, herring b. Heat stable toxin from proteus morganii c. Sx ~ histamine rxn i. Flushing, HA, dizziness, cramping, V/D d. Tx: antihistamines 3. Tetraoden poisoning a. Consumption of puffer fish b. Neurotoxin paresthesia of face and extremities c. May need ventilator support Dx: In general, stool culture is not necessary or cost-effective Electrolytes and renal function (if dehydrated) Determine etiology: o CBC: eosinophilia (parasities) o Leukocytes = bacterial infx o Fecal leukocytes = salmonella, shingella Stool cultures may require different media Ova and parasites x3 if pt recent travel ELISA – enzyme linked immunosorbent assay Tx: Supportive – rest, hydration, electrolyte correction BRAT diet Pepto-Bismol – bismuth subsalicylate and Kaolin-pectin (Kaopectate) o Anti-secretory agent decreases fluid in lumen Anti-motility drugs – Lomotil, Imodium, codeine o Contraindicated in infx diarrhea Avoid aspirin and NSAIDS – could irritate GI tract Other causes of N/V Drugs, ABx, NSAIDs, chemotherapy Psychiatric Pregnancy Acute MI Neuro – motion sickness, vertigo GI – obstructions, PUD, GERD, paralytic ileus, peritonitis, IBS, IBD, gastritis, appendicitis Visceral acute conditions Metabolic Celiac sprue Milk/food allergies Complications: Hypotension/dehydration Sepsis Electrolyte disturbance Metabolic acidosis