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Acute Gastroenteritis: An Approach. Paolo Aquino, M.D., M.P.H. Outline. Approach Etiology Diagnosis Treatment Prevention. Considerations Rule out acute/surgical abdomen Hydration status. Approach. Acute Abdomen. Approach. History Symptoms Nausea, emesis, retching Abdominal pain
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Acute Gastroenteritis: An Approach Paolo Aquino, M.D., M.P.H.
Outline • Approach • Etiology • Diagnosis • Treatment • Prevention
Considerations Rule out acute/surgical abdomen Hydration status Approach
Approach • History • Symptoms • Nausea, emesis, retching • Abdominal pain • Bowel movements • Timing • Age • Onset • Relation to feeds • Focus of infection, other affected individuals
Approach • Physical examination • Temperature, heart rate, blood pressure, pain • Abdominal examination • Auscultation before palpation • Palpation • Masses • Tenderness • Auscultation for bowel sounds
Approach • Objectives • Assess the degree of dehydration • Prevent spread of the enteropathogen • Selectively determine etiology and provide specific therapy
Dehydration • Mild (3-5%) • Normal or increased pulse • Decreased urine output • Thirsty • Normal physical exam
Dehydration • Moderate (7-10%) • Tachycardia • Little/no urine output • Irritable/lethargic • Sunken eyes/fontanelle • Decreased tears • Dry mucous membranes • Skin- tenting, delayed cap refill, cool, pale
Dehydration • Severe (10-15%) • Rapid, weak pulse • Decreased blood pressure • No urine output • Very sunken eyes/fontanelle • No tears • Parched mucous membranes • Skin- tenting, delayed cap refill, cold, mottled
Dehydration • Treatment • Calculate deficits • Water: % dehydration x weight • Sodium: water deficit x 80 mEq/L • Potassium: water deficit x 30 mEq/L • Treat mild-moderate dehydration with oral rehydration solutions • May treat severe dehydration with intravenous fluids • Hyponatremic v. isotonic v. hypernatremic
Etiology • Enteropathogens • Non-inflammatory vs. inflammatory diarrhea • Non-inflammatory • Enterotoxin production • Destruction of villi • Adherence to GI tract • Inflammatory • Intestinal invasion • Cytotoxins
Etiology • Chronic diarrhea • Giardia lamblia • Cryptosporidium parvum • Escherichia coli: enteroaggregative, enteropathogenic • Immunocompromised host • Non-infectious causes: anatomic, malabsorption, endocrinopathies, neoplasia
Etiology • Bacterial • Inflammatory diarrhea • Aeromonas • Campylobacter jejuni • Clostridium dificile • E. coli: enteroinvasive, O157:H7 • Plesiomonas shigelloides • Salmonella • Shigella • Vibrio parahaemolyticus • Yersinia enterocolitica
Etiology • Bacterial • Non-inflammatory • E. coli: enteropathogenic, enterotoxigenic • Vibrio cholerae • Viral • Rotavirus • Enteric adenovirus • Astroviruus • Calcivirus • Norwalk • CMV • HSV
Etiology • Parasites • Giardia lamblida • Entamoeba histolytica • Strongyloides stercoralis • Balantidium coli • Cryptosporidium parvum • Cyclospora cayetanensis • Isospora belli
Diagnosis • History • Stool examination • Mucus • Blood • Leukocytes • Stool culture
Diagnosis • Examination for ova and parasites • Recent travel to an endemic area • Stool cultures negative for other enteropathogens • Diarrhea persists for more than 1 week • Part of an outbreak • Immunocompromised • May require examination of more than one specimen
Antimicrobial therapy • Aeromonas • TMP/SMZ • Dysentery-like illness, prolonged diarrhea • Campylobacter • Erythromycin, azithromycin • Clostridium dificile • Metronidazole, vancomycin • E. coli • TMP/SMZ
Antimicrobial therapy • Salmonella • Cefotaxime, ceftriaxone, ampicillin, TMP/SMZ • Infants < 3 months • Typhoid fever • Bacteremia • Dissemination with localized suppuration • Shigella • Ampicillin, ciprofloxacin, ofloxacin, ceftriaxone • Vibrio cholerae • Doxycycline, tetracycline
Therapy • Antidiarrheal medication • Alter intestinal motility • Alter adsorption • Alter intestinal flora • Alter fluid/electrolyte secretion • Antidiarrheal medication generally not recommended • Minimal benefit • Potential for side effects
Prevention • Contact precautions • Education • Mode of acquisition • Methods to decrease transmission • Exclusion from day care until diarrhea subsides • Surveillance • Salmonella typhi vaccine