1. Infectious Diarrhea

2. Definition Of Diarrhea • Increase in stool frequency or a decreased stool consistency • Usual stool fluid content: 10 ml/kg/d in an infant and > 200 g/d in the teenager and adult • Acute diarrhea- lasting less than 2 weeks

3. Acute Infectious Diarrhea • Inflammatory -intestinal invasion - Cytotoxins (enhanced electrolyte secretion by the crypts) • Noninflammatory • enterotoxin production • -villous surface destruction

5. Approach to a Patient with Diarrhea • Assess hydration status (PO intake, stool output, level of activity, UO.) • Prevent spread. • Determine etiologic agent and provide specific therapy if indicated.

6. History • Daycare attendance • Recent travel • Use of antibiotics • Sick contacts • Diet • Duration and severity of diarrhea • Stool consistency • Presence of mucus and blood • Other symptoms: fever, diarrhea

7. Food history • Dairy- Campylobacter and Salmonella • Eggs- Salmonella • Meats- C. perfringens, Aeromonas, Campylobacter, Salmonella • Ground beef- EHEC • Poultry- Campylobacter • Pork- Clostridium, Yersinia • Seafood- Aeromonas, Plesiomonas, Vibrio • Giardia, Cryptosporidium, Entamoeba- resistant to water chlorination (look for possible exposure to contaminated water)

8. Infectious causes of acute diarrhea in children • Viral Rotavirus Calicivirus Astrovirus Parvovirus Pestivirus Adenovirus • Bacterial Campylobacter Salmonella E. coli Shigella Vibrio cholera Aeromonashydrophiliia Yersiniaenterocolitica Clostridium difficile

9. Parasitic Giardia Entamoeba histolytica Cryptosporidium Isospora belli Strongyloides Trichuris trichuria Balantidium coli

10. Labs • Fecal leukocytes (shows invasion, cytotoxin production) • Stool O and P • Stool culture

11. Always culture stool for Salmonella, Shigella, Yersinia and Campylobacter in the presence of clinical signs of colitis or if fecal leucocytes are found.

12. Acute Diarrhea Y Special Considerations Defined Approach N Y fever, watery stool, gross blood N N Abrupt onset, frequent stools, no initial vomiting Y Methylene blue, stool exam PMN None Giardia Culture Shigella Salmonella Campylobacter Rehydration & Indicated Therapy

13. White blood cells in a stool sample (Methylene Blue Stain).

14. Antibiotic Treatment

15. References Behrman R., R. Kliegman and H.Jenson. Nelson’s Textbook of Pediatrics, 16th ed. 2000, W.B. Saunders, pp 765-768. DeWitt, T. Acute Diarrhea in Children. Pediatrics in Review. 1989; 11; 6-12 Huicho, Luis MD. Diagnostic Approach to Acute Infectious Diarrhea: The State of the Art. Bull. Inst. Fr. Etudes Andines. 1995, 24 (2): 317-339. www.uptodate.com www.emedicine.com

16. A 2-yo girl has diarrhea and a temp of 38◦C. Which of the ff would suggest that she has viral, rather than a bacterial, enteritis? • Stool leukocytes • Mucus in stools • Blood in stools • Vomiting before onset of diarrhea • Frequent, mildly watery, small- volume stools