Acute (Infectious) Gastroenteritis

Non-pregnant patient with no h/o GI disease, endocrine disease, or radiation therapy presents with acute onset diarrhea. Describes increased stool frequency, volume, and water content x 2 days. Additional symptoms include thirst, lightheadedness, vomiting, and decreased urine output. Reports recent consumption of unpurified water/undercooked meat and antibiotic treatment while hospitalized in a developing nation. Sick contacts include child who attends daycare. Acute weight loss, dry mucous membranes, hyperactive bowel sounds, and mild/diffuse abdominal tenderness on exam.

  • Diarrhea lasting > 7 days with h/o immunosuppression, bloody stools, or fever: Obtain fecal lactoferrin (if positive, obtain stool cultures +/- analysis for stool ova/parasites)

  • Hospitalization with previous 3 days or antibiotic treatment within past 3 months: Test for C. difficile toxins A and B

  • Treatment

    • Oral rehydration therapy with 1/2 teaspoon salt and 6 teaspoons sugar mixed in 1 liter of water

    • BRAT (bananas, rice, applesauce, toast) diet until symptoms improve

    • Sensation of bloating/gas pain: Start simethicone 80 mg TID PRN

    • Non-bloody diarrhea: Start loperamide 2 mg q4h PRN, maximum 16 mg/day

    • Fever and/or bloody diarrhea: Trial of Pepto-Bismol

    • Patient advised that lactobacillus 1 to 4 packets qd may shorten illness duration

    • Antibiotics

      • C. difficile: Vancomycin 125 mg PO q6h x 10 days

      • Elderly, immunocompromised, or severely ill: Empiric ciprofloxacin 500 mg BID x 3 days

      • Recent travel: Azithromycin 500 mg qd x 5 days (Asia) vs. ciprofloxacin 500 mg BID (other continents)

      • Giardia: Metronidazole 500 mg TID x7 days

  • Pt counseled about importance of hand washing to prevent infection of others

  • Schedule follow-up appointment is symptoms last > 14 days

Notes

  • Etiology

    • Viral gastroenteritis is the most common etiology

    • C. difficile should be suspected s/p recent hospitalization

    • Advanced organizer for bacterial causes of bloody (inflammatory) diarrhea: You’re Constantly SShitting EErythrocytes

      • Yersinia

      • Campylobacter

      • Salmonella (non-Typhi), Shigella

      • Enteroinvasive E. coli, Entamoeba histolytica

    • Consider giardia in pt with recent consumption of unpurified water, e.g. while camping

    • Additional risk factors

      • Recent treatment with antibiotics

      • Exposure to high-risk individuals, e.g. children in daycare

      • Travel in underdeveloped nations

  • Special populations

    • In children, presence of two or more of the following indicates > 5% fluid deficit and need for oral rehydration therapy: Capillary refill > 2 seconds, absence of tears, dry mucous membranes, generally ill appearance

    • Pregnant patients are at increased risk for listeriosis

    • Immunocompromised patients are at greater risk overall

    • GI/endocrine disease and treatment with radiation therapy may cause gastroenteritis, but are beyond the scope of this vignette

  • Lactoferrin: Marker for fecal leukocytes (sensitivity 90%, specificity 70%)