AdultPediatric
Most pediatric diarrhea is viral and self-limited. Priority is assessing dehydration and starting ORT. Investigate (and culture) only if bloody, prolonged > 14 d, immunocompromised, or recent antibiotics/travel/daycare outbreak.
🚩 Red-flag clues (must not miss)
- •Bloody diarrhea + microangiopathic anemia + thrombocytopenia + AKI = HUS (post-STEC O157)
- •Bilious or projectile vomiting > diarrhea in infant = obstruction, not gastroenteritis
- •Severe dehydration (≥10%) — sunken fontanelle, no tears, mottled, lethargic
- •Recent antibiotics + bloody diarrhea = C. difficile
History
- Frequency, volume, blood/mucus, duration
- Sick contacts, daycare outbreaks, travel, food
- Antibiotic use (last 8 weeks → C. diff)
- Wet diapers, weight loss, urine output
Exam
- Hydration: weight (vs baseline), HR, cap refill, mucous membranes, fontanelle, tears
- Abdomen: tenderness, distention, mass (intussusception)
Labs
- Mild–moderate viral: none needed
- Bloody / severe / prolonged: stool culture, FOBT, CBC + smear, BMP, Mg/Phos
- If HUS suspected: smear for schistocytes, LDH, haptoglobin, BMP, UA
- C. diff PCR if antibiotic exposure
Differential & next step
| Diagnosis | Clue | Next step |
|---|---|---|
| Viral gastroenteritis (norovirus, rotavirus) | Watery, low-grade fever, vomiting | ORT, anti-emetic if needed |
| Bacterial (Salmonella, Shigella, Campy, EHEC) | Bloody, high fever, tenesmus | Stool cx; AVOID antibiotics if STEC/EHEC suspected (↑ HUS risk) |
| C. difficile | Recent antibiotics | PO vancomycin or fidaxomicin; STOP offending abx |
| HUS | Bloody diarrhea + AKI + thrombocytopenia + hemolysis | PICU, supportive care, NO antibiotics, dialysis if needed |
| Intussusception | Episodic pain, currant-jelly stool | US → air enema reduction |
| Appendicitis (atypical) | Pain → diarrhea, RLQ tenderness | Imaging, surgery consult |
| Cow milk protein allergy (infant) | Blood-streaked stool, well infant | Trial extensively hydrolyzed formula |
| IBD (older child) | Chronic, weight loss, growth failure | GI referral, scopes |
Medications & dosing
| Drug | Dose | Notes |
|---|---|---|
| Ondansetron (PO) | 8–15 kg: 2 mg; 15–30 kg: 4 mg; > 30 kg: 8 mg PO ×1 | Single dose facilitates ORT; CI: long QT |
| ORS (oral rehydration solution) | Mild dehydration: 50 mL/kg over 4 h; Moderate: 100 mL/kg over 4 h | Plus 10 mL/kg per loose stool |
| Zinc | 10 mg/day < 6 mo; 20 mg/day ≥ 6 mo × 10–14 d | WHO recommendation in resource-limited settings |
| PO vancomycin (C. diff) | 10 mg/kg PO QID (max 125 mg/dose) |
Management / next steps
- Assess % dehydration (Gorelick / WHO scale)
- Mild (3–5%): ORT at home; Moderate (6–9%): supervised ORT in ED, anti-emetic
- Severe (≥ 10%): IV NS bolus 20 mL/kg, repeat to 60 mL/kg; admit
- Continue feeds (no BRAT-only restriction); breastfeeding throughout
Source: https://fprmed.com/fprmedcom/Pages/Pedi/Diarrhea.html
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