Acute Gastroenteritis- Paediatric Patients

Scope: Immunocompetent pediatric patients with diarrhea < 5 days.

Differential Diagnoses (DDx)

Common considerations

Viral AGE (most common; often with sick household members)

Allergic colitis / Cow’s milk protein allergy

< 3 months, well-appearing, may have bloody diarrhea

Food-protein–induced enterocolitis (FPIES)

Forceful emesis, pallor, floppiness, ill-looking

Serious or alternative causes

Ingested foreign body

Appendicitis

Choledocholithiasis / cholecystitis / cholelithiasis

Gastritis, hepatitis, pancreatitis

IBS

SBO, pyloric stenosis, intussusception, malrotation/volvulus, Hirschsprung

Cyclic vomiting syndrome

Incarcerated hernia

PID, testicular or ovarian torsion

Pregnancy / ectopic pregnancy

Urolithiasis, UTI / pyelonephritis

Strep throat, pneumonia

DKA, anaphylaxis, asthma

Tumor, meningitis, raised ICP, myocarditis / heart failure, HSP

Inflammatory bowel disease – cannot be diagnosed in the ED; patients usually have known cases

Red flags

Age < 12 months → higher risk of volvulus/intussusception

Persistent vomiting for more than 24–48 h without diarrhea → reconsider diagnosis (not AGE)

Key History Points

Duration of symptoms

Urine output (difficult in diapered infants with watery stools)

Presence of sick contacts

Recent antibiotic use (→ possible C. difficile)

Last known normal weight (for dehydration assessment)

Physical Examination

Vitals: Fever, BP, RR, HR, CRT (< 2 s normal)
Dehydration assessment:
- No/Mild (< 50 mL/kg loss): Normal exam
- Moderate (50–100 mL/kg loss): ≥ 2 of: restless/irritable, sunken eyes, thirsty, slow skin pinch
- Severe (> 100 mL/kg loss): ≥ 2 of: lethargic/unconscious, very sunken eyes, unable to drink, very slow skin pinch (> 2 s)
Abdominal exam: tenderness, mass, distension → alternate diagnosis
Jaundice: not seen in AGE
GU exam: check for torsion/ovarian pathology

Investigations

None for mild–moderate dehydration

Stool studies if:

Symptoms > 3–4 days
Bloody diarrhea
Child appears sick

C. diff testing:

Only if > 1 year old and recent antibiotic use
Not in < 12 months due to high asymptomatic carriage

Labs (RBS, UCE, others) only in:

Severe dehydration
Comorbidities
As clinically indicated

Treatment

PLAN A

PLAN B

PLAN C

Antiemetic

Ondansetron – 1st line: 0.15 mg/kg
Avoid metoclopramide / domperidone → may worsen diarrhea
Oral preferred in mild–moderate dehydration

Oral Rehydration (ORS)

Start 5–10 mL every 5 min × 30 min
If tolerated → increase by 5 mL increments every 30 min
Target: 50–100 mL/kg over 3–4 hours
Replacement: 10 mL/kg per diarrhea or vomiting episode
Refusal of ORS: reconsider diagnosis

If Unable to Tolerate PO

Use NG or IV route
Discuss pros/cons with parents – IV often more painful and less successful than NG

Severe Dehydration

Send labs (RBS, UCE)
Fluid resuscitation:
- Bolus: 20 mL/kg LR (faster if in shock)
- If < 12 months (not in shock):
  - 30 mL/kg in 1 h → then 70 mL/kg in 5 h
- If ≥ 1 year:
  - 30 mL/kg in 30 min → then 70 mL/kg in 2.5 h
- Repeat 30 mL/kg bolus if radial pulse weak
If hypoglycemia, use sugar-containing fluids (initial + maintenance)

Adjuncts

Probiotics: recommended

Zinc supplementation:

< 6 months: 10 mg/day × 10–14 days
≥ 6 months: 20 mg/day × 10–14 days

No loperamide, especially in < 2 years

Disposition

Discharge if

Mild-moderate dehydration, tolerating oral fluids

No significant comorbidities

Discharge instructions

Continue ORS and probiotics

No food restrictions

Continue breastfeeding

Explain: Diarrhea may increase as intake improves

Ondansetron is not required on discharge

If recent antibiotics + moderate symptoms → consider metronidazole 30 mg/kg/day in four divided doses

Return if

Unable to tolerate fluids / drowsy
Urine output < 3 times / 24 h
Drinking poorly or unable to breastfeed
Becomes sicker or develops fever
Blood in stool (more than a few drops)

References

WHO Integrated Management of Childhood Illness (IMCI)
EB Medicine: Paediatric Diarrhea

Author: Faysal Subhani

Editor: Ayesha Saeed

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