Bacterial diarrhea in an 18-month-old (9 kg) with green stool and vomiting

1. Assess first

• Dehydration: check for sunken eyes, drinking eagerly, slow skin pinch, lethargy, and no urine for 6 hours or more.
• Stool: blood in the stool means dysentery, which needs an antibiotic.
• Danger signs: persistent vomiting (can't keep anything down), convulsions, lethargy, high fever, abdominal distension, or severe dehydration. These need hospital care.

2. Rehydration (the main treatment)

• No or mild dehydration (Plan A): give 50-100 mL ORS after each loose stool, plus normal fluids and feeds.
• Some dehydration (Plan B): give about 75 mL/kg over 4 hours, which is about 675 mL ORS for 9 kg. The WHO ORS table gives 400-700 mL for a child of 6 to under 10 kg. Reassess after 4 hours.
• Severe dehydration or unable to drink: use IV Ringer lactate. For a child over 12 months this is 100 mL/kg, which is 900 mL for 9 kg. Give 30 mL/kg (about 270 mL) in the first 30 minutes, then 70 mL/kg (about 630 mL) over the next 2.5 hours. Shift to ORS as soon as the child can drink.

• Give ORS in small, frequent sips, about 1 teaspoon (5 mL) every 1-2 minutes by spoon or syringe.
• If the child vomits, wait 10 minutes and restart more slowly. Most vomiting settles once rehydration starts.
• If vomiting is persistent, a single dose of ondansetron (about 0.15 mg/kg, roughly 1.3-2 mg for this weight) helps ORS tolerance. Check the dose with the treating doctor.

3. Zinc

• The traditional dose, still used in India, is 20 mg/day for a child over 6 months.
• WHO's newer guideline conditionally suggests 5 mg/day, because it reduces vomiting without being less effective. Zinc gluconate also causes less vomiting than other forms. See the WHO guideline.

4. Feeding

5. Antibiotics (selective, not routine)

• Fluoroquinolone resistance is common, so prefer local sensitivity data or stool culture where available.
• Azithromycin is preferred for Shigella and Campylobacter, and a trial in children found it superior to ciprofloxacin for cholera. The first two points are from Swanson's Family Medicine Review (Shigella and C. jejuni) and the last from Yamada's Textbook of Gastroenterology.
• Park's Textbook of Preventive and Social Medicine, in its IMNCI diarrhoea chart, uses ciprofloxacin for 3 days for blood in stool.
• Avoid antibiotics if enterohemorrhagic E. coli (bloody stool without fever) is suspected.

6. What to avoid

• Antimotility drugs such as loperamide.
• Routine antiemetics other than a single ondansetron dose.
• Routine probiotics. WHO suggests against them for acute watery diarrhea.

7. Go to hospital or review urgently if

• The child can't drink or keeps vomiting everything.
• There is blood in the stool, high fever, or no improvement in 2-3 days.
• The child is very drowsy, has sunken eyes, or passes no urine for 6 hours or more.
• There are convulsions or the abdomen is distended.

Evidence note