Treatment of Acute Diarrhea in an 18-Month-Old Child
The best treatment for an 18-month-old with 3 days of diarrhea is oral rehydration solution (ORS) to correct any dehydration, followed by immediate resumption of age-appropriate foods including starches, cereals, yogurt, fruits, and vegetables—antibiotics and antimotility drugs are not indicated. 1
Immediate Assessment of Hydration Status
Evaluate the child's degree of dehydration by examining:
- Skin turgor 1
- Mucous membrane moisture 1
- Mental status (lethargy or irritability are red flags) 1
- Capillary refill time 1
- Pulse quality 1
Categorize dehydration severity:
- Mild (3-5% fluid deficit): Give 50 ml/kg of ORS over 2-4 hours 1
- Moderate (6-9% fluid deficit): Give 100 ml/kg of ORS over 2-4 hours 1
- Severe (≥10% fluid deficit): Requires immediate IV isotonic fluids (lactated Ringer's or normal saline) until pulse, perfusion, and mental status normalize, then transition to oral rehydration 1
Oral Rehydration Technique
For children who are vomiting, use small frequent volumes:
- Start with 5 mL every 1-2 minutes using a spoon or syringe 1
- Gradually increase the amount as vomiting diminishes 2
- Common pitfall: Allowing a thirsty child to drink large volumes rapidly will worsen vomiting 1
Replacement of Ongoing Losses
After initial rehydration is complete:
- Give 10 ml/kg of ORS for each watery stool 1
- Give 2 ml/kg of ORS for each vomiting episode 1
- Continue maintenance fluids until diarrhea and vomiting resolve 1
Nutritional Management
Resume age-appropriate diet immediately during or after rehydration—do not delay feeding: 1
- Continue breastfeeding on demand if breastfed 1
- Resume full-strength formula immediately upon rehydration if bottle-fed 2
- Recommended foods: starches, cereals, yogurt, fruits, and vegetables 2
- Avoid: Foods high in simple sugars (soft drinks, undiluted apple juice, Jell-O, presweetened cereals) and high-fat foods 2
The BRAT diet (bananas, rice, applesauce, toast) is reasonable but should not be prolonged, as it provides inadequate energy and protein 2
What NOT to Use
Antimotility drugs (loperamide) are absolutely contraindicated in all children under 18 years of age: 1
- The FDA labels loperamide as contraindicated in pediatric patients less than 2 years of age due to risks of respiratory depression and serious cardiac adverse reactions 3
- Reports of severe abdominal distention, ileus, drowsiness, and at least six deaths in children have been documented 2
Antibiotics are NOT indicated for typical acute watery diarrhea in this age group 2
When Antibiotics ARE Indicated
Consider antibiotics only in specific circumstances:
- Bloody diarrhea (dysentery) is present 2, 1
- High fever accompanies the diarrhea 2
- Watery diarrhea persists beyond 5 days 2
- Stool cultures identify a treatable pathogen 2
Adjunctive Therapies
Zinc supplementation may reduce diarrhea duration in children 6 months to 5 years of age who live in areas with high zinc deficiency prevalence or show signs of malnutrition 1
Probiotics may be offered to reduce symptom severity and duration in immunocompetent children 1
Warning Signs Requiring Immediate Medical Attention
Instruct parents to return immediately if the child develops:
- Lethargy or altered consciousness 1
- Irritability 1
- Decreased urine output 2
- Intractable vomiting preventing oral rehydration 1
- High stool output (>10 mL/kg/hour) 1
- Bloody stools 1
Key Clinical Pitfalls to Avoid
- Do not use sports drinks, fruit juices, or soft drinks for rehydration—they lack adequate sodium and have excessive osmolality that can worsen symptoms 1
- Do not delay rehydration while awaiting diagnostic tests 1
- Do not use nonspecific antidiarrheal agents (kaolin-pectin, loperamide)—they do not reduce stool water losses, may increase electrolyte losses, and carry serious risks 2
- Do not withhold feeding after rehydration—early refeeding prevents nutritional damage and does not prolong diarrhea 2