What is the best course of treatment for an 11-month-old with acute watery diarrhea?

Management of Watery Diarrhea in an 11-Month-Old

Oral rehydration therapy (ORT) using reduced osmolarity oral rehydration solution (ORS) is the cornerstone of treatment for this child, with the specific approach determined by the degree of dehydration assessed clinically. 1

Initial Assessment

Immediately assess the degree of dehydration by examining:

• Skin turgor and tenting (prolonged tenting >2 seconds indicates severe dehydration) 2
• Mucous membranes (dry indicates at least moderate dehydration) 2
• Mental status (lethargy or altered consciousness suggests severe dehydration) 2
• Capillary refill time (prolonged refill correlates with fluid deficit) 2
• Perfusion status (cool, poorly perfused extremities indicate severe dehydration) 2
• Respiratory pattern (rapid, deep breathing suggests acidosis from severe dehydration) 2

Obtain an accurate body weight and auscultate for adequate bowel sounds before initiating oral therapy. 2

Categorize dehydration severity:

• Mild (3-5% fluid deficit): increased thirst, slightly dry mucous membranes 2
• Moderate (6-9% fluid deficit): loss of skin turgor, skin tenting, dry mucous membranes 2
• Severe (≥10% fluid deficit): severe lethargy, prolonged skin tenting, cool extremities, decreased capillary refill, signs of shock 2

Rehydration Phase

For Mild Dehydration (3-5% deficit)

• Administer 50 mL/kg of ORS over 2-4 hours 1
• Use small volumes initially (5-10 mL) every 1-2 minutes with a teaspoon, syringe, or medicine dropper, gradually increasing as tolerated 1
• Critical pitfall to avoid: Do not allow the child to drink large volumes ad libitum from a cup or bottle, as this worsens vomiting 2, 1

For Moderate Dehydration (6-9% deficit)

• Administer 100 mL/kg of ORS over 2-4 hours using the same small-volume technique 1
• If vomiting is present, give 5-10 mL every 1-2 minutes via spoon or syringe 1
• Reassess hydration status after 2-4 hours 2

For Severe Dehydration (≥10% deficit, shock)

• This is a medical emergency requiring immediate IV rehydration 2
• Give 20 mL/kg boluses of Ringer's lactate or normal saline until pulse, perfusion, and mental status normalize 3
• Then transition to ORS to complete the remaining fluid deficit 3

Maintenance Phase (After Rehydration)

Once rehydration is achieved:

• Replace ongoing losses: Give 10 mL/kg of ORS for each watery stool and 2 mL/kg for each vomiting episode 1
• Continue maintenance fluids until diarrhea and vomiting resolve 1

Nutritional Management

Continue feeding during and immediately after rehydration—do not withhold food. 1

• If breastfed: Continue breastfeeding on demand throughout the entire episode without interruption 1
• If formula-fed: Resume full-strength formula immediately upon rehydration 1
• Resume age-appropriate diet during or immediately after rehydration is completed 1
• Recommended foods include starches, cereals, yogurt, fruits, and vegetables 1
• Avoid foods high in simple sugars and fats 1

The traditional practice of "gut rest" is harmful—fasting reduces enterocyte renewal and increases intestinal permeability. 2

Adjunctive Therapies

Zinc Supplementation

• Administer zinc supplementation to reduce diarrhea duration in this 11-month-old child, particularly if there are any signs of malnutrition or if living in an area with high zinc deficiency prevalence 1

Medications to Consider

• Ondansetron: May be given if vomiting is present and the child is >4 years old, but this 11-month-old is too young 1
• Antimotility drugs (loperamide): Absolutely contraindicated in all children <18 years of age due to risks of respiratory depression and serious cardiac adverse reactions 1

Probiotics

• May be offered to reduce symptom severity and duration in immunocompetent children 1

When to Use Antibiotics

Antibiotics are not routinely indicated for acute watery diarrhea. 1

Consider antibiotics only if:

• Bloody diarrhea (dysentery) is present 1
• High fever occurs 1
• Watery diarrhea persists >5 days 1
• Stool cultures indicate a treatable pathogen 1

Stool cultures are indicated for dysentery but not needed for typical acute watery diarrhea in immunocompetent patients. 2

Warning Signs Requiring Immediate Medical Attention

• Severe dehydration with shock or near-shock 1
• Intractable vomiting preventing successful oral rehydration 1
• High stool output (>10 mL/kg/hour) 1
• Decreased urine output 1
• Lethargy or irritability 1
• Signs of glucose malabsorption (dramatic increase in stool output with ORS administration) 1

Key Clinical Pearls

• More than 90% of children with vomiting can be successfully rehydrated orally when small volumes (5-10 mL) are given every 1-2 minutes 2
• For persistent vomiting, continuous slow nasogastric infusion of ORS via feeding tube can be helpful 2
• The presence of reducing substances in stool alone does not indicate ORT failure—this is common and does not require switching to IV therapy 2
• ORT is safer and more physiologic than IV fluids, avoiding risks of phlebitis and IV infiltrates 2