What is the appropriate management for a 15-month-old patient presenting with vomiting and diarrhea, considering the risk of dehydration?

Management of Vomiting and Diarrhea in a 15-Month-Old

Begin oral rehydration solution (ORS) immediately at 5-10 mL every 1-2 minutes using a teaspoon or syringe, targeting 100 mL/kg over 2-4 hours for moderate dehydration, and escalate to IV fluids only if the child shows signs of shock, severe dehydration, or fails oral rehydration despite proper technique. 1, 2

Immediate Assessment Priorities

Assess dehydration severity first by examining:

• Skin turgor and mucous membrane moisture 2
• Mental status and activity level 2
• Urine output (when last urinated) 3
• Capillary refill and perfusion 1

Identify red flag signs requiring immediate escalation:

• Bloody or bilious vomiting 4
• Altered mental status or lethargy 1, 4
• Signs of shock (poor perfusion, weak pulse) 1
• Severe dehydration (≥10% deficit) 5
• Toxic or septic appearance 4

Rehydration Protocol

For mild to moderate dehydration (most common scenario):

• Administer reduced osmolarity ORS at 100 mL/kg over 2-4 hours 1, 2, 3
• Give 5-10 mL every 1-2 minutes using a teaspoon, syringe, or medicine dropper—never allow the child to drink rapidly from a cup or bottle as this perpetuates vomiting 1, 2
• Replace ongoing losses: add 10 mL/kg ORS for each watery stool and 2 mL/kg for each vomiting episode 2, 5

Critical technique for vomiting patients: The 2017 IDSA guidelines emphasize that small, frequent volumes (5-10 mL every 1-2 minutes) succeed in >90% of children with vomiting, whereas allowing ad libitum drinking is a common pitfall that leads to treatment failure 1, 2

Adjunctive Pharmacotherapy

Ondansetron may be considered if vomiting prevents adequate oral intake:

• Dose: 0.2 mg/kg oral (maximum 4 mg) 4
• Evidence shows ondansetron reduces ORT failure from 62% to 31% and improves ORS tolerance 6
• The 2017 IDSA guidelines note this is appropriate for children >4 years, though research supports use in younger children with persistent vomiting 1, 6

Antimotility agents are absolutely contraindicated:

• Loperamide must not be given to any child <18 years with acute diarrhea 1, 5

When to Escalate to IV Fluids

Switch to isotonic IV fluids (lactated Ringer's or normal saline) if:

• Severe dehydration (≥10% deficit) or shock is present 1, 5
• Altered mental status develops 1
• ORS therapy fails despite proper small-volume technique 1, 2
• Stool output exceeds 10 mL/kg/hour 5
• Ileus is present (absent bowel sounds) 1

Alternative route before IV: Consider nasogastric tube administration at 15 mL/kg/hour if the child cannot tolerate oral volumes but is not in shock 1, 2

Feeding During Illness

Continue breastfeeding throughout the illness without interruption 1

Resume age-appropriate diet immediately after rehydration (within 4 hours):

• Full-strength formula or regular foods should not be delayed 1, 2
• Early feeding improves nutritional outcomes and intestinal recovery 2, 3
• Recommended foods include starches, cereals, yogurt, fruits, and vegetables 1

Antibiotic Considerations

Empiric antibiotics are NOT recommended for this presentation:

• The 2017 IDSA guidelines explicitly state that empiric antimicrobial therapy should not be given to immunocompetent children with acute watery diarrhea and vomiting 1, 5
• Exceptions requiring antibiotics: bloody diarrhea (dysentery), high fever with septic appearance, immunocompromised status, or watery diarrhea persisting >5 days 1, 5

Monitoring and Reassessment

Reassess hydration status after 2-4 hours:

• Check skin turgor, mucous membranes, mental status, and urine output 2
• Successful rehydration criteria: normal pulse and perfusion, improved alertness, moist mucous membranes, adequate urine output 3

Discharge criteria:

• Rehydration complete 3
• Tolerating adequate oral intake without immediate vomiting 3
• Reliable caregiver with clear return precautions 3

Admission indicated for:

• Failure of ORS therapy despite proper technique 3
• Inability to maintain hydration with ongoing losses 3
• Severe acidosis or electrolyte abnormalities 3

Common Pitfalls to Avoid

The CDC and IDSA guidelines highlight these critical errors:

• Allowing rapid drinking from a cup/bottle instead of small, frequent volumes 1, 2
• Using antimotility agents in children 1, 5
• Prescribing empiric antibiotics for uncomplicated viral gastroenteritis 5
• Delaying feeding until diarrhea resolves 2, 3
• Switching to IV fluids prematurely without attempting proper ORS technique 2

Differential Diagnosis Considerations

While viral gastroenteritis is most likely in this age group, the initial assessment should identify life-threatening causes requiring different management 4:

• Surgical emergencies: Intussusception, malrotation with volvulus (bilious vomiting is the key red flag) 4
• Metabolic: Inborn errors of metabolism, diabetic ketoacidosis (altered mental status, severe dehydration) 4
• Infectious: Sepsis, meningitis (toxic appearance, fever, altered mental status) 4
• Toxic ingestion: (history of access to medications/toxins) 4

The presence of red flag signs (bilious/bloody vomiting, altered sensorium, toxic appearance, severe dehydration) mandates immediate laboratory evaluation and imaging to rule out these conditions 4