What is the best course of treatment for a 2-year-old child with intermittent vomiting and diarrhea for 10 days, presenting with risk of dehydration and electrolyte imbalance?

Management of Intermittent Vomiting and Diarrhea in a 2-Year-Old for 10 Days

This 2-year-old requires immediate oral rehydration solution (ORS) administered in small, frequent volumes (5 mL every 1-2 minutes via spoon or syringe), with consideration of ondansetron if vomiting prevents adequate oral intake, and urgent evaluation for possible bacterial infection given the 10-day duration. 1, 2

Immediate Assessment and Red Flag Recognition

The 10-day duration is a critical red flag that warrants urgent attention:

• Watery diarrhea lasting >5 days requires consideration of antibiotics and stool cultures to rule out bacterial pathogens (Salmonella, Shigella, enterohemorrhagic E. coli), as viral gastroenteritis typically resolves within 3-7 days 3
• Assess dehydration severity immediately through: prolonged skin tenting (>2 seconds), dry mucous membranes, decreased capillary refill, mental status changes (lethargy or irritability), and decreased urine output 1, 2
• Severe dehydration (≥10% fluid deficit) with altered mental status, prolonged skin tenting, cool extremities, or rapid deep breathing constitutes a medical emergency requiring immediate IV rehydration 1, 2

Primary Treatment: Oral Rehydration Protocol

The cornerstone of management is proper ORS administration technique, which successfully rehydrates >90% of children with vomiting and diarrhea without antiemetic medication:

• Begin with 5-10 mL of ORS every 1-2 minutes using a teaspoon or syringe - this small-volume, frequent approach is critical to prevent triggering more vomiting 3, 2
• Never allow the child to drink large volumes rapidly from a cup or bottle, as this perpetuates the vomiting cycle 2
• Gradually increase volume as tolerated without triggering vomiting 2
• For moderate dehydration (6-9% deficit): administer 100 mL/kg ORS over 2-4 hours 1, 2
• Replace ongoing losses continuously: 10 mL/kg ORS for each watery stool and 2 mL/kg for each vomiting episode 1

Adjunctive Ondansetron Therapy

• Consider ondansetron if vomiting prevents adequate oral intake, as it improves ORS tolerance, reduces need for IV therapy, and decreases ED length of stay 2, 4, 5
• Ondansetron is appropriate for children >4 years, though evidence supports use in younger children when vomiting is significant 1
• This medication should facilitate oral rehydration, not replace it 5

Nutritional Management During Illness

Early refeeding is essential and should not be delayed:

• Resume age-appropriate diet immediately during or after rehydration (within 4 hours) - there is no justification for "resting the bowel" through fasting 1, 2, 6
• Recommended foods include starches, cereals, yogurt, fruits, and vegetables 3, 6
• Avoid foods high in simple sugars (soft drinks, undiluted apple juice) and high-fat foods, as these exacerbate diarrhea through osmotic effects 3, 1
• Continue breastfeeding on demand if applicable 1, 2

Critical Diagnostic Evaluation Given 10-Day Duration

The prolonged course necessitates specific workup:

• Obtain stool cultures immediately to identify bacterial pathogens requiring specific antibiotic therapy 3
• Consider stool microscopy for ova and parasites if history suggests exposure 3
• Blood cultures if febrile or toxic-appearing 1
• Serum electrolytes only if severe dehydration requiring IV therapy 4

Medications to Absolutely Avoid

• Never administer loperamide or other antimotility agents to any child <18 years with acute diarrhea - serious adverse events including ileus and deaths have been reported 3, 1, 2
• Do not use adsorbents, antisecretory drugs, or toxin binders - they demonstrate no effectiveness in reducing diarrhea volume or duration 1
• Avoid empiric antibiotics for uncomplicated watery diarrhea, but given the 10-day duration, targeted antibiotic therapy based on stool culture results is appropriate 3, 2

Monitoring and Reassessment

• Reassess hydration status after 2-4 hours by examining skin turgor, mucous membrane moisture, mental status, urine output, and weight changes 1, 2
• If still dehydrated after initial rehydration attempt, reestimate deficit and restart rehydration protocol 1
• Monitor for failure of oral rehydration therapy: persistent vomiting despite small-volume ORS administration, worsening mental status, or absent bowel sounds (absolute contraindication to oral therapy) 1

Indications for IV Rehydration or Hospitalization

• Severe dehydration (≥10% fluid deficit) with signs of shock 1, 2
• Failure of oral rehydration therapy after appropriate trial 1, 2
• Altered mental status or severe lethargy 1, 2
• Intractable vomiting despite ondansetron 1, 2
• Absent bowel sounds on examination 1

Alternative to IV therapy: Nasogastric tube administration at 15 mL/kg/hour can be used if the child cannot tolerate oral volumes but is not in shock 2

Infection Control and Prevention

• Instruct caregivers on proper handwashing after diaper changes, before food preparation, and before eating 3, 1
• Separate ill child from well siblings until at least 2 days after symptom resolution 1
• Clean and disinfect contaminated surfaces promptly 1

Return Precautions for Caregivers

Instruct parents to return immediately if the child develops:

• Decreased urine output or no urination for 6-8 hours 3, 6
• Severe lethargy, irritability, or altered consciousness 3, 6
• Bloody stools 1, 6
• High fever with systemic toxicity 3
• Persistent vomiting despite small-volume ORS administration 3