What is the diagnosis and treatment for a 9-year-old boy with headache, abdominal pain, bloating, vomiting, and diarrhea, with a white blood cell count (WBC) of 16g/L and no high-grade fever?

Acute Viral Gastroenteritis

This 9-year-old boy most likely has acute viral gastroenteritis, and treatment should focus on immediate oral rehydration therapy with ORS (50 mL/kg over 2-4 hours), continued age-appropriate feeding, and avoidance of antimotility agents and antibiotics. 1, 2

Clinical Diagnosis

The presentation of headache, abdominal pain, bloating, vomiting (2 episodes), and diarrhea (3 episodes) without high-grade fever is classic for viral gastroenteritis in children. 1, 3

• WBC of 16 g/L (16,000/μL) is mildly elevated but does not suggest bacterial infection requiring antibiotics, as viral gastroenteritis can cause mild leukocytosis. 4, 5
• The absence of high-grade fever and the clinical pattern strongly favor a viral etiology over bacterial causes like Salmonella, Shigella, or Campylobacter. 1, 3
• Rotavirus accounts for approximately 25% of acute diarrhea cases in children under 5 years and up to 40% of hospitalizations for diarrhea in this age group. 1

Immediate Assessment and Management

Hydration Status Evaluation

Assess dehydration immediately using clinical signs: 1, 2

• Skin turgor, mental status, mucous membrane moisture, capillary refill, and vital signs
• Categorize as mild (3-5% deficit), moderate (6-9% deficit), or severe (≥10% deficit)

Rehydration Protocol

For mild to moderate dehydration (most likely in this case): 1, 2

• Initiate oral rehydration solution (ORS) immediately without waiting for diagnostic testing
• Give 50 mL/kg ORS over 2-4 hours
• Continue ORS to replace ongoing losses until diarrhea and vomiting resolve
• Low-osmolarity ORS formulations are preferred over sports drinks or juices

For severe dehydration (if present): 2

• Use IV isotonic fluids (lactated Ringer's or normal saline)
• Continue until pulse, perfusion, and mental status normalize
• Transition to ORS once patient improves

Nutritional Management

Resume age-appropriate diet during or immediately after rehydration. 1, 2

• Early refeeding is recommended rather than fasting or restrictive diets
• Avoid foods high in simple sugars (soft drinks, undiluted apple juice) as they can exacerbate diarrhea through osmotic effects 2

Medications: What to Give and What to Avoid

DO NOT USE:

• Antimotility agents (loperamide): Contraindicated in children as they can cause serious complications including ileus and death. 1, 2
• Antibiotics: Not indicated for viral gastroenteritis; provide no benefit and may cause harm. 1, 2
• Adsorbents, antisecretory drugs, or toxin binders: Do not demonstrate effectiveness in reducing diarrhea volume or duration. 2

MAY CONSIDER:

• Ondansetron: May be given to children >4 years to facilitate oral rehydration when vomiting is significant. 2
• Probiotics: May reduce symptom severity and duration. 2

When to Hospitalize

Admit to hospital if: 1

• Severe dehydration requires IV fluids
• Inability to tolerate oral fluids despite ORS attempts
• Altered mental status or signs of shock
• Persistent high fever with signs of sepsis

Red Flags Requiring Further Investigation

Consider bacterial etiology if: 1

• Bloody or mucoid stools develop (suggesting Salmonella, Shigella, Campylobacter, or STEC)
• Symptoms persist beyond 7 days
• High fever develops (>39°C)

Consider appendicitis if: 6

• WBC count remains elevated with left shift (sensitivity 80%, specificity 79% when combined)
• Localized right lower quadrant pain develops
• Fever persists or worsens

Common Pitfalls to Avoid

• Do not delay rehydration while awaiting diagnostic testing – start ORS immediately. 1, 2
• Do not use inappropriate fluids like apple juice or sports drinks as primary rehydration solutions for moderate to severe dehydration. 2
• Do not unnecessarily restrict diet during or after rehydration. 1, 2
• Do not give antimotility drugs to children or in cases of bloody diarrhea. 1, 2

Infection Control

Implement proper hygiene measures: 2

• Hand hygiene after toilet use, before eating, and after handling soiled items
• Separate ill child from well persons until at least 2 days after symptom resolution
• Clean and disinfect contaminated surfaces promptly