Nocturnal Lower Abdominal Pain with Nausea and Vomiting in a 9-Year-Old
Acute appendicitis must be ruled out first in this 9-year-old with nocturnal lower abdominal pain and nausea/vomiting, as it represents the most common abdominal surgical emergency in children and can lead to life-threatening complications if diagnosis is delayed. 1
Initial Clinical Assessment
Immediately assess for red flag signs that indicate surgical emergency or severe illness:
- Bilious or bloody vomiting 2
- Altered mental status or toxic appearance 2
- Severe dehydration (sunken eyes, decreased skin turgor, dry mucous membranes, decreased urine output, tachycardia) 2
- Right lower quadrant pain with guarding or migration of periumbilical pain to RLQ 1
- Fever with localized abdominal tenderness 1
Appendicitis Evaluation
The nocturnal timing and lower abdominal location raise concern for appendicitis, which peaks in incidence during school age and adolescence. 1
Key Clinical Features to Assess:
- Classic presentation includes periumbilical pain, anorexia, nausea, vomiting, and migration to the right lower quadrant, though this is only moderately reproducible 1
- Physical examination should focus on RLQ tenderness, guarding, and rebound 1
- Fever may or may not be present 1
Imaging Approach:
- Clinical scoring systems (Alvarado Score or Pediatric Appendicitis Score) should guide imaging decisions 1
- Ultrasound is typically the initial imaging modality of choice in pediatric patients to avoid radiation 1
- If ultrasound is non-diagnostic and clinical suspicion remains moderate to high, MRI or CT may be indicated 1
- Imaging has been shown to decrease negative appendectomy rates and facilitate appropriate management 1
Hydration Management
If gastroenteritis is suspected after ruling out surgical causes, oral rehydration therapy is the cornerstone of management and takes precedence over antiemetic therapy. 2
Rehydration Protocol:
- Begin with small, frequent volumes of oral rehydration solution (5 mL every minute using a spoon or syringe), gradually increasing as tolerated 1, 2
- Replace ongoing losses with 10 mL/kg of ORS for each episode of vomiting or diarrhea 1, 2
- Intravenous rehydration is required only if severe dehydration is present or oral fluids cannot be tolerated 2
Antiemetic Therapy
Ondansetron is indicated for children >4 years with persistent vomiting that prevents oral rehydration, but only after surgical causes are excluded. 2, 3
Ondansetron Dosing:
- Oral: 4 mg for ages 4-11 years 3
- Purpose is to facilitate oral rehydration tolerance and reduce immediate hospitalization need 2
- May increase stool volume as a side effect, but this does not outweigh vomiting control benefit 2
Common pitfall: Do not use ondansetron until bilious vomiting and surgical abdomen are ruled out, as it may mask worsening symptoms. 2
Nutritional Management (If Gastroenteritis Confirmed)
Resume normal age-appropriate diet immediately upon adequate rehydration—do not delay feeding. 2
- Offer starches, cereals, yogurt, fruits, and vegetables 1, 2
- Avoid foods high in simple sugars (soft drinks, undiluted apple juice) and high-fat foods 1, 2
- Continue regular diet; prolonged restrictive diets can result in inadequate nutrition 1
Red Flags Requiring Immediate Return
Instruct caregivers to return immediately if:
- Child becomes increasingly lethargic or difficult to arouse 2
- Decreased urine output develops 2
- Intractable or bilious vomiting occurs 2
- Blood appears in vomit or stool 2
- Severe or worsening abdominal pain develops 2
Antibiotic Considerations
Antibiotics are not indicated for routine gastroenteritis but should be considered if:
- Dysentery or high fever is present 1
- Watery diarrhea persists >5 days 1
- Stool cultures indicate a treatable pathogen 1
Critical caveat: The nocturnal pattern of pain is atypical for simple gastroenteritis and warrants careful evaluation for appendicitis or other surgical causes before attributing symptoms to viral illness. 1