What is the diagnosis for a 4-12 year old female with severe abdominal pain, nausea, vomiting, and an episode of diarrhea with mucus?

Diagnosis: Intussusception

The most likely diagnosis for this 4-12 year old female with severe abdominal pain, nausea, vomiting, and diarrhea with mucus is intussusception, which classically presents with crampy intermittent abdominal pain that can progress to bloody/mucoid stools. 1

Clinical Presentation Supporting Intussusception

The constellation of symptoms in this patient aligns with the characteristic presentation of intussusception:

• Severe abdominal pain - The crampy, intermittent nature is typical of intussusception, which occurs when one segment of bowel telescopes into another 1
• Nausea and vomiting - Present in approximately 36% of intussusception cases, though more common in pediatric emergency presentations 2
• Diarrhea with mucus - This represents the early stage before progression to the classic "currant jelly" bloody stools that occur as bowel ischemia develops 1

Age-Specific Considerations

While intussusception is unusual in the first 3 months of life, it becomes more common in the 4-12 year age range of this patient 1. In school-aged children, intussusception must be distinguished from more common causes like gastroenteritis and constipation 3. However, the severity of pain and presence of mucus in stool point away from simple viral gastroenteritis, which typically presents with milder symptoms, fever, and watery diarrhea without mucus 1, 4.

Key Diagnostic Features

The presence of severe abdominal pain with mucoid stools in a child of this age should raise immediate suspicion for intussusception, even before the classic triad (abdominal pain, hematochezia, and palpable abdominal mass) fully develops. 5

Important distinguishing features from other diagnoses:

• Not simple gastroenteritis - The severity of pain and mucoid character of diarrhea are atypical for viral gastroenteritis, which presents with milder symptoms and watery diarrhea 1, 6
• Progression pattern - Intussusception characteristically shows intermittent crampy pain that may progress to lethargy and bloody stools as ischemia develops 1, 5
• Mucus in stool - This finding is more consistent with an obstructive/ischemic process like intussusception rather than infectious diarrhea 1

Immediate Diagnostic Approach

Ultrasonography should be performed urgently as it is safe, sensitive, and specific for diagnosing intussusception, showing the characteristic "target sign" or "pseudokidney sign." 5, 3

The diagnostic workup should proceed as follows:

• Physical examination - Look for a palpable abdominal mass (though present in only a minority of cases), abdominal distension, and signs of peritoneal irritation 5, 3
• Abdominal radiography - May show bowel obstruction patterns but lacks sensitivity to exclude intussusception 5
• Ultrasound - The preferred initial imaging modality with high sensitivity and specificity 5, 3
• Contrast enema - Gold standard for both diagnosis and first-line treatment via pneumatic or hydrostatic reduction 5

Critical Management Steps

Before proceeding with contrast enema for diagnosis and potential reduction:

• Establish intravenous access and begin fluid resuscitation - Essential before any intervention 5
• Notify pediatric surgery - Surgical backup must be available in case reduction fails or perforation occurs 5
• Assess for peritoneal signs - Fever, rigidity, rebound tenderness, or absent bowel sounds suggest perforation or advanced ischemia requiring immediate surgery rather than attempted reduction 3

Common Pitfalls to Avoid

• Dismissing as gastroenteritis - The severity of pain and mucoid stools should prompt consideration of intussusception even without frank blood 1, 5
• Waiting for the complete classic triad - Only a minority of patients present with all three findings (pain, bloody stool, palpable mass); early diagnosis requires high clinical suspicion 5
• Relying solely on plain radiography - Abdominal X-rays lack sufficient sensitivity to exclude intussusception 5
• Delaying surgical consultation - Pediatric surgery should be notified early, as approximately 20% of cases will require operative intervention 2