Intussusception is the Most Likely Diagnosis
In a child with Henoch-Schönlein purpura (HSP) presenting with acute colicky abdominal pain and rectal bleeding, intussusception is the most likely diagnosis and represents the most common surgical complication of HSP. 1, 2
Why Intussusception is the Answer
Intussusception occurs as the most common surgical complication in HSP, typically presenting as ileo-ileal or ileo-colic intussusception. 1 The clinical presentation described—acute colicky abdominal pain combined with bleeding per rectum—is the classic presentation pattern for HSP-associated intussusception. 3, 2
Key Clinical Features Supporting This Diagnosis:
- Colicky abdominal pain is the most common gastrointestinal manifestation in HSP, occurring in 98.1% of patients with GI involvement 2
- Rectal bleeding combined with colicky pain strongly suggests intussusception rather than simple HSP vasculitis 4
- The intermittent, crampy nature of pain is characteristic of intussusception 3
- HSP causes submucosal edema and hemorrhage from leukocytoclastic vasculitis, creating a lead point for intussusception 1
Why Other Options Are Less Likely
Perforated Duodenal Ulcer (Option A):
While HSP can cause duodenal ulceration (characteristically involving the second portion more than the bulb), perforation would present with sudden severe epigastric pain, fever, abdominal rigidity, and peritoneal signs—not colicky pain. 5, 1 The patient would appear toxic with signs of peritonitis rather than intermittent colicky discomfort.
Bleeding Meckel's Diverticulum (Option B):
Meckel's diverticulum typically causes painless rectal bleeding, not colicky abdominal pain. 1 The combination of significant pain with bleeding points away from this diagnosis.
Enterocolitis with Perforation (Option C):
Spontaneous perforation in HSP is rare and usually involves the ileum. 1, 2 When perforation occurs, it presents with acute peritonitis, fever, abdominal rigidity, and systemic toxicity—not colicky pain. 6 Only one bowel perforation was noted among 261 HSP patients in one large series. 4
Critical Diagnostic Approach
Immediate Imaging:
Ultrasonography should be performed urgently as the first-line diagnostic test when intussusception is suspected in HSP. 1, 4 Ultrasound findings include:
- Target or doughnut sign on transverse view
- Pseudokidney sign on longitudinal view
- Asymmetric bowel wall thickening mainly involving jejunum and ileum 1
Additional Imaging Considerations:
CT scan may demonstrate intussusception and bowel wall thickening if ultrasound is inconclusive. 1, 4
Important Clinical Pitfalls
Timing of GI Symptoms:
Be aware that GI symptoms can precede the characteristic purpuric rash in 25.3% of HSP cases. 2 This can lead to misdiagnosis and unnecessary surgery—four patients in one series underwent laparotomy for suspected appendicitis or peritonitis before HSP was recognized. 2
Severity Assessment:
When stool occult blood is 3+ or 4+, the incidence of positive imaging findings is high, indicating severe GI involvement requiring urgent evaluation. 4 Monitor vital signs closely, especially for signs of hypovolemic shock from massive GI bleeding. 4
Surgical Indications:
While most HSP resolves spontaneously, intussusception in HSP requires surgical intervention when it cannot be reduced by air or contrast enema, or when there are signs of bowel compromise. 2, 7 The typical ileo-ileal location in HSP makes hydrostatic reduction less successful than the more common ileo-colic intussusception in non-HSP patients. 1