1. Background

• see the file on "HENOCH-SCHOENLEIN PURPURA COLITIS (HSP)"

2. Etiology

• an unknown antigenic stimulant (infectious agent, drugs, cold) causes an elevation of IgA which activates pathways leading to an IgA-mediated necrotizing vasculitis in the small vessels of involved organs. In the GI tract, this leads to a mesenteric vasculitis.
• subsequent submucosal and intramural extravasation of fluid and blood into the intestinal wall results in abdominal pain and eventually to localized mucosal ulcerations and bloody stool. The intussusception associated with HSP is secondary to submucosal hematomas.

1. Classic HSP

• rash (nonthrombocytopenic purpura)
• abdominal pain
• arthritis
• nephritis

2. Gastrointestinal Manifestations

• occur in 35-85% of patients with HSP
• usually follow rash & joint pain (may precede rash in 14% of cases)
• abdominal pain - severe colicky pain with vomiting
• bloody diarrhea - gross or occult with hematemesis
• hepatomegaly
• complications:
  • intussusception - in 2-3% of cases, ileoileal in 65%
  • bowel infarction or perforation - uncommon
  • pancreatitis - with acute onset of vomiting & increased amylase
  • hydrops of the gallbladder - with RUQ pain and mass
  • protein-loosing enteropathy
  • ileus
  • ileal stricture

1. Imaging Studies

• 5 features on abdominal U/S and barium enema:
  1. "stack of coins or picket fence"

  • uniform regular thickening of small bowel (>jejunum) wall folds causing parallel, symmetric features
  2. loss of definition of small bowel wall folds

  • due to small bowel wall edema and inc. secretions
  3. thumbprinting and scalloping of small bowel wall

  • due to local hemorrhage within bowel wall
  4. filling defects

  • due to mucosal edema and vascular occlusion of submucosa
  5. intramural or extramural masses

  • due to bleeding into mesentry
• 2 features of intussusception:
  1. coil-spring appearance of small bowel on barium enema
  2. round mass with echocentric structures ("sliced-onion") on abdominal ultrasound

2. Stool

• culture, look for blood (gross or occult)

3. Biopsy

• perivascular cuffing of the small vessels with PMN's and fibrinoid necrosis of these vessels

1. Supportive

• for HSP

2. Medications