Henoch-Schonlein Purpura

Henoch-Schonlein purpura is a small-vessel vasculitis that usually occurs in children and affects multiple organs, including the skin rash that gives the disease its name. Up to 80% of patients develop joint involvement, and a similar percentage have gastrointestinal tract involvement. Renal involvement can be seen in 20%–100% of patients. Diagnostic criteria are clinical and pathological.

Gastrointestinal disease can precede the skin rash, with colicky pain, diarrhea, nausea, or vomiting. Any portion of the bowel distal to the esophagus can be involved, with ulceration and bowel wall thickening due to edema and intramural hemorrhage.

The role of the radiologist is in recognizing Henoch-Schonlein purpura in order to avoid unnecessary surgery, because the gastrointestinal involvement is self limited and treatment is essentially medical (corticosteroids or intravenous immunoglobulin therapy). Having said that uncommon complications of Henoch-Schonlein purpura include, obstruction, ischemia, infarction, irreducible intussusception, and perforation.

Abdominal CT may show duodenal and jejunal wall thickening (homogeneous and circumferential), luminal narrowing, fold thickening, and ulceration. Multifocal bowel involvement with skip lesions has also been reported. Intestinal dilatation, enlarged mesenteric nodes (<1.5 cm), engorged mesenteric vessels, increased attenuation of the mesenteric fat, and ascites have also been reported. It must be noted that these findings are based on series with small numbers of patients.

The case above is from a young man with known Henoch-Schonlein purpura. We see duodenal and proximal jejunal wall thickening, which is homogeneous and circumferential, associated with luminal narrowing and fold thickening. A small amount of fluid is seen in the pelvis. The appearance is nonspecific and in the absence of the clinical history could have represented ischemia, small bowel hemorrhage, infection, or Crohn disease. Another vasculitis that is known to cause a skin rash and small-bowel ischemia is systemic lupus erythematosus, and may be considered in the appropriate clinical setting.

Case courtesy of Dr. Sibin Thachet.

References

Johnson PT, Horton KM, Fishman EK. Case 127: Henoch-Schonlein purpura. Radiology. 2007 Dec;245(3):909-13.