Dünndarmbeteiligung bei Purpura Schönlein-Henoch

Imaging of

intestinal vasculitis focusing on MR and CT enterography: a two-way street between radiologic findings and clinical data. Intestinal ischemia in a 37-year-old male with a history of known Henoch–Schönlein purpura (HSP) presenting with abdominal pain and bloody diarrhea. The patient underwent pre (A)- and post (B)-IV contrast CT scans using positive dilute oral contrast. Segmental mural thickening (thick white arrows) is seen in the terminal ileum with a focal area of mural hypoenhancement (thin white arrows) proximal to the ileocecal valve. Ileocolonoscopy confirmed mucosal ischemic changes, and signs/symptoms were improved following treatment by corticosteroid

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IgA vasculitis (formerly known as Henoch-Schonlein purpura (HSP)) is a type of non-thrombocytopenic immune-mediated small vessel acute leukocytoclastic vasculitis.

In order to differentiate from other types of vasculitides, the four commonly adopted diagnostic criteria by the American College of Rheumatology are:

age of onset less than 20 years (although some case series show disease involvement in older individuals)
palpable skin purpura
gastrointestinal bleeding
intussusception, typically ileoileal
biopsy showing granulocytes around small arteriolar/venular walls

Epidemiology

It tends to occur in the pediatric population (peak incidence 3-10 years) . IgA vasculitis is the most common type of vasculitis in children .

Pathology

There is the deposition of IgA immune complexes in small vessels.

Distribution

Commonest organ systems which get involved are:

skin: 95-100%, usually the first organ to get involved
gastrointestinal tract: 50-75%
joints: ~80%
kidneys

Rare sites:

central nervous system

Radiographic features

Gastrointestinal tract

Plain radiograph

May show evidence of bowel wall thickening due to hemorrhage and/or evidence of bowel obstruction. Plain film features are however non-specific.

Fluoroscopy

Small bowel follow-through may show evidence of separation of bowel loops, "thumbprinting" and/or mucosal thickening.

CT

May show multifocal bowel thickening, lymphadenopathy, mesenteric edema and vascular engorgement. Although non-specific, CT findings may aid in the diagnosis of IgA vasculitis in a young patient with acute gastrointestinal illness along with other, e.g. cutaneous features of IgA vasculitis. Intussusception, typically ileoileal type, is also seen.

Ultrasound

Echogenic kidneys, target or doughnut sign in case of intussusception. IgA vasculitis has also been shown to cause massive scrotal edema and can be a source of severe pain in young boys .

Treatment and prognosis

The disease is self-limiting in most instances. Treatment is usually supportive including fluids and pain relief in the pediatric population. Steroids are used in adults due to the risk of serious renal involvement .