S2300 Henoch-Schönlein Purpura Induced Terminal Ileitis Mimicking Crohn's Disease

Abstract

INTRODUCTION: Henoch-Schönlein purpura (HSP), also known as immunoglobulin A (IgA) vasculitis, is an acute generalized immune complex-mediated small-vessel vasculitis. It characteristically presents with palpable purpura on buttocks and lower extremities. Renal dysfunction, joint involvement and gastrointestinal (GI) symptoms are also frequently seen. Although gastrointestinal involvement is common, it primarily shows up in the form of nonspecific symptoms such as abdominal pain, nausea, vomiting, diarrhea or constipation. Terminal ileitis associated with HSP has rarely been reported in the medical literature. CASE DESCRIPTION/METHODS: A 22-year-old male presented with bilateral knee arthralgia, abdominal pain and intractable nausea and vomiting accompanied by a non-blanching erythematous coalescing maculopapular rash on the dorsal aspect of the feet and around the ankles bilaterally (Figure 1). CT (Figure 2) showed fold thickening of proximal loops of jejunum and wall thickening and luminal narrowing of the terminal ileum extending several centimeters proximally. Fluid-filled mildly dilated small bowel loops measuring up to 3 cm in diameter were visualized. Additionally, significant abdominal and pelvic ascites was noted. There was no evidence of bowel obstruction. During colonoscopy (Figure 3), granular, erythematous, ulcerated, hemorrhagic and ecchymotic mucosa was visible in the terminal ileum. There was blood in the terminal ileum and the colon. However, no discrete areas of bleeding were identified. These findings were consistent with moderate to severe active terminal ileitis. A skin biopsy was performed which confirmed the diagnosis of HSP. Methylprednisolone was commenced and the patient experienced relief in his GI symptoms. DISCUSSION: Although terminal ileitis is the pathognomonic hallmark of Crohn’s disease, it is important to consider alternative causes such as HSP in the differential diagnosis of ileitis indicative of Crohn’s disease. The resemblance between inflammatory lesions in the terminal ileum in HSP and those seen in Crohn’s disease hints at a potential pathophysiological link between the two disorders which is supported by an emerging body of literature.Figure 1.: Non-blanching erythematous coalescing maculopapular rash on the dorsal aspect of both feet and around the ankles.Figure 2.: CT Abdomen & Pelvis Coronal Section: small bowel inflammatory changes involving the jejunum and ileum.Figure 3.: Colonoscopy showing moderate to severe active terminal ileitis.