Henoch-Schonlein Purpura (HSP): small bowel involvement

Clinical History

A six-year-old boy presented with a purpuric, non-blanching rash over his arms, legs and genitalia and arthralgia of both wrist and knee joints. A sore throat one week earlier was also noted. The patient was managed conservatively and discharged. Seven days later he presented with vomiting with streaks of...

Imaging Findings

..fresh blood. His abdomen was mildly tender but there were no signs of peritonism or bowel obstruction and no blood PR.
The abdominal radiograph was unremarkable (Fig.1)
Ultrasound abdomen showed significant oedema/thickening of the wall involving the duodenum and in particular the upper jejunum, where overall thickness of the wall was 8mm, and was with slight increase echogenicity and increased intramural Doppler flow (Fig 2). Mild-moderate ascites, no distal small bowel pathology or intussusception was noted. A diagnosis of vasculitis of the small intestines on the background of the primary disease HSP was made.
Second abdominal radiograph (Fig.3) showed only gas and faecal loading.
CT same day showed no obstruction or perforation.
Repeat ultrasound, (Figs. 4 ) following five days of iv steroids, showed inflammation to improve, with only distal ileum remaining with thick wall.
Six days later following further steroid therapy repeat USS (Fig.5) showed that inflammation and ascites had completely resolved.

Discussion

HSP is a small-vessel, immune-mediated vasculitis associated with immunoglobulin A (IgA) deposition (1,2). In 90% of cases it occurs in the paediatric age group but can occur in adults. It presents in children usually between 3 and 15 years, with a peak incidence between 4 and 6 years and is more predominant in males then females (1.8:1). In the UK the annual incidence of HSP has been reported as 20 per 100, 000 in children less than 17 years (3).
Approximately half of the cases of HSP are preceded by an upper respiratory tract infection, like in this case, which possibly explains why HSP occurs primarily in the autumn and winter and not in the summer months. The exact aetiology of HSP is unknown.
The major clinical manifestations of HSP include purpuric rash (100%), arthralgia/arthritis (43-75%), gastrointestinal symptoms (70%), and renal disease (50%).
Gastrointestinal involvement occurs in approximately two thirds of children with HSP and is most commonly manifested by abdominal pain, but also, like in this case, by GI bleeding. On average 5% of cases with abdominal involvement result in serious complications e.g. perforation, bowel ischemia, bowel obstruction and by far the most common intussusception (4,5).
Abdominal ultrasound is the modality of choice in diagnosing and evaluating the extent of gastrointestinal involvement in HSP. It is an easy, non invasive method that allows direct visualisation of the bowel and detection of complications such as intussusception. Routine abdominal-radiographs are not indicated unless perforation is suspected (6). Typical ultrasound features include free intraperitoneal fluid, diffuse eccentric bowel wall thickening , focal haemorrhagic infiltrated lesions due to the vasculitis (7). Colour Doppler is very useful to detect hyperdynamic blood flow (8).
Abdominal CT-scanning has been proven to be useful in the differential diagnosis of acute abdomen in patients with vasculitis. However, like in this case, not every HSP patient with gastrointestinal involvement presents with an acute abdomen and therefore as well as exposing the child to radiation should not be first line investigation. A number of small case series have reported the appearance of HSP on abdominal CT films, features described include duodenal and jejunal wall thickening, luminal narrowing, fold thickening and ulceration (9).
This case highlights the effectiveness of ultrasound and CT in diagnosing and evaluating the extent of gastrointestinal involvement in a patient with HSP but also in monitoring the patient’s progress following treatment with corticosteroids.

Differential Diagnosis List

Final Diagnosis

Henoch-Schonlein Purpura (HSP) with vasculitis of small bowel

URL:	https://www.eurorad.org/case/9595
DOI:	10.1594/EURORAD/CASE.9595
ISSN:	1563-4086