To the Editor: A 27-year-old man who had recently emigrated from Sudan was admitted to our department with a 7-hour history of constant peri-umbilical pain.

Physical examination revealed inconstant voluntary guarding of the lower abdomen. Full blood and electrolyte examinations were unremarkable. Urinalysis showed protein and traces of blood. A condition requiring surgery was considered unlikely and further investigations were undertaken.

Significant bladder calcification was noted from an abdominal x-ray. A computed tomography scan confirmed this finding (Box), and also revealed circumferential distal ureteric calcification, appendiceal thickening with appendicolith, and adjacent fat stranding. Repeat abdominal examination demonstrated right iliac fossa tenderness with a positive Rovsing sign. Acute appendicitis was diagnosed and an inflamed, thickened, retrocaecal appendix was removed laparoscopically. The patient was discharged 2 days later, but did not attend his post-operative review.

Histological examination of the appendix demonstrated transmural neutrophil infiltration, without eosinophils. Within the lumen there were numerous oval-shaped helminth ova, some with terminal spines, consistent with acute appendicitis caused by schistosomiasis. The patient did not have a general practitioner, therefore a referral to an infectious diseases clinic was made. He was thereafter lost to follow-up.

Infection by schistosomes leads to chronic granulomatous inflammation in many body systems, including the gastrointestinal tract. Adult worms are not usually harmful to the host — eggs provoke a Th2-mediated immune response.1

Three major species of Schistosoma cause schistosomiasis in humans, of which two are endemic in sub-Saharan Africa — Schistosoma mansoni and Schistosoma haematobium. S. haematobium migrates against portal venous flow to the vesical venous plexus, causing urinary tract calcification through chronic inflammation and fibrosis. This species has also been described as a cause of appendicitis.2 Examinations of appendices removed from patients with acute appendicitis in endemic areas have demonstrated schistosomiasis in 2.3%–4.2% of samples, with 2.7% having histological evidence of acute schistosomal appendicitis in one study.3,4

Schistosomiasis can be diagnosed by histological analysis, or urine and stool microscopy. Serological testing cannot be used to differentiate past and present infection, however positive serological results are the basis for treatment of patients in endemic areas. After diagnosis, praziquantel should be prescribed.

It is assumed that our patient did not receive praziquantel. He thus risks significant morbidity and mortality from possible gastrointestinal, hepatic, urinary, pulmonary and neurological complications related to chronic schistosomal infection.

Surgeons and pathologists should be aware of the atypical pathology of acute schistosomal appendicitis. The number of immigrants arriving in Australia from endemic areas has increased markedly in recent years and further presentations may occur.

Non-contrast computed tomography scan of a 27-year-old man with schistosomal appendicitis

Calcification of the bladder (black arrow) and distal ureters (white arrows) is evident.