Basidiobolus infection in children – a mimic of inflammatory bowel disease
May 02 2017
Basidiobolomycosis is a rare chronic inflammatory disease affecting immunocompetent hosts caused by the fungus Basidiobolus ranarum. Dr Khalid Shreef from the Zagazig University Hospital, Egypt and colleagues report the largest series to date - 18 patients (5-10 years old).
The infection results in human disease mimicking soft tissue tumours restricted to subcutaneous tissues in the limbs, trunk and buttocks. Visceral involvement is rare but there are increasing reports of its role in gastrointestinal infections presenting with non-specific signs & symptoms. Prior ranitidine use and prolonged residence in endemic areas seem to contribute to the risk of acquiring gastrointestinal basidiobolomycosis (GIB).
Shreef et al describe the commonest presenting features of: abdominal pain (94%), right sided abdominal masses (77%) involving the caecum and ascending colon at surgery and constipation (83.3%) which alternated with diarrhoea in a few patients. Other uncommon presentations included hepatomegaly (3 patients) and isolated liver abscess. Fever, vomiting, weight loss, abdominal pain and abdominal masses are some of the presenting symptoms of GIB infection.
(Courtesy of Hail M. Al-Abdely, Riyadh, Saudi Arabia)
Diagnosis is often delayed because these symptoms simulate other conditions such as inflammatory bowel disease, intestinal TB, sarcoidosis, amoebiasis, and schistosomiasis granuloma.
While definitive diagnosis requires microbiological culture and serological testing, histopathology demonstrating fungal elements surrounded by a thick eosinophilic cuff (Splendore- Hoeppli phenomenon) is used. Elevated inflammatory markers with prominent eosinophillia is often found. GI imaging reveals a colonic mass with local spread. Since the infection involves the non-mucosal layers of the intestine, endoscopic imaging is often unhelpful. Renal involvement is sometimes an issue.
Itraconazole is the drug of choice for GIB with voriconazole reserved for itraconazole-resistant fungus. Surgery is often necessary. Shreef reports excellent outcomes with itraconazole: 6 months therapy lead to dramatic improvement in symptoms within days and complete clinical and radiological resolution of symptoms by 8-12 months.
Basidiobolus ranarum may cause chronic subcutaneous disease in any location, and also causes infections in animals.
Shreef et al 2017. Eur J Pediatr Surg. 2017 Feb 6. doi: 10.1055/s-0037-1598104.