Renal zygomycosis: an under-diagnosed cause of acute renal failure.

BACKGROUND Invasive zygomycosis (mucormycosis) occurs predominantly in immunocompromised patients in whom it carries a grave prognosis. While renal involvement is not so uncommon in disseminated infection, isolated renal zygomycosis is rare. METHODS AND RESULTS Forty-five patients with systemic zygomycosis were seen over a 12-year period from January 1986 to December 1997. Among these, 18 had renal involvement, nine with disseminated disease and nine with isolated renal zygomycosis. No underlying predisposing disease was identified in the majority of patients (72%). Renal involvement was confirmed at autopsy in 13 and by ante-mortem renal biopsy in five patients. The infection involved one kidney in five patients and was bilateral in the remaining. The manifestations included fever, flank pain, haematuria and pyuria with evidence of enlarged non-functioning kidneys on computerised tomography (CT). Of those with bilateral disease, 12 (92.3%) had anuric acute renal failure. Anti-fungal therapy was given to six patients (amphotericin B in mean total dose of 1.1 g) and of these only two with unilateral disease who also underwent nephrectomy survived while all the other 16 died. CONCLUSION This study shows that renal zygomycosis has emerged as a cause of acute renal failure in the last decade since no patient with renal involvement was identified at our centre prior to 1986 even though autopsies have been done regularly in patients dying of unknown causes. Bilateral renal zygomycosis should be suspected in any patient who presents with haematuria, flank pain and otherwise unexplained anuric renal failure. Characteristic CT findings and an early renal biopsy can confirm the diagnosis and help in effective management of this serious disease.