L BYWATER1, S THOMAS1, A ASHOK1, B PAWAR1, S NAYAR1, P GEORGE1, S KODGIRE1, M BROWN1, D FERNANDES1, F CHIONG1, S CHERIAN1
1Department of Nephrology, Alice Springs Hospital, Alice Springs, Northern Territory
Background: Microsporidia are ubiquitous fungi. Several species can infect humans, particularly those with significant immunosuppression, causing significant morbidity and mortality.
Case report: A 39-year-old indigenous female with end-stage diabetic nephropathy was on haemodialysis for three years prior to receiving a deceased-donor renal transplant of moderate immunological risk. Baseline creatinine was 120umol/L and she received standard immunosuppression. A renal graft biopsy at 12 weeks identified T-cell mediated rejection (TCMR) treated with methylprednisolone and an increase in background immunosuppression. Following initial treatment failure and retreatment with steroids, biopsy showed borderline TCMR. Deteriorating graft function was complicated by Escherichia coli pyelonephritis with incomplete recovery of renal function post treatment with antibiotics (creatinine 180umol/L). Another biopsy was performed. This demonstrated spore-like microorganisms in the tubular lumen and epithelium. There was associated non-necrotising granulomatous intratubular and interstitial inflammation with negative SV40 immunohistochemistry. There was no rejection. The light and electron microscopy findings from two previous biopsies were re-examined. Several microsporidia were visible in the form of meronts (immature form) and mature spores were seen in the capillaries. PCR on sputum, faeces and urine detected disseminated microsporidia infection of the Encephalitozoon cuniculi species. The patient recovered with reduction in immunosuppression and albendazole treatment.
Conclusion: Of the few reported cases of microsporidia infection in renal graft recipients, a significant proportion had high mortality related to escalation of immunosuppression and late diagnosis due to confounding with rejection. Deteriorating graft function with disproportionate biopsy features of rejection and inadequate improvement in allograft function after anti-rejection treatment should prompt consideration of indolent fungal infection.
Laura is a second year renal advanced trainee who spent time in Alice Springs this year. She has an interest in infectious diseases and the kidneys.