Isolated bilateral renal mucormycosis in apparently immunocompetent patients-a case series from India and review of the literature

Abstract

Background: Isolated renal mucormycosis (IRM) is a potentially fatal disease affecting immunocompromised hosts. IRM affecting apparently immunocompetent patients is rare, with few previous reports, mostly from India. We describe 10 cases of bilateral IRM with no underlying risk factors.

Methods: We performed a retrospective analysis of cases of IRM from our hospital information system admitted between 2009 and 2016. We analyzed the data of this cohort of IRM, including epidemiological characteristics, clinical presentation, diagnostic procedures, treatment details and outcome.

Results: In all, 10 cases of bilateral IRM were identified. All of them were males with a mean age of 24.7 years (range 10-42). Most patients were initially managed as acute bacterial pyelonephritis with acute kidney injury. A total of eight patients were diagnosed antemortem. Diagnostic clues include sepsis not controlled with broad-spectrum antibiotics and enlarged kidneys with or without hypodensities on ultrasound/computed tomography imaging. Three patients also gave a specific history of passing white flakes in their urine. Eight patients received specific antifungal therapy with amphotericin B with or without posaconazole. Three patients in whom the disease was apparently confined to the pelvicalyceal system underwent local irrigation with Amp-B. One patient underwent bilateral nephrectomy. Four patients succumbed to the disease while five patients were successfully treated. One patient was discharged against medical advice.

Conclusions: IRM is a rare, life-threatening disease associated with high mortality even in immunocompetent individuals. Typical clinical and radiological findings and a high index of suspicion may help in early diagnosis, but definitive diagnosis requires histopathological and/or microbiological confirmation. Early and rapid diagnosis along with aggressive multidisciplinary management including initiation of specific antifungal therapy with or without surgical debridement is vital for a successful outcome.

Keywords: amphotericin B; immunocompetent; isolated renal mucormycosis; nephrectomy; posaconazole.

FIGURE 1

Clinical findings in IRM patients. (A) Patient’s abdomen shows erythema and subcutaneous edema of the flank region. (B) Urine sample: gross hematuria with white flakes containing papillary tissue and fungus settled at the bottom. (C) Mucor bezoars passed in the urine of an IRM patient complaining of abdominal colics. (D) Non-contrast CT of the abdomen in the coronal plane at the level of the kidneys shows bilateral bulky kidneys with parenchymal hypodensities. (E) Contrast CT of the abdomen in the axial plane at the level of the kidneys shows bilateral bulky kidneys with enhancing thickening of the wall of the renal pelvis. (F) Contrast CT of the abdomen in the coronal plane shows bilateral bulky kidneys with multiple nonenhancing areas with preserved normal subcapsular parenchyma (Rim sign). (G) Contrast CT of the abdomen (excretory phase) in the coronal plane shows the right kidney demonstrating a filling defect in the calyceal system. (H) CT angiogaphy (reformatted in the coronal plane) shows normal main renal arteries with attenuated segmental branches in the region of nonenhancing areas suggestive of vasular invasion. (I) Noncontrast CT of the abdomen shows bilaterally enlarged kidneys with irregular, nonhomogeneous, hypodense areas within the renal parenchyma and perinephric fat stranding.

FIGURE 2

(A) Urine cytopathology shows broad, ribbon-like fungal hyphae. (B) Extensive cortical necrosis of the renal parenchyma with broad, ribbon-like fungal hyphae (hematoxylin and eosin,  ×200). (C) Broad, aseptate hyphae with right-angle branching in necrosed renal parenchyma (chromic acid silver methenamine stain, oil immersion).

FIGURE 3

Algorithmic approach to the (A) diagnosis of IRM and (B) management of IRM. KUB, kidney ureters bladder; MRI, magnetic resonance imaging. AmB, Amphotericin; CT, computerized tomography; KUB, kidney ureter bladder; MRI, magnetic resonance imaging; PCN, percutaneous nephrostomy; USG, Ultrasound.