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Kidney Week

Abstract: SA-PO053

A Rare Case of Severe Myositis with Microsporidia Invasion of the Kidneys

Session Information

Category: Acute Kidney Injury

  • 102 AKI: Clinical, Outcomes, and Trials

Authors

  • Abro, Sheeraz G., The University of Alabama at Birmingham Division of Nephrology, Birmingham, Alabama, United States
  • Abro, Paras A., Liaquat University of Medical and Health Sciences, Jamshoro, Sindh, Pakistan
  • Neyra, Javier A., The University of Alabama at Birmingham Division of Nephrology, Birmingham, Alabama, United States
  • Fatima, Huma, The University of Alabama at Birmingham Division of Nephrology, Birmingham, Alabama, United States
  • Bell, Emmy Klip, The University of Alabama at Birmingham Division of Nephrology, Birmingham, Alabama, United States
Introduction

Anncaliia algerae is an obligate intracellular microsporidian parasite known to cause severe myositis among immunocompromised patients. The majority of reported cases are limited to renal transplant patients. We present a case of native renal parenchymal microorganism invasion in a patient with disseminated microsporidia.

Case Description

A 59-year-old man presented with a six-month history of progressive muscle weakness and pain. His condition deteriorated to the point he could no longer ambulate or care for himself. Medical history included Crohn's disease and arthritis, diagnosed in his early twenties and managed with long-term steroid use. Prior to his current illness, he was receiving methotrexate for 6 months and infliximab for 3 months. He only received 3 doses of infliximab before discontinuation due to presumed anti-TNF-induced myositis.

Despite administration of intravenous immunoglobulin and pulse-dose steroids, his condition continued to deteriorate. A muscle biopsy revealed necrotizing myositis. Extensive work-up revealed no autoimmune causes for myositis. Urinalysis showed 3+ blood and 2+ protein, along with RBC casts on microscopy. The urine protein-to-creatinine ratio was 1.9 g/g. Renal biopsy (Figure 1) revealed uniform-sized, oval-shaped intratubular microorganisms without inflammation, highly suspicious for microsporidia invasion. A tongue biopsy (Figure 2) supported this diagnosis, which was confirmed by cell-free DNA testing identifying Anncaliia algerae.

Treatment with albendazole was initiated, and immunosuppressants were tapered off. Due to persistent parasitemia complicated with septic shock and multiorgan failure including acute kidney injury requiring dialysis, fumagillin -a mycotoxin from Aspergillus- was administered. Subsequently, his clinical condition improved significantly, with marked recovery of multiorgan function including kidney function.

Discussion

This complex case underscores the importance of comprehensive investigations to uncover rare infectious etiologies and highlights the challenges of managing disseminated microsporidia.