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Abstract: TH-PO518

Abiotrophia defectiva-Induced Cryoglobulinemic Glomerulonephritis

Session Information

Category: Glomerular Diseases

  • 1303 Glomerular Diseases: Clinical‚ Outcomes‚ and Trials

Authors

  • Turk, Michael, Allegheny Health Network, Pittsburgh, Pennsylvania, United States
  • Khalil, Patricia, Allegheny Health Network, Pittsburgh, Pennsylvania, United States
Introduction

Infection-related glomerulonephritis (GN) has several unique presentations. Some microorganisms may not be detected on routine diagnostic testing. Abiotrophia defectiva, for instance, is a nutritionally deficient streptococcus that is slow growing on culture media. Here, we describe a case of A. defectiva associated GN and infective endocarditis (IE).

Case Description

A 65-year old female with past medical history of paroxysmal A-fib, mitral valve repair due to chordae tendinae rupture presented to her PCP office with myalgias in the setting of elevated inflammatory markers so was sent to Rheumatology for further work up, which was significant for Creatinine (Cr) of 1.0, microscopic hematuria, positive c-ANCA, PR3 serologies and rheumatoid factor, but normal complement levels. She was negative for dsDNA and Hepatitis B & C.

Her symptoms of worsened with fatigue and malaise so she was referred to the hospital for admission. At this point, her Cr had risen to 1.5. Urine microscopy showed dysmorphic RBCs. She underwent kidney biopsy which showed immune complex mediated focal segmental GN with crescent formation. Immunofluorescence showed granular, mesangial and capillary loop staining for IgM and C3. Electron microscopy showed subendetholelial and mesangial immune deposits. CD68 staining was positive in macrophages, consistent with cryoglobulins. These results were consistent with cryoglobulinemic GN.

In the meantime, she became more short of breath, and transthoracic echo was obtained which showed severe transvalvular mitral regurgitation along with a mobile echodensity arising from the mitral valve, new from echo 1 month prior. A transesophageal echo confirmed the presence of a vegetation, consistent with IE. Her blood cultures, drawn about 5 days prior, finally resulted as positive for pansusceptible A. defectiva in 1/4 bottles. She was treated with antibiotics and underwent surgical repair of her mitral valve.

Discussion

A. defectiva has been described in the literature as a rare cause of culture negative IE however there has only been one case of ANCA GN associated with this bacteria. This case highlights the importance of a thorough infectious workup that goes beyond blood cultures in patients with biopsy proven cryoglobulinemic GN, especially in hepatitis-negative patients. Should all patients with similar presentation undergo more advanced imaging such as TEE to evaluate indolent infections?