Resolution of syphilis-related rapidly progressive glomerulonephritis with penicillin therapy: Case report
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Renal manifestations of syphilis are variable, with membranous nephropathy being the most commonly described lesion. Rapidly progressive glomerulonephritis (RPGN) is rare and there is only one case report in the literature describing syphilis-associated crescentic glomerulonephritis. We report a rare case of RPGN secondary to latent syphilis, which resolved with penicillin treatment in the absence of immunosuppressive therapy. A 28-year-old Black male with a history of HIV was evaluated for severe acute kidney injury, nephrotic-range proteinuria, and active urine sediment. Serologies for glomerulonephritis were negative. Rapid plasma reagin and treponema pallidum particle agglutination assay were reactive, confirming syphilis diagnosis. Kidney biopsy revealed focal and segmental necrotizing and crescentic lesion. Patient received weekly benzathine penicillin (PCN) for 3 weeks, and renal function improved to baseline. This dramatic improvement happened with PCN alone, a finding which has not been previously reported. We recommend that syphilis be considered in the differential diagnosis of all patients with proteinuria or suspected glomerulonephritis.

Acute Kidney Injury Associated with Linagliptin.

Linagliptin is a dipeptidyl peptidase-IV (DPP-IV) inhibitor that is approved for the treatment of type 2 diabetes mellitus. About 5% of linagliptin is eliminated by the kidneys and no dose adjustment is recommended in kidney impairment. We report a first case of linagliptin-associated acute kidney injury (AKI) in a patient with preexisting chronic kidney disease (CKD). We hypothesize that AKI was due to renal hypoperfusion from linagliptin-induced natriuresis and intravascular volume contraction in the setting of concomitant lisinopril use, which is known to impair autoregulation and potentiate hypotension-induced AKI. It may be prudent to exert caution and closely monitor kidney function when initiating linagliptin in combination with ACE-inhibitors in CKD patients.