Membranous Glomerulonephritis as an Uncommon Presentation of Secondary Syphilis: A Reminder on Therapeutic Decision-Making in Clinical Practice

Syphilis as the great mimicker: A case of full-house pattern membranous nephropathy

Syphilis is a known cause of membranous nephropathy. We describe a case of a patient presenting with nephrotic syndrome whose renal biopsy demonstrated a 'full house' immunohistochemical pattern with positive IgG, IgM, C1q, IgA, C3c, and C4d staining. He was treated with immunosuppressive agents for minimal change nephropathy and subsequently class V lupus nephritis, before syphilis infection was confirmed. Following treatment with a single dose of intramuscular benzathine penicillin there was complete and rapid resolution of nephrotic syndrome. With progressive rising incidence in the western world, syphilis is an important and under-recognised differential diagnosis in cases of nephrotic syndrome.

Ocular manifestations and full house membranous nephropathy as a rare presentation of secondary syphilis

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Ocular symptoms and membranous nephropathy as a presentation of secondary syphilis.

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Secondary syphilis presenting with a full house staining pattern on renal biopsy.

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Diagnostic challenge with positive autoimmune labs confounding the diagnosis.

Syphilis is an often-overlooked diagnosis and without timely diagnosis and treatment, can have serious repercussions. Although its prevalence had decreased with the introduction of penicillin, it has had a resurgence over the years. Discerning the proper patient population to test for syphilis should be led by a patient’s risk factors. Here, we present a patient diagnosed with secondary syphilis, with initial concern for a possible concomitant lupus diagnosis. He initially presented with visual symptoms and optic nerve inflammation, along with a positive antinuclear antibody (ANA). Due to an unprotected sexual encounter, there was suspicion for a sexually transmitted infection. Testing revealed reactive rapid plasma reagin (RPR) (≥1:256 titer) and reactive treponemal antibody, consistent with active syphilis. He was immediately started on intravenous Penicillin G. Lumbar puncture was consistent with a reactive venereal disease research laboratory test (VDRL). Urinalysis revealed nephrotic range proteinuria, which along with the positive ANA, prompted renal biopsy. This showed membranous nephropathy with full house staining, which is seen primarily in lupus nephritis and further confounded the diagnosis. He completed a two-week course of penicillin and steroids inpatient with clinical improvement. On follow up, his RPR improved (≥1:64 titer), and lumbar puncture showed a non-reactive VDRL. Due to the resolution of proteinuria, decrease of the ANA titer and no further positive testing or symptoms convincing for a concomitant rheumatologic disorder, the presence of lupus was collectively determined to be of low concern. and the sole diagnosis of secondary syphilis was made.