Rapid Remission of Secondary Membranous Glomerulonephritis Due to Syphilis: A Case Report

Membranous glomerulonephritis (MGN) is an antibody-mediated autoimmune disease that targets the glomerular basement membrane-podocyte complex, causing defects in the glomerular filtration barrier and resulting in nephrotic syndrome. Management of patients with MGN now relies on identifying the underlying etiology. A 36-year-old female patient, with a recent history of transient vision loss, presented with 11 days of progressive edema and episodes of vomiting, headache, and stomach pain. Evaluation of progressive proteinuria led to a renal biopsy, which showed normal glomerular histology by light microscopy and a full-house pattern of immune-complex deposits by immunofluorescence microscopy. Electron microscopy showing very occasional subepithelial deposits confirmed the diagnosis of MGN. Testing for anti-PLA2R antibody, a biomarker for primary (idiopathic) MGN, was negative by immunohistochemistry and serology. Extensive clinical evaluation and workup led to a rapid plasma reagin (RPR) test for syphilis, which was positive. Treatment was immediately initiated with furosemide, losartan, and weekly intramuscular benzathine penicillin, and within two weeks, the patient's edema had subsided, and her proteinuria had resolved. The patient remained in clinical remission at 11-month follow-up with good overall health. We emphasize the importance of early diagnosis of syphilis-induced MGN as prompt treatment results in rapid remission of renal disease. In the evaluation of secondary MGN, atypical presentations of syphilis should be considered in the differential diagnosis to ensure the timely initiation of appropriate management.