SYPHILIS-INDUCED MEMBRANOUS NEPHROPATHY

Document Type

Conference Proceeding

Publication Date

4-1-2025

Publication Title

Am J Kidney Dis

Abstract

Membranous nephropathy (MN) can be primary or secondary, with causes including autoimmune diseases, infections, and malignancies. Syphilis is increasingly recognized as a trigger for MN through immune complex deposition causing renal damage. A 22-year-old man with asthma presented to the ED with abdominal pain, diarrhea, and a rash on his ankles and feet. He reported high-risk sexual activity one month earlier. Stool studies showed Shigella, treated with ciprofloxacin. The rash was initially treated as a fungal infection. He returned with severe leg swelling and hypertension (169/96 mmHg). Labs showed creatinine 1.34 mg/dL (baseline 0.9), albumin 1.3 g/dL, UA with RBC 0, WBC 5, UACR 4,200 mg/g, and UPCR 7 g/g. Workup revealed normal C3/C4, reactive HIV Ag/Ab (on repeat was negative), positive RPR titers (1:256), and ANA (1:640). ANCA, anti-GBM, HBV, and HCV were negative. Kidney ultrasound showed cortical thinning and mildly hypertrophic kidneys (13 cm) without hydronephrosis. He was treated for syphilis with IM penicillin G. Kidney biopsy LM showed no sclerosis, necrosis, crescents, or fibrosis, and normal glomerular basement membranes (GBM). EM revealed subepithelial electron-dense deposits along the GBM and severe foot process effacement, consistent with MN (Figure 1). IF showed a full house pattern (IgG, IgM, IgA, C3, C1q, albumin, fibrinogen, kappa/lambda light chains). PLA2R and EXT2 were negative. Despite non-compliance with ACE inhibitors, UPCR improved to 2.3 g/g after syphilis treatment. MN in syphilis is due to immune complex deposition. Neuron-derived neurotrophic factor (NDNF) is a novel antigen linked to this condition, enhancing understanding of its mechanisms. Syphilis-associated MN improves significantly with antibiotics. Syphilis should be considered in secondary MN, especially in patients with STI risk factors. Early diagnosis and treatment can significantly improve outcomes, highlighting the reversible nature of this condition.

Volume

85

Issue

4

First Page

S52

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