Diabetic nephropathy masquerading as systemic disease: The critical role of renal biopsy in a young uninsured woman with nephrotic syndrome.

Nephrotic syndrome can have overlapping features across multiple diseases, making diagnosis difficult without tissue confirmation. We describe a 30-year-old uninsured Hispanic woman with type 1 diabetes, hypertension, and CKD3B who presented with nephrotic syndrome, sepsis, and progressive muscle weakness. Her pleural effusions, periorbital changes, elevated free light chains, and dysphagia raised concern for systemic conditions such as amyloidosis or polymyositis, especially given inconsistent outpatient follow-up. Because her management would differ significantly depending on the underlying cause and due to the high risk of loss to follow-up, a renal biopsy was pursued. Serologic studies were unremarkable, and biopsy ultimately confirmed diabetic nephrosclerosis. This case highlights how clinical findings alone may be misleading in diabetic patients with heavy proteinuria. Renal biopsy remains the most reliable tool for distinguishing diabetic nephropathy from other systemic diseases. An individualized approach that considers comorbidities and social determinants of health is essential for accurate diagnosis and care.