Early Onset Renal Amyloidosis in a Case of Rheumatoid Arthritis: A Case Report

Abstract

Amyloidosis refers to a group of disorders characterised by the deposition of misfolded amyloid proteins in various tissues, leading to organ dysfunction. Secondary (AA) amyloidosis is most commonly associated with chronic inflammatory conditions such as Rheumatoid Arthritis (RA), where persistent inflammation triggers the overproduction of Serum Amyloid A (SAA) protein, which subsequently deposits as amyloid fibrils. Renal involvement is frequent in AA amyloidosis, often manifesting as nephrotic syndrome due to amyloid deposition in the glomeruli. Present case is of a 38-year-old female with a five-year history of RA, who was on methotrexate and sulfasalazine, and presented with frothy urine and progressive anasarca over two months. She exhibited a high-grade fever, cough, shortness of breath and right-sided chest pain. Examination revealed bilateral pedal oedema, facial puffiness, and signs of pleural effusion and ascites. Urine examination indicated nephrotic-range proteinuria, and pleural fluid analysis revealed a transudative effusion. A kidney biopsy confirmed AA amyloidosis, with positive Congo red staining and apple-green birefringence. This case highlights the unusual early onset of AA amyloidosis in RA, developing only five years postdiagnosis, significantly earlier than the typical median of 19 years. Despite well-managed RA and minimal disability, the patient developed nephrotic syndrome and subsequent immunosuppression, culminating in empyema. This case underscores the unpredictable progression of RA-related complications and highlights the critical need for vigilant monitoring and proactive management strategies.

Keywords

• empyema
• pleural fluid
• proteinuria