A 48-year-old man with biopsy-proven primary membranous nephropathy (anti-PLA2R antibody positive) presents with sudden left flank pain, gross haematuria, and unilateral leg oedema. Doppler ultrasound shows a filling defect in the left renal vein extending into the inferior vena cava. What is the most appropriate immediate management?

• A Start therapeutic anticoagulation with low molecular weight heparin ✓
• B Increase furosemide dose and continue antiproteinuric therapy
• C Start rituximab for the underlying glomerular disease
• D Insert an inferior vena cava filter

Explanation

Membranous nephropathy carries the highest risk of renal vein thrombosis among glomerular diseases because urinary losses of antithrombin III and other anticoagulant proteins create a hypercoagulable state. Acute renal vein thrombosis is treated with therapeutic anticoagulation, typically LMWH followed by a vitamin K antagonist. An IVC filter is reserved for patients with contraindications to anticoagulation, and rituximab treats the underlying disease but does not address the acute thrombus.

Reference: Harrison's Principles of Internal Medicine, 21st ed.

High-yield for: NEET PGINI-CETNExTFMGEUSMLEPLABMRCP

Written and medically reviewed by the StethoPrep medical team.