A 35-year-old man presents with episodic painless dark urine, fatigue, and venous thrombosis of hepatic veins (Budd-Chiari syndrome). CBC shows anaemia, reticulocytosis, and pancytopenia. Flow cytometry of peripheral blood erythrocytes shows absence of CD55 and CD59. The MOST appropriate treatment for haematological control is:

• A Glucocorticoids (prednisolone 1 mg/kg/day)
• B Folic acid supplementation only
• C Allogeneic stem cell transplantation immediately
• D Eculizumab (anti-C5 monoclonal antibody) ✓

Explanation

Paroxysmal nocturnal haemoglobinuria (PNH) is caused by a somatic PIGA mutation causing GPI-anchor deficiency, resulting in absence of CD55 (decay-accelerating factor) and CD59 (membrane inhibitor of reactive lysis) on blood cell surfaces, making them vulnerable to complement-mediated lysis. Eculizumab, a terminal complement inhibitor (anti-C5), dramatically reduces haemolysis, transfusion requirements, and thrombotic events in PNH (TRIUMPH and SHEPHERD trials). Thrombosis (especially at unusual sites like hepatic, portal, mesenteric veins) is the most common cause of death in PNH. Allogeneic SCT is curative but reserved for severe aplastic anaemia-PNH overlap or eculizumab failure.

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

High-yield for: NEET PGINI-CETNExTFMGEUSMLEPLABMRCP

Written and medically reviewed by the StethoPrep medical team.