RÉSUMÉ
Paroxysmal Nocturnal Hemoglobinuria [PNH] literally means to have episodes of hemoglobin in the urine during the night. It is a Coomb's negative rare hemolytic disorder characterized by non-malignant clonal expansion of haemopoietic stem cells due to acquired genetic mutations. A 30 years old male patient presented with 5 years history of transfusion dependent anemia with intermittent episodes of passing dark colored urine in the morning. Blood complete picture showed decreased hemoglobin and reticulocytosis upto 30%. Coomb's test was negative with unconjugated hyperbilirubinemia and markedly raised serum LDH. Urine analysis showed marked hemosiderinuria and flow cytometry revealed 60% RBCs deficient for CD-59, confirming the diagnosis of paroxysmal nocturnal hemoglobinuria. The management of the patient depends on whether anemia is due to hemolysis or as consequence of impaired erythropoiesis. Corticosteroids at a dose of 0.25-1 mg/kg/day was selected as it is amongst the various treatment options in patients with predominant hemolysis