Paroxysmal nocturnal hemoglobinuria (PNH) is a rare, chronic, debilitating disorder that most frequently presents in early adulthood and usually continues throughout the patient's life.
The name of the disorder is a descriptive term for the clinical consequence of red blood cell (RBC) breakdown with release of hemoglobin into the urine, which manifests as dark-colored urine in the morning. PNH results in the death of approximately 50% of affected individuals due to thrombotic complications and, until recently, had no specific therapy.
The term "nocturnal" refers to the belief that hemolysis is triggered by acidosis during sleep and activates complement to hemolyze an unprotected and abnormal RBC membrane. However, hemolysis has been shown to occur throughout the day and is not actually paroxysmal.
PNH has been referred to as "the great impersonator" because of the variety of symptoms observed during its initial manifestation and course. The triad of hemolytic anemia, pancytopenia, and thrombosis makes PNH a unique clinical syndrome.
How much do you know about PNH? Test your knowledge with this quick quiz.
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Cite this: John L. Reagan. Fast Five Quiz: Paroxysmal Nocturnal Hemoglobinuria - Medscape - Mar 21, 2023.