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Genetic and Rare Diseases Information Center (GARD)

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Paroxysmal nocturnal hemoglobinuria

Other Names for this Disease
  • Marchiafava-Micheli disease
  • PNH
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Your Question

Why does it appear that hemolysis occurs mostly at night?

Our Answer

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Why does it appear that hemolysis mostly occurs at night?

The term "nocturnal" refers to the belief that hemolysis is triggered by acidosis during sleep. However, this observation was later disproved. In individuals with paroxysmal nocturnal hemoglobinuria, hemolysis has been shown to occur throughout the day, but the urine concentrated overnight produces the dramatic change in color.[1] It is most noticeable in the morning, upon passing urine that has accumulated in the bladder during the night.[2]
Last updated: 1/15/2011