Paroxysmal Nocturnal Hemoglobinuria

Also known as: PNH.

What is paroxysmal nocturnal hemoglobinuria?

Paroxysmal nocturnal hemoglobinuria is a rare, dangerous, acquired blood disorder during which unpredictable episodes of blood red cell breakdown occurs, the bone marrow stops making new blood cells and blood clots.

It's called PNH because the breakdown products of the red cells, hemoglobin, which are excreted in the urine, make the urine dark.


What causes paroxysmal nocturnal hemoglobinuria? 

Usually an acquired genetic mutation, it is not passed down from parent to child that results in the blood's red cells lacking protective proteins which allows their own immune system to attack them and cause their destruction.

Sometimes PNH can result from injuries to healthy early blood cells in the bone marrow, for example from toxins, a viral infection, previous radiation or chemotherapy.

PNH may increase the risk of other bone marrow disorders.


What are the signs/symptoms of paroxysmal nocturnal hemoglobinuria? 

Symptoms include:

  • Dark urine (particularly in the morning)

  • Paleness of skin (anemia)

  • Weakness

  • Fatigue

  • Frequent infections

  • Headaches

  • Back pain

  • Bleeding

  • Other complications.  


What are paroxysmal nocturnal hemoglobinuria care options? 

In many children only supportive care to help with symptoms, and iron and folic acid supplementation to increase red cell production is needed. Depending on severity other medications will be used.

The only cure for paroxysmal nocturnal hemoglobinuria is a transplant of bone marrow stem cells/bone marrow transplant.


Reviewed by: Jack Wolfsdorf, MD, FAAP

This page was last updated on: 11/10/2017 9:16:26 AM

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