Definition, Etiology, Pathogenesis and Clinical Manifestations of (PNH)

Paroxysmal Nocturnal Hemoglobinuria (PNH)



Definition of Paroxysmal Nocturnal Hemoglobinuria (PNH)

Paroxysmal Nocturnal Hemoglobinuria (PNH) is an acquired chronic disorder, which is characterized by the occurrence of intravascular hemolysis and hemoglobiuria which generally occurs when patients sleep at night.

PHN is characterized by a decrease in the number of red blood cells (anemia) and the presence of blood in the urine (hemoglobinuria) and plasma (hemoglobinemia), which occurs after sleep. PNH patients are at high risk of major thrombotic events, most thrombosis in the abdominal aorta. Most patients die from this thrombosis.


Etiology and Pathogenesis

Causes of these disorders is enzyme PIG-A (phosphatidylinositol glican class A) required for the synthesis of cell binding protein. Proteins that are attached to the outer portion of the cell membrane of cells with the help of glicosilfosfatidilinositol proteins (GPI) and PIG-A is needed for the synthesis of these proteins. If there is interference with the formation, the surface protein that protects cells from complement missing, making it easier for blood cell destruction. The percentage of red blood cell damage determines the severity of the disease.


Clinical Manifestations
The three most frequent manifestations are:

1. Hemolytic anemia,
2. Venous Thrombosis, and
3. Impaired hematopoiesis.

Hemoglobinuria and hemosidenuria periodically occurs in most patients. Granulocytopenia and thrombocytopenia are common, indicate impaired hematopoiesis. Picture normoselular bone marrow.