Paroxysmal Nocturnal Hemoglobinuria is a rare acquired form of hemolytic anemia, in which there is excessive breakdown of red blood cells in the bloodstream, that is, an acquired hemolytic anemia. It occurs due to hematopoetic stem cell defects, that is, innate defects in the stem cells that form the blood.
The prevalence of Paroxysmal Nocturnal Hemoglobinuria is estimated to be as low as 1–10 cases per million people. This means that on the low end there are likely 10,000 to 80,000 Paroxysmal Nocturnal Hemoglobinuria sufferers globally, although some estimates say it may be as high as 1 to 5 million sufferers.
It is characterized by the passage of red colored urine, due to presence of hemoglobin from the breakdown of RBCs occurring in blood. An element of thrombosis is also generally associated with Paroxysmal Nocturnal Hemoglobinuria.
Clinical Features of Paroxysmal Nocturnal Hemoglobinuria
Paroxysmal Nocturnal Hemoglobinuria has a spectrum of presentation, not always manifesting at the same time. There may be:
– An acquired hemolytic anemia with cell membrane defects in RBCs, presenting with characteristic red to dark cola colored urine due to passage of hemoglobin. Other features of anemia may be seen, including palpitations, easy fatigability, shortness of breath, and in some cases, abdominal pain as well.
A thrombus in the abdominal veins causes severe pain and may lead to bowel infarct, if prolonged. If bowel sounds are not heard any more, it suggests that bowel necrosis has already begun.
Thrombi affecting the blood supply of the skin cause formation of painful red nodules all over the affected area, usually the back. The nodules may vanish over the next few weeks, but if they undergo necrosis the patient will need skin grafting.
Any thrombi in the cerebral veins supplying the brain can have potentially fatal complications, ranging from severe headaches to an uncommon form of venous stroke.
– Prolonged hemolytic anemia can lead to features of severe anemia being manifested, for example, aplastic anemia leading to pancytopenia (reduced production of all the blood cells), and bone marrow insufficiency. The consumption of platelets in microthrombi formation leads to bleeding tendencies in other locations, causing petechiae, purpurae, echymoses, mucosal bleeding, etc.
With this diverse clinical picture, Paroxysmal Nocturnal Hemoglobinuria is a unique clinical condition. While the individual features are not life threatening, the predisposition for thrombus formation in unusual location causes a high risk of pulmonary embolism, when blood clots break away from other sites and get impacted in the lungs.
Treatment of Paroxysmal Nocturnal Hemoglobinuria
The management of Paroxysmal Nocturnal Hemoglobinuria mostly depends on its diagnosis at the right time, and the severity of the mutations. Tests conducted include Complete Blood Analysis, Coomb’s test, Urinalysis, and Serum Hemoglobin and Haptoglobin.
Treatment consists of management of the pre-existing condition as well as preventing future complications. Corticosteroid therapy is useful in suppressing the immune system. The continuous loss of hemoglobin is combated by blood transfusions and iron and folic acid supplementation. A drug called Soliris (Eculizumab) is effective as t blocks the breakdown of RBCs. Similarly, bone marrow transplantation, though risky, can be a complete cure as well.
Although complications like stroke or aplastic anemia are present, Paroxysmal Nocturnal Hemoglobinuria is a completely manageable disease and should be approached as one as well.
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