Paroxysmal nocturnal hemoglobinuria (PNH)
PNHParoxysmal nocturnal hemoglobinuria is a rare disease in which red blood cells break down earlier than normal.
Causes
People with this disease have blood cells that are missing a gene called PIG-A. This gene allows a substance called glycosyl-phosphatidylinositol (GPI) to help certain proteins stick to cells.
Without PIG-A, important proteins cannot connect to the cell surface and protect the cell from substances in the blood called complement. As a result, red blood cells break down too early. The red cells leak hemoglobin into the blood, which can pass into the urine. This can happen at any time, but is more likely to occur during the night or early morning.
The disease can affect people of any age. It may be associated with aplastic anemia, myelodysplastic syndrome, or acute myelogenous leukemia.
Aplastic anemia
Aplastic anemia is a condition in which the bone marrow does not make enough blood cells. Bone marrow is the soft, tissue in the center of bones tha...
Myelodysplastic syndrome
Myelodysplastic syndrome is a group of disorders in which the blood cells produced in the bone marrow do not mature into healthy cells. This leaves ...
Acute myelogenous leukemia
Acute myeloid leukemia (AML) is cancer that starts inside bone marrow. This is the soft tissue in the center of bones that helps form all blood cell...
Risk factors, except for prior aplastic anemia, are not known.
Symptoms
Symptoms may include:
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Abdominal pain
Abdominal pain
Abdominal pain is pain that you feel anywhere between your chest and groin. This is often referred to as the stomach region or belly.
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Blood clots, may form in some people
Blood clots
Blood clots are clumps that occur when blood hardens from a liquid to a solid. A blood clot that forms inside one of your veins or arteries is calle...
Read Article Now Book Mark Article - Dark urine, comes and goes
- Easy bruising or bleeding
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Headache
Headache
A headache is pain or discomfort in the head, scalp, or neck. Serious causes of headaches are rare. Most people with headaches can feel much better...
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Shortness of breath
Shortness of breath
Breathing difficulty may involve:Difficult breathing Uncomfortable breathingFeeling like you are not getting enough air
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Pallor
Pallor
Paleness is an abnormal loss of color from normal skin or mucous membranes.
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- Difficulty swallowing
Exams and Tests
Red and white blood cell counts and platelet counts may be low.
Red or brown urine signals the breakdown of red blood cells and that hemoglobin is being released into the body's circulation and eventually into the urine.
Hemoglobin
Hemoglobin is a protein in red blood cells that carries oxygen. The hemoglobin test measures how much hemoglobin is in your blood.
Tests that may be done to diagnose this condition include:
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Complete blood count (CBC)
Complete blood count (CBC)
A complete blood count (CBC) test measures the following:The number of white blood cells (WBC count)The number of red blood cells (RBC count)The numb...
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Coombs test
Coombs test
The Coombs test looks for antibodies that may stick to your red blood cells and cause red blood cells to die too early.
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- Ham (acid hemolysin) test
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Serum hemoglobin and haptoglobin
Serum hemoglobin
Serum free hemoglobin is a blood test that measures the level of free hemoglobin in the liquid part of the blood (the serum). Free hemoglobin is the...
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Sucrose hemolysis test
Sucrose hemolysis test
The sugar-water hemolysis test is a blood test to detect fragile red blood cells. It does this by testing how well they withstand swelling in a suga...
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Urinalysis
Urinalysis
Urinalysis is the physical, chemical, and microscopic examination of urine. It involves a number of tests to detect and measure various compounds th...
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Lactate dehydrogenase (LDH) test
Lactate dehydrogenase
The lactate dehydrogenase (LDH) isoenzyme test checks how much of the different types of LDH, called isoenzymes, are present in the blood.
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Reticulocyte count
Reticulocyte count
Reticulocytes are slightly immature red blood cells. A reticulocyte count is a blood test that measures the amount of these cells in the blood....
Treatment
Steroids or other medicines that suppress the immune system may help slow the breakdown of red blood cells. Blood transfusions may be needed. Supplemental iron and folic acid are provided. Blood thinners may also be needed to prevent clots from forming.
Soliris (eculizumab) and Ultomiris (ravulizumab) are medicines used to treat PNH. They block the breakdown of red blood cells.
Bone marrow transplantation can cure this disease. It may also stop the risk for developing PNH in people with aplastic anemia.
All people with PNH should receive vaccinations against certain types of bacteria to prevent infection. Ask your health care provider which ones are right for you.
Outlook (Prognosis)
The outcome varies. Most people survive for more than 10 years after their diagnosis. Death can result from complications such as blood clot formation (thrombosis) or bleeding.
In rare cases, the abnormal cells may decrease over time.
Possible Complications
Complications may include:
-
Acute myelogenous leukemia
Acute myelogenous leukemia
Acute myeloid leukemia (AML) is cancer that starts inside bone marrow. This is the soft tissue in the center of bones that helps form all blood cell...
Read Article Now Book Mark Article - Aplastic anemia
- Blood clots
- Death
-
Hemolytic anemia
Hemolytic anemia
Anemia is a condition in which the body does not have enough healthy red blood cells. Red blood cells provide oxygen to body tissues. Normally, red ...
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Iron deficiency anemia
Iron deficiency anemia
Anemia is a condition in which the body does not have enough healthy red blood cells. Red blood cells provide oxygen to body tissues. There are man...
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Myelodysplasia
Myelodysplasia
Myelodysplastic syndrome is a group of disorders in which the blood cells produced in the bone marrow do not mature into healthy cells. This leaves ...
When to Contact a Medical Professional
Contact your provider if you find blood in your urine, if symptoms worsen or do not improve with treatment, or if new symptoms develop.
Prevention
There is no known way to prevent this disorder.
References
Araten DJ, Brodsky RA. Paroxysmal nocturnal hemoglobinuria. In: Hoffman R, Benz EJ, Silberstein LE, et al, eds. Hematology: Basic Principles and Practice. 8th ed. Philadelphia, PA: Elsevier; 2023:chap 32.
Michel M. Autoimmune and intravascular hemolytic anemias. In: Goldman L, Cooney KA, eds. Goldman-Cecil Medicine. 27th ed. Philadelphia, PA: Elsevier; 2024:chap 146.
Review Date: 3/31/2024
Reviewed By: Todd Gersten, MD, Hematology/Oncology, Florida Cancer Specialists & Research Institute, Wellington, FL. Review provided by VeriMed Healthcare Network. Also reviewed by David C. Dugdale, MD, Medical Director, Brenda Conaway, Editorial Director, and the A.D.A.M. Editorial team.