Paroxysmal nocturnal hemoglobinuria (PNH)
PNH
Paroxysmal 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...
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.
- Back pain
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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...
- Dark urine, comes and goes
- Easy bruising or bleeding
-
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...
-
Shortness of breath
Shortness of breath
Breathing difficulty may involve:Difficult breathingUncomfortable breathingFeeling like you are not getting enough air
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 red blood cells (RBC count)The number of white blood cells (WBC count)The tota...
-
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.
- Flow cytometry to measure certain proteins
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Ham's (acid hemolysin) test
Ham's (acid hemolysin) test
The Ham test is a blood test to diagnose paroxysmal nocturnal hemoglobinuria (PNH). This rare condition causes red blood cells to die before they sh...
-
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...
-
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 low-...
-
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...
- Urine hemosiderin
Treatment
Steroids or other drugs 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) is a drug used to treat PNH. It blocks the breakdown of red blood cells.
Bone marrow transplantation can cure this disease.
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
- Aplastic anemia
- Blood clots
- Death
- Hemolytic anemia
-
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...
- Myelodysplasia
When to Contact a Medical Professional
Call 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
Brodsky RA. Proxymal nocturnal hemoglobinuria. In: Hoffman R, Benz EJ Jr., Silberstein LE, Heslop HE, Weitz JI, Anastasi J, eds. Hematology: Basic Principles and Practice . 6th ed. Philadelphia, PA: Elsevier Churchill Livingstone; 2013:chap 29.
Michel M. Autoimmune and intravascular hemolytic anemias. In: Goldman L, Schafer AI, eds. Goldman's Cecil Medicine . 25th ed. Philadelphia, PA: Elsevier Saunders; 2016:chap 160.
Schafer AI. Thrombotic disorders. In: Goldman L, Schafer AI, eds. Goldman's Cecil Medicine . 25th ed. Philadelphia, PA: Elsevier Saunders; 2016:chap 176.
Review Date: 2/1/2016
Reviewed By: Todd Gersten, MD, Hematology/Oncology, Florida Cancer Specialists & Research Institute, Wellington, FL. Review provided by VeriMed Healthcare Network. Also reviewed by David Zieve, MD, MHA, Isla Ogilvie, PhD, and the A.D.A.M. Editorial team.