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Paroxysmal Nocturnal Hemoglobinuria: Symptoms and Complications

Symptoms of PNH tend to occur in episodes, but PNH can lead to serious complications, especially if untreated.

Blood transfusions may be given to increase the amount of red blood cells or platelets that have been destroyed by PNH.

Paroxysmal nocturnal hemoglobinuria (PNH) is a rare and potentially life-threatening blood disorder. When a person has PNH, genetic mutations cause the bone marrow to produce defective blood cells, which are then destroyed by a part of the immune system called the complement system. PNH affects the body’s supply of red blood cells, white blood cells, and platelets, leading to a number of symptoms and complications.

Symptoms of PNH

The symptoms of PNH can vary from one person to the next. Symptoms can occur in episodes, which may be triggered by an illness or physical exertion. The severity of the disease can range from mild to life-threatening. Signs and symptoms include:

  • Dark urine
  • Fatigue
  • Shortness of breath
  • Pale skin (pallor)
  • Abdominal pain
  • Headaches
  • Blood clots (thrombosis)
  • Easy bruising or bleeding
  • Difficulty swallowing
  • Enlarged spleen
  • Infections

Treatment for PNH

There is no cure for PNH, but there are treatments that can help control the disease, reduce symptoms, and reduce the risk of complications. Treatment can include:

  • Anticomplement drugs. Also called complement inhibitors. These are medications that act on the complement system, the part of the immune system that destroys blood cells when a person has PNH. These drugs work by blocking or inhibiting certain proteins in the complement system.
  • Blood transfusions. If a person is anemic as a result of having PNH, blood transfusions may be given to increase the amount of red blood cells or platelets that have been destroyed by PNH.
  • Stem cell transplant. An allogenic stem cell transplant is a potential cure for PNH, but it carries significant risks and is only recommended for people with severe PNH who have not been successful with other treatments. An allogenic stem cell transplant is also called a bone marrow transplant.

Sometimes, even with treatment, symptoms can return. This is known as breakthrough hemolysis. Contact your healthcare provider if you experience any new symptoms, any reappearance of symptoms, or any worsening symptoms.

Complications of PNH

Because every organ and system in the body depends on an adequate supply of blood cells to function and remain healthy, PNH can cause a wide variety of complications and can damage the body in a number of ways. Examples of possible serious complications of PNH include:

  • Thrombosis. Thrombosis refers to blood clots that form in the veins and arteries. It is not fully understood how PNH contributes to thrombosis, but thrombosis is common among people who have PNH. Symptoms depend on where the clot occurs. Some blood clots cause no symptoms. Others can block blood supply to major organs, including the heart, lungs, and brain, causing life-threatening complications (heart attack, pulmonary embolism, stroke).
  • Bone marrow failure. PNH can also lead to bone marrow failure, where the body can no longer make enough blood cells, including red blood cells, white blood cells, and platelets. Complications can include infections, bleeding, and some cancers.
  • Chronic kidney disease. PNH can damage the kidneys, organs that the body depends on to filter out waste and balance blood volume. This can lead to high blood pressure, fluid retention, and other problems.

These are not the only possible complications of PNH. PNH is a condition that affects different people in different ways. If you have questions about your diagnosis, your treatment options, and reducing your risk of complications, your best source of information will be your healthcare provider.

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