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Hemolysis Is the Cause of PNH


What you should know about hemolysis

  • Hemolysis is the destruction of red blood cells by complement , part of the body’s own defense system
  • In PNH , hemolysis is always happening
  • Ongoing hemolysis is the root cause of the signs, symptoms, and serious health problems of PNH
  • A simple blood test for LDH measures the level of your hemolysis
  • Reducing hemolysis is key to managing PNH

PNH is just like an iceberg

What you can’t see or feel can hurt you the most

You cannot always see or feel hemolysis, which makes it tough to discover. Left unmanaged, hemolysis can make you feel very tired and weak. It can also lead to signs and symptoms like:

  • Fatigue
  • Impaired health-related quality of life
  • Trouble swallowing
  • Stomach pain
  • Shortness of breath
  • Dark-colored urine
  • Erectile dysfunction (ED)

Why is hemolysis so bad?

When red blood cells burst during hemolysis, they release hemoglobin . Hemoglobin is good for the body when it’s inside your red blood cells. When it’s outside, it is very dangerous and can harm your body in many ways.

Even if you can’t see or feel hemolysis, you can still have serious health problems. These health problems can include:

  • Kidney failure
  • Blood clots
  • Stroke
  • Heart attack
  • Damage to your liver, brain, and lungs

In this way, PNH is just like an iceberg—what you can’t see or feel can hurt you the most.


Is there a test for hemolysis?

Your doctor can test for hemolysis through a simple blood test for lactate dehydrogenase (LDH) . LDH is an enzyme found inside red blood cells. If you have high levels of LDH in your bloodstream, it means a lot of your red blood cells have been destroyed.

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Dr. Jack Goldberg, a specialist of blood and blood diseases, explains how destruction of red blood cells by the body’s immune system can lead to a condition called intravascular hemolysis.

Listen as Batina, an actual PNH patient, describes her experience with PNH.

Watch Scott, a PNH patient, talk about being proactive with his disease.

References: 1. Hillmen P, Lewis SM, Bessler M, et al. N Engl J Med. 1995;333:1253-1258. 2. Rachidi S, Musallam KM, Taher AT. Eur J Intern Med. 2010;21:260-267. 3. Rosse WF. Paroxysmal nocturnal hemoglobinuria. In: Hoffman R, Benz EJ Jr, Shattil SJ, et al, eds. Hematology: Basic Principles and Practice. 3rd ed. New York, NY: Churchill Livingstone; 2000:331-342. 4. Borowitz MJ, Craig FE, DiGiuseppe JA, et al; for Clinical Cytometry Society. Cytometry Part B. 2010;78B:211-230. 5. Lee JW, Jang JH, Kim JS, et al. Blood. 2011;118: Abstract 3166. 6. Rother RP, Rollins SA, Mojcik CF, et al. Nat Biotechnol. 2007;25:1256-1264. [Published correction appears in Nat Biotechnol. 2007;25:1488]. 7. Hill A, Sapsford RJ, Scally A, et al. Br J Haematol. 2012;158:409-414. 8. Rother RP, Bell L, Hillmen P, et al. JAMA. 2005;293:1653-1662. 9. Hillmen P, Elebute M, Kelly R, et al. Am J Hematol. 2010;85:553-559. 10. Kelly R, Richards S, Hillmen P, et al. Ther Clin Risk Manag. 2009;5:911-921. 11. Hillmen P, Muus P, Dührsen U, et al. Blood. 2007;110:4123-4128. 12. Adams T, Fleischer D, Marino G, et al. Dig Dis Sci. 2002;47:58-64. 13. Brodsky RA. Paroxysmal nocturnal hemoglobinuria. In: Hoffman R, Benz EJ Jr, Shattil SJ, et al, eds. Hematology: Basic Principles and Practice. 4th ed. Philadelphia, PA: Elsevier Churchill Livingstone; 2005:419-427.