What is Mechanical Hemolytic Anemia and how to manage it?


Mechanical hemolytic anemia is a form of hemolytic anemia (rupturing of cells) that is caused by mechanically-induced damage to the red blood cells in the bloodstream. The red blood cells are exposed to trauma that literally causes them to tear open despite the flexibility of their cellular membranes.



The repetitive impact to certain areas of the body may result in this condition and examples of involved anatomy and activities include:

  • The feet of runners and those who use their feet for extensive physical exertion such as soldiers who have been marching for long periods of time.1 Others who may experience the same issue include weightlifters, cyclists, rowers, ballet dancers, basketball players, and tennis players.
  • The hands of people who perform excessive hand strengthening exercises such as martial artists and also those who bang on Conga or Candombe drums.

Other factors may also cause the membranes of the red blood cells to become compromised and weak and include intrinsic and extrinsic issues.2

Intrinsic (internal) factors may include:

  • Thalassemia
  • Sickle-cell anemia
  • G6PD deficiency of an enzyme of a red blood cell
  • Paroxysmal nocturnal hemoglobinuria
  • Hereditary spherocytosis

Extrinsic (external) factors may include:

  • Infections causing damage to red blood cells.
  • Autoimmune conditions such as systemic lupus erythematosus, rheumatoid arthritis, and chronic lymphocytic leukemia, as well as autoimmune reactions from receiving ABO incompatible blood through transfusions.
  • Exposure to medications such as rifampin, quinine, interferon alpha, ibuprofen, acetaminophen, procainamide, ampicillin, penicillin, and methicillin.
  • Infections from Plasmodium parasites and malaria.
  • Prosthetic heart valve replacement which also causes a mechanical type of hemolysis.


Risk factors

The following factors increase the chances of developing mechanical hemolytic anemia by increasing the physical impact on feet:

  • Using incorrect or old, worn out running shoes.
  • Using very hard trail paths to run on.
  • Performing high-intensity training at an increased frequency.
  • Overtraining by performing consecutive exercise sessions.
  • Having a faulty running stride or gait.
  • Having any pre-existing condition like those already mentioned.


Signs and symptoms

Since the red blood cells are damaged the following signs and symptoms occur in marching hemolytic anemia:

  • Anemia – increased paleness of the skin due to decreased hemoglobin being available in the red blood cells to give the skin a characteristic reddish/pink appearance.
  • Dizziness, confusion, lightheadedness, and fatigue – since the hemoglobin leaks out of the red blood cell, the non-availability of this protein reduces oxygen transport to areas of the body that need this essential life-sustaining gas such as the brain and muscles.
  • Shortness of breath and heart palpitations – since oxygen transport is compromised, the body tries to compensate by involving the lungs and heart to get more air in and increasing the blood flow through the body.
  • Enlargement of the spleen – this occurs due to the destroyed red blood cells becoming trapped in this organ thereby causing it to enlarge.
  • Dark colored urine – the hemoglobin that leaks out of the red blood cells end up in the urine causing the fluid to appear darker. This is called hemoglobinuria.
  • Yellow discoloration of the eyes and/or skin – bilirubin also leaks out of the red blood cells thereby re-entering the bloodstream to make the skin appear jaundiced and also causes the skin to become itchy.

These issues will occur when the rate of red blood cell hemolysis occurs faster than the production of these cells.




If the condition is left untreated or not managed adequately enough then the following complications may occur:

  • Strength loss due to poor oxygen supply to the muscles.
  • Gallstones develop in the gallbladder.
  • Blood clots (thrombosis) may form in the deep venous system.



Mechanical hemolytic anemia due to increased physical impact to the feet can be prevented by making sure the correct running equipment is used, wearing proper insoles to help absorb some of the impact, running on softer surfaces, using the correct posture and gait when running, and incorporating folic acid supplementation to help improve the stability of the cell membranes of the red blood cells.




1. Telford R.D., Sly G.J., Hahn A.G., Cunningham R.B., Bryant C., & Smith J.A. Footstrike is the major cause of hemolysis during running. Journal of Applied Physiology. January 2003 Vol. 94 no. 1, 38-42

2. Tabbara I.A. Hemolytic anemias. Diagnosis and management. Med Clin North Am. 1992.

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