FAMILY MEDICINE® COLUMN
By John C. Wolf, D.O.
Associate Professor of Family Medicine®
Ohio University College of Osteopathic Medicine

WITHOUT PLATELETS MINOR BUMPS AND BRUISES WOULD BE DEADLY

Question: My daughter has had a platelet count of 83,000 for the last two months. I understand that this is low. She has been taking treatment for this. Could you explain in layman's terms just what platelets are and what they do?

Answer: Human blood contains many important things, including glucose, hormones, red blood cells, white blood cells and platelets. Each of these components performs an "essential for life" job. Glucose provides each cell with necessary nutrition, hormones regulate metabolism, red blood cells carry oxygen to each cell, white blood cells fight infection, and platelets are an important link in our defense against bleeding. You may think that this isn't very important because you haven't cut yourself in years but it is.

Each of us bleeds every day. Minute damage occurs to small blood vessels from very minor trauma such as pulling on a drawer handle, firmly grasping a steering wheel or brushing our teeth. This allows the blood to escape from the blood vessels into the neighboring tissue. A simple bruise results when this occurs in a vessel that is close to the skin surface. Yes, bruises are nothing more elaborate than bleeding under the skin.

Platelets stick to the surface of an injured blood vessel and start a cascade of physical and biochemical events that ultimately stop the bleeding. Individuals with a low count usually considered below 150,000 platelets per cubic millimeter (a tiny cube, 1/25 inch on each side) often have easy bruising, nosebleeds, bleeding from minor gum injury such as from brushing teeth, blood in the urine, and if female, heavy menstrual periods. Occasionally, though, individuals can have low platelet counts without any symptoms.

There are several problems that can cause a person to have a low platelet count. Occasionally this occurs as part of an inherited disorder such as Bernard-Soulier syndrome or Glanzmann's thrombasthenia, but more commonly it results from complications of chronic kidney failure, coronary artery bypass surgery or medications.

The best treatment for the condition depends upon the platelet count level and the underlying cause. Very low platelet counts increase the risk of serious bleeding, and therefore, require more aggressive treatment. Moderately low counts, such as your daughter's, are usually best treated by being careful to avoid injury that would cause bleeding while identifying and treating the underlying condition.

Low platelet counts occur most often because of taking medications. Antibiotics, particularly sulfa and penicillin, seizure medication, some heart medicines, and arthritis drugs are the most common offenders. In addition, aspirin and other non-steroidal anti-inflammatory drugs interfere with the proper functioning of platelets even though they don't actually decrease the number of them. (This is how aspirin reduces the risk of a second heart attack in someone who has already had one.)

So, platelets are physically a very small component of blood, but they play a very large role in keeping each of us from bleeding to death from the minor bangs and bruises of daily living.

Family Medicine® is a weekly column. To submit questions, write to John C. Wolf, D.O., Ohio University College of Osteopathic Medicine, Grosvenor Hall, Athens, Ohio 45701.