Thrombocytopenia, Low Platelet Count and Bleeding

Blood platelets, also called thrombocytes, are made in the bone marrow. They play an important role in blood clotting and wound healing. The body has to regulate their numbers carefully: too many platelets, and blood clots can form where they don’t belong, obstructing blood flow; too few platelets, and a person could bleed to death from an injury. Thrombocytopenia is a condition in which the blood has a low platelet count.

Large cells in the bone marrow called megakaryocytes release cell fragments, which become the platelets. Platelets are much smaller than red blood cells and white blood cells and have a flat, disc shape until they are activated. They were given their name by earlier scientists, who thought that they looked like tiny plates. Platelets enter the blood and live for about seven to ten days.

The endothelium is the internal lining of the blood vessels. When the endothelium is damaged, chemicals which attract and activate platelets are exposed. As platelets are activated they change their shape. They become spherical and produce tentacle-like extensions. The activated platelets stick to each other and to the wound, forming a platelet plug that stops the bleeding from the wound. The activated platelets and proteins in the blood then work together to create a blood clot through a series of chemical reactions. The final reaction is the conversion of a dissolved blood protein called fibrinogen into solid fibrin threads, which form a mesh over the wounded area, trapping blood and platelets in a blood clot.

Human blood normally contains between 150,000 to 450,000 platelets in each microliter of blood. If someone’s platelet count is below 150,000 per microliter of blood, he or she is said to suffer from thrombocytopenia. A mild case of thrombocytopenia may not produce any symptoms. When the platelet count is reduced to around 50,000 platelets per microliter of blood, the person may experience minor bleeding problems. A platelet count of below 20,000 platelets per microliter of blood will cause serious symptoms.

If the bone marrow doesn’t make enough platelets, or if platelets are destroyed once they are made, thrombocytopenia will result. A person may have inherited a genetic problem that prevents him or her from making enough platelets. Alcohol and poisonous chemicals like arsenic, benzene and some pesticides can slow platelet production. In a disease called aplastic anemia the bone marrow doesn’t make enough blood cells or platelets. A deficiency in vitamin B12 and folic acid can reduce platelet manufacture. Cancer and cancer treatments can damage bone marrow and stop it from making blood platelets. An HIV, parvovirus or hepatitis C virus infection can decrease platelet production, and some types of diuretics and epilepsy drugs will also interfere with platelet manufacture.

Certain viruses can lower the platelet count. These include the Epstein-Barr virus, which causes mononucleosis and other health problems, the viruses that cause chickenpox, rubella (German Measles) and mumps, and the virus that causes dengue fever. Some bacterial infections in the blood also lower the platelet count.

The use of heparin, quinine, sulfa antibiotics, and some epilepsy drugs can lead to platelet destruction. Aspirin, ibuprofen and some antihistamines stop platelets from working normally, which will increase bleeding. Women may develop mild thrombocytopenia during pregnancy.

Autoimmune diseases are conditions in which a person’s body attacks its own cells. If these cells are platelets, thrombocytopenia can result. Platelets may be destroyed in rheumatoid arthritis and lupus. The body also destroys platelets in a disorder called idiopathic thrombocytopenic purpura (ITP). The term “idiopathic” means that the cause of the platelet destruction is unknown. “Purpura” means “bruises", referring to the bleeding under the skin that appears during this disease.

The spleen, which is located on the left side of the upper abdomen under the ribcage, normally stores up to one third of the platelets in the body. If the spleen is enlarged it will store too many platelets and a low blood platelet count will result. An enlarged spleen is a symptom of many disorders, such as viral and bacterial infections, some types of anemia, liver diseases and some types of cancer.

Internal or external bleeding is the main symptom of thrombocytopenia. There may be bruises on the skin and small red or purple skin spots which are known as petechiae. These spots usually appear on the legs. Someone with a low platelet count may find that they bleed a long time often even a small cut, and after brushing their teeth or visiting a dentist. Gums may bleed even without any mouth irritation. There may be bad nosebleeds and menstrual blood flow may be heavy. There may also be blood in the urine or stool, or bleeding from the rectum, which are serious symptoms because they indicate internal bleeding. In very severe thrombocytopenia there may be bleeding from the brain or heavy digestive tract bleeding, which can be fatal.

You should get checked by your doctor if you have any signs of increased bleeding. However, if you are found to have a mild case of thrombocytopenia you may not need treatment. More serious cases will require some form of treatment. Medication may need to be changed, infections will need to be treated, or drugs may be given to suppress the immune system. Corticosteroids may be prescribed to slow platelet destruction. Blood or platelet transfusion or spleen removal (splenectomy) may be necessary in severe cases.

Thrombocytopenia may be unnoticeable or a very minor problem, may be moderately serious or may be life threatening. If you have thrombocytopenia there are things that you can do to help yourself, even if you are receiving medical treatment. Avoid chemicals and medications which are known to hinder platelet production or destroy platelets, if possible. Eat nutritious foods and exercise regularly to boost your immune system and try to avoid infections. Tell your doctor about any supplements or herbal medicines that you are taking, since some of them may affect the blood platelet level. Try to avoid injuries as much as possible. Ask your doctor whether participating in contact sports or sports with a high risk of injury, such as skiing, are appropriate activities for you. Wear protective gloves, helmets or clothing when performing any activity that may cause an injury. Consider taking vaccines for illnesses known to lower platelet levels, if vaccines are available, and wear a medic alert bracelet or ID.