Thrombocytopenia refers to a low number of platelets in the blood. Normally, platelets help blood clot so that the bleeding will stop quickly. When the number of platelets is too low, a person may bleed or bruise more easily, even after a minor injury.
The normal value for platelets is 150–300 x 109 /L, but these values may vary from laboratory to laboratory. A person has thrombocytopenia when their platelet count is less than 100 x 109 /L. Their risk of bleeding and hemorrhage increases as the number of platelets drops.
Causes
- Platelet production can be decreased when cancer involves the bone marrow.
- Many drugs used during chemotherapy affect platelets in the bone marrow.
- Bone marrow suppression can also occur because of radiation. This will depend on the amount of bone marrow in the radiation treatment area.
- Some biological therapies, such as aldesleukin (Proleukin, Interleukin-2) or rituximab (Rituxan) may affect platelet levels.
- The amount of platelets circulating in the blood can be affected by cancers or conditions that can cause an enlarged spleen (hypersplenism) or if cancer spreads to the spleen. An enlarged spleen removes platelets from the bloodstream, making them unavailable for general circulation.
Symptoms
If the platelet count becomes very low, a person can have:
- bruising easily and/or tiny red spots (petechiae) under the skin
- unusual bleeding from the gums or nose
- excessive bleeding from a small cut
- prolonged bleeding from an injection site
- blood in the urine
- blood in the stool or black coloured stool
- vomiting "coffee ground" material
- vaginal bleeding (in women) that is different from the normal menstrual period and lasts longer
- persistent headache, blurred vision or change in level of consciousness
Low platelet counts caused by chemotherapy are usually temporary, but can cause a serious loss of blood or bleeding that can damage internal organs.
Diagnosis
Thrombocytopenia is usually diagnosed by:
taking a history of symptoms, medications, treatments and doing a physical examination
taking blood tests to check the level of platelets, bleeding and clotting times
doing a bone marrow aspiration and biopsy to find out the underlying cause (if not already known)
Management
To help prevent bleeding or bruising while platelet counts are decreased, try the following:
- Brush teeth gently with an extra soft toothbrush, sponge toothette, cotton swabs or gauze. Be very gentle and careful with flossing and avoid areas that are bleeding. Follow the healthcare team's advice about flossing. They may recommend not flossing for awhile.
- Keep lips moist and prevent cracking by using a lip balm.
- Use pads instead of tampons during menstruation.
- Be very gentle when blowing the nose.
- Avoid straining with bowel movements and take steps to prevent constipation. Ask the doctor about taking a stool softener.
- Use an electric razor instead of a razor for shaving.
- Do not take any over-the-counter medications, such as pain relievers or cold remedies, without checking first with the doctor or healthcare team. These medications may contain aspirin or other drugs that can weaken the platelets and make bleeding problems worse.
- Avoid activities or contact sports that might result in an injury or bruising.
- Check with the healthcare team about restrictions on sexual activity when platelet counts are low.
- Be extra careful when using a knife or any type of sharp tool.
- Wear protective gloves when working in the garden or near plants that have thorns.
- Rectal temperatures, rectal suppositories, enemas or injections into the muscle (intramuscular) cannot be given while platelet counts are low.
- Report easy bruising or unusual bleeding to the doctor or healthcare team.
If the platelet count becomes too low, cancer treatments may be delayed for a short period of time. Chemotherapy drugs are sometimes stopped temporarily if the platelet count is too low.
Blood transfusions
Platelet transfusions are the main treatment for thrombocytopenia that results from bone marrow suppression caused by cancer treatment. Platelet transfusions are given if the platelet count becomes very low or if the person has symptoms of bleeding. Fever and infection can increase the use of platelets, so pre-medications may be given before a transfusion to help lessen this effect.