Low platelet count (thrombocytopenia)

Thrombocytopenia is a condition caused by a low number of platelets in the blood. Platelets are also called thrombocytes. They are made in the bone marrow and help the blood to clot. People with a low number of platelets may bleed or bruise easily, even after a minor injury. A low platelet count increases the risk of bleeding, especially from the mouth, nose and gastrointestinal tract.

Normal levels of platelets may vary between labs. Generally, the normal range for platelets is 150,000–300,000/mm³. A person has thrombocytopenia when the platelet count is less than 150,000/mm³.

Thrombocytopenia may develop if the bone marrow isn’t working normally and doesn’t make enough platelets. Some cancers, such as leukemia, can cause thrombocytopenia. The following cancer treatments can also affect the bone marrow and lead to a low platelet count:

• chemotherapy drugs, biological therapies or other drugs
• radiation therapy to the pelvis or to a large amount of bone marrow

People can also develop thrombocytopenia if the spleen is enlarged (hypersplenism) or if cancer spreads to the spleen. The spleen makes lymphocytes, which are a type of white blood cell that fights germs, foreign substances or cancer cells. It also stores blood cells, filters the blood and destroys old blood cells. An enlarged spleen removes too many platelets from the bloodstream, making them unavailable to circulate throughout the body.

Symptoms of thrombocytopenia usually don’t develop until the number of platelets is very low. Symptoms of low platelet count may begin soon after chemotherapy starts, but they are usually at their worst 10–14 days after you first receive chemotherapy.

Symptoms of a low platelet count include:

• bruising easily
• tiny red spots, or petechiae, under the skin
• unusual bleeding from the gums or nose
• a lot of or long-lasting bleeding from a small cut or injection site
• blood in the urine, which may look pink, red or brown
• blood in the stool or black-coloured stool
• vomiting blood or something that looks like coffee grounds
• vaginal bleeding that is different from and lasts longer than the normal menstrual period
• constant headache, blurred vision or change in level of consciousness

Thrombocytopenia caused by chemotherapy is usually temporary, but it can cause a serious loss of blood or bleeding that can damage internal organs.

Your doctor will try to find the cause of thrombocytopenia. This may include asking questions about your symptoms, any medicines you take and treatments you’ve had. Your doctor will also do a physical exam.

Thrombocytopenia is usually diagnosed by:

• blood tests to check the level of platelets as well as bleeding and clotting times
• bone marrow aspiration and biopsy to find out the underlying cause (if not already known)

It may be difficult to prevent thrombocytopenia caused by cancer or chemotherapy. You can try the following to help prevent bleeding or bruising if your platelet counts are low.

Rinse and brush your teeth after you eat. Brush your teeth gently with an extra-soft toothbrush, sponge toothette, cotton swabs or gauze so that gums do not bleed. Soften your toothbrush with hot water before each use.

Be very gentle and careful when flossing. Avoid areas that bleed easily. The healthcare team may recommend that you not floss until platelet counts return to normal.

Use a lip balm or petroleum jelly to keep lips moist and prevent cracking.

Check with your healthcare team before having any dental work done.

Avoid activities or contact sports that might result in an injury or bruising. Check with your healthcare team before using any complementary therapy that uses pressure or massage techniques, such as acupuncture, shiatsu, yoga or chiropractic therapy. Ask your healthcare team if any precautions should be taken during sexual activity when platelet counts are low.

Bend your knees and squat instead of bending over. This keeps the head above the level of the heart and avoids extra pressure on the blood vessels in the head and neck.

If children have low platelet counts, pad their bed, crib and playpen.

Apply a moisturizing lotion regularly to keep the skin moist. Use an electric razor instead of a disposable razor to prevent cutting the skin. Wear protective gloves when working in the garden or near plants that have thorns.

Be extra careful when using a knife or any type of sharp tool. Avoid getting burned when ironing or cooking. Use oven mitts instead of pot holders to remove hot items from the oven.

Check with your doctor before receiving any injections in the muscle (intramuscular).

Use pads instead of tampons during menstruation. Do not use rectal suppositories, enemas or rectal thermometers. Avoid blowing the nose forcefully.

Avoid foods that are sharp, crunchy, spicy or acidic. Eat a soft diet, such as soup, mashed potatoes, custards, Jell-O or pudding. Do not drink alcohol. Drink plenty of fluids and eat enough fibre to avoid constipation. Avoid straining during bowel movements. If you are constipated, ask your doctor about taking a stool softener.

Do not take any over-the-counter medicines, such as pain relievers or cold remedies, without checking with the doctor first. These medicines may contain aspirin or other drugs that can weaken the platelets and make bleeding problems worse.

Contact your healthcare team if any of the following bleeding problems get worse or cannot be controlled after 10 minutes.

If you get a nosebleed, sit up with your head tilted forward. Press a cold cloth on both sides of your nose continuously for 10 minutes. You can also apply a cold cloth to the back of your neck.

If you can easily reach the bleeding area, apply gentle pressure until it stops. If you can’t apply pressure to the area, hold ice water in your mouth or suck on a popsicle or ice cubes until the bleeding stops.

Hold a clean dry cloth against the cut for at least 10 minutes. If possible, lift the injured body part above the level of the heart. Do not apply a tourniquet to control bleeding because this can cause permanent tissue damage.

Hold a soft cloth or an ice pack on the area with gentle but firm pressure for at least 10 minutes. Lift the area above the level of the heart if possible.

If cancer causes low platelet counts, every attempt is made to treat the cancer. However, the treatment itself may cause thrombocytopenia. When chemotherapy causes low platelet counts, the dose may have to be lowered or the length of time between chemotherapy cycles may have to be longer.

If your platelet count is less than 20,000/mm³ and you are bleeding or have a lot of bruising, you may need a platelet transfusion. Transfused platelets only last about 3 days, so some people may need more than one transfusion.

Fever and infection can increase the body’s need for platelets. Medicines may be given before a transfusion to reduce a fever and clear up an infection so the body doesn’t need as many platelets.

The healthcare team may also give medicines to help the body make more platelets. These are called growth factors. Interleukin-11 is an example of a growth factor. Growth factors may help prevent severe thrombocytopenia.