Thrombocytopenia

What is thrombocytopenia?

Thrombocytopenia is an abnormally low level of platelets in the blood. Platelets are made by the bone marrow. They help your blood to clot. People with thrombocytopenia can have excessive bleeding.

This condition can occur in varying degrees. The risk of bleeding increases as the platelet count decreases.

Thrombocytopenia can occur alone. Or, it can develop as a complication of another disease, such as cancer or a viral infection. In some cases, it is a chronic (long-lasting) condition that persists for years. In other cases, it develops suddenly and dramatically.

In general, thrombocytopenia develops for one or more of the following reasons:

• The body's bone marrow fails to produce enough platelets. This has many possible causes, including:
  • Cancer gets into the bone marrow and destroys megakaryocytes. These are the cells that produce platelets.
  • Aplastic anemia affects platelet production.
  • A toxic chemical, radiation therapy, or chemotherapy destroys megakaryocytes.
  • Genetic problems hinder production of normal platelets.
  • Exposure to certain drugs or alcohol slows the production of megakaryocytes. Thrombocytopenia is common in heavy drinkers.
  • After suffering from a viral infection, some patients will have decreased platelet production. This problem is usually short-term and improves without treatment.
• The bone marrow produces enough platelets, but the body destroys them. Causes of platelet destruction include:
  • Immune thrombocytopenic purpura (ITP): With ITP, platelets are attacked by antibodies produced by a faulty immune system. This condition can pass quickly or can last a long time. ITP can occur by itself, or it can be associated with other autoimmune disorders such as systemic lupus erythematosus (SLE).
  • A complication of pregnancy: While a mildly low platelet count is common and usually harmless during pregnancy (due to expected changes in the concentration of blood), a small percentage of pregnant women develop platelet destruction when they are close to delivery.
  • A reaction to a medication: For example, heparin, quinine, and valproic acid (Depakote) can trigger the immune system to make antiplatelet antibodies. In most cases, the condition develops within days of starting a new drug.
  • Physical trauma: Platelets can be injured or destroyed as they pass through:
    • an artificial heart valve
    • a blood vessel graft
    • machines and tubing used in massive blood transfusions or cardiopulmonary bypass surgery.
  • Infections: The condition can develop after some infections as HIV, mononucleosis, or cytomegalovirus.
  • Thrombotic thrombocytopenic purpura (TTP): This is a rare disease. Blood clots form in the smallest arteries throughout the body. Platelets are consumed by this process. People with TTP also have anemia (low red blood cell count), fever, kidney malfunction, and neurological symptoms.
• Too many platelets remain in the spleen. Normally, about a third of your platelets are in your spleen. The rest are circulating in your blood. However, if the spleen gets larger because of liver disease, cancer, infection, or another condition, it can begin to hoard too many platelets. This leaves fewer platelets to circulate in your bloodstream.

Symptoms of thrombocytopenia

People with severe thrombocytopenia may have abnormal bleeding almost anywhere in the body.

Symptoms can include:

• reddish or purplish spots in the skin (called petechiae), often concentrated in the lower legs
• excessive bruising, even from minor trauma
• blood in the urine or stool
• abnormal or excessive bleeding from the mouth or nose
• abnormal vaginal bleeding, especially unusually heavy menstrual flow
• bleeding inside the gastrointestinal tract, including bleeding from the rectum
• excessive bleeding after surgery or dental work
• fatigue or shortness of breath due to anemia that follows blood loss
• headache and other neurological symptoms caused by bleeding inside the brain. This is extremely rare and only occurs when platelet counts become extremely low. 

Diagnosing thrombocytopenia

Your doctor will begin by asking you about your medical history. He or she will ask about:

• recent medical procedures or hospitalizations (people often get heparin in the hospital to prevent blood clots)
• whether you have received any blood transfusions
• current medications (including over-the-counter and herbal remedies)
• how much alcohol you drink
• your diet
• recent infections or vaccinations
• if you have any achy joints or rashes
• if anyone in your family has ever had low platelets levels
• whether you are pregnant and, if so, your due date.

Your doctor will examine you for specific signs of abnormal bleeding. These include bruises or blood spots in your skin. He or she also will feel your abdomen to determine whether your spleen is enlarged. The doctor will look for any signs of liver disease.

To confirm the diagnosis, your doctor will order a blood test. The blood test will measure the number of platelets in your blood. Additional blood tests will be ordered at the same time to help diagnose why you have thrombocytopenia.

If your doctor thinks you may be having a reaction to a drug, he or she may ask you to stop taking the medication. The doctor will then see if your platelet count rises. If that happens, you have drug-induced thrombocytopenia.

Your doctor may recommend a bone marrow biopsy. In this procedure, a long needle is used to remove a small piece of bone marrow. The marrow is examined in a laboratory. The appearance of your bone marrow and platelet-producing cells may help to determine what is causing the condition.

Expected duration of thrombocytopenia

How long thrombocytopenia lasts depends on its cause.

For example, some patients with chronic ITP experience years of easy bruising and abnormally heavy vaginal bleeding. They may have repeated episodes of more severe bleeding.

Most children with acute ITP recover within four to six weeks, and most cases of pregnancy-related thrombocytopenia improve soon after delivery.

Many people with drug-induced thrombocytopenia recover within seven to 10 days after they stop taking the medication.

Preventing thrombocytopenia

Many cases of thrombocytopenia cannot be prevented.

You can avoid drinking large amounts of alcohol to lower your risk of developing alcohol-related thrombocytopenia.

If you already have had one episode of drug-induced thrombocytopenia, the problem is likely to return if you take the same medication again. To help prevent this, record the name of the specific medication that caused the problem. Tell every health care professional that you visit about your sensitivity to this drug, and wear a medical alert bracelet with this information.

If your doctor has determined that you are at risk of developing this condition, he or she may suggest you not take aspirin or other anti-inflammatory drugs such as ibuprofen, because these medicines impair platelet function and could further increase the risk of bleeding.

Treating thrombocytopenia

How thrombocytopenia is treated depends on its cause and severity.

If your thrombocytopenia is mild and is not causing any significant bleeding, you may not need treatment. This is often the standard strategy for children with acute ITP, and for most prgenancy-related cases of thrombocytopenia.

If your thrombocytopenia is drug-induced, your physician may change your prescription. Most people recover without additional treatment after they stop taking the medication.

Patients with very low platelet counts and/or significant bleeding will need more aggressive treatment. For example, people with ITP may be treated with:

• Steroids, immunoglobulin, or transfusions: The first choice of treatment is usually glucocorticoids taken by mouth or given intravenously. Immunoglobulin also may be given intravenously. Transfusions of platelets are usually reserved for patients with very low platelet counts or active bleeding. Red blood cell transfusions may be recommended for significant blood loss and/or anemia.
• Medications that can increase production or decrease destruction of platelets: Rituximab (Rituxan), romiplostim (Nplate), eltrombopag (Alvaiz, Promacta, others), avatrombopag (Doptelet), or fostamatinib (Tavalisse) may be helpful. If not, other treatments are available including danazol (Cyclomen, others), dapsone (generic), or other immune-suppressing medications (such as mycophenolate mofetil/Cellcept or azathioprine/Imuran). Combinations of these treatments may be effective when individual treatments are not.
• Splenectomy (surgical removal of the spleen): This may be offered for ITP that has not improved with other treatments. If the spleen is removed, a lasting improvement follows in up to three-fourths of cases.

When to call a professional

Call your doctor if you develop any of the symptoms of thrombocytopenia. Be sure to call if you notice abnormal bruises or if you experience significant bleeding from your nose, mouth, vagina, rectum or urinary tract.

Prognosis

The overall outlook is generally good. This is especially true if the cause can be identified and removed or treated. Long-term management of the condition is often successful. The prognosis is excellent for those who have such mild disease that they have no noticeable bleeding problems and require no treatment.

Additional info

National Heart, Lung, and Blood Institute (NHLBI)
https://www.nhlbi.nih.gov/