Thrombocytopenia

Definition

Thrombocytopenia is any disorder in which there are not enough platelets. Platelets are cells in the blood that help blood to clot. This condition is sometimes associated with abnormal bleeding.

Causes, incidence, and risk factors

Thrombocytopenia is often divided into three major causes of low platelets:

1. Low production of platelets in the bone marrow
2. Increased breakdown of platelets in the bloodstream (called intravascular)
3. Increased breakdown of platelets in the spleen or liver (called extravascular)

Disorders that involve low production in the bone marrow include:

• Aplastic anemia
• Cancer in the bone marrow
• Infections in the bone marrow (very rare)
• Myelodysplasia

Use of certain drugs may also lead to a low production of platelets in the bone marrow, although this is rare.

Disorders that involve the breakdown of platelets include:

• Disseminated intravascular coagulation (DIC)
• Drug-induced nonimmune thrombocytopenia
• Drug-induced immune thrombocytopenia
• Hypersplenism
• Immune thrombocytopenic purpura (ITP)
• Thrombotic thrombocytopenic purpura

Symptoms

• Bruising
• Nosebleeds or bleeding in the mouth
• Rash (pinpoint red spots called petechiae)

Other symptoms may be present as well, depending on the cause of the condition. Mild thrombocytopenia can occur without symptoms.

Signs and tests

Complete blood count (CBC) shows low number of platelets. Blood clotting studies (PTT and PT) are normal.

Other tests that may help diagnose this condition include:

• Bone marrow aspiration or biopsy
• Platelet associated antibodies

Treatment

Treatment depends on the cause of the condition. In some cases, a transfusion of platelets may be required to stop or prevent bleeding.

Expectations (prognosis)

The outcome depends on the disorder causing the low platelet counts.

Complications

Severe bleeding (hemorrhage) is the main complication. This can include:

• Bleeding in the brain (intracranial hemorrhage)
• Gastrointestinal bleeding (vomiting blood or blood in the stools )

Calling your health care provider

Call your healthcare provider if you experience unexplained bleeding or bruising.

Prevention

Prevention depends on the specific cause.

References

Goldman L. Ausiello D. Cecil Textbook of Medicine. 23rd ed. Philadelphia, Pa: WB Saunders; 2007:1291-1299.