Thrombocytopenia

Definition

Thrombocytopenia is any disorder in which there is an abnormally low amount of platelets. Platelets are parts of the blood that help blood to clot. This condition is sometimes associated with abnormal bleeding.

Alternative Names

Causes, incidence, and risk factors

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

1. Not enough platelets are made in the bone marrow
2. Increased breakdown of platelets in the bloodstream
3. Increased breakdown of platelets in the spleen or liver

Your bone marrow may not make enough platelets if you have:

• Aplastic anemia
• Cancer in the bone marrow such as leukemia
• Cirrhosis (liver scarring)
• Folate deficiency
• Infections in the bone marrow (very rare)
• Myelodysplasia
• Vitamin B12 deficiency

Use of certain drugs may also lead to a low production of platelets in the bone marrow. The most common example is chemotherapy treatment.

The following health conditions cause increased breakdown of platelets:

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

Symptoms

You may not have any symptoms. General symptoms include:

• Bleeding in the mouth and gums
• Bruising
• Nosebleeds
• Rash (pinpoint red spots called petechia)

Other symptoms depend on the cause.

Signs and tests

Your health care provider will perform a physical exam and ask questions about your medical history and symptoms. The following tests may be done:

• Complete blood count (CBC) 
• Blood clotting studies (PTT and PT)

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.

Support Groups

Expectations (prognosis)

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

Complications

Severe bleeding (hemorrhage) is the main complication. Bleeding may occur in the brain or gastrointestinal tract.

Calling your health care provider

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

Prevention

Prevention depends on the specific cause.

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References

McMillan R. Hemorrhagic disorders: abnormalities of platelet and vascular function. In: Goldman L, Ausiello D, eds. Cecil Medicine. 24th ed. Philadelphia, Pa: Saunders Elsevier; 2011:chap 175.