Congenital platelet function defects

Definition

Congenital platelet function defects are problems with platelets, one of the blood elements needed for normal blood clotting. Congenital means present from birth.

Alternative Names

Platelet storage pool disorder; Glanzmann's thrombasthenia; Bernard-Soulier syndrome; Platelet function defects - congenital

Causes

Platelets are elements in the blood that help form clots. Congenital platelet function defects are bleeding disorders that cause reduced platelet function, even though there are normal platelet counts.

People with these disorders usually have a family history of a bleeding disorder that causes prolonged bleeding after minor cuts or surgery, or easy bruising.

• Bernard-Soulier syndrome occurs when platelets lack a substance that sticks to the walls of blood vessels. This disorder may cause severe bleeding.
• Glanzmann's thrombasthenia is a condition caused by the lack of a protein needed for platelets to clump together. This disorder may also cause severe bleeding.
• Platelet storage pool disorder (also called platelet secretion disorder) is due to one of several defects that cause easy bleeding or bruising. It is caused by the faulty storage of substances inside platelets. These substances are usually released to help platelets function properly.

Symptoms

• Bleeding during and after surgery
• Bleeding gums
• Easy bruising
• Heavy menstrual periods
• Nosebleeds (epistaxis)
• Prolonged bleeding with small injuries

Exams and Tests

The following tests may be used to diagnose this condition:

• Bleeding time
• Complete blood count (CBC)
• Partial thromboplastin time (PTT)
• Platelet aggregation test
• Prothrombin time (PT)

You may need other tests. Your relatives may need to be tested.

Treatment

There is no specific treatment for these disorders.

People with bleeding disorders should avoid taking aspirin and nonsteroidal anti-inflammatory drugs (such as ibuprofen and naproxen) because they are known to affect blood clotting. Patients who have severe bleeding may need platelet transfusions.

Outlook (Prognosis)

Treatment can usually control the bleeding. However, congenital platelet function defects are life-long conditions. There is no cure. Patients should take precautions to avoid bleeding.

Possible Complications

• Severe bleeding
• Iron deficiency anemia in menstruating women

When to Contact a Medical Professional

Call your health care provider if:

• You have bleeding or bruising and do not know the cause
• Bleeding does not respond to the usual method of control

Prevention

A blood test can detect the gene responsible for the platelet defect. Genetic counseling may be helpful to couples with a family history of a congenital platelet function defect who are planning to have children in the future.

References

Bennett JS. Hereditary disorders of platelet function. In: Hoffman R, Benz EJ, Jr., Shattil SJ, et al, eds. Hoffman Hematology: Basic Principles and Practice. 5th ed. Philadelphia, Pa: Churchill Livingstone Elsevier; 2008:chap141.

McMillan R. Hemorrhagic disorders: Abnormalities of platelet and vascular function. In: Goldman L, Ausiello D, eds. Cecil Medicine. 23rd ed. Philadelphia, Pa: Saunders Elsevier;2007:chap 179.

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