An acquired platelet function disorder refers to an abnormality in the clotting ability of the platelets that develops sometime after birth. Platelets are a type of cell found in the blood that help the blood to clot. A number of disorders can affect the function of platelets.
Platelets, along with a number of other substances in the blood, help blood to clot. When a person cuts him- or herself, blood must clot, or turn solid, to stop the bleeding. When platelets lose their ability to function for any reason, abnormal bleeding and bruising may occur.
An acquired platelet function disorder may cause no symptoms at all. When symptoms do occur, they are usually mild, unless the person has another blood-clotting problem. Some of the symptoms include: abnormally heavy bleeding from cuts or other injurieseasy bruisingnosebleedspetechiae, which are small red dots on the skin that signal tiny areas of bleeding
There are many possible causes of acquired platelet function defect. Common causes are as follows: certain cancers of the blood, such as multiple myeloma and polycythemia veralong-standing kidney failure, known as chronic renal failuremedicines, including aspirin, penicillin, and nonsteroidal anti-inflammatory drugs, which are called NSAIDsopen heart surgerysevere liver disease, such as cirrhosissystemic lupus erythematosus (SLE), which is an autoimmune disorder where a person's immune system attacks his or her own body for unknown reasons
Most cases of acquired platelet function defect cannot be prevented. Avoiding alcohol abuse, which is the most common cause of cirrhosis, could prevent many cases due to liver disease.
Diagnosis of acquired platelet function defect begins with a medical history and physical exam. A blood test called a complete blood count, or CBC, is often done first. This test counts the number and types of cells in the blood.
If the platelet count is in a healthy range, a test called the bleeding time can help confirm the diagnosis. In this test, the forearm is scratched to cause a small area of bleeding. The amount of time it takes for the scratch to stop bleeding is then measured. When the platelets are not working properly, this time will be longer than normal.
More specialized tests of platelet function may also be done. These tests can help detect the exact type and severity of the problem.
Most long-term effects are related to the cause of the acquired platelet function defect. For example, cases due to medicines usually go away when the medicine is stopped. These cases may cause no long-term effects. If the cause is cancer or liver disease, death may result. In rare cases, platelet function problems can cause serious abnormal bleeding in certain areas, such as the brain.
Acquired platelet function disorders pose no risk to others.
If the cause is a medicine, the medicine can be stopped, and the problem usually goes away.
In cases due to other causes, treatment is directed at the cause when possible. Someone who has blood cancer may need chemotherapy. An individual with systemic lupus erythematosus (SLE) may need medicines such as prednisone to suppress the immune system.
Regardless of the cause, a platelet transfusion, which is similar to a blood transfusion, can be given if severe bleeding occurs. Rarely, a drug called desmopressin (i.e., DDAVP) is used when platelet bleeding problems occur in a person with kidney failure.
A platelet transfusion may cause an allergic reaction or infection. DDAVP may cause fluid retention and high blood pressure.
If the condition is caused by a medicine, it will go away after the medicine is stopped. No further treatment may be needed in these cases. Those with more serious causes, such as cancer or liver failure, often need further treatment for these conditions.
Any new or worsening symptoms should be reported to the healthcare professional. Tests of platelet function may also be repeated in some cases.
Harrison's Principles of Internal Medicine, 1998, Fauci et al.