Acquired Platelet Function Defect

What are the other Names for this Condition? (Also known as/Synonyms)

• Acquired Disorders of Platelet Function
• Acquired Qualitative Platelet Disorders

What is Acquired Platelet Function Defect? (Definition/Background Information)

• Platelets (thrombocytes) are the major components in blood that help in the process of blood clotting. They are the smallest in size among the blood cells types. The major function of platelets is to stop bleeding. They do this by changing their plate-like shape through a series of long processes and attaching themselves at the site of a broken blood vessel to patch it
• When there are problems with the proper functioning of platelets in blood, the condition is referred to as platelet function defects. In these uncommon conditions, the platelet count is normal, but their function is abnormal. An abnormal bleeding can occur due to two major reasons, namely decrease in coagulation factors (proteins) and platelets, and when the platelets do not function properly
• Platelet function defects can be either inherited (present at birth), or it can be acquired (secondary) due to some other underlying mechanism or disease. Acquired Platelet Function Defects are more common than inherited defects
• The use of aspirin is one of the most common causes of Acquired Platelet Function Defect, which results in significant bleeding. Each causative factor can cause this bleeding disorder by affecting one of the many functions of platelets. Because of this reason, the treatment option varies from one causative factor to the other
• Treatment of the condition is undertaken by treating the underlying cause, discontinuation of the medication (causing bleeding), and through other supportive measures. The prognosis is generally favorable, if the underlying condition is manageable or bleeding occurred secondary to some prescribed medication (which may be then discontinued)

Who gets Acquired Platelet Function Defect? (Age and Sex Distribution)

• Acquired Platelet Function Defect may occur at any age. But, it is more common in older adults owing to the prevalence of medical illnesses and greater medication use on a daily basis among this group
• Both the male and female sexes are equally affected
• Acquired Platelet Function Defect is seen all over the world; there is no particular geographical restriction or racial/ethnic preference observed

What are the Risk Factors of Acquired Platelet Function Defect? (Predisposing Factors)

The risk factors of Acquired Platelet Function Defect include:

• Medications, such as aspirin, clopidogrel, abciximab, tirofiban, etc., taken for heart diseases
• Herbal medications such as gingko, ginseng, and garlic
• Antibiotics, especially penicillin and cephalosporin
• Severe kidney disease such as chronic renal failure or uremia
• Certain types of bone marrow disorders such as multiple myeloma, leukemia, polycythemia vera, chronic myeloid leukemia, and many others

It is important to note that having a risk factor does not mean that one will get the condition. A risk factor increases one's chances of getting a condition compared to an individual without the risk factors. Some risk factors are more important than others.

Also, not having a risk factor does not mean that an individual will not get the condition. It is always important to discuss the effect of risk factors with your healthcare provider.

What are the Causes of Acquired Platelet Function Defect? (Etiology)

Many of the risk factors associated with Acquired Platelet Function Defect can cause this condition. The causative factors include:

• Aspirin is one of the most common causes of Acquired Platelet Function Defect. This is because of its prevalence among a greater number of older adults for preventing cardiovascular diseases. It reversibly inhibits platelet function for up to a period of 7 days (total platelet lifespan).  If aspirin is combined with clopidogrel, the risk of bleeding is even higher
• Medications: Close to 100 medications have been found to affect the platelet function; although, not all of them cause significant bleeding. The common medications are clopidogrel, abciximab, tirofiban, eptifibatide, penicillin, cephalosporin, phenothiazines, and prednisone
• Herbal medications, such as ginkgo, ginger, bilberry, ginseng, etc., can inhibit platelet activity
• Kidney failure: The function of the kidney is to remove the end-products of metabolism in blood. In kidney failure, these substances accumulate in blood and impair the platelet function (adhesion, activation, and aggregation)
• Individuals with leukemia and polycythimia Vera may also be affected
• Valvular heart disease such as aortic stenosis (narrowing of one of the heart valve)
• Multiple myeloma: It is a form of cancer that results in excess production of specific type of proteins called paraproteins. These paraproteins adhere to the surface of the platelet and interfere with the platelet-to-platelet adhesion, which is an important step in stopping bleeding
• Myeloproliferative disorders are disorders of the bone marrow, in which there is excess production of one or all of the three types of blood cells (red blood cells, white blood cells and platelets). Such abnormal numbers in blood cells are also believed to hamper platelet function

What are the Signs and Symptoms of Acquired Platelet Function Defect?

Acquired Platelet Function Defect increases one’s risk of bleeding. The signs and symptoms may include:

• Superficial “mucocutaneous” bleeding, which includes bleeding into the skin or mucosa (lining of the gastrointestinal tract, urinary tract, etc.)
• Abnormally-colored urine due to the presence of blood
• Increased menstrual bleeding or prolonged menstrual period
• Bleeding in the gastrointestinal tracts, which may be present as:
  • Blood in the vomitus
  • Dark black or bloody stools             
• Nosebleeds can occur spontaneously without trauma or with minimal trauma
• Petechial bleeding: These are pin-point purple or red spots on the skin that look like a skin rash, caused by capillary bleeding
• Bruises, which are blue or black bleeding spots under the skin

How is Acquired Platelet Function Defect Diagnosed?

The following tools may be used to help diagnose Acquired Platelet Function Defect:

• Thorough evaluation of the individual’s medical history and a complete physical examination including examination of the skin and mucosal surfaces such as the nose, throat, etc.
• During history taking, the physician may want to know the following:
  • When the symptoms began and whether they are becoming worse
  • A list of prescription, over-the-counter, and herbal medications currently being taken
  • About one’s personal and family history of bleeding disorders
• Laboratory blood tests are the primary tools to make a diagnosis of this bleeding disorder. The initial (screening) tests may include:
  • Complete blood count (CBC) gives a measure of the platelet count. When the count is within normal limits, bleeding due to low platelet count may be ruled-out
  • Prothrombin time (PT) and partial thromboplastin time (PTT) are tests done to rule-out bleeding due to coagulopathy (decreased coagulation factors)
  • Bleeding time, when prolonged, could be indicative of platelet dysfunction or low platelet count
  • Platelet function analyzer (PFA) closure time is routinely performed when platelet dysfunction is suspected
  • von Willebrand factor (vWF) assays are done to eliminate von Willebrand disease
  • Renal function tests and liver function tests help to determine if an underlying renal disease or liver disease is present         
• Additional tests may be required, if the screening tests do not yield a confirmatory diagnosis. The specialized tests include Platelet aggregometry, platelet flow cytometry, lumiaggregometry, and platelet electron microscopy
• Bone marrow biopsy: If the underlying cause of platelet dysfunction is suspected due to bone marrow disorders, a bone marrow biopsy is performed to make a definitive diagnosis

Many clinical conditions may have similar signs and symptoms. Your healthcare provider may perform additional tests to rule out other clinical conditions to arrive at a definitive diagnosis.

What are the possible Complications of Acquired Platelet Function Defect?

The complications of Acquired Platelet Function Defect are usually due to excessive loss of blood. These include:

• If it is not treated promptly, the condition may progress to life-threatening bleeding into the brain or gastrointestinal tract
• Severe anemia, which may present itself as pale skin, severe fatigue, and chest pain
• Confusion, loss of consciousness

How is Acquired Platelet Function Defect Treated?

The treatment of Acquired Platelet Function Defect is dependent on the factor that caused the bleeding disorder in the first place. This varies from one individual to another.

• Treating the underlying disorder responsible for the condition usually can help rectify the condition. For example, plasmapheresis (removal of plasma from the blood cells) is used in individuals affected with multiple myeloma to correct Acquired Platelet Function Defect
• If there is a bleeding situation due to a medication, discontinuing the medication would sometimes control the bleeding
• If there is bleeding due to a renal failure, then dialysis, blood transfusions, erythropoietin DDAVP, or high doses of estrogen may be helpful
• If the bleeding is significant, then supportive treatments such as hospitalization, IV fluids, monitoring of vital signs, and other such measures may be necessary
• Platelet transfusion is given when the above treatment options fail to arrest the bleeding, irrespective of the cause

The healthcare provider will recommend the best treatment options based upon each individual’s specific circumstances.

How can Acquired Platelet Function Defect be Prevented?

The preventative measures of Acquired Platelet Function Defect may include:

• Avoiding the medications that are known to increase the risk of platelet dysfunction. However, sometimes it is not possible to stop the medication, when it is prescribed to treat other illnesses. In such situations, careful monitoring of the individual with periodic health center visits and blood tests can help prevent any significant bleeding issues
• Careful monitoring and treatment of Acquired Platelet Function Defect associated disorders

In some cases, when the underlying disorder causing the disorder is incurable, it cannot be prevented.

What is the Prognosis of Acquired Platelet Function Defect? (Outcomes/Resolutions)

• The prognosis of Acquired Platelet Function Defect depends on the underlying disorder. If the underlying disorder is curable, then the prognosis is generally favorable
• Medication-induced Acquired Platelet Function Defect usually has a favorable prognosis, when the condition is appropriately followed up with a healthcare provider. The healthcare provider may suggest whether to keep or discontinue the medication, depending on one’s ‘benefits versus risks’ assessment
• Though there are many medications or clinical conditions that can cause Acquired Platelet Function Defect, not all of them cause significant bleeding issues

Additional and Relevant Useful Information for Acquired Platelet Function Defect:

• Congenital platelet function defects are a group of disorders characterized by various abnormalities in platelet function that is present at birth

The following article link will help you understand congenital platelet function defects:

http://www.dovemed.com/diseases-conditions/congenital-platelet-function-defects/