Platelet storage pool deficiency

The signs and symptoms of platelet storage pool deficiency vary but may include:^[1][3][4]

• Frequent nosebleeds
• Abnormally heavy or prolonged menstruation
• Easy bruising
• Recurrent anemia
• Abnormal bleeding after surgery, dental work or childbirth

Platelet storage pool deficiency refers to a group of conditions that are caused by problems with the platelet granules. Platelet granules are tiny storage sacs found within the platelets which release various substances to help stop bleeding. Some platelet storage pool deficiencies are due to reduced or absent granules or granule contents. Others occur if the platelets are unable to empty the contents of the platelet granules into the bloodstream.^[3] 

Platelet storage pool deficiencies can be genetic or acquired (non-genetic). The four major genetic forms include dense body deficiency, gray platelet syndrome, Factor V Quebec, and mixed alpha-granule/dense body deficiency. Platelet storage pool deficiency is also a feature of several inherited conditions such as Hermansky-Pudlak syndrome, Chediak-Higashi syndrome, thrombocytopenia-absent radius (TAR) syndrome, and Wiskott-Aldrich syndrome.^[3][4]

Causes of acquired platelet storage pool deficiencies include:^[3]

• Systemic lupus erythematosus
• Cardiovascular bypass
• Hairy-cell leukemia

Platelet storage pool deficiency refers to a group of conditions that can be acquired (non-inherited) or inherited. Hereditary forms of the condition may be inherited in an autosomal dominant, autosomal recessive, or X-linked manner.^[4]

In autosomal dominant conditions, one changed (mutated) copy of the responsible gene in each cell is enough to cause signs or symptoms of the condition. When a person with an autosomal dominant condition has children, each child has a 50% (1 in 2) risk to inherit the mutated copy of the gene from the affected parent.

When a condition is inherited in an autosomal recessive manner, a person must have a change in both copies of the responsible gene in each cell. The parents of an affected person usually each carry one mutated copy of the gene and are referred to as carriers. Carriers typically do not show signs or symptoms of the condition. When two carriers of an autosomal recessive condition have children, each child has a 25% (1 in 4) risk to have the condition, a 50% (1 in 2) risk to be a carrier like each of the parents, and a 25% chance to not have the condition and not be a carrier.

A condition is considered X-linked if the mutated gene that causes the condition is located on the X chromosome, one of the two sex chromosomes (the Y chromosome is the other sex chromosome). Women have two X chromosomes and men have an X and a Y chromosome. X-linked conditions can be X-linked dominant or X-linked recessive. The inheritance is X-linked dominant if one copy of the altered gene in each cell is sufficient to cause the condition. Women with an X-linked dominant condition have a 50% chance of passing the condition on to a son or a daughter with each pregnancy. Men with an X-linked dominant condition will pass the condition on to all of their daughters and none of their sons. The inheritance is X-linked recessive if a gene on the X chromosome causes the condition in men with one gene mutation (they have only one X chromosome) and in females with two gene mutations (they have two X chromosomes). A woman with an X-linked condition will pass the mutation on to all of her sons and daughters. This means that all of her sons will have the condition and all of her daughters will be carriers. A man with an X-linked recessive condition will pass the mutation to all of his daughters (carriers) and none of his sons.

A diagnosis of platelet storage pool deficiency is often suspected based on the presence of characteristic signs and symptoms. Specialized laboratory tests can then be ordered to confirm the diagnosis. This testing may include:^[5][4]

• Bleeding time studies
• Platelet aggregation studies
• Peripheral blood smear
• Flow cytometry (detects a reduction in certain types of granules in affected platelets)

Treatment for platelet storage pool deficiency is symptomatic. For example, people who have severe episodes of bleeding may require platelet transfusions or antifibrinolytic medications, particularly during periods of high risk such as during surgical procedures or after an injury. Transfusions are generally used with caution as the potential risks often outweigh the benefits when bleeding is not life-threatening.^[1][3]

People with a platelet storage pool deficiency should avoid antiplatelet drugs such as aspirin and other nonsteroidal anti-inflammatory drugs (NSAIDS).^[1][3]