What Causes Giant Platelet Disorder?

Giant cell platelet disorder refers to a condition in which a person has abnormally large platelets and thrombocytopenia and an increased tendency to bleed. Giant platelets fail to stick together and cannot form adequate clots, resulting in severe bleeding when injured. A large platelet has a diameter greater than 4 µm, whereas a giant platelet has a diameter greater than 7 µm. The larger the size of the platelets, the lesser the platelet count, which results in bleeding disorders. 

Conditions that have giant platelets include:

• Myeloproliferative neoplasms: These are rare blood cancers that are caused by mutations in stem cells in the bone marrow. The mutations cause excess production of any combination of white blood cells, red blood cells, and platelets.
• Myelodysplasia: Rare blood cancer in which the blood cells in the bone marrow fail to mature into healthy blood cells.
• Bernard-Soulier syndrome: Is associated with large-sized platelets and decreased platelet count. The combination is called macrothrombocytopenia. People with Bernard-Soulier syndrome are at an increased risk of bruising and bleeding (more severely than usual). Sometimes, the condition causes tiny red spots on the skin called petechiae. Women with Bernard-Soulier syndrome have heavy or prolonged bleeding during their menstrual periods, known as menorrhagia. Bernard-Soulier syndrome is a rare disorder that affects one in a million people.

Symptoms of giant platelet disorder include:

• Nosebleeds
• Gum bleeding
• Spontaneous bleeding without any trauma
• Severe bleeding even after a minor injury
• Heavy and prolonged menstrual bleeding
• Petechiae

Giant platelet disorders can be diagnosed using various tests, such as:

• Complete blood count tests, which help ascertain the platelet count and confirm the diagnosis.
• Platelet function tests, which include:
  • Closure time, which determines the time taken to form a clot.
  • Viscoelastometry, which confirms the strength of the blood clot.
  • Platelet aggregometry, which helps find how well the platelets help to form a clot.
  • Lumiaggregometry, which helps identify abnormal platelets.
  • Bleeding time, which is used to determine various platelet disorders. It helps determine the time taken to stop bleeding after a minor cut.
• Glycoprotein tests, which help determine abnormal clot formation.
• The peripheral smear test, which is used to detect abnormalities in red blood cells, white blood cells, and platelets.
• Blood clotting test, which is done to evaluate clotting time.

There is no treatment for giant platelet disorder, but the symptoms can be treated.

The treatment options, which mainly include steroids and intravenous gamma globulin, are as follows:

• Steroids: Help increase the number of platelets in two to three weeks, but they may have side effects such as irritability, stomach irritation, increased blood pressure, acne, and weight gain.
• Medication changes: If the condition is suspected to be caused, a change in medication or discontinuation of the medicine is required. Avoid medicines such as antiplatelet medications.
• Platelet transfusion: This may be necessary in case of severe bleeding either due to surgery or major trauma.
• Lifestyle changes: Include avoiding sports that may increase the risk of injuries.
• Medications: Drugs such as romiplostim and Promacta (eltrombopag) are recently approved to treat thrombocytopenia.