Management of Platelet Function Assays
The management and treatment of bleeding/clotting disorders due to platelet dysfunction relies initially on ruling out other causes unrelated to platelets. This can be difficult, since platelets play a role in more than one clotting cascade of biochemical reaction. A history of drugs that interfere with platelet function (e.g., aspirin) can result in a cure from simply discontinuing the drug.
Once a distinct intrinsic platelet dysfunction is identified, treatment is implemented to restore normal function by either inhibiting platelet overreaction to clot or improve platelet function when platelets fail to clot.
Treatment of Platelet Dysfunction Leading to Bleeding
This is usually due to an inherited genetic disorder, such as von Willebrand disease, giant platelet dysfunction, microplatelet dysfunction, etc. Dysfunction can also be acquired, as with liver disease, uremia, diabetes, trauma, cardiopulmonary bypass, and malnutrition. Drugs that reverse or improve insufficient platelet function are limited in number:
- Desmopressin is related to vasopressin, a pituitary hormone that acts as an anti-hemophilic and hemostatic agent.
- Estrogens can be used to take advantage of their tendency to increase coagulability.
- Erythropoietin (bone marrow stimulator) has been successful in increasing production of platelets in patients with kidney failure and uremia.
- Platelet transfusion: used when other methods fail or in cases of overt thrombocytopenia which can occur in malignancies, pregnancy, and HIV/AIDS.
- Antifibrinolytic agents: just as platelets are the beginning of the clotting process, dissolution of the clot by “fibrinolytic” factors in the blood participates in finalizing the healing process. Drugs that oppose these clot-dissolving factors can maintain what platelet aggregation and clotting does occur. Agents: tranexamic acid, aminocaproic acid.
Treatment of Platelet Dysfunction Leading to Thrombosis
An overreaction of the clotting process with premature, unprovoked, or exaggerated platelet initiation can use medications that interfere with this, i.e., anti-platelet agents:
- Aspirin: in doses of 50-100 mg/day.
- Non-aspirin NSAIDs: non-steroidal anti-inflammatory drugs. Complications can include upper gastrointestinal bleeding.
- Dipyrimadole, sometimes used in combination with low-dose aspirin.
- Platelet receptor site antagonists: interfere with platelet activation.
- Nitrates: reduce platelet reactivity, adhesion, and aggregation.
- Calcium channel blockers: reduce platelet aggregation and adhesion.
- Heparin: reduces platelet adhesion.