thrombopathy

Thrombopathy, also known as a platelet function disorder, refers to abnormalities of platelet function that impair primary hemostasis. Unlike conditions with a low platelet count, thrombopathy involves qualitative defects in platelets, which may affect adhesion, activation, aggregation, or secretion and can lead to a tendency to bleed.

Causes of thrombopathy are divided into inherited and acquired forms. Inherited disorders include Glanzmann thrombasthenia, caused by defects in the GPIIb/IIIa receptor complex and characterized by defective aggregation; Bernard-Soulier syndrome, due to a GPIb-IX-V defect with abnormal adhesion and often enlarged platelets; storage pool diseases and Gray platelet syndrome, which involve granule defects and abnormal platelet function. Acquired forms arise from medications such as aspirin and other NSAIDs, thienopyridines (for example, clopidogrel), uremia, liver disease, and systemic conditions or immune-mediated processes that affect platelet function. In addition, conditions like von Willebrand disease can contribute to a functional platelet defect, though they are typically categorized separately as quantitative or qualitative defects of von Willebrand factor.

Clinical features commonly include mucocutaneous bleeding (epistaxis, gum bleeding, heavy menses), easy bruising, and prolonged bleeding after injury or surgery. Platelet counts are often normal, so diagnosis relies on detailed bleeding history and specialized testing, including platelet function studies (aggregation testing with ristocetin, ADP, collagen, and arachidonic acid), PFA-100 closure times, flow cytometry for receptor expression, and genetic testing when a hereditary thrombopathy is suspected. Exclusion of drug effects and other bleeding disorders is important.

Management emphasizes bleeding control and removing or addressing the underlying cause. This may involve stopping causative medications, antifibrinolytics such as tranexamic acid for mucosal bleeding, and, in certain disorders, desmopressin. Platelet transfusions are considered for severe bleeding or before major procedures in specific inherited defects, with caution for alloimmune refractoriness. Prognosis varies by specific disorder and severity.