Which of the following is the most likely diagnosis for a patient with a normal platelet count, prolonged bleeding time, and no aggregation with any agent except ristocetin?

Question

Quizplus · Accepted Answer

Glanzmann thrombasthenia is a rare congenital disorder in which platelets cannot aggregate due to a defect or deficiency in the platelet glycoprotein IIb/IIIa receptor. This results in a prolonged bleeding time, normal platelet count, and no response to most platelet aggregation agents except for ristocetin. Aspirin ingestion would result in a decrease in platelet function and aggregation, but would not specifically affect response to ristocetin. Gray platelet syndrome is a rare inherited platelet disorder characterized by large, gray-colored platelets and a decreased number of platelet alpha-granules. Vitamin C deficiency can lead to bleeding due to weakened blood vessels, but would not specifically result in a lack of response to platelet aggregation agents.

Which of the Following Is the Most Likely Diagnosis for a Patient