PLT disorders

Question 1

Glanzmann’s Thrombasthenia

Answer 1

Aggregation defect. Characteristics: Abnormal clot retraction test due to defective thrombasthenin, absent aggregation with all agenst EXCEPT risotcetin

Question 2

Thrombotic Thrombocytopenic Purpura

Answer 2

Deficienct ADAMTS-13 gene protease which cleaves vWF, plts aggregate in multiple organs (Quantitative disorder, PLTs used up)

Question 3

Immune thrombocytopenic purpura

Answer 3

autoantibodies formed against plts, causes low count, usually seen in kids after viral infection (Quantitative disorder)

Question 4

VonWillebrand’s disease

Answer 4

PLT adhesion defect, autosomal dominant hereditary disorder, defect of vWF, Aggregation abnormal with ristocetin only. 1# hereditary bleeding disorder

Question 5

PTT can be prolonged in

Answer 5

VonWillebrand’s disease, primary type

Question 6

Bernard’s-Soulier Disease

Answer 6

Adhesion defect, defective GP receptor that binds to vWF, abnormal aggregation with risotcetin and Giant PLTs

Question 7

Storage pool disease

Answer 7

Release defect, ADP release from dense bodies not normal, which impairs aggregation (ADP needed for irreversible PLT plug formation)