Search
Glanzmann's thrombasthenia
Etiology:
1) low platelet glycoprotein IIb-IIIa complex
2) fibrinogen will not interlink
Epidemiology: most common inherited disease of platelets
Pathology:
- congenital platelet defects
- inability of this integrin alpha-2b to recognize macromolecular or synthetic peptide ligands
- type 1: platelets show absence of the glycoprotein IIb/beta-3 complexes at their surface & lack fibrinogen & clot retraction capability
- type 2: platelets express the glycoprotein IIb/beta-3 complex at diminishedlevels (5-20% controls), have detectable amounts of fibrinogen, & have low or moderate clot retraction capability
- normal or near normal (60-100%) expression of dysfunctional receptors
Genetics:
- autosomal recessive
- associated with defects in ITGA2B (CD41)
Clinical manifestations:
1) early hemorrhagic complications in the neonatal period
2) hemorrhagic events perists throughout life
a) epistaxis
b) purpura
c) petechiae
d) ecchymoses
Laboratory:
1) complete blood count (CBC) - platelet count is normal
2) peripheral blood smear
a) normal platelet morphology
b) no clumping of platelets
3) platelet aggregation
a) defect in the 1st phase of platelet aggregation with: ADP, epinephrine, thrombin or collagen
b) normal platelet aggregation with ristocetin cofactor
Management:
1) nasal packing & other local hemorrhage control measures
2) when local hemorrhage control measures fail
- epsilon-aminocaproic acid [2]
- recombinant factor VIIa or platelet transfusion [2]
- cryoprecipitate with or without platelets
Related
glycoprotein IIB/IIIA
General
platelet disorder; thromboasthenia
References
- Mayo Internal Medicine Board Review, 1998-99, Prakash UBS (ed)
Lippincott-Raven, Philadelphia, 1998, pg 439
- Medical Knowledge Self Assessment Program (MKSAP) 11, 17, 18.
American College of Physicians, Philadelphia 1998, 2015, 2018
- UniProt :accession P08514