| Glanzmann's thrombasthenia | |
|---|---|
| Classification and external resources | |
| ICD-10 | D69.1 |
| ICD-9 | 287.1 |
| OMIM | 187800 273800 |
| DiseasesDB | 5224 |
| eMedicine | med/872 |
| MeSH | D013915 |
Glanzmann's thrombasthenia is an abnormality of platelets.[1] It is an extremely rare coagulopathy (disorder of the blood), in which the platelets lack glycoprotein IIb/IIIa (GpIIb/IIIa). As a result, no fibrinogen bridging of platelets to other platelets can occur, and the bleeding time is significantly prolonged.
Contents |
Glycoprotein IIb/IIIa (GpIIb/IIIa) is an integrin aggregation receptor on platelets. This receptor is activated when the platelet is stimulated by ADP, epinephrine, collagen or thrombin. GpIIb/IIIa is essential to blood coagulation since the activated receptor has the ability to bind fibrinogen (as well as fibronectin and vitronectin), which is required for fibrinogen-dependent platelet-platelet interaction (aggregation.)
In contrast, Glanzmann's thrombasthenia has normal glycoprotein Ib receptors, the role of which is to enable platelets to be activated by contact with the von Willebrand factor-collagen complex that is exposed when the endothelial blood vessel lining is damaged.
Understanding of the role of GpIIb/IIIa in Glanzmann's thrombasthenia led to the development of GpIIb/IIIa inhibitors, a class of powerful antiplatelet agents.[2]
Glanzmann's thrombasthenia can be inherited in an autosomal recessive manner[2] or acquired as an autoimmune disorder.[3]
Characteristically, there is increased mucosal bleeding:
The bleeding tendency is variable but may be severe.
Platelet numbers and morphology are normal. Platelet aggregation is normal with ristocetin, but impaired with other agonists such as ADP, thrombin, collagen or epinephrine.
| Condition | Prothrombin time | Partial thromboplastin time | Bleeding time | Platelet count |
|---|---|---|---|---|
| Vitamin K deficiency or warfarin | prolonged | normal or mildly prolonged | unaffected | unaffected |
| Disseminated intravascular coagulation | prolonged | prolonged | prolonged | decreased |
| von Willebrand disease | unaffected | prolonged | prolonged | unaffected |
| Hemophilia | unaffected | prolonged | unaffected | unaffected |
| Aspirin | unaffected | unaffected | prolonged | unaffected |
| Thrombocytopenia | unaffected | unaffected | prolonged | decreased |
| Liver failure, early | prolonged | unaffected | unaffected | unaffected |
| Liver failure, end-stage | prolonged | prolonged | prolonged | decreased |
| Uremia | unaffected | unaffected | prolonged | unaffected |
| Congenital afibrinogenemia | prolonged | prolonged | prolonged | unaffected |
| Factor V deficiency | prolonged | prolonged | unaffected | unaffected |
| Factor X deficiency as seen in amyloid purpura | prolonged | prolonged | unaffected | unaffected |
| Glanzmann's thrombasthenia | unaffected | unaffected | prolonged | unaffected |
| Bernard-Soulier syndrome | unaffected | unaffected | prolonged | decreased or unaffected |
It is named for Eduard Glanzmann (1887-1959), the Swiss pediatrician who originally described it.[4][5][6]
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