Search
prothrombin deficiency (hypoprothrombinemia)
Etiology:
- acquired:
- autoimmune, lupus antigoagulant (prothrombin inhibitor)
- vitamin K deficiency
- anticoagulants (warfarin)
- antibiotics inhibit vitamin K synthesis by gut bacteria
- inherited
Epidemiology:
- inherited prothrombin deficiency is rare
- autoimmune forms may occur at any age, otherwise a disease of infants
Genetics:
- associated with defects in prothrombin (coagulation factor II)
Clinical manifestations:
- easy bruising
- epistaxis
- prolonged bleeding with injury, tooth extraction, or surgery
- oral mucosal bleeding
- melena
- hematochezia
- hematuria
- Intracranial hemorrhage
- hemarthroses
- menorrhagia
Laboratory:
- prothrombin time (PT) increase
- aPTT increased
- with vitamin K deficiency, decreased
- plasma factor VII
- plasma factor IX
- plasma factor X
- plasma protein C
- plasma protein S
Management:
- replenish vitamin
- fresh frozen plasma contains ~ 1 U/mL of prothrombin
- prothrombin concentrate available
- lupus anticoagulant has been treated with
- glucocorticoids
- intravenous immunoglobulin
- fresh-frozen plasma
- azathioprine
- epsilon aminocaproic acid (Amicar)
- minimizes severity of mucosal bleeding
- enhances hemostasis when fibrinolysis contributes to bleeding
- avoid surgery if possible
- use of prothrombin concentrate if surgery necessary
- attempt to decrease inhibitor titer (if present)
- avoid contact sports
Specific
antibiotic-induced prothrombin deficiency
anticoagulant-induced prothrombin deficiency
General
coagulation factor deficiency
Database Correlations
OMIM 176930
MORBIDMAP 176930
References
- Hagstrom SJ and Harper JL
eMedicine: Hypoprothrombinemia
http://emedicine.medscape.com/article/956030-overview