A patient with a hereditary deficiency of prothrombin (Factor II) may develop a bleeding disorder depending on the extent of the deficiency.


Inheritance: autosomal, incompletely recessive


Clinical findings:

(1) easy bruisability

(2) epistaxis

(3) soft tissue bleeding and/or hematomas

(4) bleeding after surgery or trauma

(5) menorrhagia (if female)

(6) post-partum bleeding (if female)

(7) rarely hemarthroses

(8) rarely intracerebral hemorrhage


Laboratory findings (assuming no factor replacement):

(1) prolonged PT

(2) prolonged aPTT

(3) normal thrombin time

(4) decreased prothrombin activity and/or antigen


Differential diagnosis:

(1) vitamin K deficiency

(2) other acquired prothrombin deficiencies

(3) Factor V or X deficiency


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