Congenital factor VII deficiency presenting as delayed bleeding following dental extraction. A review of the role of factor VII in coagulation.
Recent updated models of the coagulation mechanism suggest that factor VII/thromboplastin complex is the main initiator or trigger of coagulation. Factor VII activation of factor IX is likely to be an important activation pathway. Inhibition of factor VII by tissue factor pathway inhibitor may have a regulatory role in the initiation of coagulation. Defining factor VII's interactions in coagulation physiology may lead to answers for some clinical problems in both hemostasis and thrombosis. We describe a 15-year-old Chinese boy with factor VII deficiency and a factor VII level of 0.08 U/ml. His symptoms were recurrent epistaxis and moderate delayed bleeding post-dental extraction. Such specific symptoms have been reported previously in a study of 40 European patients. It is one diagnosis to consider if a patients main symptom is significant post-dental bleeding. It is possible that there is requirement for higher levels of factor VII at these anatomical sites making them the common sites for symptoms in patients with moderate deficiency. Case reports of rare clotting factor deficiencies will illustrate what may be important in vitro functions of clotting proteins. Therefore reporting should be encouraged, especially during review and reconsideration of models of the coagulation mechanism.
Wei
D C
DC
Department of Pathology, University of Hong Kong, Hong Kong.
Wong
R W
RW
Robertson
E P
EP
D000293:Adolescent; D001777:Blood Coagulation / Q000502:physiology*; D005167:Factor VII / Q000502:physiology; D005168:Factor VII Deficiency / Q000151:congenital / Q000175:diagnosis*; D006801:Humans; D008297:Male; D014081:Tooth Extraction / Q000009:adverse effects
D005167:Factor VII