How does the disease present and what are the laboratory findings?
The most common clinical presentation of
hemophilia A is hemarthroses. Typically in infants, as ambulation begins, bleeding
into joints and muscles occurs even after minor trauma. Up to 90% of patients
with severe disease demonstrate evidence of bleeding by 1 year of life. Of note
is the fact that although factor VIII does not cross the placenta, newborns
will often not exhibit symptoms.
Bleeding associated with hemophilia A can occur
virtually anywhere in the body and give rise to secondary complications.
Bleeding in the neck or pharynx may cause airway obstruction. Central nervous
system hemorrhages, although uncommon, may be life-threatening and are a common
cause of death.
Prolonged and excessive bleeding associated
with even minor surgery is common and can be present in mild disease where
there may be no history of previous sponta-neous or surgical bleeding. The importance
of identifying the severity of the deficient factor is therefore underscored.
In fact, the diagnosis should be suspected in any male with unusual bleeding.
The laboratory data consistent with the diagnosis are a prolonged activated
partial thrombo-plastin time (PTT), a normal platelet count, and normal
prothrombin time (PT). Specific assay for factor VIII activity confirms and
quantifies the disease.