TOC |
HEME
HEMOPHILIA A ( factor VIII
deficiency)
See also
Hemophilia B
A rare hereditary hemorrhagic disorder affecting 1:10,000 MALES
a. Symptom:
It is correlated to the Factor VIII Coagulant Activity Level.
< 1% : bleeding present in first yr of life; has spontaneous hemarthrosis
& deep tissue bleeding
1 - 5% : bleeding after trauma in childhood; spontaneous bleeding is rare.
5 - 20% : may present in childhood with hemorrhage after trauma, surgery
or dental extraction
20 - 50% : may be undetected until adult life when major trauma or surgery
results in severe hemorrhage
b. Management:
-
Genetic counseling
-
Avoid aspirin & trauma if possible
-
Administration of donor screened, heat treated
Factor VIII concentrates based on the
extent of the disease & bleeding & the location of hemorrhage.
The calculated Factor VIII concentrate (unit) requirement =
40 ml/kg x body weight(kg) x 0.25 units/ml (for raising 25% of the Factor
VIII level from <1%) as initial bolus; then 1/2 of the initial dose at
6 hrs later, then q12h as long as is needed to control the hemorrhage.
Each bag of the concentrate has 100 unit.
For most acute hemathroses of knee, ankle, elbow: 28 36% level
For serious deep tissue bleeding: raise up to 50% level
For dental work: up to 50% level + EACA 0.1 g/kg IV bolus, then EACA 0.1
g/kg q6h PO for 10d after the dental work.
Prior to elective surgery: raise to 5 100% level, then maintain above 50%
for the next 10 14d
-
DDAVP can be used to treat acute traumatic
hemorrhage in mild or moderate hemophilics. (Dose IV 0.3 ug/kg in 50 ml salin
over 15 30 min)
-
For some pts with antibody inhibitor against Factor VIII: The amount of Factor
VIII concentrate is about 40 unit/kg + an additional 20 units/kg for each
Bethesda unit of inhibitor.
Ref:
National Hemophilia Foundation
World Federation of Hemophilia
Hemophilia Home Page