What causes hemorrhage into joints in the pathophysiology of hemophilia A?

Updated: Jun 05, 2020
  • Author: Douglass A Drelich, MD; Chief Editor: Srikanth Nagalla, MBBS, MS, FACP  more...
  • Print

The hallmark of hemophilia is hemorrhage into joints. This bleeding is painful and leads to long-term inflammation and deterioration of the joint.

Human synovial cells synthesize high levels of tissue factor pathway inhibitor, resulting in a higher degree of factor Xa (FXa) inhibition, which predisposes hemophilic joints to bleed. This effect may also account for the dramatic response of activated factor VII (FVIIa) infusions in patients with acute hemarthroses and FVIII inhibitors.

Bleeding into a joint may lead to synovial inflammation, which predisposes the joint to further bleeds. A joint that has had repeated bleeds (by one definition, at least 4 bleeds within a 6-month period) is termed a target joint. Commonly, this occurs in knees though ankles and elbows are other commonly affected joints.

Repeated hemarthroses lead to progressive synovial hypertrophy, hemosiderin deposition, fibrosis, and damage to cartilage, with subchondral bone-cyst formation. This results in permanent deformities, misalignment, loss of mobility, and extremities of unequal lengths.

Did this answer your question?
Additional feedback? (Optional)
Thank you for your feedback!