Diagnosis
Hemophilic arthropathy
Findings
Radiographs of the right knee were normal. The radiographic images
of the left knee reveal extensive erosive and degenerative change
about the femoral-tibial and femoral-patellar joints and diffuse,
severe osteopenia (Figure 1). MR imaging shows extensive
subchondral cystic change and edema. The T2-weighted MR image
shows, particularly well, multiple, intra-articular dark irregular
foci corresponding to hemosiderin deposits (Figure 2).
Discussion
The coagulation dysfunction in hemophilia A is a sex-linked
deficiency or abnormality of a plasma protein called factor VIII
(FVIII) found in 1 of 5000 male births. Physiologically, FVIII is
found circulating in the plasma bound to von Willebrand's factor,
which acts as a carrier protein. The degree of FVIII deficiency
correlates with the extent of bleeding, and hemophilia A can be
classified as severe (<1% activity), moderate (1% to 5%), or
mild (5% to 25%). Typically, symptoms begin in childhood associated
with hemorrhage after minor trauma. As the individual ages and
becomes more prudent, symptoms become less frequent. Although a
presumptive diagnosis can be made based on age, sex, family
history, and clinical presentation, the presentation is not always
classic. Up to 30% of patients may have a normal family history due
to mild disease or lack of males in the family tree. Mild disease,
however, may not present until well into adulthood; there has even
been a case in which the patient was diagnosed during his
60s.
1 Hemophilia has been well documented in females in
whom X chromosome inactivation occurs at an early stage of
embryogenesis, resulting in unusually low levels of
FVIII.
2 The differential diagnosis for congenital
bleeding disorders includes hemophilia B (deficiency of factor IX),
factor XI deficiency, and von Willebrand's disease (deficiency of
vWF). Acquired coagulation disorders should also be considered,
such as vitamin K deficiency, liver disease, and factor
deficiencies that may be seen in conditions like systemic lupus
erythematosus or lymphoma.
Radiographically, the diagnosis is often suggested by recurring
changes of hemarthrosis in the knees, elbows, and
ankles.3 Although there is no universally accepted
classification system, several common patterns of joint disease in
hemophilic arthropathy have been described by Arnold and
Hilgartner.4 The initial episode of intra-articular
bleeding, often following minor trauma, is usually associated with
joint effusion without osseous or articular involvement. With
recurrent small bleeds or after a large bleed, peri-articular
osteoporosis and regional soft-tissue swelling are common sequelae.
In adolescents, the hyperemic joint may lead to localized,
accelerated growth and limb-length discrepancies. Eventually
osseous irregularity and erosion develop, accompanied by
subchondral cysts. Synovial effusions are common and may appear
radiodense due to hemosiderin deposition. An important diagnostic
clue to hemophilic arthropathy during this phase is the
preservation of joint space. As osseous erosions continue, however,
joint space narrowing is seen, associated with progressive,
symmetric cartilaginous destruction. Eventually, complete
obliteration of the joint space will occur and secondary
degenerative signs, including osteophytes and eburnation, develop.
With chronic disease, muscle imbalances and joint contractures may
develop.
MR imaging can detect early erosions not visualized on
conventional radiography and is probably the best modality for
assessing intra-articular abnormalities associated with hemophilic
arthropathy. Generally, hemarthrosis can be seen as areas of low to
intermediate signal on T1-weighted MR images and increased signal
on T2-weighted MR images.5 Chronic peri-articular
changes are often visualized as decreased signal intensity on both
T1- and T2-weighted MR images. Synovial hypertrophy results from
fibrosis and appears as nodular areas of low to intermediate signal
intensity on T1- and T2- weighted MR images. Subchondral cysts
containing inflammatory fluid show increased signal on T2-weighted
MR images, while fibrotic cysts are hypointense.6
Because articular cartilage is well visualized on MR imaging, focal
areas of thinning or absent cartilage can be easily detected.
Treatment for hemophilia typically involves some form of factor
replacement depending on the severity of the disease. The pain and
swelling associated with joint injuries can be treated with
conservative measures such as immobilization, cooling, and
nonsteroidal anti-inflammatory medication, which do not interfere
with the coagulation pathway or platelet function. Aspiration
therapy is contraindicated unless necrosis, due to joint tension or
compartment pressure, is imminent. Radiotherapy for vascular
sclerosis can be useful in the treatment of soft-tissue masses and
acute joint hemarthrosis. When irreversible osseous and
cartilaginous changes have occurred, and pain and joint
contractures limit activities of life, joint replacement should be
considered.
CONCLUSION
Hemophilic arthropathy is a rare joint-destroying disorder that
is more prevalent before adulthood. A wide spectrum of radiographic
and MR changes are possible depending on the stage of the disorder.
Correlating a good history with characteristic imaging findings can
result in prompt diagnosis and treatment and may prevent, or at
least delay, the need for joint replacement.
Prepared by Michael W. Matchette, MD from
the University of Texas Health Science Center, San Antonio, TX and
Justin Q. Ly, MD from Wilford Hall Medical Center,
San Antonio, TX.
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