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AVN:
a potentially serious complication of HIV infection—
Are the number of cases increasing?
AIDS Research Alliance has learned that unusually high numbers
of the potentially serious condition avascular necrosis, or
AVN, have been seen recently in HIV+ individuals at several
Los Angeles-area medical practices.
Throughout
the epidemic, AVN has only rarely been seen in HIV-infected
individuals. As one index of the rarity of AVN in this population,
only 23 cases had been reported in the medical literature
before 1996. With such a sporadic incidence, clinicians have
not been able to solidly identify the associated cause(s)
or risk factor(s) for the HIV+ patient, although hyperlipidemia
(high fats and cholesterol in the blood) and steroid use might
be involved.
AVN
occurs when the blood supply to the bone is diminished. Bone
is living tissue, and without proper blood supply, it can
become brittle and susceptible to breakage. Thus, with time,
AVN sufferers can require hip replacement surgery. One unusual
aspect of the AVN cases reported to us is that other joints
have been affected, such as ankles and knees.
Patients
suffering from AVN will experience joint pain. Joint pain,
of course, can have many causes. An MRI scan is required to
diagnose AVN, because X-rays will not detect the problem.
The
fact that physicians at several practices have been seeing
more AVN cases recently might indicate that there is an increasing
incidence of this condition in the HIV+ population at large.
If the number of new cases of AVN in HIV-infected individuals
is in fact increasing, that would raise the possibility that
these cases are related to treatment choices available only
recently, rather than a direct consequence of HIV infection
itself.
At the 6th Conference on Retroviruses and Opportunistic Infections,
held in February 1999, a group from Georgetown University
Medical Center also reported a high incidence of AVN in their
HIV patient population, and suggested a link between some
cases of AVN in HIV+ individuals and the use of protease inhibitors.
However, this suggestion was based on data from only 5 patients.
This link cannot be proven without further study of larger
numbers of affected patients.
Patients experiencing unusual joint pain should consult
a physician. No one should consider discontinuing their medication
without first consulting their doctor.
Given
the importance of determining whether there has been a true
increase in AVN in the HIV+ population, and identifying the
risk factor(s) underlying such an increase, AIDS Research
Alliance requests that primary care physicians, treatment
advocates, and clinical trial investigators who are aware
of HIV+ individuals diagnosed with AVN to contact us at the
following e-mail address: avn@aidsresearch.org.
As of press time, ARA is scheduled to sponsor a meeting of
Los Angeles area healthcare practitioners to discuss this
issue on April 27. We will evaluate whether to express our
concerns to the FDA based on the responses that we receive.
(The internet contains good resources for learning about AVN,
for both lay people and health care professionals. Performing
a search for "AVN" on the site orthopedics.about.com/health/orthopedics
will yield links worth exploring).
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