Bone Pain/Gout
For your information re bone and joint pains in MPD.
Several of you have mentioned that you suffer from
bone and/or
joint pains - sometimes attributed to arthritis. I have seen a
number of patients who have this complaint and it has been
related to very active proliferative disease. There is a
technique for demonstrating active sites of bone marrow
proliferation using nuclear scans. The agent that is injected
is technicium-sulfur-colloid. It is the same scanning agent
that is used to image the liver and spleen. It is taken up by
macrophages which are cells derived from monocytes and,
ultimately, from the bone marrow precursor cell that is
involved in MPD.
In normal people bone marrow is confined to the
central
skeleton (cranium, ribs, sternum, vertebrae, and pelvis. The
long bones contain mostly fat. In MPD the bone marrow expands
outward to the long bones and can be seen even out in the
fingers and toes when bone marrow scanning is done.
The proliferation within the bone marrow cavity
may cause
pressure inside the bone that, in turn, causes inflammation of
the covering of the bone (periostium). The resulting
periostitis may be painful. In some patients with bone and
joint pain treatment with myelosuppressive therapy has
decreased or eliminated these symptoms by reducing the amount
of bone marrow in the cavity and reducing the pressure that it
causes.
Although other forms of arthritis may be causing
your pains, if
no conventional cause is found, they may be due to MPD. Talk
to your doctor about it if you have bone or joint pains. Also,
consider gout which produces very acute arthritis involving
only one joint.
Hope this helps.
Dr. Gilbert...
For your information re uric acid in MPD:
Uric acid is a by-product of the metabolism of
nucleoproteins.
These are molecules that arise from DNA and RNA released by
cells when they die. Patients with MPD turnover a lot of bone
marrow cells when they are in a proliferative phase and, thus,
produce a lot of uric acid.
Uric acid is cleared from the blood by the kidney.
When levels
of uric acid are high in the plasma there may be
crystallization of uric acid in the joints. This is what
produces gout. When a lot of uric acid has to be cleared by
the kidney uric acid may crystallize in the kidney tubules,
causing kidney stones or sludge that may damage the kidney.
In patients who have a lot of uric acid production
it is
advisable to interrupt uric acid metabolism at the step before
it is produced from a precursor called hypoxanthine. This is a
more soluble molecule that does not precipitate in joints or
kidneys and is cleared more readily by the kidney.
Uric acid levels may be measure in the blood. If
they are
elevated there is clearcut evidence that uric acid production
is increased. However, even if the plasma level is not
increased, uric acid production may still be increased. This
can be detected by measuring the total uric acid that appears
in the urine.
I generally use a drug - Allopurinol (Zyloprim)
- that inhibits
the step the turns hypoxanthine into uric acid. I use this
prophylactically in patient with MPD. Side effects are unusual
and occur early in its administration. If it is well tolerated
I suggest that the patient take one pill/day throughout the
course of their disease.
You might want to ask your doctor about this medication.
Once
gout has occurred, it must be treated with colchicine and anti-
inflammatory drugs, since uric acid is already crystallized in
the joint.
Dr. Gilbert...