PRETIBIAL MYXEDEMA
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I have a 50 y/o F pt who has classic clinical and biopsy changes of
myxedema.  Quite generalized, involving pre-tibial areas, arms, breasts,
neck.  The internist was questioning my diagnosis because her TSH was only
5.8 (upper limit in our lab is 5.0).  My questions are:  Anyone know of
any relationship between the degree of hypothyroidism and the degree of
myxedema in the skin?  Other than correction of the hypothyroidism and
topical steroids any other treatment for the myxedema?  I had her on Lidex
ointment to the areas while awaiting the bx results and she got no effect
from that.
.
Claire L. Haycox
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Claire, I would suspect her TSH was beginning to elevate because her gland
had been pooping out for awhile. She probably had Graves or thyroiditis,
causing hyperthyroidism and myxedema. Myxedema may respond to high potency
steroids under occulsion, and I seem to remember a case melting with PUVA,
and another witht he aromatic retinois.   

Diane Thaler
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Would you consider intralesional steroids?  Is it feasible?  

Elliot Puritz
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It was my understanding that pretibial myxedema is not associated with any
particular status of the thyroid at time of Dx. There could have neen
pre-existing hyper or current hypo or even a euthyroid state.  If LATS (long
acting thyroid stimulator) is still considered in the etiology of this
condition or any other circulating protein plasmaphoresis might be a
consideration. 

Steve Wiener
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Her lesions cover too large an area for me to realistically consider
intralesional steroids. For localized, more discrete lesions I think it
would be an option, but not in this lady.

Claire L. Haycox
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No references, but I thought that myxedema was the result of
hyp*er*thyroidism.

Have personally seen folks with normal TSH and myxedema.

Barbara R. Reed, MD
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I would still empirically search for hx of hyperthyroidism preceding the
normal TSH, getting Thyroid antibodies etc, because they could be in the
process of burning out their thyroid and becoming hypothyroid.

Diane Thaler
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Apparently in hyperthyroidism (usually Graves disease) the myxedema is
localized to the pre-tibial area.  In hypothyroidism, generalized myxedema
is reported, which is the case in my patient.

Claire L. Haycox, M.D., Ph.D.,
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Re: Pretibial Myxedema
This form of mucinosis is 'probably' related to a circulating IgG
molecule [LATS-long acting thyroid stimulator] that activate fibroblasts
in some way to increase producation of mucopolysaccharaides.  There is
also some information regarding heat-shock proteins being activated. 
I've used PUVA (local) and free-radical scavengers (allopurinol,
acetylcysteine, etc. in Aquaphor) and had some success.  Some= somewhat
less than 100% efficacy.  My mainstay is intralesional triamcinolone AND
p.o. NSAIDS, both of which may have somewhat of an inhibitory effect on
fibroblasts.

Patrick Carrington
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