PDFQuestion
I have a 63 year old lady with hx of hypothyroidism for at least 8 years and on 50 to 75 ug of generic LT4. Since August ' 06 she noticed left eye proptosis and double vision. Her hypothyroidism is NOT postablative from previous Grave's disease. Reviewing her chart ( since I have only seen her once for consultation) in Nov '06 her TSH was undetectable but no Ft4 was done by the PCP but prior to that the TSH were more than 1- 2 uiu/ml. Based on these TSH levels her LT4 was changed appropriately by 25 mcg depending on TSH.
I am aware of hashitoxicosis but not presenting this way i.e. primary hypothyroidism then presenting with proptosis. I should mention that CT of the orbits did not reveal any mass lesions and that TSI antibody is positive at 2.2 ( Mayo send out). Due to double vision, I gave her prednisone 30 mg but I'm unsure if I should start MMI since her recent TSH was 0.61 on 75 mcg of LT4. I would appreciate any insight on this matter.
Maria Mercado MD KS
Response
Your patient certainly has one variety of autoimune thyroid disease. Exophthalmos presenting with primary hypothyroidism is unusual, but definitely occurs. Basically she has a partially destroyed thyroid being driven by TSAb. She is intrinsically hypothyroid, not hyperthyroid, and I doubt there is value in ATD treatment. What to do with her exophthalmos is a different story.. Maybe nothing, if it is non-progressive and with modest symptoms. Prisms might help a bit. The conventional treatments with steroids and/or radiation might help. Beyond that therapy gets into the unproven. I believe the current evidence is that octreotide is of little benefit. Use of the anti-B cell monoclonal rituximab has lately been touted, and has a logical basis, with some efficacy in one report. In time, muscle surgery may help.
If the ocular problem progressed, my personal approach would be to remove the thyroid surgically and destroy residual with RAI. The idea is to remove antigen driving the problem. Most reviews do not even mention this approach, so you can see that it is also unproven. It probably is mainly effective over the course of several months and years, as anti- thyroid immunity declines, and may be less effective once the TSH-R antigen in the eyes becomes important in the immune process.
L De Groot, MD