Subclinical Hypothyroidism

The term 'subclinical hypothyroidism' applies to patients who have mildly increased levels of serum thyrotropin hormone (TSH) and normal levels of thyroxine and liothyronine (triiodiothyronine). This very common condition, also called 'mild thyroid failure', accounts for 75% of patients who have increased serum TSH. For patients with sustained increases above 10 mIU/L, there is uniform agreement that thyroxine therapy is indicated. Therapy for milder forms of hypothyroidism is controversial. Some randomized clinical trials favor therapy for mild thyroid failure, but they are inconclusive because they lack stratification for the subgroup of patients with TSH levels below 10 mIU/L. For this subgroup, we recommend individualized management. The presence of goiter, positive thyroperoxidase (TPO) antibodies, manic-depressive disorder, fertility problems, or pregnancy or the anticipation of pregnancy favors the initiation of therapy. Positive TPO antibodies are a strong indication for therapy because of the high likelihood in these patients of progression to overt hypothyroidism; patients who are already receiving thyroxine should have adjustments of their dosage. Children and adolescents with mild thyroid failure should also be treated because of possible adverse effects on growth and development. It has been suggested that subclinical hypothyroidism is a cardiovascular risk factor, however further investigation is needed. The controversy surrounding therapy will not be resolved until more randomized studies are available for the subgroup of patients with TSH <10 mIU/L, and until the question of cardiovascular risk factors is further clarified.     

Graves' dermopathy and acropachy are markers of severe Graves' ophthalmopathy.

It is generally considered that thyroid dermopathy and acropachy almost always occur with Graves' ophthalmopathy and that these two extrathyroidal manifestations are indicators of severe autoimmune disease and hence of more severe ophthalmopathy. However, documentation of these anecdotal impressions is needed. We assessed the presence of optic neuropathy and frequency of orbital decompression in 2 referral cohorts: 40 patients with acropachy and dermopathy (acropachy group) and 138 patients with Graves' dermopathy and no acropachy (dermopathy group). We compared those cohorts with a cohort of 114 patients who had ophthalmopathy without dermopathy and acropachy (control group). We considered optic neuropathy and the need for orbital decompression to be indicators of severe Graves' ophthalmopathy. The frequency of orbital decompression was significantly higher in the dermopathy group than in the control group (odds ratio, 3.55) and even higher in the acropachy group (odds ratios: 20.68 for acropachy group compared with control group; 5.83 for acropachy group compared with dermopathy group). The same trend occurred with optic neuropathy but was not statistically significant (alpha = 0.05; p = 0.07). Five patients were exceptions: they had definite Graves' dermopathy without clinically obvious ophthalmopathy. In conclusion, dermopathy and acropachy appear to be markers of severe ophthalmopathy. Occasionally, however, Graves' dermopathy occurs without clinical ophthalmopathy.     

Torsional diplopia after transantral orbital decompression and extraocular muscle surgery associated with Graves' orbitopathy.

Graves' orbitopathy can be associated with horizontal, vertical, and torsional diplopia. Of 428 patients treated with transantral orbital decompression, 21 had incycloduction (mean, 12.8 degrees; range, 5 to 20 degrees) and five had excycloduction (mean, 12 degrees; range, 5 to 20 degrees). All 26 patients had had recessions of the medial or inferior rectus muscle (or both) before onset of torsional diplopia. Mean recession was 5.5 mm (range, 4 to 10 mm) and 5.3 mm (range, 2 to 10 mm) of medial rectus muscle and inferior rectus muscle, respectively. An A pattern was often associated with the condition. Superior oblique tenectomy and inferior oblique myectomy were performed most frequently for incycloduction and excycloduction, respectively. Superior oblique tenectomy induced a mean incycloduction decrease of 7.1 degrees (range, 0 to 12 degrees). Exotropia in downgaze was decreased, and a small ipsilateral hyperdeviation was induced. Bilateral inferior oblique myectomy in one patient decreased excycloduction 10 degrees without inducing new deviation. At follow-up (mean, 63.7 months) after last strabismus operation, 15 patients with incycloduction and two with excycloduction had no diplopia.