Studies of Thyroid and Sympathetic Nervous System Interrelationships. I. The Blepharoptosis of Myxedema*

Blepharoptosis (drooping of the upper eyelid) was observed in 20 of 27 patients (74 per cent) with untreated myxedema of various types and in 6 of 18 myxedematous patients (33 per cent) treated with desiccated thyroid. The blepharoptosis was characteristically of modest degree and could bo overlooked easily. Lid edema, although frequent, was not always associated with ptosis. The tarsal fold was intact and normal voluntary and conjugate lid elevation was possible. Phenylephrine hydrochloride, when instilled into the conjunctival sac, corrected the ptosis in all cases. Electromyograms of the levator palpebrae superioris muscles were normal in 4 patients. Urinary catecholamine excretion was normal in 4 patients. Intravenous infusion of epinephrine did not correct the ptosis in 6 patients. The evidence suggests that blepharoptosis in myxedema results primarily from diminished tone of the sympathetic nerve fibers to Müller's superior palpebral muscle rather than from an abnormality of the levator palpebrae superioris muscle. Blepharoptosis appears to be the converse of the lid retraction of hyperthyroidism, and is a valuable clinical sign of myxedema. It is further evidence of the relationship between the thyroid hormone and the catecholamines of the sympathetic nervous system.