Unilateral Oculomotor Nerve Palsy Associated With Primary Hypothyroidism: Two Case Reports

Abstract

We report two cases of unilateral oculomotor nerve palsy associated with primary hypothyroidism, both of which were admitted with monocular diplopia and ptosis as the first symptoms. On examination, there were no neurological abnormalities other than the signs of oculomotor nerve palsy. Blood biochemistry revealed a severe decrease in thyroid function with an elevation of A-TG. Cranial MRI and angiography showed no abnormalities. Thyroid hormone replacement therapy resulted in significant improvement in symptoms without meaningful changes in A-TG. Ongoing treatment found continued relief of ocular muscle palsy symptoms if thyroid function was maintained at normal levels. Our report suggests that the pathogenic mechanism may be related to the dysfunction of thyroid hormones in maintaining cellular function and enhancing β-adrenergic receptors in the eyes. In addition, this report recommends as well that clinicians should be aware that hypothyroidism may be an independent etiology of oculomotor nerve palsy.