Isolated Inferior Rectus Paresis as the Presenting Manifestation of Myasthenia Gravis

Abstract

Isolated inferior rectus paresis is an uncommon clinical finding, but may be the presenting manifestation of myasthenia gravis. We report a patient with an isolated inferior rectus paresis in the right eye. Initial Tensilon® testing, Prostigmin® testing, antiacetylcholine receptor antibody testing, and single fiber EMG were negative. A second Tensilon® test was positive after the patient developed ptosis and weakness of the left medial rectus muscle. Myasthenia gravis should be considered in any patient with an isolated, non-traumatic inferior rectus muscle palsy.

• Inferior rectus muscle paresis
• myasthenia gravis