Internuclear ophthalmoplegia
28 year old previously healthy lady complaining of diplopia with vertigo and a mild headache that resolved 2 days ago. Vitals normal, exam normal except as noted on photos. strength 5/5, sensory intact, rest of cranial nerves normal, speech fluent clear and coherent. Gait normal no ataxia. CT of head normal.
Photo shows bilateral internuclear ophthalmoplegia (INO) with inability to adduct either eye across the midline. Horizontal movement is preserved indicating no ""one and one half syndrome"". Patient found to have multiple sclerosis; this, her presenting episode.
INO is caused by a lesion in the medial longitudinal fasciculus which is responsible for coordinated eye movement. unilateral cases in older patients are often due to infarction. Bilateral lesions in younger patients are often multiple sclerosis. Trauma, infections, vasculitis and tumors. Diagnosis is clinical supported by neuroimaging and CSF testing.
