|Title||WHEN DIPLOPIA IN THE ELDERLY IS NOT SMALL VESSEL DISEASE: A CASE OF MYASTHENIA GRAVIS MIMICKING A 6TH CRANIAL NERVE PARESIS|
|Author, Co-Author||Stuart Frank|
|Abstract|| BACKGROUND: Diplopia in the elderly, when appearing as an isolated, unilateral cranial nerve palsy in patients with concommitant vascular disease, usually represents infarction of the nerve trunk from small vessel ischemia. These patients are frequently subjected to careful office examination, blood pressure measurement, and laboratory studies; but, in cases without progression, additional involvement, or persistence of deviation, costly or invasive workup is often deferred in favor of close clinical monitoring. This case describes an elderly gentleman whose diplopia was not ischemic, but rather the presenting symptom to his rapid demise from myasthenia gravis.
CASE REPORT(S): An 88 year old gentleman with known history of hypertension, atrial fibrillation, CHF, and diabetes mellitus presented with a 6-week history of sudden onset horizontal diplopia. Examination revealed an isolated left-sided abduction deficit consistent with a VIth cranial nerve paresis. However, follow-up examination over 2 months revealed an increase in deviation, along with additional ocular and systemic symptoms. A subsequent Tensilon test proved positive, with resolution of his diplopia. He was placed on Mestinon therapy, but after 2 months, he failed to thrive and subsequently succumbed from respiratory failure.
CONCLUSIONS: Small vessel ischemic disease is a rather common cause of isolated, unilateral cranial nerve palsies in the elderly; whereas, the mean age of onset for myasthenia gravis is 33 years. Nevertheless, as one of the "great mimickers" in medicine, it must always be considered as part of the differential for diplopia in the elderly, particularly when there is an instability or increase in deviation, or when additional signs or symptoms develop.
|Affiliation of Co-Authors|