THE MANAGEMENT of neurologically isolated, nontraumatic oculomotor nerve palsy is a challenge in the wise deployment of expensive and potentially harmful diagnostic tools.
Most cases are caused by ischemia of the nerve and do not require any diagnostic tests.1- 5 Others are caused by inflammatory or neoplastic meningitis that can be diagnosed with a combination of magnetic resonance imaging and lumbar puncture. But some patients harbor a cerebral aneurysm that could kill them within days and for which timely treatment is curative. In the past, the diagnosis of aneurysm has depended entirely on catheter cerebral angiography, a test that maims or kills in about 1% to 2% of cases, and perhaps more among the elderly and those with ample arteriosclerotic risk factors.6
Trobe JD. Managing Oculomotor Nerve Palsy. Arch Ophthalmol. 1998;116(6):798. doi:10.1001/archopht.116.6.798