The symptomatic IV nerve palsy

Abstract

The majority of IV nerve palsies are benign, either idiopathic, congenital, or the result of known trauma. This report describes the stories and atypical features of five patients with isolated IV nerve palsies on examination, who proved to have underlying structural lesions. The first case had a trochlear schwannoma that caused a IV nerve palsy that recurred years later. The second had an orbital apex metastasis that caused a IV nerve palsy with a history of mild fluctuating ptosis. The third had a cavernous sinus fistula that presented with an unusual month-long prodrome of headaches and eye pain prior to diplopia. The fourth was a young patient who suffered a hemorrhage along the tentorium cerebelli from excessive anticoagulation. The fifth had an arachnoid cyst posterior to the cavernous sinus that presented with long-standing head tilt, suggesting a congenital palsy, but normal vertical fusional amplitudes. Detailed imaging of the sella with coronal and axial sections and gadolinium administration was critical to diagnosing most of the lesions causing these symptomatic IV nerve palsies. In most, atypical aspects of their history were key indicators of the need for imaging in this usually benign type of nerve palsy.