Evaluation of a Complete Third Nerve Palsy With Aberrant Regeneration in a Traumatic Brain Injury Patient

Introduction. Aberrant regeneration occurs with traumatic, aneurismal, or compressive third nerve palsy. In a pupil involving third nerve palsy secondary to traumatic brain injury (TBI), careful observation with visual rehabilitation is warranted. Case Presentation. A 33 year-old male presented for sensory motor evaluation secondary to TBI, which occurred three years prior. He complained of intermittent diplopia in all secondary gazes yet was able to obtain single vision in primary gaze. Best correct acuity is 20/20 OD, OS. Pupil testing revealed a minimally reactive dilated left pupil, which was responsive to accommodation and constricted upon inferior gaze and adduction. EOMs revealed underaction OS in 6 out of 9 gazes excluding left and inferior left. Also an elevation of the upper eyelid was present with down gaze OS. Near cover test revealed 5 pd constant left hypertropia and 8-10 pd exophoria in primary gaze. Deviation From the Expected. This case presents a TBI patient with complete third nerve palsy and aberrant regeneration. Discussion. There are several etiologies for a complete third nerve palsy and the prognosis varies for each. Some may develop aberrant regeneration, which should be monitored closely. It is important to differentiate between the etiologies in order to understand the prognosis of each. Conclusion. In this case, visual rehabilitation should be implemented, due to the limited resolution of this condition. Visual rehabilitation is scheduled to begin with goals of improving visual skills, primary and secondary vergence fusional ability, and scanning techniques.