Fourth cranial nerve palsy in a collegiate lacrosse player: a case report.

OBJECTIVE: To present the case of a National Collegiate Athletic Association Division I men's lacrosse athlete with fourth cranial nerve injury as the result of a minor traumatic blow.
BACKGROUND: The athlete was struck on the right side of his head during a lacrosse game. On-field evaluation revealed no cervical spine involvement or loss of consciousness. He complained of headache and dizziness, with delayed reports of visual disturbance. Sideline visual acuity and cranial nerve screenings appeared within normal limits. Consultation with the team physician indicated that immediate referral to the emergency department was unnecessary. DIFFERENTIAL DIAGNOSIS: Concussion, third cranial nerve palsy, fourth cranial nerve palsy. TREATMENT: The certified athletic trainer safely removed the athlete from the playing field and monitored him on the sideline. After being seen by the team physician, the patient was referred to a neurologist, ophthalmologist, and finally a neuro-ophthalmologist before a definitive diagnosis was made. The palsy did not necessitate surgical intervention, resolving with conservative treatment. The athlete was able to return to full athletic ability at his preinjury level by 8 months postinjury. UNIQUENESS: Superior oblique palsy as the result of fourth cranial nerve injury is the most frequent isolated cranial nerve palsy; however, these palsies are often underdiagnosed by health professionals. Such palsies are uncommon within the athletic realm, making timely diagnosis even less likely.
CONCLUSIONS: Cranial nerve palsy may present very subtly in patients. Therefore, on-field health care providers should be aware of the descriptions and types of compensations that signal nerve injury.