Bilateral fourth-nerve palsy occurring after shaking injury in infancy

Trauma to the cranial nerves

Cranial nerve injury is often an overlooked aspect of neurotrauma, which is diagnosed later in the course of recovery. Most of these injuries do not require active intervention in the acute stage. Cranial nerve injuries are important cause of morbidity, which requires long-term management, repeated surgical procedures or reconstructive measures. Management of optic nerve injury remains controversial, and injury to lower cranial nerves may influence the ultimate outcome due to paralysis of aerodigestive passage. Cranial nerve injury in the setting of head injury should be diagnosed early, so that appropriate treatment can be planned early.

Isolated trochlear nerve palsy with perimesencephalic subarachnoid haemorrhage

Perimesencephalic subarachnoid haemorrhage is usually asymptomatic other than meningeal irritation sign. The authors report a case of subarachnoid haemorrhage at the quadrigeminal cistern showing ipsilateral trochlear nerve palsy and discuss the pathogenesis. A 71-year-old man with a history of diabetes mellitus and acute myocardial infarction presented with diplopia. He underwent CT, which revealed subarachnoid haemorrhage at the left quadrigeminal cistern. Neurological examination revealed left isolated trochlear nerve palsy, with results otherwise normal. The diagnosis of perimesencephalic subarachnoid haemorrhage was established on neuroimaging. The amount of haemorrhage is related to symptoms. A dense clot in the quadrigeminal cistern might have been the cause of trochlear nerve palsy.