A 29-year-old woman with a history of long-standing well-controlled type 1 diabetes mellitus presented with a one week history of horizontal double vision on looking to the left. She had noticed this after waking up one morning. In the preceding 2 weeks the patient had developed an increasingly severe generalized headache, which was particularly noticeable throughout the night and in the morning. She had vomited on several occasions, and she had also been aware of right-sided pulsatile tinnitus. Six weeks previously the patient had been treated for a presumed ear infection. Although her...

A 29-year-old woman with a history of long-standing well-controlled type 1 diabetes mellitus presented with a one week history of horizontal double vision on looking to the left. She had noticed this after waking up one morning. In the preceding 2 weeks the patient had developed an increasingly severe generalized headache, which was particularly noticeable throughout the night and in the morning. She had vomited on several occasions, and she had also been aware of right-sided pulsatile tinnitus. Six weeks previously the patient had been treated for a presumed ear infection. Although her earache had improved, it had never quite settled. The patient denied any associated photo- or phonophobia, neck stiffness, or motor or sensory symptoms. She was feeling well within herself. Clinical examination some days after the onset of the double vision revealed a left sixth nerve palsy and bilateral papilloedema. There was no other neurological deficit.