Recurrent cranial neuropathy in diabetes

Abstract

Case report A 59-year-old man presented to our department with sudden onset of right-sided ptosis (figure 1) and diplopia, preceded by pain behind the right orbit. This patient had a left sixth nerve palsy a year ago, which had resolved spontaneously. His past history was notable for type 2 diabetes of 15 years duration. On examination, the visual acuity, colour vision and visual fields were normal. Both pupils reacted equally to light. Retinal examination showed features consistent with non-proliferative diabetic retinopathy. There was ptosis of the right eye (figure 1). On lifting the eyelid, abduction was observed in the natural position, with pupillary sparing (figure 2), consistent with a diagnosis of third nerve palsy. The results from examination of other cranial nerves, pyramidal tracts, sensory and cerebellar systems were normal. Glycaemic control was satisfactory on a combination of insulin and metformin with an admission HbA1C of 7.2%. Blood investigations including full blood count, renal and liver functions, lipid profile, serum electrolytes, erythrocyte sedimentation rate, ANA, viral markers and cerebrospinal fluid analysis were within normal limits. A brain MRI did not reveal any structural lesions, especially around the cavernous sinuses or posterior orbits. A clinical diagnosis of recurrent cranial neuropathy secondary to diabetes was considered and the patient made a complete recovery within 12 weeks of this presentation.