Lessons of the month 4: Giant cell arteritis with normal inflammatory markers and isolated oculomotor nerve palsy.

Giant cell arteritis (GCA) is an important condition to suspect and treat early, as failure to do so can result in anterior ischaemic optic neuropathy and subsequent permanent visual loss.A 71-year-old woman presented to her local emergency department with a 1-week history of constant, moderate-severe global headache associated with intermittent periorbital pain. Two weeks later she developed sudden horizontal diplopia. Examination demonstrated right oculomotor nerve palsy. Her erythrocyte sedimentation rate (ESR) was 9 mm/hr. Repeat blood tests 1 month later showed an ESR of 67 mm/hr. Temporal artery biopsy was positive.A review from a cohort of 764 patients with suspected GCA who underwent biopsy found the sensitivity of an elevated ESR and c-reactive protein was 84% and 86%, respectively, but the specificity was only 30%. Therefore, inflammatory markers should only act as a guide, and caution should be taken in their interpretation especially with respect to the time of sampling in the disease evolution.Isolated oculomotor nerve palsy in association with GCA is rare. The first case series was described by miller fisher in 1959 who observed two patients presenting with diplopia, ptosis and ocular palsies. In anyone over the age of 50 who develops a new, refractory headache and cranial neuropathy, GCA should be the first consideration. © Royal College of Physicians 2020. All rights reserved.