Simultaneous Unilateral Abducens Nerve Palsy and Contralateral Anterior Ischaemic Optic Neuropathy as the Presenting Signs of Giant Cell Arteritis.

Ischaemic optic neuropathy is the most common, feared, and recognised ocular manifestation of giant cell arteritis (GCA), while extraocular muscle palsy rarely occurs in the disease. Overlooking the diagnosis of GCA in aged patients with acquired diplopia and strabismus is not only sight- but also life-threatening. Here, we present, for the first time, a case of unilateral abducens nerve palsy and contralateral anterior ischaemic optic neuropathy as the presenting signs of GCA in a 98-year-old woman. Prompt diagnosis and treatment prevented further visual loss and systemic complications and allowed for rapid resolution of the abducens nerve palsy. We also aim to discuss the possible pathophysiological mechanisms of diplopia in GCA and to emphasise that acquired cranial nerve palsy must raise suspicion of this severe disease in elderly patients, particularly in association with ischaemic optic neuropathy.