A rare red eye: cavernous sinus dural arteriovenous fistula masquerading as conjunctivitis and sinusitis

A 77‐year‐old woman with a background of hypertension, diet‐controlled type 2 diabetes and bilateral cataract surgery was referred by her general practitioner to the emergency department of the Royal Darwin Hospital with a progressive history of red eyes, lacrimation, rhinorrhoea and, more recently, diplopia. The patient first sought medical attention 6 weeks prior at symptom onset. Her GP had initially diagnosed and managed the presentation as sinusitis and, after failed resolution, as viral conjunctivitis. There was no history of trauma. Following onset of new diplopia, the patient was referred to hospital.