86TRANSIENT LOSS OF CONSCIOUSNESS - STROKE, THE FORGOTTEN DIFFERENTIAL

Abstract

Introduction: 'Strokes don't cause acute loss of consciousness' is a widely taught clinical statement. When faced with a comatose patient we are much more likely to seek a metabolic, traumatic, toxic or epileptic cause. We present a case which challenges the status quo and highlights the importance of keeping stroke as a differential in the management of a comatose patient. Case Details: This is a case of a 93 year old lady who is normally independent at home and cognitively intact. She presents with acute loss of consciousness with a persistent Glasgow Coma Score (GCS) of 3 and episodic apnoea. Traumatic, metabolic and infective causes were explored and ruled out. There did not appear to be any evidence of status epilepticus. CT Brain performed on admission was unremarkable. The definitive diagnosis was unclear but the admitting team felt death was imminent and she was commenced on a palliative approach. Thirty hours later the patient began to wake up with GCS of 7, then subsequently improved after transfer to Medicine for Elderly. Although there was no focal neurology the patient appeared to be mildly confused and had developed dysphagia. An MRI Head with diffusion weighted imaging was performed and confirmed bilateral subacute thalamic infarcts. She was commenced on anti-platelet therapy and transferred to Acute Stroke Unit, 5 days after initial admission. Discussion: Thalamic strokes account for 11% of vertebrobasilar infarcts. In particular bilateral paramedian thalamic infarcts characteristically present as altered consciousness, including coma, vertical gaze paresis and cognitive disturbance. There have been several case reports of this phenomenon and Honig et al describes a series of 12 patients, three of which had prompt imaging and received acute intervention with IV tissue plasminogen activator to good effect. Most patients with bilateral thalamic infarcts who were not acutely treated developed severe neurological deficits. Furthermore patients with basilar artery thrombosis can also present with altered consciousness in 17-33% of cases. When faced with a patient in a sleep-like coma there should always be consideration of posterior circulation stroke and prompt investigation to facilitate early treatment options.