Not so FAST: pre-hospital posterior circulation stroke

Posterior circulation strokes account for 20% of ischaemic strokes, but may present differently to their anterior circulation counterparts. Patients may not exhibit unilateral facial weakness, speech disturbances and unilateral limb weakness, but instead present with more vague symptoms of sudden headache, dizziness, loss of balance and visual problems. This case describes a patient displaying signs and symptoms of a posterior stroke, but who eluded the FAST (face, arm, speech, time) test.

An ambulance was called for a 60-year-old man who had a sudden onset of generalised weakness, diaphoresis and one episode of emesis at home in rural Ireland. He had a history of hypertension, hypercholesterolaemia, angina and a coronary stent placed 4 months previously. Cardiac, respiratory, abdominal, urinary and gastrointestinal exams were unremarkable. Vital signs and 12-lead electrocardiogram were normal. He was FAST negative on exam. Due to persistent dizziness, further neurological exams were carried out, showing a left visual field neglect, new nystagmus, left-sided dysmetria on finger-to-nose and heel-to-shin tests and he was unable to walk unassisted upon standing. A posterior circulation stroke was suspected, and the nearest stroke unit was pre-alerted en route. A rapid assessment and computed tomography took place at hospital, with timely thrombolysis with tissue plasminogen activator. The patient subsequently had a full neurological recovery.

This case describes a patient displaying signs and symptoms of a posterior circulation stroke albeit being FAST negative on exam. There is potential here to improve our recognition of posterior stroke in the pre-hospital field by including additional neurological exams to the FAST test. Use of 'BEFAST' (balance, eyes, face, arm, speech, time), the finger-to-nose test, and the '5 Ds' and 'DANISH' mnemonics may help increase recognition of these subtle presentations.