Stroke warning syndromes

It is important for physicians to be aware of stroke warning syndromes because, although rare, there is a high associated risk of subsequent ischaemic infarction. Stroke warning syndromes present as stereotypical, recurrent transient episodes of focal neurological deficit, in the absence of cortical signs, occurring within a short period of time. They are broadly divided into two main subtypes, based on vascular territory: capsular warning syndrome and pontine warning syndrome. The exact underlying pathophysiology related to stroke warning syndromes is incompletely established, but proposed pathophysiological hypotheses for cerebral hypoperfusion include micro-atherosclerosis (cerebral small vessel disease) and haemodynamic instability (e.g. hypotension). Atherosclerotic disease involving small perforating arteries in the anterior circulation (e.g. lenticulostriatal arteries) gives rise to capsular warning syndrome and subsequent risk of capsular infarcts. Conversely, involvement of the posterior circulation pontine perforator arteries gives rise to pontine warning syndrome, which can result in paramedian pontine infarcts. Although the evidence is limited, recommended treatment modalities include permissive hypertension, intravenous recombinant tissue plasminogen activator, dual antiplatelet therapy and statins.