What are the key clinical features to differentiate between ischaemic and haemorrhagic stroke during initial assessment?

During the initial assessment, UK guidelines primarily focus on the rapid recognition of suspected stroke or transient ischaemic attack (TIA) using validated tools, rather than providing distinct clinical features to differentiate between ischaemic and haemorrhagic stroke at this stage ¹. Tools such as FAST (Face Arm Speech Test) are used outside hospital to screen for sudden onset neurological symptoms indicative of stroke or TIA ¹. Similarly, in the emergency department, the ROSIER (Recognition of Stroke in the Emergency Room) tool is used to rapidly establish a diagnosis of suspected stroke or TIA ¹.

Definitive differentiation between ischaemic and haemorrhagic stroke relies on brain imaging ¹. However, for a specific type of haemorrhagic stroke, subarachnoid haemorrhage (SAH), certain red-flag symptoms are highlighted during initial assessment. A 'thunderclap' headache, characterised by a sudden severe headache typically peaking in intensity within 1 to 5 minutes, is a key red-flag symptom for SAH ². Other symptoms and signs that may be present with SAH include neck pain or stiffness, photophobia, nausea and vomiting, new symptoms or signs of altered brain function (such as reduced consciousness, seizure, or focal neurological deficit), and limited or painful neck flexion on examination ². It is important to note that SAH can present with non-specific symptoms, and most people with a thunderclap headache do not have SAH, though further investigation is warranted if suspected ².