What Are the First Warning Signs of a Brain Stroke?

Every minute during a stroke, approximately 1.9 million neurons are lost. The brain does not send pain signals when its blood supply is cut off, which means stroke symptoms are neurological rather than painful, and easily mistaken for tiredness, dizziness, or anxiety by both patients and bystanders. Recognising the warning signs and acting within the treatment window is what determines whether a patient walks out of hospital with minimal deficit or is left with permanent disability.

According to Dr. Guruprasad Hosurkar, a leading Neurologist in Bangalore, “The biggest problem with stroke is that patients wait. They think the numbness will pass, the speech will come back, or they do not want to cause a fuss. By the time they reach the emergency room, the treatment window has closed. Stroke is the one neurological emergency where the entire outcome depends on what happens in the first two hours, not what happens in the hospital.”

Stroke symptoms come on suddenly and without warning. Their sudden onset is the key feature that separates a stroke from other neurological conditions, and every symptom below should be treated as an emergency until proven otherwise.

• Sudden one-sided face drooping or numbness: Asymmetric facial weakness, particularly with drooping of one corner of the mouth or inability to smile symmetrically, indicates involvement of the motor cortex or corticobulbar tracts and is one of the most reliable stroke signs.
• Sudden arm or leg weakness on one side: Unilateral limb weakness, where one arm drifts downward when both are raised with eyes closed, is a direct sign of contralateral hemisphere or internal capsule ischaemia and should trigger immediate emergency response.
• Sudden speech difficulty or confusion: Slurred speech, inability to find words, or failure to understand spoken language points to involvement of the dominant hemisphere language areas, and bystanders should not assume the person is intoxicated or confused for other reasons.
• Sudden severe headache, vision loss, or loss of balance: A thunderclap headache suggests subarachnoid haemorrhage, sudden vision loss in one eye points to ophthalmic artery occlusion, and gait imbalance with nausea indicates posterior circulation stroke. Brain stroke treatment outcomes depend entirely on how fast each of these is recognised.

Any single one of these symptoms appearing suddenly is enough to call emergency services immediately, without waiting to see if it resolves on its own.

The treatment window for stroke is narrow and fixed. What happens in the first 4.5 hours determines whether damaged brain tissue can be salvaged or the deficit becomes permanent. 

• Intravenous thrombolysis works only within 4.5 hours: tPA breaks down the clot causing an ischaemic stroke, but its benefit narrows sharply with time and can’t be given after the window closes making accurate symptom onset time the first question every stroke team asks.
• Mechanical thrombectomy extends the window to 24 hours in selected cases: For large vessel occlusion with salvageable tissue confirmed on imaging, endovascular clot retrieval can be performed up to 24 hours after onset in patients meeting specific criteria.
• TIA carries up to 10% stroke risk within 48 hours: A transient ischaemic attack resolves completely but needs same-day evaluation, not a scheduled outpatient appointment stroke risk is highest in the first two days.
• Every delay compounds irreversible damage: The NINDS time-is-brain calculation makes explicit what the numbers mean in practice, and why stroke units measure door-to-needle time in minutes rather than hours.

The FAST acronym Face, Arm, Speech, Time remains the single most practical tool for bystander recognition, requiring no medical training to apply. But posterior circulation strokes often miss all four FAST criteria, which is why knowing when vertigo is a sign of something serious matters just as much.

Dr. Guruprasad Hosurkar practises at KIMS Hospital, Mahadevapura, with specialist expertise in acute stroke management, TIA evaluation, and secondary stroke prevention. For patients who have experienced a TIA or minor stroke, or those with multiple vascular risk factors who want a structured prevention assessment, early specialist review is where the most meaningful long-term outcomes are secured.