A stroke happens when blood flow to part of the brain is cut off or when a blood vessel in the brain bursts. During a large vessel stroke, roughly 1.9 million brain cells are destroyed every minute blood flow is blocked. Recognizing the signs quickly and calling emergency services is the single most important thing you or a bystander can do.
The BE FAST Check
The most reliable way to spot a stroke is a six-point check known as BE FAST. Each letter stands for a warning sign:
- Balance: Sudden loss of balance or coordination, trouble walking, or unexplained stumbling.
- Eyes: Vision changes in one or both eyes, including blurriness, double vision, or sudden partial blindness.
- Face: One side of the face droops. Ask the person to smile. If the smile is uneven, that’s a red flag.
- Arms: Weakness or numbness on one side of the body. Ask the person to raise both arms. If one arm drifts downward, that signals a problem.
- Speech: Slurred words, garbled sentences, or difficulty understanding what you’re saying to them.
- Time: Call emergency services immediately. Every minute counts.
Paramedics use a simplified version of this same check (facial droop, arm weakness, and speech) to assess stroke probability in the field. If even one of these signs is present, the chance of stroke is high enough to warrant emergency treatment.
Symptoms That Are Easy to Miss
Not every stroke announces itself with dramatic face drooping or arm weakness. Strokes that affect the back of the brain (the posterior circulation) often produce symptoms that look nothing like the classic warning signs. The most common of these is sudden, severe dizziness or vertigo. In fact, dizziness and vertigo are the symptoms most tightly linked to strokes that get missed in the emergency room. Isolated vertigo is the most frequent warning symptom before a posterior stroke, and it is rarely recognized as stroke-related at first contact with a healthcare provider.
These posterior strokes can also cause ringing in the ears, sudden hearing loss, difficulty swallowing, or intense nausea. Fewer than 20% of stroke patients with this type of presentation have the obvious neurological signs that screening tools are designed to catch. Some even score a zero on the standard stroke assessment scale used in hospitals. If someone experiences sudden, unexplained vertigo that feels different from anything they’ve experienced before, especially alongside any other neurological symptom, it deserves urgent evaluation.
How Strokes Can Look Different in Women
Women experience all the classic stroke symptoms, but they also report vague, atypical signs more frequently than men. Instead of obvious one-sided weakness, a woman having a stroke might feel sudden whole-body fatigue, confusion, or general weakness that isn’t clearly limited to one side. Nausea and vomiting are common and often get blamed on a stomach bug. A sudden, unusually severe headache might be dismissed, especially by women who already deal with regular headaches.
Many women attribute these symptoms to stress, being overworked, or not sleeping well. The pattern of dismissal is dangerous because it delays the one thing that makes the biggest difference: getting to a hospital fast. Any combination of sudden fatigue, confusion, difficulty walking, or an unusually bad headache appearing out of nowhere warrants a call to emergency services, even if the symptoms seem explainable by something less serious.
What a Mini-Stroke Looks Like
A transient ischemic attack, often called a mini-stroke, produces the same symptoms as a full stroke: numbness or weakness (especially on one side), confusion, trouble speaking, vision problems, dizziness, and loss of coordination. The difference is that these symptoms resolve on their own, usually within an hour, though they can last up to 24 hours.
The fact that symptoms disappear does not mean the event was harmless. A TIA is a warning that the conditions for a full stroke are in place. People who experience a TIA have a significantly elevated risk of a major stroke in the days and weeks that follow. If you or someone near you experiences stroke-like symptoms that go away, treat it as an emergency anyway.
Hemorrhagic Stroke: The Thunderclap Headache
Most strokes are caused by a blockage (ischemic strokes), but about 13% involve bleeding in the brain. A hemorrhagic stroke caused by bleeding inside the brain itself, usually driven by high blood pressure, tends to come on suddenly with no warning signs beforehand. Bleeding can be severe enough to cause loss of consciousness rapidly.
The hallmark symptom that may distinguish a hemorrhagic stroke is an explosive headache, sometimes described as the worst headache of your life, arriving in seconds. This can be accompanied by nausea, vomiting, neck stiffness, sensitivity to light, or sudden confusion. Any headache that reaches maximum intensity almost instantly is a medical emergency.
Silent Strokes
Some strokes produce no noticeable symptoms at all. These “silent” strokes are typically small and affect areas of the brain that don’t control obvious functions like movement or speech. They’re usually discovered incidentally when a brain scan is done for another reason. Silent strokes are surprisingly common in older adults, and while any single event may go unnoticed, they cause cumulative damage over time. Repeated silent strokes are linked to memory problems, difficulty thinking clearly, and increased risk of a larger, symptomatic stroke later.
There’s no way to identify a silent stroke on your own since, by definition, it doesn’t produce symptoms you’d recognize. But if a brain scan reveals evidence of one, it’s a signal that the underlying risk factors (high blood pressure, irregular heart rhythm, or narrowed arteries) need aggressive management.
What Happens at the Hospital
When you arrive at the emergency room with suspected stroke symptoms, the first priority is a brain scan to determine whether the stroke is caused by a blockage or by bleeding. This distinction determines treatment. A CT scan is fast and widely available, and it’s good at detecting bleeding immediately. MRI is more sensitive for detecting blockages, especially within the first 12 hours of symptom onset, and current guidelines recommend it over CT during that window when it’s available. In practice, many hospitals start with CT because it takes minutes rather than the longer time an MRI requires, and ruling out bleeding is the most urgent first step.
The clock starts when symptoms first appear, not when you arrive at the hospital. This is why emergency dispatchers and paramedics will ask when the person was “last seen normal.” If you witness someone developing stroke symptoms, note the time. That detail directly affects which treatments are available. For blockage-type strokes, clot-dissolving treatment is most effective when given early, and the window for certain interventions can close within hours.