Having a stroke is a medical emergency that requires immediate treatment. But how can doctors at the hospital determine if someone has had a stroke? There are several diagnostic tests and procedures that healthcare providers use to quickly identify if a patient has suffered a stroke.
What is a Stroke?
A stroke occurs when blood flow to part of the brain is interrupted or severely reduced, depriving brain tissue of oxygen and nutrients. Within minutes, brain cells begin to die. There are two main types of stroke:
- Ischemic stroke – An ischemic stroke accounts for about 87% of all strokes. It happens when a blood clot blocks an artery leading to the brain.
- Hemorrhagic stroke – A hemorrhagic stroke accounts for about 13% of strokes. It results from a weakened blood vessel rupturing and preventing blood flow to part of the brain.
During a stroke, every minute that passes without treatment increases the chance of permanent brain damage, disability or death. That’s why it’s so important to recognize the signs of stroke and seek emergency care immediately.
Recognizing the Signs of Stroke
Using the mnemonic device FAST can help identify the most common signs and symptoms of stroke:
- Face drooping – One side of the face may droop or experience paralysis.
- Arm weakness – Arm weakness or numbness might occur on one side of the body.
- Speech difficulty – Slurred speech or trouble understanding speech can signal a stroke.
- Time to call 911 – If any of these other signs are present, it’s time to call 911 even if the symptoms seem to fluctuate.
Other symptoms of stroke can include sudden confusion, trouble seeing, dizziness, loss of balance or coordination, and severe headache with no known cause. Sometimes strokes are described as “silent” when they lack the more obvious symptoms.
Medical History and Physical Exam
When a potential stroke patient arrives in the emergency room, doctors will immediately try to gather information about current symptoms along with medical history. They will ask questions such as:
- When did the symptoms start?
- Have the symptoms changed or progressed since they began?
- What other stroke-like symptoms are occurring?
- Does the patient have any underlying health conditions like heart disease, diabetes, or high blood pressure?
- Is the patient taking any medications, including blood thinners that could impact bleeding risk?
- Has the patient ever had a previous stroke or transient ischemic attack (TIA)?
A physical exam will also check for signs of a stroke, including:
- Changes in level of consciousness
- Abnormal reflexes
- Muscle weakness
- Impaired coordination or balance
- Vision problems
- Trouble speaking or understanding
- Facial droop
Doctors will also look for visible signs of head injury or trauma.
Blood Tests
Blood tests may be ordered to help rule out other possible medical issues that could mimic a stroke. These can include:
- Complete blood count (CBC) – Checks for signs of infection, anemia, and platelet levels.
- Basic metabolic panel – Measures sodium, potassium, and glucose levels.
- Liver function tests
- Toxicology screen
- Pregnancy test
- Blood alcohol level
Brain Imaging
Medical imaging of the brain is a key part of diagnosing a stroke. It can identify if a stroke has occurred, what part of the brain is affected, and what type of stroke it is. Brain imaging may include:
- CT scan – This produces cross-sectional X-ray images of the head and brain. It can detect bleeding in or around the brain shortly after symptoms begin.
- MRI – An MRI uses radio waves and strong magnets to generate more detailed images of brain anatomy and structures without radiation exposure.
- Carotid ultrasound – This test uses sound waves to create images of the carotid arteries in the neck. It can detect buildup of fatty deposits called plaque that can increase stroke risk.
- Cerebral angiogram – Contrast dye is injected into the bloodstream to highlight blood vessels in the brain and neck on an X-ray image.
- Transcranial Doppler ultrasound – Sound waves measure blood flow in the brain’s major arteries.
- Echocardiogram – Used to visualize the heart structure and check for sources of clots like an abnormal heart rhythm.
These tests can identify blockages and bleeding that characterize strokes. They may also rule out conditions like tumors or other brain abnormalities.
Other Diagnostic Tests
Additional diagnostic tests that may be used include:
- Chest X-ray – Can detect heart failure, pneumonia, heart enlargement, or lung diseases.
- Electrocardiogram (EKG) – Records electrical activity of the heart to detect irregular rhythms, coronary artery disease, and evidence of a previous heart attack.
Classifying Ischemic Strokes
If an ischemic stroke is diagnosed, additional classification can help determine the best treatment approach. Ischemic strokes may be categorized as:
- Thrombotic – Resulting from atherosclerosis or hardening of arteries. Plaque buildup narrows arteries, limiting blood flow.
- Embolic – An embolus or blood clot forms elsewhere in the body (like the heart) and travels through the bloodstream to lodge in an artery in the brain.
- Lacunar – Occurs due to chronic high blood pressure. This damages small arteries, causing them to block.
Assessing Stroke Severity and Damage
Once a stroke diagnosis is made, healthcare providers assess the location and extent of brain injury. This helps determine treatment options and predict outcome. Assessments may include:
- NIH Stroke Scale – Rates impairment in areas like consciousness, vision, movement, sensation, and speech on a scale from 0 to 42.
- Modified Rankin Scale – Measures degree of disability from 0 (no symptoms) to 6 (death).
- Glasgow Coma Scale – Scores ability to open eyes, respond verbally, and move purposefully on a 3-15 point scale.
- Brain imaging – Shows location and extent of damaged brain tissue.
Identifying Hemorrhagic Strokes
Hemorrhagic strokes have different causes than ischemic strokes and require alternative treatments. Hemorrhagic strokes can be further divided into categories:
- Intracerebral hemorrhage – An artery ruptures and bleeds into surrounding brain tissue.
- Subarachnoid hemorrhage – Bleeding occurs between the brain and thin tissues covering the brain.
- Intraventricular hemorrhage – Bleeding directly into the fluid-filled spaces in the brain.
Identifying the location of the bleeding helps guide treatment. Brain imaging, angiograms, and other tests are used to detect and characterize hemorrhagic strokes.
Labs and Tests to Determine Stroke Cause
Once an acute stroke is diagnosed, additional lab tests may help pinpoint the cause. These can include:
- Cholesterol levels – Elevated LDL and triglycerides may indicate risk of atherosclerosis.
- Blood counts – A high red blood cell or platelet count can thicken blood and increase clot risk.
- Blood typing – Determines blood type and Rh factor.
- Infection screening – An infection could trigger a transient ischemic attack (TIA) or ischemic stroke.
- Toxicology – Illicit drug use may cause hemorrhagic or ischemic stroke.
How Quickly Can a Stroke Be Diagnosed?
Doctors must work very quickly to diagnose a stroke. The phrase “time is brain” emphasizes that rapid treatment is crucial to preserving brain cells and minimizing lasting impairments. On average:
- Brain scans can detect stroke within minutes.
- Doctors can confirm stroke diagnosis within ~30 minutes of arriving in emergency room.
- Ischemic stroke can often be definitively diagnosed within 60 minutes.
- Specialized lab tests help reveal stroke cause within hours.
The speed of diagnosis and treatment has a huge impact on stroke outcomes. Faster diagnosis enables faster treatment.
Emergency Stroke Treatments
Once stroke is diagnosed, emergency treatments try to dissolve clots or stop bleeding as quickly as possible. These may include:
- IV tPA – A potent clot-busting drug for ischemic stroke if given within 3-4.5 hours of symptom onset.
- Endovascular therapies – Microcatheters and devices can physically remove clots in ischemic stroke.
- Hemorrhagic stroke surgery – Stop bleeding vessels, drain hematomas, repair aneurysms.
Without rapid stroke diagnosis, the short treatment windows for interventions like IV tPA would be missed.
How Diagnosis Guides Ongoing Hospital Care
The tests and results generated during initial stroke diagnosis guide care during the rest of the hospital stay and begin planning for rehabilitation. This information helps with:
- Monitoring brain tissue at risk
- Preventing further stroke damage
- Providing medications and interventions to support recovery
- Beginning physical, occupational and speech therapy
- Educating and involving family in care decisions
- Planning for discharge needs and services
Steps in Stroke Diagnosis Summary Table
| Diagnostic Step | Testing Used | Information Provided |
|---|---|---|
| Patient History & Physical Exam | – Question patient or family about symptom onset and medical history – Check vital signs, neurological deficits, motor abilities |
– Determine if symptoms indicate a stroke – Identify other existing medical conditions |
| Blood Tests | – Complete blood count, metabolic panel, cardiac markers | – Help rule out conditions like infection, diabetes, hematological disorders |
| Brain Imaging | – CT scan, MRI, carotid ultrasound, cerebral angiogram | – Identify location, type, severity of stroke – Detect clots, bleeding, area of infarction |
| Other Diagnostics | – EKG, chest x-ray, echocardiogram | – Identify heart conditions that may have contributed to stroke |
| Classify Ischemic Stroke | – Patient history, imaging studies | – Categorize stroke mechanism – thrombotic, embolic, or lacunar |
| Assess Severity | – NIHSS, Modified Rankin Scale, Glasgow Coma Scale, imaging | – Grade impairments to guide treatment approach and predict outcome |
| Determine Cause | – Blood tests, patient history | – Identify factors like atherosclerosis, blood disorders, drug use |
Initiating Post-Stroke Care
The speed and accuracy of the initial stroke diagnosis guides immediate treatments as well as ongoing care throughout hospitalization and rehabilitation. Key steps include:
- Providing medications and interventions to help prevent another stroke.
- Beginning stroke rehabilitation with physical, occupational and speech therapy.
- Taking steps to prevent post-stroke complications like pneumonia, blood clots, and depression.
- Educating the patient and family about lifestyle changes to reduce recurrence risk.
- Coordinating home health services, medications, and follow-up care needed at discharge.
Conclusion
Healthcare providers have a variety of tools available to rapidly diagnose a stroke, determine the cause, and initiate emergency treatments. A detailed patient history, physical examination, brain imaging tests, lab work, and diagnostic procedures all contribute to quickly identifying if a patient has had a stroke. Faster diagnosis paves the way for faster treatment, which can dramatically improve outcomes and reduce disability from stroke.