Diagnosing Stroke: Identifying The Signs And Symptoms

Stroke diagnosis is a medical emergency. Tests for stroke usually begin in the ambulance, before the patient reaches the hospital. The first step in assessing a stroke patient is to determine whether they are experiencing an ischemic or hemorrhagic stroke so that the correct treatment can begin. Doctors use a combination of neurological examinations, diagnostic imaging, and other tests to diagnose a stroke. This includes physical and neurological exams, imaging tests such as CT scans and MRIs, and blood tests.

Physical and neurological exam

A physical and neurological exam is an important step in diagnosing a stroke. This exam evaluates the nervous system, which includes the brain, spinal cord, and nerves from these areas. The extent of the exam will depend on the patient's initial problem, age, and condition. Here are the key components of a physical and neurological exam in the context of stroke diagnosis:

Motor Function and Balance:

The patient's motor function and balance can be assessed by having them push and pull against the healthcare provider's hands with their arms and legs. Balance can also be checked by observing how the patient stands and walks or by asking them to stand with their eyes closed while gently pushing them to one side.

Sensory Exam:

The healthcare provider may perform a sensory test to evaluate the patient's ability to feel. This can be done using various instruments such as dull needles, tuning forks, or alcohol swabs. The patient may be touched on different parts of the body and asked to identify sensations like hot or cold, sharp or dull.

Reflexes:

Reflexes are evaluated as part of the neurological exam, especially in newborns and infants, where specific reflexes, known as primitive reflexes, are assessed. For older children and adults, reflexes are typically examined using a reflex hammer at different points on the body.

Evaluation of Nerves of the Brain:

There are 12 main nerves in the brain, known as cranial nerves, which are evaluated during a complete neurological exam. Here's an overview of the tests associated with each nerve:

• Cranial nerve I (olfactory nerve): The patient may be asked to identify different smells with their eyes closed.
• Cranial nerve II (optic nerve): A visual test may be administered, and the patient's eye may be examined with a special light.
• Cranial nerve III (oculomotor): This involves examining the pupil's response to light and testing the patient's ability to follow the light in various directions.
• Cranial nerve IV (trochlear nerve): This nerve is also involved in eye movement.
• Cranial nerve V (trigeminal nerve): The healthcare provider may touch the patient's face in different areas and observe their response, including their ability to feel the face and move the muscles involved in chewing.
• Cranial nerve VI (abducens nerve): The patient may be asked to follow a light or finger to test eye movement.
• Cranial nerve VII (facial nerve): The patient may be asked to identify tastes, smile, move their cheeks, or show their teeth to test the movement of facial muscles and taste.
• Cranial nerve VIII (acoustic nerve): A hearing test may be performed.
• Cranial nerve IX (glossopharyngeal nerve): The patient may be asked to identify different tastes on the back of the tongue, and the gag reflex may be tested.
• Cranial nerve X (vagus nerve): The patient may be instructed to swallow, and a tongue blade may be used to elicit the gag response.
• Cranial nerve XI (accessory nerve): The patient may be asked to turn their head against mild resistance or shrug their shoulders to test the movement of the shoulders and neck.
• Cranial nerve XII (hypoglossal nerve): The patient may be asked to stick out their tongue and speak to assess tongue movement.

Mental Status:

The patient's mental status, including their level of awareness and interaction with the environment, may be assessed through conversation. The healthcare provider will observe the patient's speech and their ability to make sense while talking.

Imaging tests: CT, MRI, CT/MR angiogram, carotid ultrasound, etc

Imaging tests are a crucial component of stroke diagnosis as they allow doctors to visualise the brain and its blood vessels. This helps them determine the type, location, and severity of the stroke, which in turn informs treatment planning.

CT Scan

Computed tomography (CT) scans are often the first test performed after a suspected stroke. They use X-rays to create detailed images of the brain, helping doctors identify any bleeding or damage to brain cells. CT scans can also detect other issues that may be causing stroke-like symptoms. CT angiography (CTA) may also be performed, where a contrast material is injected intravenously to obtain images of the cerebral blood vessels. CT perfusion (CTP) can be done at the same time to provide information on blood flow.

MRI Scan

Magnetic resonance imaging (MRI) uses a powerful magnet, radio waves, and a computer to produce detailed images of the brain. It can show brain changes caused by a stroke sooner than a CT scan and can also detect bleeding and blood flow problems. MRI is also used to image the cerebral vessels in a procedure called MR angiography (MRA). MR perfusion (MRP) is a procedure that produces images of blood flow. Diffusion-weighted MRI is a special type of MRI that can help detect ischemia in the brain and can identify ischemic strokes early on.

CT/MR Angiogram

An angiogram is an X-ray movie of the blood vessels and blood flow. A dye is injected into the veins to provide a detailed picture of the blood vessels after a stroke. A CT angiogram is used in conjunction with a CT scanner, while a MR angiogram is used with an MRI.

Carotid Ultrasound

Carotid ultrasound uses sound waves to create images of the carotid arteries, which supply blood to the brain. It is often used in conjunction with a CT or MR angiogram to check for plaque buildup that may be blocking blood flow to the brain.

Trans-cranial Doppler (TCD) Ultrasound

Doppler ultrasound uses sound waves to measure blood flow. It helps doctors identify which artery in the brain is blocked.

Other Imaging Tests

Other imaging tests that may be used include digital subtraction angiography (DSA) and positron emission tomography (PET) to look for narrowed blood vessels in the neck, aneurysms, or tangled blood vessels (arteriovenous malformation) in the brain.

Blood testing

Complete Blood Count

A complete blood count (CBC) test provides valuable information about the composition of your blood, including the levels of platelets and electrolytes. Platelets are cells that play a critical role in clotting blood, while electrolytes help assess kidney function. This test is essential in stroke diagnosis as it can reveal any underlying issues with blood clotting or kidney health that may impact treatment options.

Clotting Time

Doctors may also perform a pair of tests called PT (prothrombin time) and PTT (partial thromboplastin time) to assess how quickly your blood clots. If the clotting time is too long, it could indicate potential bleeding problems. Understanding the clotting ability of your blood is crucial in stroke diagnosis, as it can help determine if the stroke was caused by a clot or a bleeding event.

Blood Chemistry

Blood tests can also provide insights into your overall health and help rule out other conditions. For example, blood tests can measure renal (kidney) function, glucose (blood sugar) levels, electrolyte balance, leukocyte (white blood cell) count, and haematocrit (iron) levels. These measurements are important in stroke diagnosis as they can reveal any underlying health issues that may impact treatment and recovery.

Inflammation Markers

Additionally, blood tests can assess inflammation in the body by measuring the erythrocyte sedimentation rate and C-reactive protein levels. These markers can indicate the presence of inflammation, which may be relevant in stroke diagnosis to rule out other inflammatory conditions or understand the body's response to the stroke event.

Overall Diagnostic Process

When diagnosing a stroke, doctors will typically perform a comprehensive evaluation, including a physical exam, medical history assessment, and imaging tests, in conjunction with blood testing. The blood testing process provides critical information about the condition of arteries in your head and neck that supply blood to your brain. By combining this information with imaging results and other diagnostic data, doctors can determine the type of stroke, identify the affected areas of the brain, and develop an appropriate treatment plan.

Electrocardiogram (ECG or EKG)

An electrocardiogram (ECG or EKG) is a test that records the electrical activity of the heart. The heart is controlled by an electrical system, with electrical signals making the heart contract so it can pump blood out to the body. Heart disease, abnormal heart rhythms, and other heart problems can affect these signals.

During an ECG, you will lie down on a table and small patches, called electrodes, will be attached to several places on your arms, legs, and chest. The patches are connected by wires to a machine that turns the heart's electrical signals into wavy lines, often printed on a piece of paper. The health care provider then reviews the test results. It is important to remain still during the procedure and to be relaxed and warm as any movement, including shivering, can alter the results.

An ECG is used to measure any damage to the heart, how fast it is beating and whether it is beating normally, the effects of medicines or devices used to control the heart (such as a pacemaker), and the size and position of the heart chambers. It can also be used to diagnose a heart attack, heart failure, or heart damage.

A typical ECG only tracks the heart's electrical activity for a short time, so it may not pick up irregularities that only happen occasionally. To capture these erratic issues, your provider can give you a Holter monitor, which is worn for 24 to 48 hours to get a continuous recording of the heart's electrical activity, or an event monitor, which is worn for a week or more and can be manually activated when symptoms are felt.

Medical history

• Previous personal history of stroke or transient ischemic attack (TIA)
• Family history of stroke
• Risk factors, such as high blood pressure, high cholesterol, diabetes, atrial fibrillation, or other relevant conditions
• Current symptoms, including their onset and progression

Additionally, doctors will perform a physical exam to check vital signs, level of alertness, and physical signs of stroke, such as weakness or trouble with speaking or walking. They will also conduct a neurological exam to assess the functioning of the nervous system, which may involve testing reflexes, asking questions, and assigning simple tasks.

Frequently asked questions