Diagnosing Strokes: The Methods Doctors Use

how can drs diagnose strokes

Doctors can use several tests to diagnose a stroke, including medical history, a physical exam, imaging, and other tests. The first important step for a doctor is to take the patient's medical history, which helps them understand the type of stroke and its severity. They will ask the patient or their family about previous strokes, risk factors, and symptoms. A physical exam is also carried out, which includes checking vital signs, alertness, and physical signs of a stroke, such as weakness or trouble speaking. Doctors may also perform neurological exams to test how well the nervous system is working. Imaging tests such as CT scans, MRIs, ultrasounds, and X-rays are used to look at the blood vessels and brain to determine the type, location, and severity of the stroke. Blood tests are also used to provide information about the potential cause of symptoms, but they cannot diagnose a stroke on their own.

Characteristics Values
Tests CT, MRI and ultrasound scans, electrocardiogram (ECG or EKG)
Physical exam Blood pressure, mental alertness, numbness or weakness, trouble speaking, seeing or walking, reflexes, coordination and balance
Medical history Previous strokes, family history of strokes, risk factors (e.g. high blood pressure, high cholesterol, diabetes), symptoms and when they started
Imaging tests CT, MRI, DSA, PET, CT or MR angiogram, carotid ultrasound, trans-cranial Doppler ultrasound, EEG
Blood tests Complete blood count, serum electrolytes, blood clotting tests, troponin test, blood glucose test, C-reactive protein test, liver and kidney function tests

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Physical and neurological exams

Physical Exam

The physical exam helps determine the severity of the stroke and plan the patient's treatment. During the physical exam, the healthcare provider will check for:

  • Coordination and balance: The patient may be asked to stand and walk or stand with their eyes closed while being gently pushed to one side to assess balance.
  • Numbness or weakness: The doctor will check for numbness or weakness in the patient's face, arms, and legs.
  • Speech and vision problems: The exam will also evaluate any difficulties in speaking or seeing clearly.

Neurological Exam

The neurological exam, or neuro exam, evaluates the patient's nervous system, including the brain, spinal cord, and associated nerves. This exam is typically conducted in the healthcare provider's office and may involve the use of instruments like lights and reflex hammers. The extent of the neurological exam depends on factors such as the patient's initial problem, age, and overall condition. The key aspects of the neurological exam include:

Mental Status

The patient's level of awareness and interaction with the environment are assessed. This is often done through conversation, observing the patient's speech and ability to make sense while talking.

Motor Function and Balance

The patient's motor function may be tested by having them push and pull against the healthcare provider's hands with their arms and legs. Balance tests may include assessing the patient's stance and gait or gently pushing them to one side while their eyes are closed.

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, on different parts of the body, asking the patient to identify sensations like hot or cold, sharp or dull.

Reflexes

Reflexes are typically examined using a reflex hammer at different points on the body to test various reflexes.

Evaluation of the Nerves of the Brain

The neurological exam also involves evaluating the 12 main nerves of the brain, known as the cranial nerves, to determine their functioning. This includes assessing functions such as smell, vision, pupil size and eye movement, taste, hearing, swallowing, and movement of the face, tongue, shoulders, and neck.

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Imaging tests

Computed Tomography (CT) Scans

CT scans are often the first test performed after a suspected stroke as they are available at most major hospitals and can provide results quickly. The test combines special X-ray equipment with sophisticated computers to produce multiple images of the inside of the head. CT scans can show the size and location of any abnormalities in the brain, such as tumours or blood clots, and can also detect infections or areas of dead tissue. In the context of diagnosing strokes, CT scans can reveal whether there is bleeding in the brain or damage to the brain cells, helping doctors to identify whether the stroke is hemorrhagic or ischemic. To improve the detection and characterisation of a stroke, CT angiography (CTA) may be performed, where a contrast material is injected intravenously to obtain images of the cerebral blood vessels. CT perfusion (CTP) images, which detect blood flow, may be obtained at the same time. The combination of CT, CTA, and CTP can help physicians decide on the best therapy for a patient experiencing a stroke.

Magnetic Resonance Imaging (MRI) Scans

MRI scans use magnetic fields, radiofrequency pulses, and computers to produce detailed images of the brain. Like CT scans, MRI scans can take multiple images of the inside of the head, but they use more sophisticated X-rays. MRI scans are more accurate and sensitive than CT scans, and they can reveal all issues related to a stroke and any other diseases or concerning factors within the brain. They are particularly good at detecting tiny abnormalities that may be too small to be seen on a CT scan. MRI scans can also be used to diagnose whether a stroke is ischemic or hemorrhagic, and they are excellent at finding abnormalities in the skull and spinal cord. However, MRI scans take longer than CT scans and are not as readily available, making them less ideal in emergency situations when quick treatment is crucial. Additionally, MRI scans are not suitable for people with metallic or electronic implants, such as pacemakers or shrapnel wounds.

Other Imaging Tests

In addition to CT and MRI scans, doctors may also use other imaging tests to diagnose strokes, including digital subtraction angiography (DSA) and positron emission tomography (PET) scans. These tests can help detect narrowed blood vessels in the neck, aneurysms, or arteriovenous malformations (AVMs) in the brain. Angiography, using a special dye to visualise blood flow in the brain, can also be performed using either CT (CT angiography) or MRI (MR angiography) imaging technologies. Perfusion scans, which use a special dye or tracer to examine blood uptake in the brain, can help identify areas that are not receiving enough blood due to an ischemic stroke.

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Blood tests

Doctors will also perform blood tests to see how well the blood is clotting. This is done through a pair of tests called PT (prothrombin time) and PTT (partial thromboplastin time). These tests can check how quickly the blood clots, and if it takes too long, it could be a sign of a bleeding problem. Clotting issues can be a sign of a haemorrhagic stroke, where a blood vessel bursts.

Additionally, blood tests can be used to rule out other health problems with similar signs or symptoms. For example, low blood sugar could be a cause of symptoms similar to a stroke.

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Medical history

During the medical history assessment, doctors will inquire about previous personal or family history of stroke or transient ischemic attack (TIA). They will also ask about the presence of any risk factors, such as high blood pressure, high cholesterol, diabetes, smoking, or a family history of stroke. Additionally, doctors will want to know about the symptoms the patient is experiencing, when they started, and how quickly they appeared.

The medical history is followed by a physical exam, which includes checking vital signs, level of alertness, and physical signs of a stroke, such as weakness, trouble walking, or difficulty speaking. A neurological exam is also conducted to assess the nervous system's functioning through reflex tests, questions, and simple tasks. This exam helps determine the severity of the stroke and the affected area of the brain.

The combination of a thorough medical history, physical exam, and further imaging and diagnostic tests enables doctors to make an accurate stroke diagnosis, identify the type of stroke, and develop an effective treatment strategy.

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Electrocardiogram (ECG or EKG)

A computer translates the information from the electrodes into a wave pattern that a healthcare provider can interpret. The wave pattern shows the rate and rhythm of the contractions in the upper and lower chambers of the heart. The first wave, or "P wave," is created by the upper chambers (atria), where the heartbeats originate. The "P wave" is followed by a flat line when the electrical impulse goes to the bottom chambers or ventricles. The next wave, called the "QRS complex," is created by the lower chambers (ventricles). The final wave, or "T wave," represents electrical recovery or the heart returning to a resting state.

By measuring the time intervals on the EKG, a healthcare professional can determine how long the electrical wave takes to pass through the heart. This shows whether the electrical activity is normal or irregular. Additionally, by measuring the amount of electrical activity passing through the heart muscle, a cardiologist may be able to identify if parts of the heart are damaged, too large, or overworked.

An EKG can help diagnose heart problems that may have led to a stroke. For example, it can help diagnose atrial fibrillation or a previous heart attack. It can also be used to assess heart rhythm, diagnose poor blood flow to the heart muscle, detect heart abnormalities, and evaluate the performance of a pacemaker.

Frequently asked questions

Doctors can use several different tests to diagnose a stroke, including medical history, a physical exam, imaging, and other tests. They will ask the patient or their family members about their symptoms, medical history, and risk factors for stroke. They will also perform a physical exam to check the patient's vital signs, level of alertness, and physical signs of a stroke, such as weakness or trouble speaking. Imaging tests, such as CT, MRI, and ultrasound scans, can help determine the type, location, and severity of the stroke.

There are two main types of strokes: ischaemic stroke and haemorrhagic stroke. An ischaemic stroke occurs when a blood clot blocks blood flow to the brain, while a haemorrhagic stroke happens when a blood vessel bursts. There is also a transient ischaemic attack (TIA or mini stroke), which is when the symptoms of a stroke last less than 24 hours.

Common stroke symptoms include numbness, tingling, or weakness in the face, arms, or legs, especially on one side of the body; confusion or trouble communicating; trouble seeing in one or both eyes; trouble walking, dizziness, or loss of balance or coordination; and a severe headache with no known cause. The acronym FAST (Face, Arms, Speech, Time) is a quick way to remember the warning signs of a stroke.

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