How a Stroke Is Diagnosed
Stroke diagnosis history and physical exams
If you're caring for someone who's had a stroke before, there's a chance of another such event. If you suspect a stroke, act immediately: With certain strokes, treatment must begin within three hours. Here's what to expect when you take an older adult to the emergency room with symptoms of a stroke.
Doctors must work as quickly as possible to reach a diagnosis, because if the patient turns out to have an ischemic stroke, treatment with the clot-busting drug tPA must begin within a few hours after symptoms appear. The doctor will take a medical history, perform an exam, and order various tests.
The first step is to ask a series of questions. If the patient can't answer, you may need to provide the information. The questions will probably include:
- What symptoms is the person having and when did they begin?
- Has the patient had any previous medical problems, surgeries, or illnesses?
- Is there a family history of medical problems, especially of heart disease and stroke?
- What medications (prescription and over the counter) is the patient taking?
Physical exam. The next step is a thorough physical exam. The doctor will check the patient's vital signs (pulse, blood pressure, and temperature) and "ABCs" (airway, breathing, and circulation). The doctor will also examine the patient's body parts, including head, arms, and legs, to rule out other conditions that might produce similar symptoms.
Neurological exam. In this exam, the doctor will run noninvasive tests and ask more questions as part of the stroke diagnosis. The exam is divided into several areas, including mental status, cranial nerves, motor and sensory systems, deep-tendon reflexes, coordination, and gait. Of course, how extensive the neurological exam is depends on the patient's awareness and ability to function.
Additional tests a doctor might do for stroke diagnosis
These tests allow doctors to see what's happening in the brain, skull, or spinal cord.
- A computed tomography (CT) scan, or computed axial tomography (CAT) scan, uses X-rays to produce a three-dimensional image of the brain. A CT scan can be used to diagnose ischemic or hemorrhagic strokes, either within or around the brain, and to determine the extent of brain injury.
- In magnetic resonance imaging (MRI), a large magnetic field produces a three-dimensional image of the brain. Like the CT scan, an MRI can help diagnose the type of stroke and determine the location and extent of brain damage. It produces a detailed image and can pinpoint small brain injuries.
Blood flow tests
When someone has a stroke, it's important to diagnose problems with blood flow to the brain. Most blood flow tests are noninvasive, but sometimes more invasive tests are needed.
- In Doppler testing, a probe is placed over an artery in the neck or skull and ultrasound waves are used to measure blood flow. A carotid Doppler shows blood flow through the carotid arteries in the neck to the brain; a transcranial Doppler shows blood flow in arteries within the brain.
- Duplex scanning is another type of ultrasound testing. It's similar to carotid Doppler testing, but it allows the measurement of blood flow at many points in the carotid artery at once.
- A magnetic resonance angiogram (MRA) is a special type of MRI used to visualize blood vessels in the neck or brain. MRAs are noninvasive and fairly easy to perform, and they have the added advantage of offering a three-dimensional picture of the area in question.
- When noninvasive tests don't offer enough information, angiography (sometimes called arteriography) may be necessary. This test can be useful in diagnosing aneurysms or malformed blood vessels and is the best test for measuring blockages in the carotid arteries of the neck. During an angiography, a catheter is inserted into an artery in the arm or leg, a special dye is injected into the blood vessels, and X-ray images are taken.
- Electrical activity tests record electrical impulses in the brain. In an electroencephalogram (EEG), electrodes are placed on the patient's scalp and the electrical impulses are printed out as brain waves. An evoked response test is performed similarly, but it measures how the brain handles different sensory information, including hearing, touch, and vision.
- Although blood tests can't be used alone in stroke diagnosis, they can reveal stroke risk factors and other medical issues. When someone is evaluated for stroke, the doctor will probably order a series of blood tests, including blood lipid levels and blood glucose levels.
- Although not necessary in the case of an ischemic stroke, a lumbar puncture, or spinal tap, might be ordered if a subarachnoid hemorrhage (bleeding from a cerebral aneurysm) or infection such as meningitis is suspected.