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A stroke is a
medical emergency. Anyone suspected of having a stroke should be taken to a
medical facility immediately for evaluation and treatment. Initially, the doctor
takes a medical history from the patient if he/she is alert, or others familiar
with the patient if they are available, and performs a physical examination. If
a person has been seeing a particular doctor, it would be ideal for that doctor
to participate in the assessment. Previous knowledge of the patient can improve
the accuracy of the evaluation. A neurologist, a doctor specializing in
disorders of the nervous system and diseases of the brain, will often be asked
to assist in the diagnosis and management of stroke patients.
Just because a
person has slurred speech or weakness on one side of the body does not
necessarily signal the occurrence of a stroke. There are many other
possibilities that can be responsible for these symptoms. Other conditions that
can mimic a stroke include brain tumors, a brain abscess (a collection of pus in
the brain caused by bacteria or a fungus), and subdural hematomas. A subdural
hematoma is a collection of mostly clotted blood that accumulates between the
brain and the skull. This produces a mass that can enlarge and press against the
brain. In contrast, in a subarachnoid hemorrhage, blood spills out into the
space between the brain and the skull and causes more sudden and catastrophic
effects. Viral encephalitis can also produce symptoms similar to those of a
stroke, as can an overdose of certain medications. An imbalance of sodium,
calcium, or glucose in the body can also cause changes in the nervous system
that can mimic a stroke.
CAT Scan: In
order to help determine the cause of a suspected stroke, a special x-ray test
called a CAT scan (also called a CT scan), of the brain is often performed. A
CAT scan can show bleeding into the brain, which is treated differently than a
stroke that is caused by blockage of the blood supply. A CAT scan also rules out
many of the other causes of neurological conditions mentioned above that can
mimic a stroke. For more information, please see the CAT Scan
article.
MRI Scan: A
newer method of viewing the brain is Magnetic Resonance Imaging (MRI), which
uses harmless magnetic waves rather than X-rays. The major advantage of an MRI
is that the pictures it takes of the brain are much more detailed than with CAT
scans. Nonetheless, a CAT scan is often the first brain scan performed on a
stroke patient because it can detect the presence of an early hemorrhage better
than an MRI. This is a critical piece of information that is needed for
immediate treatment. An MRI can be performed afterwards if finer details are
required for further medical decision making. People with certain medical
devices (e.g. pacemakers) cannot be subjected to the powerful magnetic field of
an MRI. Other people with fear of closed spaces (claustrophobia) find the long
tube of the MRI scanner just too confining, although many centers offer "open"
MRIs that are less uncomfortable for those with claustrophobia. For more
information, please see the MRI article.
Other methods of
MRI technology: An MRI scan can also be used to specifically view the blood
vessels non-invasively (without using tubes or injections), a procedure called
an MRA (Magnetic Resonance Angiogram). An exciting new MRI method called
Diffusion Weighted Imaging (DWI) is being offered in some medical centers. This
technique can detect the area of abnormality minutes after the blood flow to a
part of the brain has ceased whereas a conventional MRI may not detect a stroke
until up to 6 hours after it has started and a CAT scan sometimes cannot detect
it until it is 12 to 24 hours old.
Conventional
Angiogram: An angiogram is another test that is sometimes used to view the blood
vessels. A long catheter tube is inserted into an artery (usually in the groin
area) and dye is injected while X-rays are simultaneously taken. While an
angiogram delivers some of the most detailed images of the blood vessel anatomy,
it is also an invasive procedure and is used only when absolutely needed. For
example, an angiogram is done after a hemorrhage when the precise source of
bleeding needs to be identified. It also is sometimes performed to accurately
evaluate the condition of a carotid artery when surgery to unblock that blood
vessel is contemplated.
Carotid Doppler
Ultrasound: A carotid doppler ultrasound is a non-invasive (without injections
or placing tubes) method that uses sound waves to screen for narrowings and
decreased blood flow in the carotid artery (the major artery in the neck that
supplies blood to the brain).
Heart Tests:
Certain tests to evaluate heart function are often performed in stroke patients
to search for the source of an embolism. An echocardiogram is a sound wave test
that is done by placing a microphone device on the chest or down the food pipe
(transesophageal echocardiogram) in order to view the heart chambers. A Holter
monitor is similar to a regular electrocardiogram (EKG), but the electrode
stickers remain on the chest for 24 hours or longer in order to identify a
faulty heart rhythm.
Blood Tests:
Blood tests (such as a sedimentation rate) are done to look for signs of
inflammation that can suggest inflamed arteries. Certain blood proteins that can
increase the chance of stroke by thickening the blood are measured. These tests
are performed to identify treatable causes of a stroke or to help prevent
further injury
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