Unfortunately, there is not a single test or exam that can determine if you have
multiple sclerosis (MS). Doctors have to use multiple tests and/or exams to see
if it's most likely you have it. In the past, misdiagnosis of MS was rather
common, especially since most people went to their general practitioner and the
majority of them had never dealt with anyone with MS before. All of the
symptoms, by themselves, could be explained as something else if not recognized
as a whole.
Differential Diagnosis
Early signs of MS are often mistaken for other disorders, including the
following:
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Cerebrovascular disease |
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Epilepsy |
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Degenerative disc disease |
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Osteoarthritis |
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Tumor |
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Vitamin B-12 deficiency |
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Weakening of the nerves (neuropathy) |
Conditions that may appear similar to MS on magnetic resonance imaging (MRI)
scan include the following:
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Congenital biochemical disorders |
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Inflammation of blood vessels (vasculitis) |
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Lyme disease |
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Lupus (another autoimmune disorder) |
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Progressive multifocal leukoencephalopathy (PML) |
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Viral infection (may cause demyelination) |
Neuromyelitis optica (NMO), also called Devic's syndrome, is a condition that
affects the optic nerves and the spinal cord and can cause symptoms similar to
MS (such as vision loss, muscle weakness, numbness and paralysis in the arms and
legs). In the past, NMO was considered a severe form of MS, but research has
shown that it's actually a separate condition.
In the early stages, MS can be difficult to diagnose since symptoms that might
indicate a number of other disorders may come and go. Some individuals have
symptoms that are quite difficult for physicians to interpret, and are told to
"wait and see." Though no single test is available to prove or discount MS, MRIs
play a great part in reaching a definite diagnosis.
The typical place to start is a neurological exam. This type of exam evaluates
sensory neurons and motor responses looking for nervous system impairment. When
problems are found, tests can be more targeted to a specific neurological
system.
Making the diagnosis of MS as quickly and accurately as possible is important
for several reasons:
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People who are living with frightening and uncomfortable
symptoms want and need to know the reason for their discomfort.
Getting the diagnosis allows them to begin the adjustment
process and relieves them of worries about other diseases such
as cancer. |
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Since we now know that permanent neurologic damage can occur
even in the earliest stages of MS, it’s important to confirm the
diagnosis so that the appropriate treatment can be initiated as
early in the disease process as possible. |
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Medical History and Exam
A medical history is usually the best place to begin and will be similar to
this:
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Symptoms onset, types, patterns |
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Additional treatment or diagnostic evaluations undergone |
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Other ongoing medical problems |
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Where did you grow up |
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Bowel and bladder habits |
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Exposure to environmental hazards |
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Travel to any exotic lands associated with certain diseases |
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Medications the person is currently taking |
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Allergies to medications |
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Past history of surgery or trauma |
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Health of immediate and extended family |
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Diet and eating habits |
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Sexual practices |
Then a neurological exam will look at your mental, emotional, and language
status. Your movement, coordination, motor responses, and balance will also be
checked along with your vision. Slurred speech or spots in your vision might be
a good indicator of a neurological issue. They will look for numbness, tingling
sensations, tremors, loss of strength, slurred speech, tripping just to name a
few. If some of these things exist, it should add up for a doctor that there
might in fact be a neurological issue.
When an internist or other general practitioner sees these signs, they will
usually set up additional tests and then refer a neurologist. The neurologist
can much better identify all of the signs or symptoms since this is what they do
on a daily basis. The first doctor may order an MRI to be taken or defer that
call to the neurologist, but that is typically the next step.
Evoked Potentials
The use of evoked potentials as a diagnostic tool has greatly declined since the
introduction of the MRI, which provides a much more comprehensive picture of
disease activity. In at least some cases of progressive forms of MS, visual
evoked potentials show changes over time where none are detected in MRI scans.
When demyelination or sclerosis occurs, the conduction of nerve impulses along
axons is slowed or interrupted. Impaired conductance is reflected in an
increased latency of evoked potentials or an increase in the amount of time that
elapses between the presentation of a sensory stimulus and the resulting change
in the brain's electrical field. Evoked potentials are measured by placing small
electrodes on the head in the region corresponding to the stimuli presented.
Abnormal evoked responses to different types of stimuli provide clues to the
location of plaques or lesions and are useful in detecting "clinically silent"
lesions that don't produce easily observable symptoms. However, abnormal evoked
responses are not unique to MS. Evoked potentials can aid in the localization of
lesions, confirm clinically ambiguous lesions, and confirm the organic basis of
symptoms. In addition, changes in evoked potentials can be used to measure
disease progression and the effectiveness of therapeutic treatment, including
treatments designed to improve conduction.
MRI
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An MRI is used as the next test so a visual confirmation can be made. The images
that an MRI produces will show any scarring or lesions that are present. By
adding a contrasting agent called Gadolinium (gd) during the MRI, it can also be
determined if there are any active lesions being made at that time. More
specifics regarding MRI's are discussed a bit later.
Over time, a person with MS will typically have an MRI one or two times a year
so a visual record will be made. This record will show the neurologists if the
lesions are progressing, remaining the same, or possibly reducing in size. This
a very good tool to track how a treatment is working or not.
The MRI by itself can't determine if you have MS since some other medical
conditions could cause spots to show up during procedure.
One of the best aspects of an MRI is that it's non-invasive, other than the
administration of the Gadolinium (gd) into a vein. A single spot or two doesn't
necessarily mean that you have MS, but the chances are greater. If it's felt
that MS is indicated, then the next step will be to collect cerebrospinal fluid.
The are many more specifics regarding MRI along with images in the later section
called MRI. An annual or bi-annual MRI is the standard way to see if
there are any new or active lesions following the initial diagnosis.
Cerebrospinal Fluid
Cerebrospinal fluid (CSF) is the fluid that circulates around and within the
brain and spinal cord, protects the CNS from injury, and cushions it from the
surrounding bone structure. CSF provides a way or vehicle for removing waste
products of cellular metabolism from the nervous system and is believed to be
nutritive for both neurons and glial cells and to function as a transport system
for biologically active substances such as releasing factors, hormones,
neurotransmitters, and metabolites. A sample of this fluid will provide
additional information on any active in the CNS and possibly those involved in
MS pathology.
A sample of the CSF is obtained through a lumbar puncture (LP), also called
spinal tap, in which a rather large looking needle is inserted in between the
4th and 5th lumbar. The lower lumbar spine is preferable because the spinal cord
stops near 2nd lumbar, and a needle introduced below this level will miss the
spinal cord and encounter only nerve roots, which are easily pushed aside. Once
the needle enters the "sack" where the fluid is present and not touching the
spinal cord, about 1 to 2 tablespoons of the fluid is then extracted and sent
for testing.
The CSF contains a variety of substances, particularly glucose (sugar), protein,
and white blood cells from the immune system. The fluid that is collected will
show if there is an elevated amount of IgG antibodies (immunoglobulin's) and
certain immune system proteins called oligoclonal bands. If these or certain
proteins that are the breakdown products of myelin are present, then it's a good
indication of an autoimmune response occurring and is suggestive of MS.
Over 90% of those with MS have oligoclonal bands in their CSF. While increased
immunoglobulin in the CSF and oligoclonal bands are seen in many other brain and
spinal cord conditions, their presence is often useful in helping to establish a
diagnosis of MS. The remaining 5 to 10% of those with MS never show these CSF
abnormalities.
The typical procedure involves you laying on your side with your knees drawn up
to your abdomen. A needle is inserted into your spinal canal through your lower
back. A sample of cerebrospinal fluid is withdrawn through the needle and the
pressure of the CSF is measured. If at any point you experience discomfort
during the procedure, the needle may need to be repositioned. After the fluid is
collected and the needle is removed, you will be asked to lie on your back or
stomach for a few hours after the procedure to prevent a spinal headache.
The area is numbed prior to the procedure so all that is felt is typically a
sense of pressure. No pain from the actual puncture should be felt since the
spinal cord itself is never touched and only fluid is extracted. The overall
discomfort is minimal to moderate. The anesthetic will sting when first
injected, and there is usually a little pain when the needle is first inserted,
but should subside in a few seconds.
An LP is safe procedure with little or no complications. There have been some
cases where a leak of CSF has developed after the procedure. The symptoms of
this problem are a headache that doesn't go away after 1 to 2 days and drainage
from the puncture site. This is, however, not a common occurrence and can be
treated with a high pressure bandage.
It's estimated that about 1 in 1,000 people who have a lumbar puncture have a
minor nerve injury. A nerve injury can occur when the needle is inserted and
comes in contact with a nerve branch or spinal cord itself. Any invasive
procedure, even with a needle, runs a risk of damaging something as it enters.
An experienced neurologist can't see into a patient's body, but rather draws on
their experience and finesse. Any nerve damage of this nature usually heals on
its own with time.
There is also a small chance of infection of the CSF such as meningitis,
bleeding inside the spinal canal, or damage to the cartilage between the
vertebrae. Your neurologist should talk with you about all of the risks prior to
this procedure. People who have bleeding problems and those who are taking
blood-thinning medication have a higher chance of bleeding after the procedure
since it does pass through the skin.
Other Conditions That Need to be Ruled Out
Because there are no laboratory tests or particular symptoms that definitively
point to a diagnosis of MS, confirming the diagnosis can be a complex process.
It's not unusual for people to be told they have MS when they actually have
something else, or for the diagnosis to be missed in people who actually have
MS. Before a diagnosis of MS can be confirmed, doctors must rule out any other
condition that could be causing your symptoms, including:
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Infections of the central nervous system (CNS): Lyme disease,
syphilis, progressive multifocal leukoencephalopathy (PML), HIV and
human T-cell lumphotrophic virus-1 (HTLV-1) |
| ● |
Inflammatory disorders of the CNS: systemic lupus erythematosus,
Sjögren's syndrome, vasculitis, sarcoidosis and Behçet's disease |
| ● |
Genetic disorders: leukodystrophy, hereditary cerebellar
degenerations, hereditary myelopathy and mitochondrial disease |
| ● |
Brain tumors: metastases and lymphoma |
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Vitamin B12 deficiency |
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Structural damage in the brain or spinal cord: cervical spondylosis,
tumor, herniated disc and Chiari's malformation |
| ● |
Other non-MS demyelinating diseases: neuromyelitis optica (NMO) and
acute disseminated encephalomyelitis (ADEM) |
Some of these diagnoses are much rarer than others. Some may be easy to rule out
with a simple blood test such as vitamin B12 deficiency, while others, such as
sarcoidosis, may require a biopsy. Therefore, it's important to work with a
physician who is familiar with these conditions and their warning signs so that
the appropriate steps can be taken to arrive at a correct diagnosis as quickly
as possible. Arriving at the correct diagnosis will enable your doctor to begin
the appropriate treatment, whether you have MS or one of these other conditions.
Normal CSF Results
Appearance:
CSF is normally clear and colorless.
Pressure:
Normal CSF pressure in the lower back for an adult ranges from 80 to 200
millimeters (mm) water. For children, the normal opening pressure range
is 30 to 60 mm water.
Protein:
The normal protein content of CSF in an adult's lower back (lumbar)
region is 55 milligrams per deciliter (mg/dL) or less. Older adults and
children may have higher values (up to 70 mg/dL) that are still in the
normal range.
Glucose:
The normal range for glucose content in the CSF is at least 60 to 70% of
the blood glucose level. The levels may be slightly increased if the
person has just eaten.
Cell counts:
Normal CSF contains no red blood cells (RBCs). The white blood cell
(WBC) count for adults is 0 to 5 WBCs per cubic millimeter (mm3).
Children may normally have a higher WBC count. Lymphocytes or monocytes
are 0 to 4 per mm3.
Other Results:
No infectious organisms (such as bacteria, fungi, or a virus) are found
in the CSF. No tumor cells are present.
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Abnormal CSF Results
Appearance:
Blood in the CSF can result from bleeding (hemorrhage) in or around the
spinal cord or brain, but it may also be caused by tiny blood vessel
poked during the spinal tap. Bleeding caused by the lumbar puncture
itself will show more red blood cells in the first sample collected than
in later samples. Cloudy CSF may mean an infection such as meningitis is
present.
Pressure:
High CSF pressure may occur as a result of swelling (edema) or bleeding
(hemorrhage) in the brain, infection such as meningitis, stroke, or
other circulatory problems. Below-normal pressure may mean a blocked
spinal canal.
Protein:
An increase in antibodies (immunoglobulin's) may
be caused by inflammation in people who have MS, immune system
disorders, or other bacterial and viral diseases. A high level of
protein may be caused by bleeding in the CSF, a tumor or cancer from
another area of the body, diabetes, infection, injury, or other nerve
diseases.
Glucose:
Low glucose levels in the CSF are abnormal and may be caused by
bacterial meningitis. Viral meningitis doesn't often cause low glucose
levels in the CSF. Brain hemorrhage may also cause low glucose levels
several days after bleeding begins. Higher-than-normal glucose levels
are often caused by diabetes.
Cell counts:
Red blood cells (RBCs) in the CSF mean bleeding. High levels of white
blood cells (WBCs) mean meningitis. Tumor cells and abnormal levels of
white blood cells mean cancer.
Other Results:
Antibodies, bacteria, or other organisms in the CSF mean that an
infection or disease is present. Bacterial markers (bacterial antigens)
that show up mean meningitis.
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