Other Problems to be Considered and
Acute disseminated encephalomyelitis
Acquired immunodeficiency syndrome (AIDS) myelopathy
Chronic fatigue syndrome
Herpes zoster myelitis
Human T-cell lymphotropic virus type 1 (HTLV-1) associated myelopathy
Inflammatory CNS disorders (ie, Lyme disease, Behcet syndrome, Sjögren
Subacute combined degeneration of the spinal cord (vitamin B-12 deficiency)
- Perform blood work to exclude collagen vascular disease, infections (ie,
Lyme disease, syphilis), endocrine abnormalities, vitamin B-12 deficiency,
sarcoidosis, and vasculitis. These test results are within the reference
range with MS.
- Draw cerebrospinal fluid (CSF) and examine for infection, oligoclonal
bands (OCBs), and intrathecal immunoglobulin G (IgG) production. OCBs are
found in 90-95% of MS patients and intrathecal IgG production in 70-90%;
however, these findings are not specific for MS.
- MRI remains the imaging procedure of choice for diagnosing and monitoring
disease progression in the brain and spinal cord. This test can show brain
abnormalities in 90-95% of patients and spinal cord lesions in up to 75% of
cases, especially in elderly patients. MRI alone cannot be used to diagnose
MS. The brain shows a characteristic pattern of lesions, usually
- New or newly active lesions in the CNS can be enhanced with gadolinium
as a result of the breakdown of the blood brain barrier. They may be
enhanced from days to several weeks. These enhancing lesions have been
seen even without clinical signs of disease activity. This finding is
significant because it demonstrates that not all lesions result in
neurologic deficits; however, it does demonstrate that the disease is
widespread and present even during the periods previously believed to be
- The T2-weighted images on MRI show edema and more chronic lesions. The
T1-weighted images demonstrate cerebral atrophy and "black
holes." These black holes represent areas of axonal death.
- With MRI, the lesion (plaque) burden, a measure of disease severity, can
be determined. Unfortunately, the lesion burden is not well correlated
with impairment or disability. MRI can help to determine cerebral and
spinal cord atrophy, even early in the disease. This atrophy signifies
widespread axonal loss in the brain and spinal cord even when active
lesions are not identified. Atrophy in the spinal cord, cerebellum, and
cerebral cortex has been correlated with disability.
- CT scan with enhancement has been used to identify acute lesions; however,
it is not particularly helpful for patients with stable disease, as the
lesions do not enhance.
- A newer neuroimaging technique, magnetic resonance spectroscopy (MRS), has
been useful in following N-acetyl-aspartate (NAA) levels in
patients with MS. NAA is an amino acid found in neurons and axons of the
mature brain. In patients with relapsing-remitting MS, NAA levels are
reduced, suggesting axonal loss; however, in patients with secondary
progressive MS with more disability, the NAA levels are reduced more
significantly. In fact, patients with MS had lower levels of NAA even in
areas of the brain previously thought to be unaffected, when compared with
levels in normal patients.
- Evoked potentials have been the most useful neurophysiological studies for
evaluation of MS. These tests include visual evoked potentials (VEPs),
somatosensory evoked potentials (SSEPs), and brainstem auditory evoked
potentials (BAEPs). These studies are used to identify subclinical lesions
but are nonspecific for MS.
- VEPs are performed by having a patient focus on a reversing black and
white checkerboard pattern. Delays in latencies indicate demyelination in
the anterior visual pathways.
- SSEPs evaluate the posterior column of the spinal cord, the brainstem,
and the cerebral cortex. Delays in latencies of various peaks indicate
demyelination in the correlated pathway of the spinal cord or brain.
- BAEPs are performed to evaluate ipsilateral asymptomatic MS lesions in
the auditory pathways but are less sensitive than VEPs and SSEPs.
- Electroencephalogram (EEG) results have been found to be outside the
reference range in some patients with MS, but the findings are
nonspecific. Nonspecific EEG abnormalities can be seen in normal
individuals in the general population.
- Lumbar puncture is performed to evaluate CSF for the presence of OCBs and
intrathecal IgG production.
Examination of demyelinating lesions, or plaques, in the spinal cord and
brain of patients with MS shows myelin loss, destruction of oligodendrocytes,
and reactive astrogliosis with relative sparing of the axon cylinder. These
active lesions show breakdown of the blood brain barrier with penetration of
leukocytes. A combination of T cells, B cells, and macrophages is believed to be
responsible for attack on the myelin antigens.