MUSC Multiple Sclerosis Clinic : About Multiple Sclerosis : Diagnosing MS

The diagnosis is based on a combination of the history, physical and laboratory testing results. There is no single test that establishes or excludes the diagnosis.

Diagnostic Studies

Other than clinical signs and symptoms magnetic resonance imaging (MRI) of the brain and/or spinal cord is the most useful diagnostic test. It may detect the characteristic plaques in the brain or spinal cord. However, MRI is subject to interpretation and results must be taken in the context of symptoms and physical findings. MRI is not in and of itself diagnostic of MS.

The MRI is abnormal in 90-95% of the MS patients. MRI scanning has been shown to be more sensitive and specific for predicting evolution to clinically definite MS than any other paraclinical measures, such as cerebrospinal fluid or evoked potentials.

Reasons for obtaining an MRI include:

• To determine the presence of asymptomatic and/or additional lesions that may aid in diagnosis
• To rule out alternative diagnoses
• To evaluate patients in whom subjective complaints are out of proportion to objective abnormalities
• To judge the extent of disease
• To assess disease activity
• To judge the effects of putative therapy

Cerebrospinal Fluid (CSF) analysis:

The CSF exam itself cannot establish or exclude the diagnosis of MS and must be evaluated in the context of symptoms, physical exam and MRI findings. CSF analysis can provide useful additional information to help establish the diagnosis. The immunoglobulin G level or IgG index is elevated in more than 90% of MS patients. Oligoclonal bands are present in 80-95% of people with MS. In addition, CSF analysis can help to exclude chronic infections as a cause of symptoms.

Evoked Potentials:

Evoked potentials (EP's) are CNS electrical events generated by peripheral stimulation of the sensory organ. The utility of EP's is the detection of a CNS abnormality that may otherwise undetectable. In other words, occasionally they can aid in diagnosis or help to identify an objective abnormality in conjunction with a symptom. The most frequently used EP's are: Somatosensory (SSER or SSEP), visual (VER or VEP), brainstem auditory evoked response (BAER or BAEP).

Blood Testing:

Blood tests are also usually obtained to exclude diseases that can mimic MS such as vitamin B12 deficiency, collagen vascular diseases such as lupus, or other infections such as HIV or syphilis, among others.

The basic "rule" for diagnosing MS relies on two criteria:

There must have been two attacks at least one month apart. An attack, also known as an exacerbation, flare, or relapse, is a sudden appearance of or worsening of an MS symptom or symptoms which lasts at least 24 hours.

There must be more than one area of damage to central nervous system myelin-the sheath that surrounds and protects nerve fibers. The damage to myelin must have occurred at more than one point in time and not have been caused by any other disease that can cause demyelination or similar neurologic symptoms.

Diagnosis Methods:

Clinical Exam Includes History and Tests of Function.

Other symptoms of MS will be evaluated during the clinical examination conducted by a physician.  This covers an extensive review of mental, emotional, and language functions, movement and coordination, vision, balance, and the functions of the five senses.  Sex, birthplace, family history, and age of the person when symptoms first began are also taken into consideration.