As part of Multiple Sclerosis Day, organized by ABC Medical Center, Dr. Gloria de Lourdes Llamosa, neurologist, discussed the tests used to diagnose multiple sclerosis, how doctors decide which tests to order, and what each one is used for.
To diagnose multiple sclerosis, neurologists must follow certain clinical indicators, since each test must be performed on the right patient, not just anyone.
Mexico’s Institute of Health for Wellbeing notes that, according to 2020 data published in the Atlas of MS by the Multiple Sclerosis International Federation, 2.8 million people worldwide had been diagnosed with this disease, meaning about 1 in every 3,000 people had this condition.
The process begins with clinical suspicion, which typically arises between ages 30 and 40, although it can occur at any age.
In its early stages, multiple sclerosis often presents with isolated episodes, such as eye problems like blurry vision, discomfort, or difficulty distinguishing colors. This kind of episode might last just a single day, without other symptoms like fever, and without any clear explanation.
A single isolated episode isn’t enough to raise suspicion of multiple sclerosis, certain criteria involving time and location within the body also need to be met. This means, for example, that a person with an eye problem eventually gets better, but several months later develops difficulty walking, which also improves, and then, months after that, experiences a new issue with muscle strength. Here, the episodes occur at different times and affect different areas of the body, which is what’s meant by “location.”
Once the neurologist identifies this kind of pattern, they’ll begin taking a complete medical history of the patient, asking questions covering every aspect of their life, where they live, their job, personal medical history, family history, and any diagnoses from other specialists, such as an ophthalmologist or orthopedist, among others.
This step allows the neurologist to identify whether there were earlier episodes, well before the first flare-up that brought the patient in, something that may have occurred years earlier, for example.
By applying these clinical criteria, the doctor can build a clinical suspicion of the disease and then order various tests to confirm or rule it out.
MRI (Magnetic Resonance Imaging)
The main test is an MRI, which not only helps confirm the diagnosis but also helps establish an early prognosis. An MRI can detect whether there’s a single lesion or multiple lesions, regardless of whether it’s the patient’s first flare-up. It can also show whether these lesions are located in specific areas of the brain or in the spinal cord. This information helps guide appropriate treatment.
Once a diagnosis is confirmed, MRI is used regularly to monitor disease progression and, if needed, adjust the treatment plan.
Cerebrospinal Fluid Analysis
If MRI results aren’t enough to confirm or rule out a suspected case of multiple sclerosis, this test involves collecting a sample of cerebrospinal fluid along with a blood sample. Both samples are analyzed for proteins known as oligoclonal bands; whether they’re found in one or both samples provides an additional diagnostic criterion for the disease.
This test also helps rule out infections or effects related to other medications the patient may be taking.
It’s important to note that this test alone can’t confirm a diagnosis of multiple sclerosis, it needs to be considered within the appropriate clinical context, where there’s already strong suspicion of the disease.
Evoked Potentials
Evoked potentials are diagnostic techniques that use visual, auditory, or somatosensory stimuli to assess sensory system function. These tests measure the brain’s response to stimuli and can help detect any interruption along the nerve pathways. While this test also isn’t diagnostic on its own, the neurologist combines its results with other findings to work toward a definitive diagnosis.
Optical Coherence Tomography (OCT)
This device measures the thickness of the optic nerve, which is an extension of the central nervous system. The OCT scanner allows the optic nerve to be examined at different points in time, so results can be compared to see whether any thinning has occurred.
Laboratory Tests
Additionally, doctors perform general lab tests, including a complete blood count and urinalysis. While neither of these can diagnose multiple sclerosis on their own, they help identify or rule out similar conditions or immune-related disorders.
In conclusion, because no single test can definitively diagnose multiple sclerosis, the neurologist follows a step-by-step process of ruling in or ruling out symptoms, which together lead to an accurate diagnosis for each patient.
At ABC Medical Center’s Neurology Center, we can provide you with specialized care. Contact us!
