A. Scott Nielsen MD, MMSc
Virginia Mason Multiple Sclerosis Center
This is a difficult question to answer because what is a "typical" case of MS?
The time from the first symptom of demyelination to presentation in a doctor's office is going to depend heavily on where in the nervous system the injury is occuring. For instance, if the injury is occuring in the pyramidal system (this is the circuit that involves strength and movement), then patients are much more likely to seek care early as opposed to a patient who experiences their first attack of MS (that produces symptoms) if it affects the sensory fibers (for instance, if there is a small area of numbness or tingling). This is particularly the case in young adults who may rationalize symptoms away as something minor because MS (or any chronic illness) is not supposed to affect us in our most productive years.
With that said, there have been some researchers who have looked into the time from first symptom onset to diagnosis. A group in Spain (Fernandez et al., Journal of Neurology 2010; 257(9); 1500-7) did just this and found that the mean time from first symptom to diagnosis is approximately 2.08 years, and the largest contributor to this delay was patients who waited an average of 19.2 months from first symptom to going to the doctor for the problem.
Since the diagnosis of MS is a clinical one (ie, we do not have a blood test--or any other test for that matter--that can definitely render an accurate diagnosis), there will be occasions where the diagnosis may be uncertain for quite some time. Since MS can be mimicked by other disease states (in particular, diseases that are treated with therapies different than the MS therapies), it is very important to "get it right" to the extent possible. While this can be frustrating for patients who struggle with the uncertainty of a diagnosis, it is too for the physician. Obviously, more research is needed to identify biomarkers of the disease that can help us diagnose sooner (and with improved accuracy). This is imperative as clinical trial evidence indicates that the sooner a person with MS is treated, the better the long-term outcomes.
A. Scott Nielsen MD, MMSc
Virginia Mason Multiple Sclerosis Center
So you’ve been told that you may have Multiple Sclerosis (MS). To borrow a common phrase, this is likely “freaking you out” and creating a great deal of anxiety. Take a breath, get comfortable and start reading.
MS is rarely fatal and it is very rare for MS to cause disability in the first few years after diagnosis. You have time to get the medical opinions you need to make decisions and determine if anything else should be done to evaluate or treat your condition. This does not mean you should have to wait months to see a doctor specializing in this condition; months perhaps spent worrying unnecessarily. If you have an unnecessarily long wait to see a specialist ask your primary doctor for another referral.
An important thing to know is that multiple sclerosis is often difficult to diagnose. Why? Well, there is no one test or exam that can definitively tell whether or not you have MS (nope, not even an MRI). Even after all tests and exams are done, some people cannot be diagnosed for years after the beginning of symptoms.
The diagnosis of MS is based on symptoms and examination findings supplemented by diagnostic testing. The process of establishing a diagnosis is inherently complex requiring, at a minimum, the consultative services of a neurologist. A radiologist CAN NOT DIAGNOSE MS based on an MRI scan alone. A radiology report of an abnormal MRI scan indicating possible MS is often a cause of confusion, frustration and undue anxiety. The clinical criteria used to establish a diagnosis may sound complex but are really quite simple; a specialist needs to uncover specific symptoms or findings on examination that indicate inflammation in different parts of your central nervous system (i.e. the brain and spinal cord only) that occurred at different points in time.
Very importantly, he or she must exclude alternative diseases capable of presenting in this fashion. Laboratory tests such as MRI scans, blood tests, spinal fluid analysis, and evoked potentials, supplement the clinical criteria and play a major role in confirming the diagnosis and eliminating alternative diagnostic possibilities.
Of all these tests, the most important is an MRI scan but this alone can not be used to diagnose MS and must be interpreted by experts with caution. The common radiology report mentioning, “non-specific white matter changes” or “ white matter changes” consistent with MS means nothing by itself. The changes observed on the MRI scans of people with MS are very specific and can be classified for their specificity. For this you will require interpretation by an expert; unfortunately, most radiologists are not aware of this diagnostic criteria.
Current diagnostic criteria for MS, revised in 2010, allow the diagnosis to be made at the onset of symptoms in certain people. Most people will need to be followed and obtain repeat MRI scans and clinical evaluations after the onset of their symptoms to determine if they have MS. In most cases the diagnosis can be established within 2 years. Those in whom it is more difficult to establish a diagnosis within 2 years tend to have a more benign prognosis.
Rule 4: Certain syndromes (a syndrome is a collection of symptoms and findings developing in a typical pattern over time) are so commonly associated with MS that this diagnosis is strongly considered whenever the syndrome is observed in a person between the ages of 13 to 50. Often these syndromes have names attached to them, such as Optic Neuritis or Transverse Myelitis while others are referred to by less notable and less specific monikers such as Acute Brainstem Syndrome. Newly diagnosed MS cases over the age of 50, and very rarely under13, are certainly seen in our clinics but require a greater deal of care to exclude other conditions (e.g. strokes, degenerative diseases, leukodystrophies).
Prior to the era of MR imaging, it was impossible to determine who would go on to develop typical MS and who would be found to have another diagnosis or never experience further neurological symptoms. Patients were considered, “At risk to develop MS” after experiencing typical symptoms for the first time, but were often not informed of this risk since the probability of MS was uncertain, and no therapies were available to reduce this risk or alter the future course of the disease. It took, on average, 5-years to establish a certain diagnosis of MS, a period of significant uncertainty and anxiety for many patients. MR imaging of the cranium and spinal cord, revolutionized this diagnostic process.
First, MR imaging allowed clinicians to exclude many alternative conditions that mimic MS and respond best to appropriate therapies initiated as early as possible. Second, MR imaging now allows clinicians to establish a relative risk for the development of MS. For instance, over 50 % of patients have typical MS appearing MRI findings at the time of their first symptoms. The number and location of these abnormalities are strongly associated with the short-term risk of developing a clinical diagnosis of MS. Those individuals with highly typical findings are now considered at “high risk” to develop MS or given a diagnosis of MS immediately.
Alternatively, those individuals without typical white matter abnormalities, especially those individuals with normal cerebrospinal fluid studies, are considered at low risk to develop MS with a 5 year diagnosis rate of less than 10 %. Therefore, imaging abnormalities at the onset of MS symptoms can be used to educate and counsel patients appropriately, and make decisions regarding early initiation of disease specific therapy.
A definite diagnosis of MS does NOT mean a future marked by disability or loss of the ability to participate in the activities you love and find fulfilling. More than 25 % of people with MS never experience any significant disability without any treatment to alter the course of the disease. Those who require treatment experience significant reductions in symptomatic recurrences; it is increasing common for people to remain without significant disability for up to 3 decades or longer.
Despite our current ability to establish a diagnosis of MS earlier and with greater certainty in many people, there are still cases where the diagnosis remains uncertain even with extensive testing. In these cases, the diagnosis should not be made prematurely; rather patients should be educated and counseled about diagnostic uncertainty from the onset. Education and follow-up plans, including repeat MR imaging studies every 6 to 12 months should be established. Repeat MR imaging will determine if characteristic white matter abnormalities have developed in the absence of new symptoms. Those people who experience continued difficulty coping with an uncertain diagnosis, even after appropriate education, may benefit from counseling to help ease the anxieties often associated with this process.
While establishing a diagnosis is beyond the scope of this discussion, it is useful to mention two common diagnostic errors. The first is diagnosing MS in patients with no definable neurological disease. The example provided in rule 1 is typical of this error. It is quite common for MS experts to see patients who have been diagnosed with MS by primary care physicians or other neurologists because of non-specific symptoms, such as general weakness, fatigue or tingling, at times supplemented by “minimal” changes on the MRI.
By far the most common syndrome in this group of patients is recurrent parenthesis (i.e. usually described as pins and needles tingling sensations) in the extremities without any discernable abnormalities on neurological exam or diagnostic testing. The condition is so frequent that we often characterize the syndrome as "benign paresthesias". Often the sensory symptoms are accompanied by a history of chronic fatigue and/or chronic diffuse pain suggesting an overlap with fibromyalgia and chronic fatigue syndrome. Rarely, do these people develop MS; more importantly, a premature or inaccurate diagnosis of MS often interferes with the effective management of their condition.
The second type of diagnostic error is incorrectly diagnosing MS in a patient who has some other neurological disease. The widespread use of MR imaging has helped to eliminate many of these diagnostic errors but they still occur, often as a result of misinterpretation of MR imaging findings or hasty diagnostic decisions made by a neurologist pressed for time. This type of error can be avoided by obtaining a second opinion with an MS Specialist and making sure you doctor reconsiders the diagnosis over time if unusual signs or symptoms should emerge.
This blog was originally posted in August 2013. We are organizing the site and in order to move the blog we had to re-post it. Our apologies to those that have already read it.
The medical information and opinions on this site are provided as an information resource only, and are not to be used or relied on for any diagnostic or treatment purposes. The information and opinions expressed do not create any patient-physician relationship, and should not be used as a substitute for professional diagnosis and treatment. Please consult your health care provider before making any healthcare decisions or for guidance about a specific medical condition.