20 years ago there was a problem with under diagnosing MS. Many physicians would feel that the symptoms were psychologic in nature and they would reassure the patient and send them home without a diagnosis of MS. In those days many MS cases were missed only to be found later when the disease progressed. MRI and a spinal fluid tests have made the diagnosis of MS more definitive in today's world but are not a sure thing like a pregnancy test would be. You are either pregnant or not pregnant and the test will tell you one way or the other. It is not so easy with MS.
Currently the pendulum has swung the other way and MS is being way over diagnosed. Recent studies have shown that about 30 - 40% of patients who have been diagnosed with MS, in fact do not have MS at all. Why is this? Isn't are diagnostic medicine better than this? Here is the problem. In order to diagnose MS the physician looks at several factors. MS is disseminated in both time and space, which means a patient will have more than one episode spaced apart by a given amount of time and the imaging and other studies will become worse at a future point in time. The patient has to have 2 or more attacks or episodes of MS symptoms and 2 or more objective clinical lesions. There is a "MS" pathology that MRI can pick up in the brain and this characteristic MRI is usually required to make the diagnosis, however a patient can have a completely normal MRI and still have MS or a patient can have the characteristic MRI findings for MS and not have MS. There is also a cerebral spinal fluid (CSF) test that can help diagnose MS. A patient with MS will have a characteristic marker found in their CSF upon spinal tap, however like the MRI a patient can have these markers found in their CSF and not have MS or a patient can have MS and not have the CSF markers.
As you can see MS is a difficult diagnosis and some physicians are too quick to make the diagnosis according to recent data. In general for a patient to be diagnosed with MS they need the following; 2 or more attacks separated by time and space. There will be an initial attack and then a relapse. The patient will also have positive MRI findings and positive CSF findings. How are so many cases over diagnosed? The problem is that many different things can cause a MS like MRI and many things can cause a MS like CSF and when physicians rely to heavily on either of these findings they tend to over diagnose.
A patient comes in with some strange neurologic symptoms like numbness but not specific to MS and the physician orders an MRI. The MRI comes back consistent with MS and the doctor says we have a diagnosis, it is MS and he tells the patient they have MS. The patient is devastated and tells their family and joins a MS support group. In reality this patient does not have MS. What does this patient have? Most of the studies show that in 80% of the cases of misdiagnosed MS where the patient does not actually have MS the underlying pathology is psychologic in nature and the 2nd most common causes are vascular in nature. How would a physician avoid making a premature diagnosis of MS. In the above case the physician would realize that a general complaint of numbness is not specific enough to qualify as a MS attack and there was only 1 episode as described by the patient. There usually needs to be at least 2 episodes. The doctor needs to look for MS specific attacks which have fairly distinct characteristics and relapsing / improving pattern. Then when a MRI and or a CSF have characteristic findings of MS the patient must also match the diagnosis of MS clinically. If you have a patient who does not have the clinical signs and symptoms but does have the CSF and MRI findings of MS then they do not have MS.
If the doctor believes he or she is catching MS early, in that a 2nd attack has not yet occurred then they should hold off on an official diagnosis of MS until a 2nd attack has occurred which if it is MS the attack usually happens within 2 years and often within months. This over diagnosis of MS is just starting to become apparent. I think until recently physicians did not realize that the "specific" MRI and CSF findings of MS are only specific for MS when the patient also has the matching specific clinical signs of MS. Further more these clinical signs of MS need to be specific and not vague. Clinically the patient will have characteristic complaints of visual problems and electric like zaps they feel shooting through their body at times. They will have a specific attack that they recover from and then later will experience another similar attack. Again these attacks are not vague in nature. If the patient is unsure that they had an attack of some sort this should be a red flag they they most likely did not have an attack.
If you meet 10 people who have been diagnosed with MS as many as 4 will not actually have MS but have been improperly diagnosed with MS. These misdiagnosed patients will not progress / decline like a true MS patient will. Often they may claim they experienced some sort of miraculous healing phenomenon when in reality they never had MS. The lesson here is that doctors need to be cautious and thorough before pulling the trigger on the diagnosis of MS and patients who have been diagnosed with MS need to make sure they actually match all the criteria and not just bits and pieces of the criteria.
Unfortunately medicine is riddled with disease states that are difficult to diagnose and thus have a large percentage of misdiagnosed cases. Just to name a few: ADD / ADHD, Bipolar, Autism, Lupus, and many others. Fortunately a large majority of diseases are more cut and dry like AIDS, TB, many cancers, etc.
No comments:
Post a Comment