How can one neurologist say I have MS and the other says I don't?

Here is My Question:
How can two different neurologists look at my MRI report and symptom list and one says I dont have MS the other says I do? I'm female and 61 years old.

Answer:
Multiple Sclerosis is a clinical diagnosis; this means that there is no definitive diagnostic test and rarely is there a piece of tissue that can be biopsied and analyzed under a microscope. Whenever a diagnosis in medicine or psychiatry is based on clinical criteria, there will always be disagreements among practitioners. We try to minimize these disagreements by developing diagnostic criteria but these criteria often fail to address certain situations or practitioners ignore the diagnostic criteria altogether. This is why the diagnostic error rate for MS is so high (25 % among general neurologists and much higher error rates among non neurologists). 

For starters there is no symptom list that suggests a diagnosis of MS. All of the common symptoms experienced by people with MS can occur with other medical and psychiatric diagnoses. Furthermore, there is no MRI appearance that is diagnostic of MS without a history and examination that is consistent with MS at some point in time. 

We diagnose disorders not through a list of symptoms but through the expert elicitation of a medical history; taking a medical history is akin to a journalist investigating a story involving a particular area of their expertise, perhaps finance or Israeli American diplomacy. The journalist must gather information from various sources, clarify certain responses (for instance the  when, where, why and how of the story elements), and ask specific questions based on their intimate knowledge of the subject. Once this is done a story emerges that may suggest a number of possibilities, and the journalist must obtain further information that confirms only one likely possibility. If the journalist can not find confirmation, then there is no story to publish. Similarly if the doctor can not find confirmation there is no diagnosis. 

You would likely benefit from an expert consultation with an MS specialist.

Good Luck

Revere (Rip) Kinkel MD
Professor of Clinical Neurosciences
Director of the Multiple Sclerosis Program
Clinical Neurosciences Director
University of California San Diego