Some patients with multiple sclerosis (MS) have symptoms so mild, their doctors believe they will never develop the debilitating symptoms often associated with the disease.
So-called "benign" MS has been diagnosed in many patients who over the course of 10 years never show any serious symptoms, and these patients are told that more than likely their disease will remain mild. However, new research shows benign MS may not be so benign after all.
In a study, researchers from the University of British Columbia in Vancouver, Canada, found that among 169 people diagnosed with benign MS, almost half had a more progressive form of the disease after 10 years. After 20 years, 21 percent of the patients were using a cane to walk.
"We need to be careful about what we tell people, and not give them false hope that their symptoms may never get worse" said Dr. Ana-Luiza Sayao, lead author of the study, published in Neurology.
MS is a potentially debilitating disease caused by inflammation in the nervous system. The disease can cause muscle weakness, balance problems, fatigue, visual difficulties, memory loss as well as trouble speaking and depression.
There are two major forms of MS. In patients who have a relapsing-remitting form of the disease, symptoms come and go. However, in patients with the secondary-progressive form of the disease, the disease steadily gets worse.
Benign MS, on the other hand, is diagnosed when a patient has one or more episodes of MS symptoms but does not develop any of the disabling symptoms of the disease over the course of several years. Previously, experts believed that this small group of patients was unlikely to begin developing more serious symptoms after those few years have passed.
However, in Sayao's study, 20 percent of the patients had developed the secondary-progressive form of MS, with steadily worsening symptoms.
It is unclear if there is a way to determine whether a patient with seemingly benign MS will be at risk for other forms of the disease. "We did not find that gender, the symptoms when the disease began or age when the disease began were associated with either disease progression or remaining benign," said Sayao. "More research needs to be done to identify criteria to determine which patients will remain with mild disability over the long term."