A prodrome is a premonitory or warning phase of a medical problem yet to come. It’s an early stage of signs or symptoms that happens before the onset of the typical symptoms.
“Prodrome for MS has been discussed and studied more in recent years; 10 or 15 years ago, we didn’t necessarily think of MS as having a prodrome,” says Otallah.
There is now more evidence to suggest that there may be some symptoms that occur in people well before their first demyelinating event or MS diagnosis, he says.
Cognitive impairment is one potential symptom of prodrome that has been identified, says Otallah, referring to a study in which researchers followed 20,000 Norwegian men who were about to enter military service, 900 of whom went on to develop MS. Investigators found that cognitive performance in those men was reduced up to two years before they had any clinical signs of MS.
Increased visits to the doctor are another possible indication of prodrome. A few studies have suggested that in the 5 to 10 years or so leading up to an MS diagnosis people use more health services for a variety of reasons compared with others who don’t go on to be diagnosed. In a recent study of 2,038 people with MS and 10,182 individuals without MS, researchers found that physician visits — for mental health or ill-defined symptoms — were elevated 14 to 15 years before the onset of MS; neurology and ophthalmology consultations increased 8 to 9 years before onset and visits for musculoskeletal, sensory, and nervous system concerns increased 4 to 8 years before onset. The findings suggest that MS may start much earlier than previously recognized.
Increased hospitalizations and medication use could also be a symptom of prodrome.
“There does seem to be an increase in depression, anxiety, and migraine prior to MS diagnosis, but all three of those conditions are also very common in the general population, and most of those people never go on to develop MS,” says Otallah.
These conditions, along with other suspected prodrome symptoms, aren’t being used to identify people who may be at an increased risk of MS yet, he says. “We’re not at a point where we can use these to predict if someone is going to go on to develop MS, but when we look back, we are noticing correlations.”
