Restless Legs Syndrome - RLS and Multiple Sclerosis (en Inglés) - Khosro Hekmat

What explains everything ends up explaining nothing.

"That’s the MS." The sentence is heard almost daily in MS clinics, and it is almost always true. Multiple sclerosis can explain exhaustion, stiff legs, pain, cramps and getting up at night to pass urine. Because it seems to explain everything, nobody asks any further questions, and restless legs syndrome, which could be treated, may go undetected behind it all.

The association between multiple sclerosis and restless legs syndrome is well documented. The largest pooled analysis, 75 studies with 15,411 patients, found RLS in 28% of people with MS, compared with 8% in the control groups. The largest single study with its own control group found RLS in 19.0% of 861 people with MS, compared with 4.2% of 649 control participants. The book also explains why individual studies range from 12.1% to 57.5%, and why two studies found no clear excess of RLS in MS.

Then it asks what may lie behind it. The most frequently replicated finding is greater disability in people with MS and RLS, reported by six of eight studies, and several findings point to the spinal cord. A lesion mapping study found lesions associated with RLS in the subcortical white matter of the left precentral gyrus. In one small post-mortem study, the levels of three major myelin components were approximately 25% lower in people with RLS. Vitamin D did not lead to a statistically significant improvement in the main controlled trial, and the only study that examined disease-modifying MS therapies systematically found no statistically significant association with RLS.

The practical core sets RLS apart from five other reasons why legs do not keep still at night in MS: spasticity, painful tonic spasms, calf cramps, neuropathic dysaesthesias and an overactive bladder. One chapter is given to fatigue, which affects more than 80% of people with MS and for which no drug is approved. The MS fatigue treatment algorithms require a search for treatable causes first, among them sleep disorders and iron deficiency. The book also shows how RLS is associated with sleep, processing speed, mood and walking distance, without claiming that RLS causes these problems.

Treatment begins with iron, with ferritin at or below 100 µg/l as the threshold for discussing iron treatment and transferrin saturation always measured. It goes on to exercise, with a randomised pilot study of 15 people with MS and RLS, and then to drugs. The book states plainly that no dedicated drug treatment study in people with MS and RLS was found, explains augmentation, and ends with a two-week night diary and four key questions for the consultation.

WHAT IS IN THE BOOK
- Why restless legs in MS so often go unnoticed
- How often the two occur together, and why the figures vary so widely
- The spinal cord, and the possibility that the cause lies in the brain
- Demyelination and iron: a possible link between the two conditions
- Vitamin D, inflammation and the search for a common root
- What the sleep laboratory shows
- Five mimics of RLS in MS, compared
- Fatigue, sleep, thinking, memory and processing speed
- Mood, quality of life and walking distance
- Iron first: the two blood tests and the threshold
- Exercise: why timing and intensity seem to matter
- Drugs, augmentation and your action plan for the medical consultation

WHO THIS BOOK IS FOR
For people with MS who cannot settle at night, for everyone whose exhaustion persists despite treatment, and for health professionals who want to recognise a diagnosis that is rarely asked about.

ABOUT THE SERIES
Volume 23 of 52 in the book series on restless legs syndrome, part "RLS with Other Conditions". Every volume can be read on its own. The statements in this volume rest on 192 professional sources, each one listed individually in the reference section.