For roughly one in every 10 individuals, long periods of inactivity can trigger an uncomfortable need to get moving again. Long bus rides, chilling out in bed, or even an afternoon at the movies give rise to unpleasant sensations in the lower limbs that can only be alleviated by repositioning the legs.

Without a clear cause or objective means of diagnosis, restless legs syndrome (RLS) could affect more people than we realize, making it one of the most common neurological disorders in the world.

For all of its mysteries, our knowledge of RLS is light years ahead of a similar syndrome affecting the arms and shoulders.

With so few cases in the literature, it's easy to assume restless arm syndrome (RAS) is comparatively rare. However, case studies on the handful of examples we do know about indicate that people tend to suffer in silence long before they receive a diagnosis.

Pain therapists Ulrich Moser and Jasmin Schwab from the Bavarian State Medical Association in Germany now suggest reports of RAS might not represent its true prevalence, especially for mild and less chronic forms.

Their recent report focuses on the case of a 66-year-old male patient who had back pain and discomfort in his right shoulder for more than 20 years.

Visits to radiologists, neurologists, and rheumatologists brought no long term relief. He was put on anti-inflammatory drugs. Gave acupuncture a shot. Massage, transcutaneous electrical nerve stimulation, and even a visit to the chiropractor didn't fix his condition.

In March 2017, the patient visited Moser reporting his symptoms of pressing, stabbing, and deep pain.

His back pain eased with treatment, but a follow-up appointment in 2020 presented reports of new symptoms – severe pain and a sense of restlessness in both hands and forearms that had steadily worsened over the previous two years.

Thinking it could be a case of 'snapping' or 'trigger finger' and perhaps some arthritis, an orthopedic surgeon prescribed surgery and a course of non-steroidal anti-inflammatories. Unfortunately for the patient, the discomfort remained.

The symptoms were uncannily like restless leg syndrome. During the day, when moving about and exercising, all seemed well. It was only during periods of relaxation that the sharp, tingling, burning sensations welled.

Intriguingly, the discomfort was only in his arms. He'd never experienced such sensations in his legs, not even a little. Still, while we know little about the mechanisms behind restless leg syndrome, we do have a few ideas on how to alleviate its symptoms.

After ruling out other possible causes, and essentially ticking all the boxes for severe RLS – albeit, in the arms – Moser prescribed a course of medication typically used for restless legs, that provided an added kick of dopamine in the brain.

The outcome for our patient is a good one, who has since continued on the treatment without any side effects.

But the case took some sleuthing, raising the question of how many people with similar experiences might be out there.

"The patient reported here had symptoms that could have been suggestive of restless arm syndrome for many years," Moser and his colleague Schwab report.

"In the last two years, these symptoms had worsened massively and the essential International Restless Legs Syndrome Study Group diagnostic criteria were fully met, except that the symptoms were exclusively in the upper limbs."

If what doctors are learning about RLS could apply to the upper limbs, there could be a chance of providing a lot of relief for patients whose diagnosis is being dragged out as they are tested for a range of unrelated conditions, from arthritis to trigger finger.

Conversely, there could be subtle differences that help improve therapies, or even lead to a better understanding of restlessness in general.

It's a field of research we should be keen to get moving on.

This research was published in BMJ Case Reports.