That crawling feeling in your legs at night could be a neurological disorder: Apollo doctor explains this common syndrome

Imagine this: you have had a long, exhausting day. You finally get into bed, switch off the lights and are ready to sleep. But within minutes, an uncomfortable sensation begins deep inside your legs. It may feel like tingling, crawling, pulling, aching, throbbing, or an indescribable inner restlessness. You feel an almost irresistible urge to move your legs. You get up and walk around, and strangely, the discomfort improves.

You return to bed. It starts again. This cycle may repeat several times a night.

This is restless legs syndrome (RLS). It is a neurological disorder that is surprisingly common but frequently misunderstood or dismissed.

Symptoms of RLS occur in roughly 5–10 per cent of adults, although only a smaller proportion have symptoms severe enough to require treatment. 

More than simply 'restless legs'.

RLS has a distinctive pattern. There is usually:

• An urge to move the legs, often accompanied by uncomfortable sensations 

• Symptoms that begin or become worse during rest, such as sitting or lying down 

• Relief with movement: walking, stretching or moving the legs 

• Symptoms that are worse in the evening or at night 

• Symptoms that cannot be better explained by another medical condition

The sensations can be difficult to describe. Some people say it feels like insects crawling beneath their skin; others describe pulling, electricity, itching, burning or unpleasant inner agitation. Importantly, pain is not essential for diagnosis.

The symptoms can be mild and occasional or severe enough to make falling asleep almost impossible. Repeated sleep disruption can result in daytime fatigue, poor concentration, irritability and reduced quality of life.

Who is likely to develop it?

RLS can begin at almost any age, including childhood, but becomes more common with increasing age. Women are affected more often than men, and a family history is common, particularly when symptoms begin at a younger age. 

Some cases are primary RLS, in which no specific underlying disease is identified. Genetic factors appear to contribute. Others are secondary RLS, associated with conditions such as iron deficiency (even without anaemia), pregnancy, chronic kidney disease, particularly advanced kidney failure, peripheral neuropathy (including diabetic neuropathy), certain spinal-cord disorders and sometimes Parkinson's disease. 

Can the hands or genital region be affected?

Yes, and this can sometimes make the diagnosis particularly confusing. Although the legs are the classic location, RLS-like symptoms can involve the arms, hands, head, abdomen and, rarely, the genital region. In some people, symptoms may spread from the legs to the arms, particularly as the disease progresses. Such unusual presentations are referred to as RLS variants. 

The crucial clue remains the same: symptoms worsen during rest, are worse later in the day and improve with movement.

How is RLS diagnosed?

There is no blood test, brain scan or electrical test that confirms RLS. RLS is primarily a clinical diagnosis, based on the characteristic history and exclusion of conditions that mimic it. A neurological examination is often normal.

Blood tests are important, particularly iron studies. Serum ferritin is the most important blood test. Depending on the clinical situation, kidney function, blood glucose and other investigations may be appropriate.

Why is iron so important? 

Iron deficiency can cause or aggravate RLS even when the haemoglobin level is normal. Therefore, a normal haemoglobin does not necessarily rule out iron-related RLS. Iron should not be taken routinely without checking iron status, because excessive iron can be harmful.

How is it treated?

Treatment begins with correcting an identifiable cause. If iron stores are low, iron replacement (oral or intravenous depending on the circumstances) can substantially improve or sometimes eliminate symptoms. The cause of iron deficiency should also be investigated, particularly in men and postmenopausal women.

Lifestyle measures can help:

Regular moderate exercise, good sleep habits, avoiding excessive caffeine and alcohol, and reviewing medications that may worsen RLS can be useful.

For persistent or troublesome RLS, medications may be necessary. Gabapentin and pregabalin are important first-line options for many patients, particularly when symptoms are frequent or interfere with sleep. 

Dopamine-enhancing drugs such as pramipexole and ropinirole and can be highly effective, but their long-term use requires caution. This is because of a phenomenon called augmentation. Instead of simply losing effectiveness, the RLS may gradually become more severe, start earlier in the day, last longer, or spread from the legs to the arms or other body parts. This is an important reason not to keep increasing dopamine medications without medical supervision. 

Is there a cure? What is the long-term outlook?

The answer depends on the type. RLS associated with pregnancy or iron deficiency may improve considerably when the underlying problem resolves. In primary RLS, however, symptoms may come and go but can persist for many years.

The encouraging news is that RLS is usually highly manageable. Finding the correct diagnosis, identifying iron deficiency or another underlying cause, removing aggravating medications and choosing appropriate treatment can dramatically improve sleep and quality of life. 

Don't ignore the legs that won't let you sleep

If you repeatedly experience an irresistible urge to move your legs at rest, particularly in the evening or at bedtime, don't simply accept it as a normal part of ageing or poor sleep. There may be a treatable neurological disorder behind it.

And sometimes, the most useful diagnostic question is also the simplest:

“Does walking make it better?” If the answer is repeatedly yes, restless legs syndrome deserves consideration.

The opinions expressed in this article are those of the author and do not purport to reflect the opinions or views of THE WEEK.