Restless Legs Syndrome

Restless legs syndrome (RLS) is a sleep disorder affecting approximately 5% of the American population. Also called Ekbom Syndrome, RLS is a neurological disorder in which the person feels a strong urge to move the lower limbs and this is accompanied by the “pins and needles” sensation that can be painful and a nuisance when trying to sleep.

The sensations have the following features:

• Occur during periods of inactivity
• Become more sensitive in the evening and at night
• Are relieved by movement of the limb
• Often cause difficulty staying or falling asleep, which leads to feelings of daytime tiredness or fatique
• May cause involuntary jerking of the limbs during sleep and sometimes during wakefulness

RLS can be hard to diagnose because the diagnosis depends primarily on the chief complaints by the patient and proper history taking by the clinician. A diagnosis of RLS is made based on complaints consisting of four criteria

1. an urge to move the lower limbs
2. the urge is accompanied with pain or unbearable sensations
3. the symptoms become worse at night or during rest
4. movement helps with urges and pain/sensations.

What are some of the known and hypothetical causes for restless legs syndrome?

There are two types of restless legs syndrome—primary and secondary. Primary is termed idiopathic RLS and the cause is not known. It is believed to involve three overlapping factors. The first factor involves the area of the brain that produces dopamine. Dopamine is a neurotransmitter involved in movement and mood regulation.

The second factor involved in primary RLS is the regulation of iron. Brain imaging and autopsies have revealed low concentrations of iron in the brains of individuals afflicted with restless legs syndrome. The link between these two factors is the finding that there are fewer receptors for iron in the brain region that is responsible for making the neurotransmitter dopamine.

The third factor is genetics. This finding was based on the family history of patients suffering from primary restless legs syndrome revealing a first degree family member who also was afflicted with primary RLS. Scientists have narrowed down three or four different regions on different chromosomes as the potential sites for a genetic link to primary restless legs syndrome, but have not identified the exact gene or genes responsible. Some classify RLS in two categories: the inherited type that shows up in people under age 45 (and sometimes even in children), and the type that does not run in families that shows up when the patient is over 45 years old.

The other form of RLS called secondary RLS is usually as a result of another problem such as renal failure or normal pregnancy causing secondary restless legs syndrome.

What treatments are there for restless legs syndrome?

The American Academy of Sleep Medicine says people should be treated for RLS only if they meet specific diagnostic criteria and if they have excessive daytime sleepiness because of their RLS.

Until 2005 there was no Federal Drug Administration approved drug to treat RLS. In 2005 the drug ropinirole (Requip) which helps to increase the amount of dopamine available, was approved by the FDA to treat RLS. Pramipexole (Marapex) is another Parkinson's Disease drug also used to treat RLS. A meta-analsysis published in the journal Sleep found "Differences in efficacy and tolerability favouring pramipexole over ropinirole can be observed."

Iron deficiency is a contributing factor in restless legs syndrome and if the case is mild and blood tests indicate a low iron level, iron supplementation can reverse the symptoms. Other medications such as ropinirole are only prescribed in moderate to severe cases. Pramipexole has also been approved, as has the anti-seizure drug gabapentin.

The benzodiazepine clonazepam is prescribed in some countries for RLS.  It is not approved by the US FDA for this condition, and US doctors do not often prescribe it. Opioids are sometimes prescribed in severe cases, but there is a dependency danger with them.

Clinicians may also prescribe low doses of levodopa, a drug normally used to treat Parkinson’s disease. If the patient is responsive, this helps clarify a solid diagnosis of RLS assuming the person does not have other symptoms related to Parkinson’s disease.

The federal government's Effective Health Care Program published this Comparative Effectiveness of Treatments for Restless Legs Syndrome recently.

Treatment and diagnosis of RLS have come a long way in the last few years. The exact mechanisms and causes for RLS are not definitively known, but research is revealing more about the condition. With treatment restless legs syndrome is manageable and the symptoms can eventually disappear.

Allegations of "disease mongering"

RLS first was described in scientific literature in 1672! But marketing of medications for restless legs syndrome has drawn criticism that it is a form of disease mongering - persuading healthy people that they are sick and need medicine. RLS is a legitimate condition recognized by the medical community, but the fear is that these advertisements will make people think they have RLS even when they don't. Just because your legs move in bed doesn't mean you have this condition. Discuss you situation with your doctor in detail in order to get a better picture of whether you should be concerned about RLS.

References:

Pichler, I., Hicks, A., Pramstaller, P., 2008, Restless Legs Syndrome: An Update on Genetics and Future Perspectives, Clinical Genetics, 73:297-305
Ball, E. and Caivano, C., 2008, Internal Medicine: Guidance to the Diagnosis and Management of Restless Legs Syndrome, Southern Medical Journal, 101(6):631-634

Baker, W., White, C., Coleman, C., 2008, Effect of Nonergot Dopamine Agonist on Symptoms of Restless Legs Syndrome, Annals of Family Medicine, 6(3):253-262

Saletu, B., Gruber, G., Saletu, M., Brandstatter, N., Hauer, C., Prause, W., Ritter, K., Saletu-Zyhlars, G., 2000, Sleep Laboratory Studies in Restless Legs Syndrome Patients as Compared with Normals and Acute Effects of Ropinirole, Neurophsychobiology, 41:181-189

Winkelman, J., Allen, R., Tenzer, P., Hening, W., 2007, Restless Legs Syndrome: Nonpharmacologic and Pharmacologic Treatments, Geriatrics, 62(10):13-17

People with restless legs syndrome are sometimes prescribed Parkinson's disease drugs. A recent study on the dopamine agonists Mirapex (pramipexole), Neupro (rotigotine), and Requip (ropinirole) found that all helped reduce symptoms, particularly in the first few weeks of treatment.

The International Restless Legs Syndrome Study Group is working on criteria for diganosing RLS.

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