Diagnosis of RLS
Background
The diagnosis of restless legs syndrome is symptomatic. An international study group set diagnostic criteria in a workshop at the NIH.
Reference
RA Allen et al. Restless legs: diagnostic criteria, special considerations, and epidemiology. A report from the restless legs diagnosis and epidemiology workshop at the National Institutes of Health. Sleep Medicine 2003 4: 101-119.
RLS in adults
The essential diagnostic criteria developed in 2003 is slightly different from previous criteria, with question 3 relating to relief with movement instead of motor restlessness. The criteria are in Table 1.
Table 1: Essential diagnostic criteria for RLS
| 1 | An urge to move the legs, usually accompanied or caused by uncomfortable and unpleasant sensations in the legs (Sometimes the urge to move is present without the uncomfortable sensations and sometimes the arms and other body parts are involved in addition to the legs) |
| 2 | The urge to move or unpleasant sensations begin or worsen during periods of rest or inactivity such as lying or sitting |
| 3 | The urge to move or unpleasant sensations are partially or totally relieved by movement, such as walking or stretching, at least as long as the activity continues |
| 4 | The urge to move or unpleasant sensations are worse in the evening or night than during the day or only occur in the evening or night (When symptoms are very severe, the worsening at night may be noticeable but must have been previously present) |
Descriptive terms for restless legs syndrome include the following (though they have a particular US bent):
- Creepy-crawly
- Ants crawling
- Jittery
- Pulling
- Worms moving
- Soda bubbling in the veins
- Electric current
- Shock-like feelings
- Pain
- The gotta moves
- Burning
- Jimmy legs
- Heebie jeebies
- Tearing
- Throbbing
- Tight feeling
- Grabbing sensation
- Elvis legs
- Itching bones
- Crazy legs
- Fidgets
Supportive features of RLS include:
- Family history: The prevalence of RLS among first-degree relatives of people with RLS is 3-5 times greater than in people without RLS.
- Response to dopaminergic therapy: Nearly all people with RLS show at least an initial positive therapeutic response the either L-dopa or dopamine receptor agonist at doses considered to be very low in relation to the traditional doses of these medications used for treatment of Parkinson disease. This initial response is not, however, universally maintained.
- Periodic limb movement (during wakefulness or sleep): Periodic limb movements in sleep (PLMS) can occur in at least 85% of people with RLS; however, PLMS also commonly occur in other disorders and in the elderly. In children, PLMS are much less common than in adults.
Associated features of RLS include:
- Natural clinical course: The clinical course of the disorder varies considerably, but certain patterns have been identified that may be helpful to the experienced clinician. When the age of onset of RLS symptoms is less than 50 years, the onset is often insidious; when the age of onset is greater than 50 years, the symptoms often occur more abruptly and more severely. In some patients, RLS can be intermittent and may spontaneously remit for many years.
- Sleep disturbance: Disturbed sleep is a common major morbidity for RLS and deserves special consideration in planning treatment. This morbidity is often the primary reason the patient seeks medical attention.
- Medical evaluation/physical examination: The physical examination is generally normal and does not contribute to the diagnosis except for those conditions that may be comorbid or secondary causes of RLS. Iron status, in particular, should be evaluated because decreased iron stores are a significant potential risk factor that can be treated. The presence of peripheral neuropathy and radiculopathy should also be determined because these conditions have a possible, although uncertain, association and may require different treatment.
RLS in the cognitively impaired
Essential criteria for the diagnosis of probable RLS in the cognitively impaired elderly are shown in Table 2, and all five are necessary for diagnosis.
Table 2:RLS in the cognitively impaired
| 1 | Signs of leg discomfort such as rubbing or kneading the legs and groaning while holding the lower extremities are present |
| 2 | Excessive motor activity in the lower extremities such as pacing, fidgeting, repetitive kicking, tossing and turning in bed, slapping the legs on the mattress, cycling movements of the lower limbs, repetitive foot tapping, rubbing the feet together, and inability to remain seated are present |
| 3 | Signs of leg discomfort are exclusively present or worsen during periods of rest or inactivity |
| 4 | Signs of leg discomfort are diminished with activity |
| 5 | Criteria 1 and 2 occur only in the evening or at night or are worse at those times than during the day |
RLS in children
Criteria for the diagnosis of definite RLS in children are shown in Table 3. They are intended for children aged two to 12 years, with adult criteria for those aged 13 or older. There are separate, lesser criteria for the diagnosis of probable or possible RLS in children.
Table 3: Definite RLS in children
| 1 | The child meets all four essential adult criteria for RLS and |
| 2 | The child relates a description in his or her own words that is consistent with leg discomfort |
or |
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| 1 | The child meets all four essential adult criteria for RLS and |
| 2 | Two of the following supportive criteria are present: |
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Questions for use in epidemiological studies
A positive diagnosis requires that respondents answer yes to the first three questions in Table 4.
Table 4: Questions for epidemiological diagnosis
| 1 | Do you have unpleasant sensations in your legs combined with an urge or need to move your legs? | Yes or No |
| 2 | Do these feelings occur mainly or only at rest and do they improve with movement? | Yes or No |
| 3 | Are these feelings worse in the evening or night than in the morning? | Yes or No |
| 4 | How often do these feelings occur? Less than one time a year At least once a year but less than once a month One time per month 2-4 times per month 2-3 times per week 4-5 times per week 6-7 times per week |
Comment
This is a really useful paper, if for no other reason that it explains each item, and supports each item with a host of references (140 of them). It makes for essential reading for anyone studying or interested in RLS.