Diagnosis
Taking the patient seriously
Describing the leg discomfort caused by RLS can be a difficult task. The symptoms vary in severity and sensation, from an unpleasant grabbing sensation to a painful shock-like feeling – not always easy for the patient to describe.
Once they are recognised, the varying symptoms of RLS require great diagnostic skills from the individual physician. Besides evaluating the subjective complaints, objective findings from polygraphic sleep recordings can provide the necessary documentation for a proper diagnosis.
The Four RLS Criteria
The Four RLS Criteria defined by the International Restless Legs Syndrome Study Group (IRLSSG) can be used as a basis for making a proper diagnosis.
The Four RLS Criteria:
- An urge to move the legs, usually accompanied or caused by uncomfortable or unpleasant sensations in the legs.
- The urge to move or unpleasant sensations begin or worsen during periods of rest or inactivity such as lying or sitting.
- 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.
- The urge to move or unpleasant sensations are worse in the evening or night than during the day or they only occur in the evening or during the night.
Furthermore, the symptoms are not better explained by any concurrent medical or psychiatric disorder.
Source: Allen RP, Hening WA, Montplaisir J, Picchietti D, Trenkwalder C, Walters AS et al. Restless legs syndrome: Diagnostic criteria, special considerations, and epidemiology: a report from The RLS Diagnosis and Epidemiology Workshop at the National Institutes of Health. Sleep Med 2003;4:101-119.
Getting the patient’s history right
Uncovering the patient’s medical history the following factors should be taken into consideration:
- Past medical problems
- Family history
- Current medications
- Symptoms
- frequency
- duration
- intensity
- Sleeping patterns
- Disturbance of sleep
- Sleepiness
- Daytime function
Laboratory tests
If a patient's medical history is suggestive of RLS, laboratory tests may be performed to rule out other conditions and support the diagnosis of RLS. These tests include;
- Blood tests to exclude anemia, decreased tissue iron stores (measured by S-Ferritin), diabetes and renal dysfunction
- Doppler sonography to evaluate the vascular supply in the legs.
- Electromyography and nerve conduction studies to measure electrical activity in muscles and nerves. These tests can document any accompanying damage or disease in nerves and nerve roots
In some cases, sleep studies such as polysomnography (including EEG, ECG, breathing and EMG of the limbs during an entire night) are undertaken to identify the presence of Periodic Limp Movement (PLM) and to exclude a concurrent sleep disorder.
No increase in mortality or morbidity
An important element when helping an RLS patient consists in describing the secondary complications, such as insomnia and sleepiness, letting the patient understand that it may decrease his or her quality of life, but that it will not increase mortality or morbidity.
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