Restless legs syndrome and periodic limb movement syndrome

Movement disorders in sleep are numerous, but most often they are considered within the framework of restless legs syndrome and the syndrome of periodic limb movements.

The syndrome of periodic limb movements (SPDG) and restless legs syndrome (RLS) are more common in middle and older age. The mechanism is unclear, but the disease can develop due to a violation of the neurotransmission of dopamine in the central nervous system. Disturbances can occur either alone or in connection with drug cancellation, or in connection with taking stimulants and some antidepressants, or in chronic kidney and liver failure, pregnancy, anemia and other diseases.

In the syndrome of periodic limb movements, repeated (usually every 20-40 s) jerking of the lower limbs during sleep is characteristic. Patients usually complain of intermittent nighttime sleep or abnormal daytime sleepiness. As a rule, movements and short awakenings - without pathological sensations in the limbs - are not realized.

In restless legs syndrome, patients complain of a feeling of crawling in the lower extremities in the prone position. To reduce symptoms, patients move the affected limb, pull it or walk. As a result, they have problems with falling asleep, repeated nocturnal awakenings or their combination.

[1], [2], [3]

Causes of Restless Leg Syndrome

The causes of these syndromes are diverse: polyneuropathies, rheumatoid arthritis (> 30%), parkinsonism, depression, pregnancy (11%), anemia, uremia (15-20%), caffeine abuse. The use of drugs (neuroleptics, antidepressants, benzodiazepines, dopaminomimetics) or the cancellation of some of them (benzodiazepines, barbiturates) can lead to the development of restless legs syndrome and the syndrome of periodic limb movements.

Primary (idiopathic):

1. sporadic and hereditary.

Secondary:

1. Insufficiency of iron, vitamin B ₁₂, folic acid (anemia).
2. Renal failure.
3. Diabetes.
4. Hypothyroidism.
5. Chronic obstructive pulmonary diseases.
6. Sjogren's syndrome.
7. Peripheral neuropathy (polyneuropathy), radiculopathy and some diseases of the spinal cord (myelopathy).
8. Multiple sclerosis.
9. Parkinson's disease.
10. Attention Deficit Hyperactivity Disorder ("Minimal Brain Dysfunction").
11. Pregnancy.
12. Iatrogenic (tricyclic antidepressants, selective serotonin reuptake inhibitors, lithium, dopamine antagonists, levodopa, condition after gastrectomy, abolition of sedatives or drugs, antagonists of calcium channels).
13. Other diseases: amyotrophic lateral sclerosis, poliomyelitis, Isaacs syndrome, amyloidosis, malignant neoplasm, peripheral vascular disease (arteries or veins), rheumatoid arthritis, hyperexcision.

[4], [5], [6], [7], [8]

Syndromic differential diagnosis

Restless legs syndrome should be distinguished from other syndromes, sometimes similar to it: akathisia, a syndrome of periodic limb movements during sleep, night cramps, physiological myoclonus during sleep. This includes the syndrome of a painful leg and moving fingers, the syndrome of painful fasciculations, myokimii, the syndrome of causalgia-dystonia, pain in the legs of another origin. An anxious-depressive syndrome with sleep disorders can sometimes manifest as symptoms resembling restless legs syndrome.

Sporadic and family cases of restless legs syndrome with autosomal dominant type of inheritance are described .. The frequency of the latter, according to the literature, significantly varies (up to 50-60% and more). The disease can begin at any age, but its frequency increases with age. The restless legs syndrome in children is often mistakenly interpreted as a syndrome of hyperactivity. At the same time, restless leg syndrome is often combined with attention deficit hyperactivity disorder.

In most cases, the symptoms are bilateral. However, a significant percentage of patients (more than 40%) report a right-sided or left-sided localization of the symptom. The truth of the symptom may vary in individual patients even within one day. Approximately half of the patients report paresthesias and motor anxiety in their hands. The presence of paresthesia in the hands does not depend on the severity of restless legs syndrome, age and sex of these patients. Paresthesias are described by patients as burning, tingling, itching, pain; often patients say that this is a very unpleasant feeling, which is difficult to describe in words. Paresthesias can be very short (seconds); they rapidly increase in intensity and instantly disappear when the limb moves. By effort of will it is possible only to delay the movement or reduce its amplitude. Many researchers believe that movements with restless legs syndrome appear as a kind of response to unpleasant paresthesia. Electrophysiological studies to date do not allow us to answer the question whether these movements are arbitrary or involuntary. The course of restless legs syndrome is often remittent, but can be stationary and even progressive. In the treatment, dopasoderzhaschie drugs and clonazepam are most effective.

Approximately 40% of cases of restless legs syndrome is idiopathic (primary). Symptomatic restless legs syndrome can be observed in diseases such as anemia associated with deficiency of iron, vitamin B12 or folic acid; kidney failure; diabetes; hypothyroidism; chronic obstructive pulmonary disease; polyneuropathy (most often); cervical spondylosis; spinal cord tumors, lumbosacral radiculopathy, multiple sclerosis, Parkinson's disease, peripheral arterial disease, hyperexclusion, rigid person syndrome, Huntington's chorea, amyotrophic lateral sclerosis, Tourette's disease, Isaacs syndrome. Observations in which restless legs syndrome were observed only during pregnancy are described. However, in many of the cases indicated above, it remains unclear whether the listed diseases are the cause of restless legs syndrome or are only a provoking factor of this syndrome. To finally answer this question it is necessary to prove that the frequency of restless legs syndrome in these diseases is higher than in the rest of the population. This has not been done to the full.

Symptoms of Restless Leg Syndrome

Restless leg syndrome and periodic limb movements syndrome have many similarities (typical combination of pain syndrome and involuntary movements, motor phenomena, most clearly manifested during sleep) and often combine with each other. However, there are some differences: in the restless legs syndrome, marked sensitive disorders are noted; the syndrome of periodic limb movements is highly stereotyped. A common link in the pathogenesis of these syndromes is the dysfunction of cerebral and peripheral dopaminergic systems, which explains the effectiveness of levodopa preparations.

• The main manifestation of restless legs syndrome is unpleasant paresthesia in the legs (patients describe them as "discomfort", "shudders", "goose bumps", "stretching", "twitching", "pricking", "itching", etc.) sleep or during sleep, which leads to an irresistible need to move your legs. Sensations most often occur in the legs (in the foot, shin, knee area, sometimes in the thigh or in the entire limb), rarely in the hands and feet. Usually, symptoms occur in both extremities, although they can predominate on one side. As a rule, they appear in the period of rest or in the period preceding the dream. May occur at any other time of day, more often with a long, monotonous position of the body (for example, when driving a car). These feelings completely or partially disappear at the time of movement of the legs and appear again after the movement ceases. The duration of such states is from several seconds to several hours, they can occur several times a day and independently pass. The degree of severity of disturbances in the "sleep-wake" cycle can be different, in a number of cases, gross disorders of the structure of sleep and pronounced daytime sleepiness are noted. The restless legs syndrome can have a perennial course with exacerbations and remissions. The following minimum diagnostic criteria are proposed: (A) the need to move the limbs + paresthesia / dysesthesia; (B) motor anxiety; (C) worsening of symptoms in a dream with a short subsequent activation or awakening; (D) worsening of symptoms in the evening or at night.
• The syndrome of periodic limb movements is characterized by episodes of repetitive, stereotyped movements in sleep. Movements usually occur in the legs and consist of the extension of the thumb combined with partial bending of the knee, and sometimes the thigh; in a number of cases, hands are involved. Patients complain of frequent nocturnal awakenings in 45% of cases, difficulties of falling asleep - 43%, daytime sleepiness - 42%, early awakenings - 11%. Given that patients can not make complaints about movements in the limbs, it must be stressed that the combination of insomnia and daytime sleepiness suggests a syndrome of periodic limb movements. To confirm the diagnosis, polysomnography is needed, which allows to reveal increased motor activity in the legs and destruction of the structure of night sleep. The integral polysomnographic index of the severity of the disease - the frequency of limb movements for 1 h (the index of periodic movements); with a light form, it is 5-20, with a moderate - 20-60, with a heavy - more than 60.

Diagnosis of Restless Leg Syndrome

The minimum criteria for the diagnosis of Restless Leg Syndrome (RLS), according to the latest data from an international group of experts are:

1. Imperative desires to move the limbs in connection with paresthesias (dysesthesias) in them.
2. Motor anxiety; while the patient realizes that he is forced to make movements, and uses various motor strategies to facilitate or get rid of unpleasant sensations.
3. The increase or appearance of symptoms at rest (when the patient lies or sits) and partially or temporarily eliminating them during movements.
4. Symptoms must increase by evening or at night.

Patients with restless legs syndrome are characterized by disturbances in night sleep (delayed falling asleep, multiple awakenings, dissatisfaction with sleep, etc.). Most patients with restless legs syndrome also note periodic movements of limbs in a dream, which are also one of the causes of sleep disorders.

[9], [10], [11]

Treatment of Restless Leg Syndrome

The most effective for restless leg syndromes and periodic limb movements dopaminomimetiki (drugs levodopa, agonists postsynaptic dopaminergic receptors, MAO inhibitors type B), benzodiazepines. Recently, gabapentin has been used successfully.

Various drugs have been tried and used (including dopaminergic drugs, benzodiazepines, anticonvulsants, vitamins and trace elements), although none of them is a means of pathogenetic therapy for nocturnal myoclonia or restless leg syndrome.

Treatment with dopaminergic drugs is effective, but it is associated with a number of side effects, in particular, aggravation of the disease (the appearance of symptoms during the day), relapse (worsening symptoms after drug withdrawal), nausea and insomnia. Effective with minimal side effects are D ₂ - and D _{g -} dopamine receptor agonists pramipexole and ropinirole. Pramipexole is prescribed at 0.125 mg for 2 hours before the onset of symptoms and, if necessary, increases the dose by 0.125 mg every 2 nights until a therapeutic effect is achieved (maximum dose of 4 mg). The worsening of symptoms during treatment with pramipexole is less frequent than with levodopa. Ropinerol is prescribed at 0.5 mg for 2 hours before the onset of symptoms and, if necessary, increase the dose by 0.25 mg at night (up to a maximum of 3 mg).

Benzodiazepines increase the duration of sleep, but do not reduce the pathological movements of the limbs, besides this, one should not forget the conjugate phenomena of habituation and induction of daytime sleepiness. If the restless leg syndrome is combined with pain, gabapentin is prescribed starting at 300 mg before bedtime; the dose is increased by 300 mg every week until a maximum dose of 2700 mg is reached. The effectiveness of opioids is not excluded, but they are used at the very least because of side effects, the development of addiction and dependence.