What is Periodic Limb Movement Disorder?
Periodic limb movement disorder (PLMD) was previously known as sleep myoclonus or nocturnal myoclonus. It is defined as repeated limb motions that occur during sleep and interrupt sleep. In addition to extending the big toe, the ankle, knee, and hip are often involved in limb motions. In some instances, limb motions might also occur in the upper extremities.
Leg motions are more common during mild non-REM sleep. The repeating movements are interrupted by 5 to 90-second intervals that are quite consistent. The frequency of limb motions might vary significantly from one night to another.
Alternate Name
Sleep myoclonus or nocturnal myoclonus
Associated anatomy
The lower extremities are frequently involved in limb motions, which include an extension of the big toe and flexion of the ankle, knee, and hip.
Stages of Periodic Limb Movement Disorder
Periodic limb movement disorder may not necessarily have stages of its own, but it occurs in stages 1 and 2 of non-rapid eye movement (NREM) sleep.
The movements are less frequently observed during stage 3 of NREM sleep and REM sleep.
Types of Periodic Limb Movement Disorder
There are two types of PLMD: primary and secondary.
- Primary PLMD isn't considered a medical emergency. However, complications from the disorder might create problems.
- Secondary PLMD is connected to underlying diseases or the use of certain medications.
Causes of Periodic Limb Movement Disorder
Although the specific aetiology of PLMD is unknown, many experts believe it stems from the central nervous system. However, no formal relationship has been established. All the following are regarded to contribute to or impact PLMD but are not necessarily considered causes:
- Caffeine consumption
- Antidepressants, anti-nausea meds, lithium, and anticonvulsants are examples of pharmaceuticals.
- Other sleep problems, such as narcolepsy or restless leg syndrome
- Attention deficit hyperactivity disorder and Williams syndrome are examples of neurodevelopmental disorders.
- Damage to the spinal cord
- Anaemia due to iron deficiency
- Diabetes and renal disease are examples of metabolic illnesses.
Natural Progression
During sleep, people with PLMD feel jerking, cramps, or twitching of their lower limbs. Periodic limb movements (PLMS) are motions that occur every 5 to 90 seconds for up to an hour.
Signs and symptoms of Periodic Limb Movement Disorder
Leg movements are not the most prevalent symptoms reported by persons with PLMD but relatively poor sleep and daytime drowsiness. Many persons with PLMD are unaware of their leg movements until their bed partner informs them. Leg motions can include one or both limbs.
- Typically, the knee, ankle, and big toe joints flex as part of the action.
- The motions range from gentle to severe and frantic kicking and thrashing.
- The motions endure around 2 seconds (and thus are much slower than the leg jerks of the myoclonus).
- The motions are regular and repeated, occurring every 20-40 seconds.
- Movements tend to cluster in bouts that last a few minutes to many hours.
- The degree of movement might vary from one night to the next.
- Although it is less prevalent, PLMD can also affect the arms.
Risk factors
Age is one of the risk variables connected with PLMD. It is more frequent in older folks, with up to 34% of those over 60 suffering from it. On the other hand, RLS affects women twice as much as males. Both sexes are equally affected by PLMD.
Complications of Periodic Limb Movement Disorder
- Daytime drowsiness,
- Poor sleep
- Persistent insomnia
Treatment and Care Required for Periodic Limb Movement Disorder
Treatment does not cure the illness, but it does relieve symptoms. Your doctor can prescribe iron supplements if you are iron deficient. It may also be beneficial to avoid caffeine-containing foods and beverages such as chocolate, coffee, tea, and soft drinks.
Medical treatment consists of medicine that either lessens or helps the person sleep through the movements.
Medication therapy does not cure PLMD, although it helps alleviate symptoms. It is worth noting that many of the drugs used to treat PLMD are also used to treat restless legs syndrome.
- Benzodiazepines: These medications work by preventing muscular spasms. They are also sedatives, allowing you to sleep through your motions. Clonazepam (Klonopin) has been demonstrated to decrease the overall number of periodic limb movements per hour. It is most likely the most often used medicine to treat PLMD.
- Dopaminergic agents: These medications boost dopamine levels, a neurotransmitter (brain chemical) that is vital in controlling muscular actions. Some people appear to benefit from these drugs, while others do not. A levodopa/carbidopa combination (Sinemet) and pergolide are two commonly used combinations (Permax).
- Anticonvulsant medicines: These drugs help some patients minimise muscular spasms. Gabapentin is the most often used anticonvulsant in PLMD (Neurontin).
- GABA agonists: These drugs suppress the release of neurotransmitters that cause muscular spasms. The contractions relax as a result. Baclofen is the most often used of these medicines in PLMD.
Diagnosis and Tests
Poor sleep and daytime tiredness are the most annoying symptoms in most persons with PLMD. Many people do not associate their sleep disorder with leg movements. There are several causes of sleep disruption. Your health care practitioner may ask you numerous specific questions based on how you explain your symptoms.
These questions are about your current and previous medical issues, family medical problems, drugs you use, your job and travel history, and your habits and lifestyle. A thorough physical examination will be performed to seek evidence of an underlying reason for your sleep disorder.
There is no lab test or imaging examination that can confirm PLMD. Specific tests, however, can detect underlying medical reasons for PLMD, such as anaemia, nutritional deficiencies, and metabolic problems.
- Blood may be obtained to examine your blood cell counts and haemoglobin levels and fundamental organ functioning, chemistry, and thyroid hormone levels. You may also be tested for illnesses that might lead to subsequent PLMD.
- A urine sample may be taken to test for drug residues that might induce sleep disorders.
Polysomnography (sleep lab testing) is the only approach to diagnose PLMD. Leg motions can be recorded as you sleep in the lab.
Your health care physician may refer you to a neurologist at any moment throughout your assessment (a specialist in disorders of the nervous system). This professional can assist in ruling out other neurological issues and confirming the diagnosis of PLMD.
Prognosis
Primary PLMD can be chronic, which means that those who have it will have it for the rest of their lives. They do, however, go through periods of remission when their symptoms go away, but relapses sometimes happen. Secondary PLMD can be treated or managed by altering drugs or addressing the underlying medical problem.
Pathophysiology
PLMD's actual aetiology is unclear. Several drugs, however, have been shown to exacerbate its symptoms. Some antidepressants, antihistamines, and antipsychotics are among these drugs. Low iron levels or issues with limb nerve conduction caused by diabetes or renal illness may be linked to PLMD.
Our Medical Periodic Limb Movement Disorder Experts
If you are facing any similar signs or symptoms please contact the Nanavati Max team to schedule an appointment at : +91 22 6836 0000
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