Module 3 - Other unintentional behaviours in sleep Flashcards
What is restless legs syndrome (RLS) and how does it typically present?
RLS (or Willis–Ekbom disease) is a sensorimotor disorder characterized by an irresistible urge to move the legs, usually accompanied by uncomfortable sensations (e.g., crawling, prickling, itching) that occur during rest or inactivity and are relieved by movement, with symptoms typically worsening in the evening.
What are the common sensations described by patients with RLS?
Patients may describe feelings of creepy crawlies, itching, crawling, pulling, or prickling under the skin, often likened to “ants crawling” or an inner restlessness that forces them to move.
What impact does RLS have on sleep?
RLS often disrupts sleep onset and maintenance, leading to sleep fragmentation and insomnia. It can also contribute to decreased quality of life and may be associated with depression.
Which conditions are known to be associated with secondary RLS?
Secondary RLS may be related to iron deficiency, renal failure, peripheral neuropathy, pregnancy (especially in the third trimester), certain medications (e.g., SSRIs, dopamine antagonists), and other systemic or neurological disorders.
What is the relationship between RLS and periodic limb movements of sleep (PLMS)?
Although many patients with RLS have PLMS (involuntary, repetitive leg movements during sleep), PLMS can also be an incidental finding in individuals without RLS. Approximately 80% of RLS patients show PLMS on polysomnography, but having PLMS alone does not confirm RLS.
What defines a periodic limb movement (PLM) during sleep?
PLMs are repetitive, stereotyped limb movements lasting 0.5 to 10 seconds each, occurring at intervals of 5 to 90 seconds. For a series to be scored, at least four movements should be present, and the movement must reach a minimum amplitude threshold relative to baseline.
What are the five essential diagnostic criteria for RLS (using the URGES mnemonic)?
– Urge to move the legs (often with unpleasant sensations)
– Rest-induced: symptoms begin or worsen during inactivity
– Gets better with movement (temporary relief while active)
– Evening worsening: symptoms are predominantly in the evening or night
– Solely not explained by another condition (i.e., the symptoms are not attributable to other causes)
What are some common differential diagnoses or “mimics” of RLS?
Differential considerations include leg cramps, positional discomfort, peripheral neuropathy, radiculopathy, venous stasis, habitual foot tapping, and drug-induced akathisia. Key distinguishing features include the specific quality, timing, and relief of symptoms with movement.
How does family history and iron status support the diagnosis of RLS?
A positive family history is present in about 50–60% of cases and supports a diagnosis of primary (idiopathic) RLS. Additionally, low ferritin or brain iron deficiency is a common finding, even when serum iron levels may be normal, and improvement with iron supplementation may occur.
What factors differentiate early-onset versus late-onset RLS?
Early-onset RLS (typically before age 45–50) is usually familial, slowly progressive, and less severe (primary RLS), whereas late-onset RLS tends to be sporadic, rapidly progressive, often secondary to other conditions, and associated with more severe symptoms and lower ferritin levels.
What is sleep bruxism and how does it typically manifest?
Sleep bruxism (SB) is a parasomnia characterized by repetitive jaw clenching or grinding during sleep. It often goes unnoticed by the patient but may cause tooth wear, temporomandibular joint pain, and discomfort for bedpartners due to the noise.
What are the proposed etiological factors of sleep bruxism?
The etiology of SB is multifactorial, with current evidence pointing toward a central origin influenced by altered dopaminergic regulation, stress, and psychosocial factors. It may be primary (idiopathic) or secondary to neurological or psychiatric conditions, medications, or substance use.
How is sleep bruxism detected and measured on polysomnography (PSG)?
On PSG, SB is identified by increased EMG activity in the jaw muscles (masseter and temporalis). Episodes can be classified as tonic, phasic, or mixed, and are scored if the EMG amplitude exceeds 25% of the maximal voluntary clench.
What are the typical PSG features of sleep bruxism?
SB is characterized by repeated phasic or tonic bursts in jaw EMG recordings, most frequently occurring during lighter sleep stages and often following arousals. Overall sleep architecture may remain largely normal unless bruxism is severe.
What clinical consequences can arise from sleep bruxism?
Chronic SB can lead to tooth wear, dental damage, temporomandibular disorder (TMD), jaw pain, and sometimes headaches. It may also be associated with increased rhythmic masticatory muscle activity (RMMA).
What is catathrenia and how is it distinguished from other sleep-disordered breathing events?
Catathrenia is a rare parasomnia characterized by prolonged expiratory groaning during sleep, often following an arousal. Unlike obstructive sleep apnea, it is not due to airflow limitation but is considered a sleep-related vocalization disorder.
What is the first-line approach to managing sleep bruxism?
Management focuses on reducing contributing factors and protecting the teeth, for example with occlusal splints or mouthguards. Addressing underlying conditions may also help.
What is exploding head syndrome and what are its core clinical features?
Exploding head syndrome is a benign parasomnia where patients experience a sudden, loud noise or sensation of explosion in the head at sleep onset or upon awakening, often accompanied by abrupt arousal and fright, but without pain.
What are the key diagnostic criteria for exploding head syndrome?
Diagnostic criteria include (A) the complaint of a sudden loud noise or explosion-like sensation in the head at sleep–wake transitions, (B) abrupt arousal with a feeling of fright, and (C) the absence of significant pain.
How do sleep-related hallucinations typically present, and what differentiates them from dreams?
Sleep-related hallucinations occur at the transition into sleep or upon awakening and are predominantly visual. They differ from dreams in that they are brief, occur at sleep transitions, and are often accompanied by sleep paralysis.
What is the relationship between sleep-related hallucinations and other conditions?
They are commonly seen in narcolepsy but can also occur in otherwise normal individuals. When associated with sleep paralysis, they may be part of the normal sleep onset experience or secondary to other sleep disorders.
What sleep-related urologic dysfunctions are included in the parasomnia category, and how are they defined?
The main entities are sleep enuresis, nocturia, and nocturnal urinary urge incontinence.
Definitions: Sleep Enuresis: Involuntary voiding during sleep; Nocturia: Three or more episodes of urination per night; Nocturnal Urinary Urge Incontinence: Involuntary leakage with urgency.
What factors should be considered when evaluating a child with sleep enuresis?
Differentiate between primary enuresis and secondary enuresis, assess for associated lower urinary tract symptoms or structural abnormalities, and consider familial predisposition.
How does the prevalence of sleep enuresis change with age?
Sleep enuresis is more common in young children (15–20% at age 5), decreasing with age to around 2% in adolescents, with a strong familial component noted in primary enuresis.
What treatment considerations exist for parasomnias like exploding head syndrome and sleep-related hallucinations?
Often reassurance and education about the benign nature of these conditions are sufficient. In some cases, improving sleep hygiene or treating associated conditions may help.
What are the key PSG criteria for scoring periodic limb movements (PLMs)?
A PLM is defined as a stereotyped, repetitive movement lasting 0.5–10 seconds, occurring at intervals of 5–90 seconds, with at least four movements forming a series.
How is sleep bruxism (SB) quantified during polysomnography?
SB is measured by recording increased EMG activity in jaw muscles. Episodes are classified as tonic, phasic, or mixed, and an index above 5 episodes per hour is considered pathological.
What is the PLMS index (PLMSI) and why is it clinically relevant?
The PLMS index is the number of periodic limb movements per hour of sleep, helping determine the severity of PLMS; values around 15/hour or greater can be clinically significant.
What are the iron supplementation guidelines for patients with RLS?
Iron supplementation is considered when serum ferritin levels are below about 75 μg/L, as brain iron deficiency may exist despite normal serum levels.
What dopaminergic therapies are commonly used in RLS management and what is their rationale?
Dopaminergic agents such as pramipexole, ropinirole, and levodopa are used to correct an altered dopaminergic state seen in RLS.
What non-pharmacological interventions are recommended for RLS?
Recommendations include maintaining good sleep hygiene, moderate exercise, avoiding caffeine and alcohol, and using behavioral strategies to reduce symptom severity.
How can clinicians differentiate true RLS from its mimics?
True RLS is characterized by an urge to move the legs with uncomfortable sensations that worsen with rest and are relieved by movement, primarily in the evening.
What distinguishes catathrenia from central apneas on sleep studies?
Catathrenia is marked by a prolonged expiratory phase with an audible groaning sound and occurs during sleep without significant oxygen desaturation.
What evidence supports a central (rather than peripheral) mechanism in sleep bruxism?
Studies show that sleep bruxism often occurs with cortical arousals and sympathetic activation, suggesting a centrally mediated origin.
How do neurotransmitters contribute to sleep bruxism and other parasomnias?
Neurotransmitters like dopamine, GABA, and catecholamines regulate muscle tone and arousal, with dysfunction linked to bruxism and RLS.
What PSG-derived indices can help assess the severity of sleep bruxism?
Key indices include the bruxism episode index, mean burst duration, and the root mean square (RMS) amplitude of the bursts.
