Sleep disorders Flashcards
What is sleep?
Nightly Associated with dreaming Important for function Portal of entry is non-REM sleep Associated with transient jerks Defined electrically but not sensed
REM sleep
Progress through non-REM sleep REM cycles every 90-110 minutes 4-6 episodes per night\ Progressively longer Associated with dreaming if woken
Sleep Duration?
6-8 hours/night
Upper airways disorders?
Snoring
Upper airway resistance syndrome
Hypopnoea
Apnoea
Snoring?
Vibration of the pharyngeal walls Noise >60dBA Classified as Snores/hour V common Increases with increased age, males, obesity and alcohol
Upper airways obstruction
Loss of tone in the upper airways which is actively controlled while awake resulting in obstruction of the upper airway
Mechanism of OSA?
Sleep onset –> loss of upper airways tone –> apnoea –> decreased O2, increased CO2 and decreased pH –> arousal–> resumption of airflow –> sleep
Predisposing factors?
Drugs - EtOH, Smoking Sleep deprivation Large pharynx Obesity Tumours and tonsils Male Hypothyroidism Acromegaly Increased nasal resistance Asthma
Arousal complications
Sleep fragmentation Unrefreshing sleep Excessive somnolence Personality disorders Memory loss
Symptoms of OSA?
Snoring Reported apnoea Restless sleep Unrefreshing sleep Nocturnal choking Headache Excessive daytime sleepiness
Assessment of sleepiness?
Epsworth sleepiness scale
Complications of OSA
Pulmonary vasoconstriction –> pulm HTN and right heart failure
Systemic vasoconstriction –> systemic HTN
Cardiac instability –> bradycardia
Erythropoiesis –> polycythaemia
HPA axis –> reduced sexual function
What does OSA look like on sleep study?
No O2 flow
Ongoing abdominal and thoracic movement
Severity of sleep apnoea?
Apnoea/hour index = AHI
Mild = AHI <20 = sats >85 Moderate = 20-40 = sats >80 Mod-Severe = 40-60 = sats >70 Severe = >60 = sats <70
What is obesity hypoventilation syndrome?
BMI >30 with PaCO2 >45 without other causes found
10-20% of patients with OSA but 90% have OSA
Worse outcomes in hospital
Managed with CPAP +/- BIPAP
Reasons to treat OSA?
Improved QOL
Reduced MVAs - improved with CPAP
Associated with:
- Increased mortality
- HTN
- Increased Cardiovascular events
- Stroke
- Renal disease
- Cancer
- Metabolic syndrome
Ways to treat OSA
WEIGHT LOSS
Avoid EtOH and sedatives
Treat nasal obstruction and asthma
CPAP
Mandibular splints
? surgical therapies
Complications of CPAP
Nasal stuffiness Conjunctivitis Bloating Mask complications COMPLIANCE
Definition of Central sleep apnoea
Absence of breathing >10 seconds without abdominal or thoracic effort resulting in a change in O2 sats
Pathophysiology of CSA
Instability of the respiratory controller
Hypocapnic threshold - PaCO2 below apnoeic threshold
Variants:
Sleep onset CSA
High altitude CSA
Secondary CSA
Congestive HF –> cheyne strokes respiration
Metabolic disorders - acromegaly, hypothyroidism
Renal failure
Neuromuscular disorders
Long acting opioids esp. methadone
Treatment for secondary CSA
Drugs Oxygen CPAP BIPAP Adaptive servo-ventilation
Idiopathic CSA
Abnormal central integration of awake and sleep stimuli
Associated with PHOX2B
AHI>5/hr with predominate central apnoeas
Improves during REM sleep
Treatment = diaphragm pacing
Periodic limb movements
Intermittent repetitive flexion of limbs during sleep
Every 20-30 seconds
Doesn’t need treatment
Restless legs syndrome definition
Neurological disorder resulting in compelling urge to move which worsens at night
2-15% of the population F>M
Increases with age
Causes of RLS
Primary
Secondary:
- Iron deficiency
- Neurological disorders - spinal cord, peripheral nerve
- Pregnancy
- Uraemia
- Drug induced - TCAs, SSRI, Li, dopamine agonists, caffeine
Treatment of RLS
Pregabalin
Definition of Narcolepsy and cataplexy
0.05% of patients
Sleepiness and muscle weakness due to daytime intrusion of REM
Cataplexy = REM inhibition of muscles. usually emotion induced
What happens during sleep in narcolepsy?
Sleepy +++ Sleep paralysis Increased dreaming Hypnagogic hallucinations PLMS 40%
Diagnosis of narcolepsy
Cataplexy
Sleep latency < 8 minutes
>2 sleep onset REM periods
Treatment of Narcolepsy
Cataplexy = TCA or SSRI
Sleepiness = dexamethasone, methylphenidate, modafinil
Cause of Nacrolepsy and cataplexy?
Reduced CSF levels of hypocretin-1/orexin A
Genetic association with narcolepsy and cateplexy?
HLA DQB1*0602
