Respiratory

Sleep Disorders

Obstructive Sleep Apnoea

Introduction

  • An apnoea is a pause in breathing of at least 10 seconds and can be more prevalent during sleep

Aetiology

  • Sleep apnoea can be divided into central (rare) and obstructive (common) which we deal with here
  • Commoner obstructive form there is usually recurrent occlusion at pharyngeal level during sleep
  • This is possibly due to negative pressure generated through inhalation
  • Smoking is a risk factor

Symptoms

  • Typically obese males with large collar sizes who snore loudly
  • Worse after sedation or alcohol.
  • Excessive day time somnolence - Fatigue, Poor concentration
  • Weariness is main complaint
  • Heavy Snoring at night with periods of witnessed apnoea
  • Nocturia
  • Morning headaches and Non satisfying sleep
  • Partner describes periods of apnoea during sleep

Complications

  • OSA is associated with increased risk of single vehicle Road traffic Collisions
  • Increased systemic hypertension
  • Mild pulmonary hypertension
  • Associated with MI and Arrhythmias and Stroke.

Investigations

  • Sleep lab studies show profound drops in PO2 and measure O2 Saturation,EEG, EMG oronasal airflow and respiratory effort and snoring
  • There are usually > 15 apnoea's (10 seconds or more) per hour)
  • With severe sleep apnoea there is an apnoea episode per minute
  • Epworth sleepiness scale is useful

Management

  • Avoid alcohol, smoking cessation, avoid sedatives
  • Aim for weight loss
  • Some may need Treatment with CPAP which reduces self reported car accidents

Narcolepsy

Introduction

  • A disorder of the sleep/wake cycle with rapid entry to REM sleep

Aetiology

  • Affected individuals usually are positive for DQB10602 and DRB11
  • Reduced hypocretin in the brains of those affected.

Clinical

  • Sudden falling asleep inappropriately due to excessive daytime sleepiness often with a REM sleep disorder
  • Narcolepsy is associated with cataplexy - Sudden loss of muscle tone and collapse induced by emotional experiences, Hypnagogic hallucinations, Sleep paralysis and Automatic behaviour.

Investigations

  • Diagnosis by polysomnogram and the multiple sleep latency test (MSLT)

Management

  • Narcolepsy may require modafinil a central alpha agonist and Cataplexy may respond to antidepressants such as clomipramine
  • Short naps may also help.