Hepatology: An Update

Sleepiness is a common symptom affecting approximately 10% of the adult population. It is defined as sleep episodes occurring at an inappropriate time or in inappropriate circumstances, such as when reading or driving. Sleepiness is commonly measured using the Epworth Sleepiness Scale. Physiological measures, including the Multiple Sleep Latency Test, are also used to estimate sleepiness. Sleep deprivation or inadequate opportunity to sleep quickly leads to clinically significant excessive sleepiness. Alternatively, the sleepy patient can be experiencing interrupted sleep caused by sleep-disordered breathing (i.e. obstructive sleep apnoea), periodic limb movements of sleep or disease (e.g. arthritis, obstructive lung disease). Rarely, narcolepsy or primary hypersomnia is the cause. Diagnostic investigations, including overnight oximetry and polysomnography, are discussed.