David was a 70-year-old retired lorry driver. He consulted on the insistence of his adult daughter after she witnessed what she thought was her father having a seizure one night.
David admitted to a seven-year history of disturbed sleep. Every two to three weeks he experienced a night where his dreams were vivid and violent involving being chased by animals or attacked by strangers.
The dreams manifested themselves in physical actions such as David punching the wall or flinging himself out of bed. These actions were carried out while still asleep but would jerk him awake. Sleep-walking was never a feature.
He did not feel unduly tired after one of these disturbed nights but had suffered some minor bruising. On other nights he would get approximately eight hours unbroken sleep.
David prided himself on keeping fit, undertaking some kind of activity every day. He had no past medical history and was taking no regular medications.
He was an ex-smoker, drank two units of alcohol each evening and took no recreational drugs. Examination of his cranial nerves and upper and lower limbs was normal.
David was referred to a neurologist. The history and examination findings pointed to a diagnosis of idiopathic REM sleep behaviour disorder (RBD).
Normal sleep has two distinct states: non-rapid eye movement and rapid eye movement (REM) sleep, the latter making up 20-25 per cent of the sleep period.
During REM sleep, the eyes move rapidly but the brain is highly active and this state is associated with dreaming.1
Usually there is also a loss of muscle tone, but in a person with RBD the normal paralysis is incomplete or absent. RBD is characterised by the acting out of dreams that are intense.
RBD is seen in older men. Its prevalence in the population is estimated as 0.5 per cent.2
Over half of chronic cases are idiopathic. A large proportion of the other cases constitute an acute form associated with alcohol or sedative withdrawal. RBD can be a feature of neurological conditions such as Parkinson's disease (PD).3
A typical history, lack of drug involvement and normal neurological examination are sufficient to diagnose idiopathic RBD. However, patients may undergo polysomnographic video recording in a sleep study centre for research or diagnostic purposes, to differentiate RBD from sleep-related seizures.2
People with RBD risk injuring themselves or their sleeping partners. Practical steps can be taken to adapt the sleeping environment, such as removing superfluous objects and placing padding around the bed.2
Clonazepam taken at night (0.5mg initially increasing to 1mg if necessary) relieves symptoms in the majority of people. SSRIs can induce or aggravate RBD and should be avoided.2
- Dr Topp is an F2 doctor on a GP rotation based in Woking, Surrey
|Key Points about RBD|
1. eMedicineHealth (2009) REM sleep behaviour disorder www.emedicinehealth.com/rem_sleep_behaviour_disorder/article_em.htm (Accessed 6 September 2009)
2. Gagnon JF, Postuma RB, Montplaisir J. Update on the pharmacology of REM sleep behaviour disorder. Neurology 2006; 67: 742-7.
3. Postuma RB, Lang AE, Massicotte-Marquez J, Montplaisir J. Potential early markers of Parkinson disease in idiopathic REM sleep behaviour disorder. Neurology 2006; 66: 845-51.