1/5. narcolepsy in the older adult: epidemiology, diagnosis and management.narcolepsy is a disorder of impaired expression of wakefulness and rapid-eye-movement (REM) sleep. This manifests as excessive daytime sleepiness and expression of individual physiological correlates of REM sleep that include cataplexy and sleep paralysis (REM sleep atonia intruding into wakefulness), impaired maintenance of REM sleep atonia (e.g. REM sleep behaviour disorder [RBD]), and dream imagery intruding into wakefulness (e.g. hypnagogic and hypnopompic hallucinations). Excessive sleepiness typically begins in the second or third decade followed by expression of auxiliary symptoms. Only cataplexy exhibits a high specificity for diagnosis of narcolepsy. While the natural history is poorly defined, narcolepsy appears to be lifelong but not progressive. Mild disease severity, misdiagnoses or long delays in cataplexy expression often cause long intervals between symptom onset, presentation and diagnosis. Only 15-30% of narcoleptic individuals are ever diagnosed or treated, and nearly half first present for diagnosis after the age of 40 years. attention to periodic leg movements (PLM), sleep apnoea and RBD is particularly important in the management of the older narcoleptic patient, in whom these conditions are more likely to occur. diagnosis requires nocturnal polysomnography (NPSG) followed by multiple sleep latency testing (MSLT). The NPSG of a narcoleptic patient may be totally normal, or demonstrate the patient has a short nocturnal REM sleep latency, exhibits unexplained arousals or PLM. The MSLT diagnostic criteria for narcolepsy include short sleep latencies (<8 minutes) and at least two naps with sleep-onset REM sleep. Treatment includes counselling as to the chronic nature of narcolepsy, the potential for developing further symptoms reflective of REM sleep dyscontrol, and the hazards associated with driving and operating machinery. Elderly narcoleptic patients, despite age-related decrements in sleep quality, are generally less sleepy and less likely to evidence REM sleep dyscontrol. Nonpharmacological management also includes maintenance of a strict wake-sleep schedule, good sleep hygiene, the benefits of afternoon naps and a programme of regular exercise. Thereafter, treatment is highly individualised, depending on the severity of daytime sleepiness, cataplexy and sleep disruption. Wake-promoting agents include the traditional psychostimulants. More recently, treatment with the 'activating' antidepressants and the novel wake-promoting agent modafinil has been advocated. cataplexy is especially responsive to antidepressants which enhance synaptic levels of noradrenaline (norepinephrine) and/or serotonin. Obstructive sleep apnoea and PLMs are more common in narcolepsy and should be suspected when previously well controlled older narcolepsy patients exhibit a worsening of symptoms. The discovery that narcolepsy/cataplexy results from the absence of neuroexcitatory properties of the hypothalamic hypocretin-peptidergic system will significantly advance understanding and treatment of the symptom complex in the future.- - - - - - - - - - ranking = 1keywords = behaviour (Clic here for more details about this article) |
2/5. Diagnostic ambiguities in a case of post-traumatic narcolepsy with cataplexy.narcolepsy arising from trauma can present particular problems of differential diagnosis. In this case study presentation the patient suffered a head trauma, without unconsciousness, and began to experience unusual episodic behaviours. Symptom presentation differed from the typical clinical manifestations of idiopathic narcolepsy leading to an 8-year search for a definitive diagnosis. Key relevant aspects that led to diagnostic ambiguities were the order of symptom development, negative for the antigen HLA DR2, significance of the Multiple Sleep Latency Test (MSLT) mean sleep latency versus number of sleep onset rapid eye movement periods, the somewhat atypical features of cataplexy, the coexistence of sleep apnoea, and the mildness of the original head injury. It is argued that cases of post-traumatic narcolepsy should be considered in the context of their clinical development over time and that practitioners should be aware that this form of narcolepsy can differ from the typical clinical history of idiopathic narcolepsy.- - - - - - - - - - ranking = 1keywords = behaviour (Clic here for more details about this article) |
3/5. Symptoms of narcolepsy in children misinterpreted as epilepsy.Differentiating an epileptic seizure from some other paroxysmal event is a common challenge in clinical practice. Many paroxysmal events mimic epileptic seizures and misdiagnosis can have disastrous consequences. Incorrectly identifying an event as an epileptic seizure can lead to unnecessary investigations and instigation of inappropriate treatment regimes. We report five patients referred to regional Paediatric Neuroscience Centres for investigation of events initially suspected of being epileptic seizures. All five patients were subsequently diagnosed as having narcolepsy. Suspected diagnoses were absence epilepsy (four patients), generalized epilepsy with astatic seizures (two patients) and focal epileptic seizures (two patients). Diagnostic confusion arose because lack of responsiveness due to excessive sleepiness was mistaken for epileptic absences, and cataplexy was confused with a variety of seizure types. In each case, videotape recording of clinical events aided in making the diagnosis of cataplexy. At presentation, all five children had excessive daytime sleepiness with cataplexy. Following correct diagnosis and appropriate management, an improvement in symptoms was reported in all cases. narcolepsy/cataplexy should be included in the differential diagnoses of paroxysmal disorders, particularly if there are associated sleep symptoms or behavioural difficulties. It is important to take a sleep history when evaluating any disorder of the central nervous system.- - - - - - - - - - ranking = 1keywords = behaviour (Clic here for more details about this article) |
4/5. narcolepsy.The symptom of excessive sleepiness in children and adolescents does not necessarily cause great concern to families and professionals involved in their care. Children may deny the symptom and minimise the adverse effects. These factors contribute to an underdiagnosis of narcolepsy in this age group when clinical diagnosis is difficult as associated symptoms may not have appeared or are hard to elicit. In this paper three children whose difficult behaviour contributed to the presentation of their sleep disorder are described.- - - - - - - - - - ranking = 1keywords = behaviour (Clic here for more details about this article) |
5/5. Marked blood pressure fluctuations during narcoleptic attacks alternating with abnormal wakefulness: effects of treatment with clonidine.A middle-aged man was admitted to our department because of sleep-wake cycle disorders (alternating hypersomnia and sleeplessness), bipolar behavioural disturbances and marked fluctuations in blood pressure and heart rate. Neither evident precipitating stimuli nor an obvious cause for his illness were found. When tests that normally activate intrinsic autonomic responses were performed, two distinct circulatory patterns were recognized. During hypersomnia (phase A), cardiovascular reflex activity was blunted or abolished and orthostasis could not be maintained. The clinical, biochemical, behavioural pictures and the observed decrease in sympathetic outflow resembled the effects of clonidine administration. On the contrary, during sleeplessness (phase B) the autonomic pathways were functionally integral and orthostatic hypotension was not detected. The clinical, biochemical, behavioural features and cardiovascular overactivity closely mimicked the abrupt withdrawal syndrome encountered with clonidine. Three hypothetical mechanisms are advanced to explain this intriguing case as well as the acute and chronic relief of our patient's clinical problem following institution of clonidine therapy (phase C). The role played by central alpha adrenoceptors in integrating sleep-wake, cardiovascular and behavioural functions is also suggested.- - - - - - - - - - ranking = 4keywords = behaviour (Clic here for more details about this article) |