Hypersomnia due to acute disseminated encephalomyelitis in a 5-year-old girl

Narcolepsy with cataplexy and comorbid immunopathological diseases

Evidence suggests that autoimmune diseases tend to co-occur so that patients with an autoimmune disorder are at higher risk of a second autoimmune disease. The association between allergic and autoimmune diseases is also of considerable interest. There are no reports on the association between sporadic or familial narcolepsy with cataplexy and other non-neurological immune-mediated diseases. This study reported on the comorbid immunopathological diseases associated with narcolepsy. One-hundred and fifty six narcoleptic patients with a mean age at diagnosis of 39.1 ± 17.8 years (range, 6-70 years) were assessed using the clinical history, physical and neurological examinations, sleep questionnaires, neuroimaging and human leucocyte antigen typing. Diagnosis was confirmed by polysomnography followed by a multiple sleep latency test or by measuring hypocretin-1 levels. Patients with immunopathological diseases were matched for gender and age at the onset of narcoleptic symptoms with narcoleptic patients without immunopathological diseases. Twenty-six patients (16.6%; 50% women; one familial, 25 sporadic) had one or more immunopathological diseases associated: autoimmune diseases, such as idiopathic thrombocytopenic purpura, multiple sclerosis, systemic lupus erythematosus, psoriasis, Crohn's disease, ulcerative colitis, autoimmune thyroid disease, Peyronie's disease and idiopathic recurrent facial palsy; other immunopathological diseases, like atopic dermatitis, allergic asthma and allergic rhinitis. Although not significant, the age at diagnosis of narcolepsy was 9.3 years earlier in patients with narcolepsy + immunopathological diseases. The results demonstrate that the prevalence of comorbid immunopathological diseases is high in narcolepsy, and cataplexy is significantly more severe in patients with narcolepsy + immunopathological diseases.

Excessive daytime sleepiness and narcolepsy--an approach to investigation and management

Excessive daytime sleepiness is a common presentation to physicians both in general practice and hospital settings. In this review, we provide an update on the latest theories on the pathogenesis of the condition, and discuss the approach to investigation of the sleepy patient, with particular reference to narcolepsy. Recommended therapy is reviewed for both narcolepsy and cataplexy, to provide physicians with an important reference on the investigation and management of these troubling conditions.

Narcolepsy: immunological aspects

Narcolepsy with cataplexy is a debilitating sleep disorder with an estimated prevalence of about 0.05%. Narcolepsy is caused by a selective loss of hypocretin (orexin) producing neurons in the perifornical hypothalamus. Based on the very strong association with the HLA subtype DQB1*0602, it is currently hypothesized narcolepsy is caused by an autoimmune-mediated process directed at the hypocretin neurons. So far however, studies focusing on general markers of (auto)immune activation, as well as humoral immunity against the hypocretin system have not yielded consistent results supporting this hypothesis.

The percipient observations of Constantin von Economo on encephalitis lethargica and sleep disruption and their lasting impact on contemporary sleep research

The study, and the preceding companion article, reviews the pioneering contributions of Constantin von Economo (1876-1931) to Neuroscience in a modern context. The neurological studies of von Economo include the discovery of a new nosological entity, encephalitis lethargica, with which his name is forever linked ('von Economo disease'). Based on a percipient analysis of pathoanatomical material from patients with encephalitis lethargica who manifested with either insomnia or somnolence, von Economo deduced the existence of distinct centres in the brain for the regulation of sleep and wakefulness. He presented a synthesis of his ideas in a series of lectures in New York in 1929 and at the First International Neurological Congress held in Berne in 1931. Constantin von Economo was nominated three times for the Nobel Prize in Physiology or Medicine for the discovery of encephalitis lethargica. As those studies have exerted and continue to exert the highest impact among von Economo's publications, the present article examines the spectrum of his observations on encephalitis lethargica and the cerebral control of sleep, documented in 63 published works--including post-humous translations into French and English of original German texts; complete bibliographic information is given. His remaining 76 works of an annotated total of 139 scientific publications deal with brain structure, evolution and intelligence, as well as general works on nervous and mental pathology and form the focus of the preceding article.

Symptomatic narcolepsy, cataplexy and hypersomnia, and their implications in the hypothalamic hypocretin/orexin system

Human narcolepsy is a chronic sleep disorder affecting 1:2000 individuals. The disease is characterized by excessive daytime sleepiness, cataplexy and other abnormal manifestations of REM sleep, such as sleep paralysis and hypnagogic hallucinations. Recently, it was discovered that the pathophysiology of (idiopathic) narcolepsy-cataplexy is linked to hypocretin ligand deficiency in the brain and cerebrospinal fluid (CSF), as well as the positivity of the human leukocyte antigen (HLA) DR2/DQ6 (DQB1*0602). The symptoms of narcolepsy can also occur during the course of other neurological conditions (i.e. symptomatic narcolepsy). We define symptomatic narcolepsy as those cases that meet the International Sleep Disorders Narcolepsy Criteria, and which are also associated with a significant underlying neurological disorder that accounts for excessive daytime sleepiness (EDS) and temporal associations. To date, we have counted 116 symptomatic cases of narcolepsy reported in literature. As, several authors previously reported, inherited disorders (n=38), tumors (n=33), and head trauma (n=19) are the three most frequent causes for symptomatic narcolepsy. Of the 116 cases, 10 are associated with multiple sclerosis, one case of acute disseminated encephalomyelitis, and relatively rare cases were reported with vascular disorders (n=6), encephalitis (n=4) and degeneration (n=1), and hererodegenerative disorder (three cases in a family). EDS without cataplexy or any REM sleep abnormalities is also often associated with these neurological conditions, and defined as symptomatic cases of EDS. Although it is difficult to rule out the comorbidity of idiopathic narcolepsy in some cases, review of the literature reveals numerous unquestionable cases of symptomatic narcolepsy. These include cases with HLA negative and/or late onset, and cases in which the occurrences of the narcoleptic symptoms are parallel with the rise and fall of the causative disease. A review of these cases (especially those with brain tumors), illustrates a clear picture that the hypothalamus is most often involved. Several cases of symptomatic cataplexy (without EDS) were also reported and in contrast, these cases appear to be often associated with non-hypothalamic structures. CSF hypocretin-1 measurement were also carried out in a limited number of symptomatic cases of narcolepsy/EDS, including narcolepsy/EDS associated with tumors (n=5), head trauma (n=3), vascular disorders (n=5), encephalopathies (n=3), degeneration (n=30), demyelinating disorder (n=7), genetic/congenital disorders (n=11) and others (n=2). Reduced CSF hypocretin-1 levels were seen in most symptomatic narcolepsy cases of EDS with various etiologies and EDS in these cases is sometimes reversible with an improvement of the causative neurological disorder and an improvement of the hypocretin status. It is also noted that some symptomatic EDS cases (with Parkinson diseases and the thalamic infarction) appeared, but they are not linked with hypocretin ligand deficiency. In contrast to idiopathic narcolepsy cases, an occurrence of cataplexy is not tightly associated with hypocretin ligand deficiency in symptomatic cases. Since CSF hypocretin measures are still experimental, cases with sleep abnormalities/cataplexy are habitually selected for CSF hypocretin measures. Therefore, it is still not known whether all or a large majority of cases with low CSF hypocretin-1 levels with CNS interventions, exhibit EDS/cataplexy. It appears that further studies of the involvement of the hypocretin system in symptomatic narcolepsy and EDS are helpful to understand the pathophysiological mechanisms for the occurrence of EDS and cataplexy.

Hypersomnia and low cerebrospinal fluid hypocretin levels in acute disseminated encephalomyelitis

A 7-year-old Japanese female diagnosed as having acute disseminated encephalomyelitis presented seizures, visual symptoms, and hypersomnia with bilateral lesions in the white matter, basal ganglia, and hypothalamus. Her clinical findings and demonstrated lesions in neuroimages were similar to those of Von Economo's encephalitis lethargica. Her hypocretin, the hypothalamic neuropeptide controlling sleep-awake cycle, was significantly low in the cerebrospinal fluid (146 pg/mL) on admission. Successive measures resulted in the gradual recovery of cerebrospinal fluid hypocretin to the normal range (263 pg/mL) as her excessive daytime sleepiness was reduced. Decreased hypothalamic hypocretin neurotransmission may be involved in this symptomatic case of hypersomnia associated with acute disseminated encephalomyelitis.

Sleep in children with neoplasms of the central nervous system: case review of 14 children

OBJECTIVE

Sleep is a complex neurologic process that is generated by and primarily benefits the brain. Sleep can be disrupted by a wide range of brain injuries, many of which may occur in children with neoplasms of the central nervous system (CNS). The specific sleep problems that have been associated with brain injuries include sleepiness, apnea, insomnia, and loss of circadian rhythmicity. The objective of this study was to characterize the sleep problems seen in children with neoplasms of the CNS through a comprehensive clinical and objective sleep evaluation.

METHODS

A retrospective case series review was conducted of all children with neoplasms of the CNS referred to the sleep clinic for a clinical evaluation between 1994 and 2002. The sleep evaluation of the 14 children in this report included a sleep history, a sleep log, and a polysomnogram. In the 12 children with complaints of daytime sleepiness and/or fatigue, a multiple sleep latency test was performed the day after the polysomnogram. Three children also had a 2-week actigraphic study.

RESULTS

The most common sleep complaint in this group of children was excessive daytime sleepiness (EDS), present in 9 of the 14 children. In these children, the sleepiness was manifest by 1 or more of the following symptoms: 1) an increase in total sleep time per 24 hours; 2) the resumption of daytime naps that had been previously discontinued at a younger age; 3) an inability to awaken in the morning to begin the days activities; or 4) the inability to remain awake during activities of daily living, such as school. Of the 9 children with daytime sleepiness, 8 had brain tumors requiring neurosurgical procedures at the time of their diagnosis, 6 of whom required ventricular shunting. The children with the most severe sleepiness had evidence of hypothalamic/pituitary injury with deficiencies in both anterior and posterior pituitary hormones. Five of the children with EDS had polysomnographic evidence of symptomatic narcolepsy with rapid eye movement sleep present on 2 or more of the daytime naps. The symptoms of EDS were effectively controlled with modest doses of daytime stimulant medication and/or scheduled naps. Central apnea leading to respiratory insufficiency and requiring mechanical ventilation to correct was present in 2 children with tumors involving the medulla. Although snoring with possible obstructive sleep apnea was the reason for referral to the sleep clinic in 5 children, none of the children in this series had polysomnographic evidence of significant obstructive sleep apnea. The other sleep problems seen in these children were hypoxia in 2 children, fatigue in 3 children, and seizures during sleep in 1 child. The interval between tumor diagnosis and sleep evaluation varied from 0 months to 9 years (mean: 42 months). The treatment of the sleep problems of this group of children took many forms, including stimulants, scheduled naps, mechanical ventilation, supplemental oxygen, and anticonvulsants.

CONCLUSIONS

Brain injuries, which invariably are present in children with neoplasms of the CNS, may result in a variety of diagnosable and treatable sleep disorders. The sleep symptoms did not appear to be directly related to the specific therapy the child received, nor the presence of residual tumor. Rather, the primary determinant of the sleep symptoms was the area of the brain that was damaged, regardless of how the damage occurred. Children who sustained damage to the hypothalamic/pituitary region developed EDS regardless of whether the damage was the result of the tumor, surgery, hydrocephalus, or radiation to the whole brain or localized to the suprasellar area. The only children who developed respiratory insufficiency had an injury to the medulla. This observation is consistent with the view that sleep is a specific, albeit complex, neurologic process that is controlled by specific brain regions. EDS and respiratory insufficiency were the most commonly diagnosed severe sleep disorders in these children. The sleep problems of children with brain tumors may develop before, but more often soon after, their tumor diagnosis and treatment. However, the sleep symptoms may not be appreciated by medical providers until years after their onset, which may delay the beginning of effective interventions.

A case of acute disseminated encephalomyelitis presenting hypersomnia with decreased hypocretin level in cerebrospinal fluid

A 12-year-old girl was diagnosed as having acute disseminated encephalomyelitis and manifested hypersomnia as the main clinical feature. Magnetic resonance imaging (MRI) revealed lesions in the bilateral hypothalamus in addition to other multifocal brain lesions involving the cerebral white matter, brain stem, and basal ganglia. The level of hypocretin in cerebrospinal fluid was decreased in this patient. Corticosteroid treatment resulted in improvement of the hypersomnia and resolution of MRI lesions in the hypothalamus and other regions. This case suggests that the arousal state control mechanism related to the hypocretin peptide/receptor system may be impaired in some patients with acute disseminated encephalomyelitis.