Pediatric Narcolepsy Symptoms Differ From Those of Adults, Review Finds

The clinical manifestations of symptoms experienced by children and adolescents with narcolepsy can differ from those seen in adults, presenting barriers to a timely diagnosis, according to a review published in Pediatric Neurology.¹

According to the review of published data, the neurological disorder, which is marked by excessive daytime sleepiness (EDS) and cataplexy, is rare in children but may be underrecognized or its symptoms misinterpreted as misbehavior or signs of another condition. Both children and adults experience EDS as frequent, extreme, and involuntary drowsiness, and they may or may not experience cataplexy—a sudden episode of muscle weakness.

In pediatric cohorts, the mean age of symptom onset is 9 to 10 years, and occurrence is rare in those younger than 5 or 6 years. Although the major symptoms of narcolepsy are similar between children and adults, the clinical manifestations may differ because of children’s developmentally related responses to sleepiness. For instance, children with narcolepsy may exhibit hyperactivity, irritability, inattention, and restlessness throughout the day, possibly in an attempt to counteract sleepiness. This clinical presentation can overlap with the symptoms of attention-deficit/hyperactivity disorder (ADHD).

Cataplexy is rarer in children than adults and can have symptoms that manifest differently. For instance, cataplexy symptoms of slurred speech, facial grimacing, and automatic behaviors (eg, scratching, touching oneself) are common in children but infrequent in adults. Children, but not adults, can also experience cataplectic facies, which are spontaneous and prolonged hypotonic attacks that cause facial, jaw, or eyelid weakness with tongue protrusion.

Diagnosis of pediatric narcolepsy is complicated not only by these differing symptoms but also by children’s limited ability to articulate and explain some symptoms, such as sleep paralysis. Additionally, the Multiple Sleep Latency Test that is used to diagnose narcolepsy does not have established normative values for prepubescent children, and other factors like comorbid sleep disorders can affect the test’s results.

Because the symptoms of pediatric narcolepsy can be misinterpreted, some young patients showing signs of EDS may instead be perceived as depressed or lazy, and cataplexy episodes can be mistaken for normal falls or clumsiness. Behavioral symptoms of EDS (eg, irritability, poor attentiveness, aggression, hallucinations) can be misinterpreted as signs of psychiatric or neurodevelopmental disorders such as ADHD, oppositional defiant disorder, or depression, which may be comorbid with narcolepsy in some patients, further complicating diagnosis.

The review also discussed the significant burden of illness (BOI) among children with narcolepsy, including the burden resulting from rapid weight gain and precocious puberty, which are both associated with the disorder. Although few reports of patients’ experiences with narcolepsy have been published, one study of patients 7 years and younger found that 90% were ashamed of their narcolepsy symptoms and 83% perceived their symptoms as keeping them from being accepted in school and social activities.²

“The emerging research on BOI of pediatric narcolepsy in children supports longtime clinical observations that narcolepsy is a particularly difficult condition for children and families to cope with, especially given the frequent long lag time to diagnosis and treatment, the lifelong nature of the disorder, uncertainty regarding natural history and prognosis, and limited treatment options in pediatric narcolepsy,” the review authors wrote.

They called for further research into the BOI of narcolepsy in children and adolescents, associations among components of that burden, the risk of self-medicating substance abuse, and potential implications for adults whose childhood narcolepsy was not recognized or treated appropriately.

References

1. Plazzi G, Clawges HM, Owens JA. Clinical characteristics and burden of illness in pediatric patients with narcolepsy. Pediatr Neurol. 2018;85:21-32. doi: 10.1016/j.pediatrneurol.2018.06.008.

2. Guilleminault C, Pelayo R. Narcolepsy in prepubertal children. Ann Neurol. 1998;43(1):135-142. doi: 10.1002/ana.410430125.