Sleep complaints are common in pediatric patients with central nervous system (CNS) tumors. These problems may result from disruption of normal homeostatic, circadian, neuroendocrine, and cardiorespiratory pathways and vary by tumor location and treatment received. Children with tumors within the hypothalamus and surrounding regions are prone to excessive daytime sleepiness. Sleep-related breathing disorders, especially those involving abnormal control of breathing, may occur in patients with tumors of the brainstem and posterior fossa. Maintaining a high index of suspicion for sleep disorders in children with CNS tumors is essential for early recognition and treatment. In this article, we will review the various sleep problems reported in pediatric brain tumor survivors, explore underlying neurobiological mechanisms, and discuss approaches to screening and diagnosis.Sleep is an essential physiologic function for growth, cognition, and physical and emotional well-being. It is particularly important in childhood, when the brain and body are undergoing rapid development. Normal sleep occurs through a complex interplay between homeostatic, circadian, neuroendocrine, and cardiorespiratory pathways. Cancer and cancer treatment may cause disruptions and imbalances in these pathways, resulting in abnormal sleep. Compared to the general population, pediatric cancer survivors are more likely to experience sleep problems. Patients with a history of brain tumors are particularly prone to sleep issues. In this article, we will review the physiology of normal sleep, describe the sleep problems and pathophysiologic mechanisms behind disrupted sleep in children with central nervous system (CNS) tumors, and discuss strategies for screening, diagnosis, and management.
Sleep Mechanisms and PhysiologySleep and wakefulness. Sleep is fundamentally important in promoting growth, repair, and neurocognitive functioning. The timing, duration, and quality of sleep depend on complex, balanced interactions between sleep-promoting and wake-promoting pathways. The majority of these pathways are housed in the basal forebrain, diencephalon, and brainstem. The balance between sleep and wakefulness is governed by two distinct biologic processes: sleep-wake homeostasis (Process S) and circadian rhythm (Process C) [1]. Homeostatic drive to sleep intensifies with continued wakefulness over time and subsides as an individual sleeps. During the day, the sleep-dependent homeostatic drive is counteracted by sleep-independent circadian arousal mechanisms. Circadian rhythms are coordinated by an internal pacemaker housed in the bilateral suprachiasmatic nuclei (SCN) of the anterior hypothalamus [1]. The near-24 hour circadian rhythm is externally entrained by the light-dark cycle on Earth through direct input received by the SCN from retinal ganglion cells via the retinohypothalamic tract, which runs through the optic chiasm [2,3]. Additional input from the intergeniculate leaflet and median raphe nucleus modulate circadian phase shifts [3]. The SCN sends...