What sleep disorder might present as excessive daytime sleepiness in a child?

Excessive daytime sleepiness in a child can be attributed to narcolepsy, which is a neurological condition that affects the brain's ability to regulate sleep-wake cycles. Narcolepsy is characterized by an overwhelming tendency to sleep during the day, which can occur even after a full night’s sleep. Children with narcolepsy may experience cataplexy—sudden loss of muscle tone triggered by strong emotions—or other symptoms such as vivid dreams and sleep paralysis.

Narcolepsy stands out as a cause for excessive daytime sleepiness because it directly disrupts the normal sleep architecture, leading to unrefreshing sleep and an inability to maintain wakefulness throughout the day. While conditions like obstructive sleep apnea can also lead to daytime sleepiness due to disrupted nighttime breathing, narcolepsy presents a more classical syndrome specifically associated with excessive sleepiness, sometimes independent of other sleep disruptors.