Narcolepsy is classified as a neurological disorder which is characterized by excessive daytime sleepiness. In children, narcolepsy with its recurring episodes of ‘sleep attacks’ can lead to social as well as academic dysfunction.
Narcolepsy syndrome (NS) features vivid pseudo-dream experiences just before sleeping or upon awakening, referred to as hypnagogic and hypnopompic hallucinations, respectively.
NS also presents with cataplexy, which is an abrupt and unexpected loss in muscular tone as a reaction to strong emotions.
Narcoleptic children often have an ongoing struggle to avoid somnolence and may fall asleep in unusual places and at unpredictable times.
Causes
The etiology of narcolepsy is poorly understood. However, disruption in the neurological pathways responsible for controlling wakefulness and sleep are thought to be involved.
Deficiency of orexins, which are neuropeptides also known as hypocretins and found in the lateral hypothalamus, is believed to play a major role in the pathogenesis of narcolepsy.
These neurochemicals were discovered in 1998. Evidence has linked pathological changes in the genes responsible for encoding orexin receptors or ligands to narcolepsy. Animal models were used to identify that orexin deficiency was enough to induce narcolepsy.
There is no gender bias with narcolepsy, because equal numbers of girls and boys tend to be affected. While the condition is often seen in young children, most reports are first made in the adolescent and young adult populations, between the ages of 15 – 25 years.
This is mostly because symptoms associated with narcolepsy can be nonspecific and can be easily mistaken for other disorders, such as epilepsy and attention deficit hyperactivity disorder (ADHD). Misdiagnoses, as a result, lead to a significant delay in identifying narcolepsy.
Based on several studies involving narcoleptic patients, there is a wide range in the age of onset. The youngest reported age of onset and/ or diagnosis is 2.1 years.
There is a peak at the age of 14 years and patients have also been diagnosed when well into middle age.
In one study, approximately 3 out of every 10 participants were diagnosed before their 15th birthdays. 16% and 4.5% of those surveyed were diagnosed before the ages of 10 and 5 years, respectively.
Signs and Symptoms
Excessive sleepiness during the daytime, cataplexy, sleep paralysis, and hypnagogic hallucinations are the four most common narcoleptic signs and symptoms.
A child constantly falling asleep in the day, for example during class, while eating, or in the middle of a chat, is typically showing one of the first warning signs of narcolepsy.
Narcoleptic children may tell their parents, guardians or teachers that they are feeling tired all the time.
It is important to note that sleepiness in these children may often cause them to have an increase in activity rather than a decrease. This is often accompanied by aggression and irritability.
Cataplexy may not be seen in all narcoleptic patients, and may take several years before becoming apparent. Furthermore, it can take on varying forms of intensity.
It is considered mild if the child experiences weakness in the lower extremities, especially buckling of the knees.
If it is more intense, then the child may collapse owing to his or her inability to maintain an upright posture. Injury may occur, but it is extremely rare.
Sleep paralysis is the loss of the ability to control the muscles when either waking up or falling asleep, whereas hallucinations may involve sounds or images that are typically frightening.
Further Reading
Idiopathic hypersomnia may not be as rare as previously thought