NARCOLEPSY IS a rare sleep disorder that causes a person to fall asleep suddenly and unexpectedly. A person with narcolepsy experiences an increase in daytime sleepiness, disturbed nocturnal sleep and episodes of cataplexy, meaning they suffer an abrupt loss of muscle tone.
Cataplexy is a symptom specific to narcolepsy, and occurs in some 70 per cent of patients with the disease. It causes sudden and transient loss of muscle tone on both sides of the body lasting less than two minutes and can be triggered by emotions such as laughter or anger.
The precise cause of narcolepsy is unknown, but may be triggered by a combination of genetic and environmental factors. It occurs when cells responsible for producing neuropeptides are destroyed in a part of the brain called the hypothalamus.
Diagnosis is by means of specialist sleep studies carried out in hospital.
Yesterday's report identified 22 cases of narcolepsy in children and adolescents aged from five to 19 related to the administration of Pandemrix vaccine. This vaccine was produced as a single flu strain vaccine in response to the emergence of the swine flu (H1N1) pandemic virus in 2009 and 2010. The authors report a significant 13-fold higher risk of narcolepsy in vaccinated compared to unvaccinated individuals; they say the absolute risk of narcolepsy was five cases per 100,000 vaccinated children and adolescents. These results are similar to ones reported by Scandinavian countries.
In spite of the real difficulties experienced by those affected, the link between the one-off flu vaccine and narcolepsy should not trigger an anti-vaccine overreaction among parents. The lessons of the MMR debacle, when immunisation rates plummeted, remain relevant.
