Qu'est-ce que le syndrome sérotoninergique et quelles en sont les causes ?

Qu'est-ce que le syndrome sérotoninergique ?

Sérotonine - also known as 5-hydroxytryptamine, or 5-HT - is a chemical that functions as a neurotransmitter to carry signals between nerve cells throughout your body. In the brain, serotonin helps to regulate humeur et la mémoire, mais elle joue également d'autres rôles importants tels que faciliter la digestion.

Serotonin's effect on mood is why it's often a target of medications that are used to treat santé mentale conditions. For example, increasing serotonin levels is the purpose of the class of antidépresseurs known as inhibiteurs sélectifs de la recapture de la sérotonine (SSRIs). However, it is possible for serotonin levels to become too high - so-called serotonin syndrome.

"Serotonin is a chemical which is naturally produced in the body and is required for nerve cells and the brain to function," says Dr Natasha Bijlani - consultant psychiatrist at the Hôpital Priory Roehampton Londres.

"Too much serotonin leads to the development of a set of potentially dangerous symptoms called serotonin syndrome. Serotonin syndrome usually occurs as a result of taking médicaments that cause high levels of serotonin to accumulate in the body," she explains. "Serotonin syndrome can be a life-threatening condition and should be regarded as a medical emergency. It requires immediate treatment."

ISRS antidépresseurs are the most commonly prescribed class of drugs for moderate to severe depression. They can be extremely effective, especially when used alongside other treatments like la thérapie par la parole.

However, serotonin syndrome can occur if someone overdoses on their antidépresseurs, ou s'ils prennent différents types d'antidépresseurs en même temps.

"SSRIs work by increasing the availability of serotonin in the brain and other parts of the body," explains Bijlani. "But if multiple ISRS are prescribed at the same time or used in conjunction with other serotonin-enhancing medications or substances, then the risk of serotonin syndrome is enhanced."

Recherche has shown that various types of antidepressant, including ISRS, serotonin and norepinephrine reuptake inhibitors (SNRIs), tricyclic antidépresseurs and monoamine-oxidase inhibitors (MAOIs), been linked to serotonin syndrome.

"Certains cas peuvent survenir après une seule dose d'un inhibiteur sélectif de la recapture de la sérotonine (ISRS). Cela peut également se produire lorsque la dose d'un médicament agissant sur les niveaux de sérotonine a été augmentée ou lorsqu'un nouveau médicament est ajouté, dit-elle. Certains compléments alimentaires et drogues récréatives ont également été associés au développement du syndrome de la sérotonine."

Illicit drugs such as cocaine, LSD, amfetamines and ecstasy can affect serotonin levels. Médicaments triptans used to treat migraines, and herbal supplements such as l'Hypericum perforatum, can also have an effect. On rare occasions, some over-the-counter températures froides les médicaments can also interact with antidepressants, which may risk increasing serotonin levels.

"Serotonin syndrome symptoms develop within six hours of initial use, change in dose or following overdose," says Bijlani. "Initial serotonin syndrome symptoms are usually mild and include diarrhée, shivering and feeling more anxieux, agitated and restless. Serotonin syndrome symptoms also include insomnie, récurrents, rigid muscles, mild fièvre and developing goosebumps."

Worsening serotonin syndrome symptoms lead to the development of increased heart rate and pression artérielle, dilated pupils, loss of muscle co-ordination and twitching, alongside heavy excessive and confusion.

"Signs of severe serotonin syndrome include high fever, crises, battement cardiaque irrégulier avec perte de connaissance et éventuellement un décès, » explique Bijlani.

Prescription medication such as ISRS should always be taken at doses recommended by your doctor.

"People should be made aware of the possible risk of sérotonine syndrome and what to do if they develop any of the signs and symptoms," says Bijlani. "One should never increase the dose of any medication, or take any additional medications or supplements, without talking to their doctor first."

Si vous pensez avoir un syndrome sérotoninergique, il est important de consulter un médecin le plus rapidement possible.

"Le syndrome de la sérotonine est considéré comme une urgence médicale. Les symptômes du syndrome de la sérotonine peuvent s'aggraver rapidement et entraîner des conséquences dangereuses,.

"Serotonin syndrome treatment involves monitoring for vital physical signs and stopping all medications that could be contributing to elevated serotonin levels," she adds. "It might involve managing agitation with suitable medication, reducing body température and the consideration of intensive-care treatment if severe serotonin syndrome has developed."