Serotonin syndrome occurs as a result of an excess of serotonin in the body. Typically this problem occurs in people who take certain medications, but it is also possible that the problem arises from the use of certain drugs. Overall, patients with serotonin syndrome have a good prognosis when treated - so what conditions should lead to the suspicion that the patient has developed serotonin syndrome?

Serotonin syndromeis an example of one of the possible drug syndromes. It can appear in basically every human being, both in a child and an adult. The exact prevalence of serotonin syndrome is unknown as some cases are simply overlooked.

According to available studies, it is estimated that serotonin syndrome may develop in up to about 15% of patients who overdose on drugs from the group of serotonin reciprocating inhibitors (SSRIs). Taking too much of the above-mentioned preparations is one of the possible, but definitely not the only causes of serotonin syndrome.

Serotonin Syndrome: Causes

As the name suggests, one of the neurotransmitters, serotonin, plays a role in the pathogenesis of serotonin syndrome, or more precisely, the problem occurs in the case of an excess of serotonin in the body. In the case of excessive stimulation by this neurotransmitter, serotonin 5-HT2A and 5-HT1A receptors (especially those that are present in the structures of the central nervous system), patients may develop the serotonin syndrome.

The main cause of serotonin syndrome is the use of drugs that lead to an increase in the amount of serotonin in the nervous system. The classic example of them are the above-mentioned SSRIs (e.g. fluoxetine, sertraline or escitalopram), in addition to them, drugs with a similar, but different mechanism of action, such as serotonin and noradrenaline reuptake inhibitors (SNRIs) can also lead to an increase in the amount of serotonin in the CNS. e.g. venlafaxine), tricyclic antidepressants (e.g. amitriptyline, clomipramine) or monoamine oxidase inhibitors (MAO-I, e.g. selegiline or moclobemide).

The above-mentioned preparations, included in the group of psychotropic drugs, are used, among others, in in depressive disorders - one of the suspected onesthe causes of these disorders are the deficiency of serotonin in the nervous system and it is for this reason that drugs increasing the amount of this neurotransmitter would improve the condition of patients.

Therefore, it can be concluded that patients treated pharmacologically due to mental disorders are most at risk of developing serotonin syndrome. Such a hypothesis may be correct, but it should be emphasized that the serotonin syndrome can also be caused by the use of completely different preparations, which may also increase the amount of serotonin in the nervous system. We are talking about drugs such as:

  • cough suppressants (e.g. dextromethorphan)
  • antiemetics (e.g. ondansetron or metoclopramide)
  • preparations used in migraine headaches (triptans, e.g. sumatriptan)
  • painkillers (e.g. tramadol, pethidine or fentanyl)

Other preparations that much less often, but also can provoke the development of the serotonin syndrome, are antiretroviral drugs (e.g. ritonavir), neuroleptics (e.g. risperidone), mood stabilizers (such as lithium s alts) or even antimicrobial agents (e.g. linezolid) or L-DOPA used in Parkinson's disease.
Patients who use any of the above-mentioned drugs can first of all be reassured - with doses of these drugs appropriately selected for the patient's needs, the risk of developing the described units is really low. It increases drastically, for example, when the patient takes excessive doses of any of the above-mentioned drugs, or when the patient uses simultaneously various preparations that increase the concentration of serotonin in the structures of the nervous system (e.g. when the patient uses two agents from the group SSRIs, or in a situation where a patient chronically treated for depression with some SSRI suddenly - e.g. due to an infection - starts taking significant amounts of the antitussive dextromethorphan).

Serotonin syndrome - interestingly - is sometimes found in patients who have not taken any of the above-mentioned drugs themselves. We are talking about a situation in which this syndrome occurs in a newborn child: cases of this possibility have been recorded and have been seen in children of mothers who took some of the aforementioned preparations during pregnancy.

Not only taking certain drugs can lead to serotonin syndrome. It can also be caused by taking various drugs that ultimately increase the amount of serotonin in the nervous system - examples of such substances include LSD, cocaine, ecstasy andamphetamines.

Serotonin Syndrome: Symptoms

The hallmark of serotonin syndrome is that its symptoms develop rapidly - even within just a few hours. Generally, the symptoms of serotonin syndrome are grouped into three different categories:

  • Autonomic symptoms of serotonin syndrome

Among them, there are disorders such as: chills, increased sweating, increased heart rate, nausea, diarrhea and an increase in blood pressure. In addition to them, there is also a significant increase in the body temperature of patients - characteristic for serotonin syndrome - (fever in this unit can even exceed 41 degrees Celsius).

  • Serotonin syndrome symptoms in the form of mental problems

This group includes symptoms such as severe agitation, anxiety, hallucinations or hypomania. In the course of the individual, there may also be disturbances of consciousness in the form of both confusion and even coma.

  • Somatic symptoms of serotonin syndrome

This group includes problems related to the neuromuscular system, such as tremors, increased tendon reflexes, and the emergence of myoclonic movements and muscle stiffness in patients.

Over time (especially in the absence of treatment), patients may develop complications of serotonin syndrome. The risk of their occurrence is associated with both hyperthermia and prolonged muscle contractions. Among the complications of the unit, several dangerous phenomena are mentioned, such as:

  • metabolic acidosis
  • rhabdomyolysis (breakdown of muscle cells)
  • seizures
  • kidney failure
  • DIC (disseminated intravascular coagulation syndrome)

Serotonin syndrome: diagnosis

There is currently no test - for example in the form of a laboratory test - that would make a reliable diagnosis of serotonin syndrome possible. In the diagnosis of the problem, the main use is to find the compilation of symptoms characteristic of the serotonin syndrome, as well as obtain information that the patient was taking a substance before the appearance of these ailments that may lead to the serotonin syndrome.

Serotonin syndrome usually leads to the characteristic symptoms, however, doctors still have to perform a differential diagnosis of patients.

In the differentiation of the serotonin syndrome, the following are mainly taken into account:

  • Neuroleptic Malignant Syndrome
  • other drug-induced syndromes (e.g. sympathomimetic syndrome)
  • malignant hyperthermia
  • heat stroke
  • meningitis

Serotonin Syndrome: Treatment

Discontinuation of the medications that led to serotonin syndrome is of fundamental importance in the treatment of serotonin syndrome. Such a procedure may already be sufficient, but if the patient's condition does not improve despite the discontinuation of drugs, cyproheptadine therapy can be used (this preparation is an antagonist of 5-HT2A serotonin receptors).

In patients with serotonin syndrome, it is also important to control the various ailments associated with this individual. Benzodiazepine agents (e.g. lorazepam) may be administered to the patient to reduce over-agitation in the patient.

In the case of patients with high blood pressure and those with too fast heart rate, preparations such as esmolol or sodium nitroprusside can be administered.

It is also very important to control hyperthermia - for this purpose, patients can be cooled down by physical means (e.g. cold compresses), their body temperature can also be reduced by using medications that reduce muscle tension.

Patients may be surprised why the use of antipyretics to lower the body temperature of patients is not mentioned here. Well, this is not an oversight - in the case of serotonin syndrome, these drugs are simply not effective in combating fever.

Serotonin syndrome: prognosis

The good prognosis of patients who develop serotonin syndrome and are treated can be described as good. With appropriate therapy, the risk of death of a patient with serotonin syndrome is estimated to be less than 1%.

In addition, it is worth mentioning that patients' ailments may disappear very quickly, even within 24 hours of stopping their use of the drug (or medications), which led to the appearance of the serotonin syndrome.

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