Under the Mytilismus the medicine understands a mussel poisoning. Symptoms can also appear in the nervous system and on the skin in addition to the gastrointestinal tract. The treatment of mussel poisoning is symptomatic, as there are no antidotes.

What is mussel poisoning?

Mytilism is a poisoning caused by the consumption of mussels. This mussel poisoning can be divided into four different forms:

  • central nervous form
  • neurotoxic form
  • diarrheal form
  • paralytic form.

The subforms are characterized by different guiding symptoms and may possibly merge into each other. In individual cases, the particular form of poisoning can occur only with diffuse boundaries to the other three forms.

Sometimes, instead of the four mentioned, only three forms of mussel poisoning are distinguished. This classification refers primarily to refer to the anatomical system in which the symptoms of intoxication occur. Neurotoxic form is distinguished by this scheme allergic and gastrointestinal form. Usually, the triggering toxins enter the mussels via the water and the food chain. In oysters, however, body toxins are produced during the spawning season. Also putrefaction in mussels can cause poisoning.


Mussel poisoning is mainly due to the consumption of mussels and mussels. Symptoms of intoxication are even less common after oysters have been consumed. In neurotoxic poisoning, the symptoms of intoxication are caused by neurotoxins. Dinoflagellates, for example, form saxitoxin in plankton. The mussels accumulate this substance during the planing filtration in the meat. Red and diatoms, on the other hand, produce domino acids and are also part of the food chain of various mussels.

The diarrheal form is caused by okadaic acids. Brevetoxins also occur as toxins in mussels and can thus also be the cause of mussel poisoning. Some mussel poisoning is caused by the decay products that form in no longer fresh mussels. These decay products cause in humans especially gastrointestinal complaints. Incidentally, it is a widespread misconception that toxins like the ones mentioned boil off or can be washed off.

Symptoms, complaints & signs

The symptoms of mussel poisoning differ with the causative toxin and its dosage. In the gastrointestinal form, the decay products of the mussels cause gastrointestinal complaints, the severity of which depends on the dose and age of the mussels. Diarrhea and vomiting are the main symptoms. Chills can be accompanied by it. Allergic mussel poisoning usually causes harmless rashes.

The paralytic form of neurotoxins is characterized by globes in the throat, sensations of discomfort and paralysis. Also movement disorders and speech disorders occur. The body temperature of patients sometimes increases life-threatening and anxiety sets in and disturbances of consciousness occur. In the central nervous form, breathing difficulties are present. The paralytic form is the most severe form of mussel poisoning and can cause respiratory or cardiac arrest.

Diagnosis & disease course

The doctor makes the diagnosis of mytilism mainly through the history. The local occurrence allows the physician to assess the likelihood of the different forms of mussel poisoning. The clinical picture is relatively typical in fish and shellfish poisoning. The differential diagnosis between the different forms of poisoning is, however, often associated with problems in individual cases.

The detection of certain toxins in shellfish is considered to be diagnostic, but can rarely be provided. The course of the poisoning depends strongly on the respective toxin and the severity. Life-threatening processes can occur especially in the paralytic form. For the other forms, the prognosis is usually more favorable.


As a result of mussel poisoning can lead to serious physical complaints. Usually, side effects such as diarrhea and vomiting or chills occur which, if left untreated, can lead to dehydration and circulatory problems. In severe cases, mussel poisoning can cause speech disorders and movement disorders. Sometimes the body temperature rises to life-threatening and it comes to anxiety and disorders of consciousness.

In the central nervous form, respiratory distress may occur, in the paralytic form respiratory and cardiac arrest. Rarely, a Toxi infection can occur in the course of which it can come to blood poisoning. Above all, people who are already physically weak or severely stressed are at risk for such complications. For example, pregnant women, the elderly, infants, patients with weakened immune systems and other risk groups.

When treating mussel poisoning, prescribed medicines may cause intolerance and allergic reactions. Many antibiotics cause gastrointestinal complaints, skin rashes and physical discomfort. In the context of commonly prescribed occupational therapy, it may come to about a physical overload or the already weakened immune system is overloaded. As a rule, a mussel poisoning can be cured without major complications, provided that it is detected and treated early.

When should you go to the doctor?

If the person experiences severe discomfort, nausea or vomiting immediately after or while eating mussels, consult a doctor. With sweats, a pale complexion and a sharp drop in blood pressure, a doctor is needed. In acute cases, an ambulance service should be alerted since the person concerned must be treated immediately with intensive care. Otherwise, a mussel poisoning threatens premature death.

Severe diarrhea, stomach pain and cramps are further signs of an irregularity. If there is an increase in body temperature, a feeling of internal heat or dizziness, consult a doctor. Sudden changes in the appearance of the skin, itching or discomfort on the skin should be examined and treated. There is also need for action in case of paralysis or respiratory complaints. If there is a failure of the respiratory activity or a sudden loss of consciousness, an emergency physician is also to be alerted. In order to ensure the survivor's survival until it arrives, first-aid measures must be taken by those present at the same time.

If the symptoms mentioned occur after or during a visit to a restaurant, a doctor's visit is also necessary. In some cases, cooks use clams to refine or season a prepared meal so that leftovers or minuscule portions of the clam meat are processed in a menu without the knowledge of the person concerned.

Treatment & Therapy

Mytilism can not be treated causally, but only symptomatically. For example, if there is respiratory distress, a patient's oxygen supply may be indicated. Symptoms of the gastrointestinal tract may cause dehydration. If necessary, this dehydration is rebalanced by the intravenous administration of fluid.

To drain the toxins from the body as quickly as possible, the water balance should be kept relatively high. The excretion of toxins with the urine is stimulated in this way. If dermatological symptoms occur, the itching is relieved by ointments and compresses. Anxiety can be alleviated by the targeted use of tranquilizers.

However, the condition of the cardiovascular system plays a decisive role, as it may lead to heart failure in the absence of consideration. Gastric emptying is usually no longer effective when the first symptoms appear, as the toxins are already absorbed into the blood within two to five hours. If paralyzes have come to an end that do not resolve themselves within the next few days, physiotherapy treatment may be indicated to regain mobility.

Ergotherapy can also make sense in this context. If persistent speech disorders are present, then usually a speech therapist is drawn.

Outlook & Forecast

The prediction of mussel poisoning depends on the exact toxin, the site of action and the dose. Many mussel poisonings are considered harmless. Thus, poisoning that affects only the digestive tract, usually well survived. Dangerous here is possibly the dehydration due to diarrhea. Permanent damage is not to be feared in this form of mytilism. This form of poisoning is mostly caused by okadaic acid.

In other forms of mussel poisoning, the prognosis is much worse. Domoic acid, ciguatoxin and saxitoxin are much more dangerous and may cause respiratory or circulatory problems. There is also the possibility for those affected to survive the poisoning despite serious symptoms. In other cases, the condition can be life-threatening, which is especially the case of high doses of poison. In these cases, poisoned persons must be treated as quickly as possible. With increasing duration of poisoning without help and treatment the mortality rate increases.

A treated and survived mussel poisoning leaves no consequential damage. Complete recovery from transient physical debility is usually the result. It should be remembered that mussel poisoning has nothing to do with the immune system and can occur again and again.


The mussel poisoning can be prevented. Mussels from impure waters should not be consumed, for example. Basically mussels should always be placed in pure water before consumption to detoxify their toxins. In the summer months a general renouncement of mussels is advisable, because in the warm season many algae form and mussels come in the summer increasingly with their toxins into contact.


Since a mussel poisoning is associated with a serious course of infection of the gastrointestinal tract, a final, complete recovery of the patient takes a few weeks. During follow-up care, the patient should be mindful of the right choice of stomach and intestinal food. The preparation of the food should be done during this time very gently and gastro-intestinal relieving.

Foods with an increased risk of germs, such as raw meat, raw foods or fish, should be avoided. As part of the post-treatment, a gastrointestinal rehabilitation is advisable. This is usually done with the help of preparations containing live lactic acid bacteria, which are used to stabilize and build a healthy intestinal flora for several weeks. Since the immune system and the gastrointestinal tract have been weakened and impaired, the organism is very susceptible to further infections and diseases caused by bacteria and germs.

The follow-up visits to the attending physician may therefore be promptly made as a result of renewed gastrointestinal complaints. If diarrhea occurs again, the patient's chair should be examined by laboratory. By means of follow-up examinations, the doctor will diagnose whether or not the mussel poisoning has developed into gastritis. This would then be treated accordingly medically and medically.

You can do that yourself

There is no antidote to mussel poisoning. Self-help measures must therefore focus on the prevention and treatment of the individual symptoms. If mussels cause gastrointestinal problems, this is mostly because the foods were not really fresh when they were consumed and they have already been formed into putrefaction. If you cook mussels yourself, you should always buy them fresh and use them the same day. However, certain symptoms of intoxication result from neurotoxins that accumulate the mussels in their flesh. There is little room for preventative measures here. However, this phenomenon is less common in oysters than in other types of mussels. So if you do not want to do without it completely, you can reduce the risk of neurotoxic poisoning by eating only oysters and avoiding mussels and mussels.

Nausea, diarrhea and vomiting are usually rather harmless symptoms of mussel poisoning. In mild cases, these side effects can also be treated with over-the-counter medicines from the pharmacy. In addition, the sufferer should take time to rest and make sure that he balances the fluid loss that is often associated with diarrhea. In addition to water unsweetened tea or vegetable broth should be drunk. Since often the electrolyte balance is disturbed, the snacking of savory biscuits can be helpful.

If paralysis, speech disorders, anxiety, impaired consciousness or breathing difficulties occur, it is essential to see a doctor immediately. In this case, the patient is in danger of death, as severe forms of mussel poisoning can lead to respiratory or cardiac arrest.

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