Fish poisoning - causes, signs and therapy

Poisonings when eating fish

Fish poisoning is a special form of food poisoning that can occur after eating mussels, fish, crabs and other marine creatures. Fish poisoning poses a serious health risk, which in the worst case can lead to the death of those affected. In case of suspected fish poisoning, a doctor should be consulted immediately.

contents

• Poisonings when eating fish
• definition
• Causes and symptoms of fish poisoning
• Poisoning by ciguatoxins in food fish
• Fish poisoning by tetrodotoxin
• Bacterial infections
• diagnosis
• Treatment for fish poisoning

definition

In the strict sense, fish poisoning is to be understood as poisoning caused by poisons in marine food. These are also called Toxidrome or fish poisoning Toxidrome. Colloquially, however, the term "fish poisoning" is also used in gastrointestinal infections caused by bacteria in fish, shellfish and crabs, although this is actually not a poisoning. The fish poisoning is sometimes further divided into fish poisoning in the true sense and mussel poisoning.

Colloquially, bacterial infections caused by food fish also count as fish poisoning. (Image: Mike Richter / fotolia.com)

Causes and symptoms of fish poisoning

The fish poisoning manifests itself usually very quickly after the toxin intake by massive gastrointestinal complaints, such as abdominal pain, diarrhea, nausea and vomiting. Here, the symptoms of fish poisoning are very similar to those caused by infection with pathological microorganisms.

But the various toxins contained in marine foods (over 50 toxic substances are known here) can bring numerous other complaints. For example, saxitoxins, which are found in mussels or oysters among other things, are often associated with visual disturbances and, worst of all, fatal paralysis of the respiratory or cardiac muscles in addition to gastrointestinal complaints.

The actual source of the poison are certain algae (or unicellular organisms that live on them, so-called dinoflagellates), which are taken up by the mussels, whereby the toxins accumulate in the mussels. Saxitoxins can kill people as little as 0.2 milligrams in humans.

Poisoning by ciguatoxins in food fish

The so-called ciguatoxins are formed by special genera of dinoflagellates and then accumulate in the marine food chain. Higher doses of ciguatoxins are therefore found mainly in predatory fish that are at the bottom of the food chain.

In humans, the Ciguatoxine trigger a so-called Ciguatera, which can be accompanied by significant gastrointestinal discomfort, rash, a numbness or tingling in the limbs, discomfort of the lips and oral mucosa, paralysis and a disturbed temperature sensation.

The so-called Ciguatera is a very serious form of fish poisoning. Among other things, it leads to stomach pain, nausea and vomiting. (Image: Wellnhofer Designs / fotolia.com)

The Ciguatera is sometimes deadly. Not infrequently, sufferers over weeks - sometimes even for several months - suffer from the symptoms, especially at a hypersensitivity.

Fish poisoning by tetrodotoxin

A special form is the tetrodotoxin poisoning. Tetrodotoxin is also known as puffer fish poison and unfolds after eating a fatal effect on the nerve and muscle function. Already in the first hour after consumption, those affected show significant deficits, such as paralysis of the muscles, coordination and consciousness disorders.

Under certain circumstances, the paralysis also affects the respiratory muscles, which leads to the death of the patient if medical care is not provided. From a dose of 0.5 milligrams to one milligram, tetrodotoxin is fatal.

In addition to the toxins mentioned here, many other toxins, such as okadaic acid or azaspiracid, may be responsible for fish poisoning. In individual cases, therefore, a differentiated consideration must be made in order to ensure appropriate treatment of the patients.

Bacterial infections

Infections with pathological microorganisms in fish consumption are often due to a lack of compliance with hygiene regulations and / or interruptions of the cold chain. The germs can multiply excessively and lead after consumption to massive gastrointestinal complaints. However, they are much less threatening than the intoxication described above, as in addition to stomach pain, diarrhea, nausea and vomiting usually no further health problems occur.

In the worst case, however, the massive fluid loss can lead to dehydration of those affected, which represents a risk that should not be underestimated, especially for already weakened patients.

If the cold chain is interrupted, bacteria in the fish can multiply rapidly and cause unpleasant gastrointestinal complaints. (Image: coffeekai / fotolia.com)

diagnosis

Since the first symptoms usually occur relatively short time after consumption, the context is often easy to recognize also for laymen. However, the question remains whether pathological microorganisms or bacteria or toxins cause the symptoms. Potentially ingested germs can be detected by a stool sample, the toxins can be determined by means of a blood test.

Treatment for fish poisoning

The treatment generally aims first to balance the fluid loss. Intoxication may also require artificial respiration. Here, an attempt is then made to relieve the effect of the poison, but often there is no specific antidote available. For example, in the Ciguatera only a therapeutic relief of the symptoms can be achieved because no antidote is known.

In order to achieve the fastest possible removal of toxins from the organism, is also used in emergency medicine with activated carbon, which should help in the form of high-dose tablets to excrete the toxins found in the digestive tract. In the case of timely initiated care of the patients, the fish poisoning can usually be controlled and rarely leads to the death of those affected. However, this presupposes that there is immediate action in case of indications of fish poisoning. (fp, updated on 10/20/2017)
Specialist supervision: Barbara Schindewolf-Lensch (doctor)