Diagnosis

The diagnosis of fish poisoning is usually based on the patient’s medical history. If symptoms in the gastrointestinal tract, such as diarrhoea, vomiting and abdominal pain, appear shortly after eating fish, it is possible to be ill with fish poisoning. The most common cause of fish poisoning is an infestation of the fish by bacteria.

To be sure, both the stool and possible remains of the fish can be examined in the laboratory. This also helps to find out the exact pathogen. If the affected person suffers massively, feels weak and has a rising body temperature, a blood sample with blood culture may also be necessary.

An indication of the presence of fish poisoning caused by botulinum toxin may be that canned fish have been consumed. The formation of the toxin is promoted by the airless environment. The botulinum toxin can be detected in the blood as well as in the stool.

Therapy

For most fish poisonings, especially those caused by bacteria and viruses, no special therapy is necessary. In most cases the symptoms disappear by themselves after a few days at the latest. The therapy is therefore symptomatic, which means that it does not fight the cause, but should alleviate the symptoms.

In the case of fish poisoning, this means treating the diarrhea and vomiting, the fever and possible pain. The problem with diarrhoea and vomiting is that it often leads to a loss of fluid and minerals. For this reason this has to be replaced.

If possible, you should drink a lot, water, tea or broth. In particularly severe cases, infusion treatment may be necessary to supply the body with sufficient fluid and minerals. Fever and pain can be treated well with antipyretic painkillers such as paracetamol, but ibuprofen is not recommended due to the side effects in the gastrointestinal tract.

To relieve abdominal pain, it may be helpful to adopt a supine position and place a knee roll underneath. This can reduce abdominal wall tension, which often reduces pain. Fish poisoning caused by toxins is often much more serious and sometimes even fatal.

Often treatment in an intensive care unit and artificial respiration is necessary. If fish poisoning caused by botulinum toxin is present, an antidote must be administered as soon as possible. This inactivates the toxin contained in the blood.

Through this treatment, the mortality caused by the botulinus toxin could be reduced from 90% to below 15%. In addition, the gastrointestinal tract should be emptied to remove the toxin that has not yet been absorbed into the bloodstream. Also in the case of fish poisoning by botulinum toxin, the symptoms of the affected person should always be treated.

Fish poisoning caused by the toxins of puffer fish must also be treated in hospital. If ciguatera poisoning is present, in addition to the gastrointestinal complaints, neurological symptoms can also occur, which can last for months despite therapy. The poison should be removed immediately.

To do this, vomiting is induced or a gastric lavage is performed, treatment with activated carbon to neutralize the toxin or with mannitol solution, which helps to eliminate the toxin from the body through urine. Here too, symptomatic treatment must always be carried out in parallel. The fish poisoning caused by the toxin of the puffer fish can be treated with activated carbon, artificial respiration is often necessary.

In case of fish poisoning, household remedies should only be used to a limited extent. In case of acute symptoms with severe diarrhea and vomiting, a visit to a doctor is essential. The loss of fluids and electrolytes must be compensated as much as possible.In the case of mild food poisoning in young immunocompromised patients, the symptoms can also be treated with home remedies.

Large quantities of drinking water, but also salty and energy-rich food, if tolerated, can help. Calf compresses and cool cloths on the forehead help against a possibly high fever. To calm the nausea, light massages of the abdomen and soothing teas, for example chamomile, ginger or thyme tea, can be effective. If you should still feel weak or if the symptoms persist for more than 3 days, a doctor must be consulted.