Ciguatera fish poisoning is a passive fish poisoning, which is the most common worldwide. It occurs particularly from fish from the Pacific Ocean, Indian Ocean, or Caribbean Sea.
What is ciguatera fish poisoning?
Ciguatera fish poisoning is one of the passive types of poisoning. This means that the symptoms of poisoning are indirectly caused by the fish. These animals contain the neurotoxins maitotoxin and ciguatoxin, which enter the animal through the food chain. The consumed fish itself is non-toxic. Only if it ingests certain toxic substances through the food chain can poisoning symptoms be induced in the consumer. This type of fish poisoning therefore includes the well-known poisoning with the muscle meat of the Japanese delicacy fugu. Ciguatera fish poisoning is thus clearly distinguished from active fish poisoning, which is usually caused by a sting from a poisonous fish such as the rockfish or stingray. The symptoms from ciguatera fish poisoning can last for many weeks, but they are not life-threatening for a healthy adult.
Causes
Ciguatera fish poisoning is based in the toxic substances maitotoxin and ciguatoxin. These are neurotoxins that enter the body through eating fish. Since they are fat-soluble, they can be easily absorbed by the body. Furthermore, they are resistant to heat, so that they are not destroyed by cooking and frying the fish. The fish, which carries these toxins, is not poisonous by nature. The reasons for its toxicity can be found at the beginning of its food chain. On the coral reefs live numerous microorganisms, which are also called dinoflagellates. They contain the listed nerve toxins and serve as food for the fish. Thus, the animals ingest them and do not feel anything of the poisoning themselves. On the dinner plate, the toxic effects unfold for the human organism, so that ciguatera fish poisoning is caused.
Symptoms, complaints and signs
The symptoms and complaints of ciguatera fish poisoning are usually very characteristic and thereby often directly indicate the disease. The affected persons suffer thereby primarily from a very strong sweating and further from numbness or from disturbances of the sensitivity. Not infrequently, there is also a burning sensation on the tongue or even in the entire oral cavity, so that the ingestion of food or liquids is no longer possible without further ado. Likewise, those affected suffer from fever or chills and exhibit dizziness. Ciguatera fish poisoning also frequently leads to stomach or intestinal complaints, so that many affected persons also suffer from diarrhea and nausea. If ciguatera fish poisoning continues to be untreated, cramps in the muscles occur, resulting in very severe pain. The proper sensation of temperatures is also significantly reduced by this poisoning. Generally, those affected also suffer from a feeling of weakness and appear tired or listless. Ciguatera fish poisoning can be treated relatively well, however, so that there is usually no reduced life expectancy. Furthermore, caffeine or alcohol can have an exacerbating effect on the symptoms of ciguatera fish poisoning.
Diagnosis and course
As with other poisonings, the confirmed diagnosis of ciguatera fish poisoning is often challenging. It can usually be diagnosed with the help of classic symptoms such as reversal of hot and cold sensations, nausea, and vomiting. Taking the patient’s history is also important. For this purpose, the physician asks the affected person which fish have been consumed and where the consumption took place. The poison responsible can usually only be detected at immense expense in special laboratories. In most cases, the course of the disease is favorable and the prognosis is good. Consequential damage is not to be expected and the survival rate is 99%. However, the symptoms of ciguatera fish poisoning can last for many weeks. Ciguatoxins are among the most potent and dangerous neurotoxins. The toxins cannot be detected by their taste, odor, or texture, nor can they be destroyed by physical processes such as heating or freezing.For mild cases of poisoning in humans, as little as 0.1 microgram of toxin per kilogram of fish is sufficient. This alone can be understood as a complication in preventing such poisonings.
Complications
In mild cases of poisoning, nausea, diarrhea, and vomiting initially occur several hours after consumption. However, in sensitive individuals, symptoms may appear much earlier and much more severe. In addition, further complications are to be expected in particularly sensitive individuals. For example, there is often a severe burning of the oral mucosa and a sharp drop in body temperature in conjunction with a non-specific feeling of weakness. In severe cases of poisoning, complications in the form of long-term damage are also possible. In some patients, the nonspecific feeling of weakness lasts for months. In addition, those affected are physically less able to work under pressure and suffer from constant fatigue. Permanent damage to the nerves that transmit tactile and temperature stimuli to the brain is also possible. Current research suggests that regular consumption of alcohol and caffeine exacerbates chronic ciguatera and, upon renewed contact with the neurotoxin, intensifies the body’s response.
When should you see a doctor?
No antidote exists for the toxins that cause ciguatera fish poisoning. Nevertheless, if this disorder is suspected, a doctor should be consulted promptly so that the accompanying symptoms of poisoning can be optimally treated and complications prevented. The risk exists only after consumption of tropical fish, and unlike microbial contamination, it does not matter whether the fish was properly cooked, since the toxin is heat-resistant. Anyone who observes symptoms such as heavy sweating, dizziness, nausea and vomiting, diarrhea, burning in the mouth or muscle cramps after eating tropical fish should consult a doctor immediately. This also applies if initially only a slight stomach upset is observed, but suddenly the temperature sensation is disturbed. After ciguatera fish poisoning, there is often a reversal of temperature sensation. Warm water, for example, is then perceived as cold and vice versa. At the latest then a doctor should be consulted immediately. How dangerous the poisoning is also depends on a patient’s age, weight and general constitution. Some people notice only a slight malaise. If ciguatera fish poisoning is suspected, a doctor should be consulted as a precaution. In severe cases, emergency medical attention may need to be called.
Treatment and therapy
Treatment of ciguatera fish poisoning is primarily concerned with relieving the signs of illness caused by the poisoning. Since the condition is accompanied by frequent vomiting and diarrhea, fluids and electrolytes should be given to the affected person. A working antidote, on the other hand, does not exist. Therefore, the causative toxin cannot be combated, but only symptomatic treatment can be given. Apart from symptomatic treatment of this fish poisoning, acute therapy is possible. As part of this treatment, the affected person receives an infusion with the sugar-containing alcohol mannitol. This stimulates urine excretion so that the organism excretes the toxin to a greater extent. If ciguatera fish poisoning becomes life-threatening, the patient can be given plasma expanders as an infusion. These solutions increase the plasma volume from the blood. If ciguatera fish poisoning has only been present in the organism for a short time, pumping out the stomach also proves useful.
Outlook and prognosis
The prognosis of ciguatera fish poisoning is favorable. Passive fish poisoning should be distinguished from active fish poisoning in its prospects for cure. Since it is not the fish in its natural state that has a toxic effect on the human organism, there is normally no serious health risk to the affected person. Adult people with a healthy immune system and without other diseases experience symptoms of ciguatera fish poisoning for a few weeks. During this time, the ingested toxin is slowly removed by the organism and excreted. Afterwards, however, the patient is considered cured and is permanently free of symptoms. Depending on the severity of the poisoning, the healing process may be shortened or prolonged for the patient.Since complaints such as fatigue, tiredness and reduced performance frequently occur, the patient must take sufficient care of himself. For optimal healing, it is important that no further harmful substances are consumed. The body is busy dealing with the poisoning of the fish and should not be subjected to further challenges. Physical sequelae or persistent impairment have not been documented in ciguatera fish poisoning. The survival of the affected individual is not at risk despite the symptoms. At most, the good prognosis may be worsened by the development of a mental illness such as an anxiety disorder due to the experience.
Aftercare
One of the relatively common fish poisonings is ciguatera fish poisoning. This passive poisoning occurs preferentially during vacations due to the consumption of intrinsically nontoxic fish. The symptoms of poisoning are caused by toxins in the fish’s food. Since ciguatera fish poisoning usually does not cause any permanent consequential damage, follow-up care is in itself obsolete. However, it is still recommended because the associated secondary symptoms can last for several weeks or even months. In this respect, ciguatera fish poisoning should be taken seriously even without a threat to life and limb. However, it should not be confused with another passive fish poisoning: the fatal poisoning caused by the Japanese puffer fish fugu. Symptoms affecting the digestive tract are over after a few days. However, in certain pre-existing conditions, persistent accompanying symptoms of ciguatera fish poisoning may lead to follow-up care. Factors such as the severity of the ciguatera fish poisoning and the age of the affected person are decisive for the possible follow-up measures. If necessary, their pre-existing conditions also become relevant if they are subject to special monitoring. In blood pressure patients, for example, a drop in blood pressure or tachycardia lasting for weeks may lead to the need for further treatment measures. Concomitant symptoms such as persistent dizziness, muscle pain or cramps may require follow-up measures. The goal of treatment is to mitigate the longer-lasting after-effects of ciguatera fish poisoning. These can impair the ability to work. They diminish well-being for months in severe cases.
Prevention
Ciguatera fish poisoning can be prevented only to a limited extent, since the fish consumed are not themselves toxic species or it is due to food manipulation. In addition, the toxin is heat resistant, so boiling or frying it does not protect against poisoning. If poisoning is known to have occurred in others, fish from the contaminated region should not be consumed. Furthermore, the likelihood of contracting ciguatera fish poisoning increases if severe storms or tempests raged before the fish were caught.
This is what you can do yourself
Since ciguatera fish poisoning is produced by eating fish that are not poisonous in themselves, and the causative neurotoxins ciguatoxin and maitotoxin cannot be destroyed even by heating or any other method of preparation, direct prevention is not possible unless fish is completely eliminated from the diet. However, if cases of ciguatera poisoning have been reported in the region, abstinence from regionally caught fish is recommended. If, in addition to nonspecific symptoms such as vomiting and diarrhea, burning sensations in the mouth and numbness occur not only in the mouth but also in the face and hands and feet, these specific symptoms may indicate ciguatera poisoning after a meal of fish. After recognizing the symptoms, the most important self-help measure is self-initiated vomiting. If all the toxins have not been absorbed by the digestive tract by then, the residual amount will thus be eliminated naturally and the effects of the poisoning will be somewhat reduced. It is important to consume adequate fluids and electrolytes during the acute diarrhea phase, which usually subsides after one to two days, to avoid secondary health effects. To assist in the elimination of toxins from the body via the kidneys, consumption of diuretic foods or spices may be helpful and possibly shorten the duration of prolonged symptoms.
