Botulism is an acute food toxicoinfection that develops as a result of ingestion of botulinum toxin into the human body. Infection occurs in an alimentary way, most often when eating canned food containing botulism spores. Botulism is characterized by damage to the nervous system as a result of blocking of acetylcholine receptors of nerve fibers by botulinum toxin, manifested in the form of muscle paralysis and paresis. The main danger of botulism is the development of complications such as acute respiratory failure and cardiac arrhythmias. Diagnosis of botulism is based mainly on the data of the anamnesis of the disease and the results of neurological examination.
Botulism is an acute food toxicoinfection that develops as a result of ingestion of botulinum toxin into the human body. Botulism is characterized by damage to the nervous system as a result of blocking of acetylcholine receptors of nerve fibers by botulinum toxin, manifested in the form of muscle paralysis and paresis.
Botulinum toxin is produced by the bacterium Clostridium botulinum – a gram-positive spore-forming rod, an obligate anaerobe. Adverse environmental conditions are experienced in the form of disputes. Clostridium spores can persist in a dried state for many years and decades, developing into vegetative forms when they get into optimal conditions for vital activity: temperature 35 C, lack of oxygen access. Boiling kills the vegetative forms of the pathogen in five minutes, the temperature of 80 C is maintained by the bacteria for half an hour. Spores can remain viable in boiling water for more than half an hour and are inactivated only in an autoclave. Botulinum toxin is easily destroyed during boiling, but it can be well preserved in brines, canned food and food products rich in various spices. At the same time, the presence of botulinum toxin does not change the taste of the products. Botulinum toxin is one of the most powerful toxic biological substances.
The reservoir and source of clostridium botulism is the soil, as well as wild and some domestic (pigs, horses) animals, birds (mainly waterfowl), rodents. Animals carrying clostridium are usually not harmed, the pathogen is excreted with feces, bacteria enter the soil and water, animal feed. Contamination of environmental objects with clostridia is also possible when decomposing the corpses of animals and birds with botulism.
The disease is transmitted through the fecal-oral mechanism by food. The most common cause of botulism is the use of canned products contaminated with pathogen spores at home: vegetables, mushrooms, meat products and salted fish. A prerequisite for the reproduction of clostridium in products and the accumulation of botulinum toxin is the lack of air access (tightly closed canned food). In some cases, infection with spores of wounds and ulcers is likely, which contributes to the development of wound botulism. Botulinum toxin can be absorbed into the blood, both from the digestive system and from the mucous membranes of the respiratory tract, eyes.
People have a high susceptibility to botulism, even small doses of the toxin contribute to the development of the clinical picture, but most often its concentration is insufficient for the formation of an antitoxic immune response. When poisoning with botulinum toxin from canned foods, cases of familial damage are not uncommon. Currently, cases of the disease are becoming more frequent due to the spread of home canning. Most often, botulism affects people from the age group of 20-25 years.
The incubation period of botulism rarely exceeds a day, most often amounting to several hours (4-6). However, sometimes it can take up to a week and 10 days. Therefore, monitoring of all people who ate the same food with the patient lasts up to 10 days. In the initial period of the disease, nonspecific prodromal symptoms may be noted. Depending on the predominant syndrome, gastroenterological, ocular variants are distinguished, as well as the clinical form in the form of acute respiratory failure.
The gastroenterological variant occurs most often and proceeds according to the type of food toxicoinfection, with pain in the epigastrium, nausea and vomiting, diarrhea. The severity of enteral symptoms is moderate, however, there is a dryness of the skin that does not correspond to the general loss of fluid, and patients often complain of a disorder of swallowing food (“lump in the throat”).
The initial period of botulism, proceeding according to the ocular variant, is characterized by visual disorders: blurring, flickering of “flies”, loss of clarity and decreased visual acuity. Sometimes acute hyperopia occurs. The most dangerous variant of the initial period of botulism is acute respiratory failure (suddenly developing and progressive shortness of breath, spreading cyanosis, cardiac arrhythmias). It develops extremely quickly and threatens to be fatal after 3-4 hours.
The clinical picture of botulism in the midst of the disease is quite specific and is characterized by the development of paresis and paralysis of various muscle groups. Patients have symmetrical ophthalmoplegia (the pupil is stably dilated, there is strabismus, usually converging, vertical nystagmus, drooping eyelid). Dysphagia (swallowing disorder) is associated with progressive paresis of the pharyngeal muscles. If initially patients experience discomfort and difficulty swallowing solid food, then with the development of the disease it becomes impossible to swallow liquid.
Speech disorders develop, passing through four stages sequentially. First, the timbre of the voice changes, hoarseness occurs as a result of insufficient moisture of the mucous membrane of the vocal cords. In the future, due to the paresis of the muscles of the tongue, dysarthria appears (“porridge in the mouth”), the voice becomes nasal (paresis of the muscles of the palatine curtain) and disappears completely after the development of paresis of the vocal cords. As a result of the disorder of the innervation of the laryngeal muscles, the cough impulse is lost. Patients may suffocate if mucus and fluid enter the respiratory tract.
Botulinum toxin promotes paralysis and paresis of facial muscles, causing facial asymmetry, dysmemia. In general, there is a general weakness, instability of gait. Due to paresis of the intestinal muscles, constipation develops. Fever is not characteristic of botulism, in rare cases subfebrility is possible. The state of cardiac activity is characterized by an increased pulse rate, some increase in peripheral blood pressure. Sensitivity disorders, loss of consciousness are not typical.
The most dangerous complication of botulism is the development of acute respiratory failure, respiratory arrest due to paralysis of the respiratory muscles or asphyxia of the respiratory tract. Such complications can lead to death. Due to the development of congestion in the lungs, botulism can provoke secondary pneumonia. Currently, there are data on the likelihood of complications of infection with myocarditis.
Due to the development of neurological symptoms, a patient with butulism needs to be examined by a neurologist. Specific laboratory diagnostics of botulism in the early stages of infection has not been developed. The basis for the diagnosis is the clinical picture and epidemiological history data. The toxin is isolated and identified using a biological sample on laboratory animals. In the midst of the disease, it is possible to determine the presence of the toxin in the blood using HGUF with an antibody diagnostic.
Pathogen antigens are detected using immunofluorescence analysis (ELISA), as well as RIA and PCR. The isolation of the pathogen by seeding feces does not carry significant diagnostic information, since there may be a development from the spores of the vegetative form of clostridium in the intestines of a healthy person.
If botulism is suspected, mandatory hospitalization is carried out in the department with the possibility of connecting a ventilator, in order to prevent and provide timely assistance in case of life-threatening complications. The first therapeutic measure performed on the first day of the disease is gastric lavage with a thick probe.
Botulinum toxin circulating in the blood of patients is neutralized by a single administration of polyvalent anti-botulinum serums by the method of Bezredki (after desensitization of the body). If a single administration of serum was not effective enough and after 12-24 hours the patient has a progression of neurological symptoms, the administration of serum is repeated.
The introduction of anti-botulinum human plasma is quite effective, but this drug is quite rare due to the short shelf life (no more than 4-6 months). Currently, anti-botulism immunoglobulin is used in the treatment of botulism. The complex of etiotropic therapy measures includes antibiotics prescribed to suppress the probable development of vegetative forms of the pathogen, as well as thiamine pyrophosphate and ATP. Hyperbaric oxygenation has a positive effect.
Otherwise, treatment is prescribed based on the severity of the course and symptoms. In case of acute respiratory failure, patients are transferred to artificial lung ventilation. Feeding of patients in case of formation of persistent dysphagia is carried out with liquid food through a thin probe, or transferred to parenteral nutrition. During the recovery period, physiotherapy has a good effect in terms of the speedy restoration of the functions of the muscular system.
The prognosis with a high dose of the received toxin and the absence of timely medical care can be extremely unfavorable, the mortality rate of such cases reaches 30-60%. The use of etiotropic treatment and intensive care methods in the development of severe complications significantly reduces the risk of death (up to 3-4%). In case of timely treatment, the disease ends with recovery with full restoration of functions in a few months.
Preventive measures against botulism imply strict adherence to sanitary and hygienic standards in the manufacture of canned food, sterilization of dishes for the preparation of long-term storage products. Fish and meat products should be preserved exclusively in fresh and thoroughly cleaned from soil particles. Preservation of overripe fruits is unacceptable. Canning at home should be carried out in strict accordance with the recipe with a sufficient concentration of salt and acid in a container open to oxygen.