Botulism

Introduction to botulism Botulism is an acute poisoning disease caused by eating food containing Clostridium botulinum exotoxin. This disease was first discovered in Wildbad in southern Germany in 1793. It is called meat after eating metabolites. Poisoning. "botulus" is the meaning of the Latin dachshund. In recent years, there have been four clinical types of botulism: ingestion botulism, infant botulism, traumatic botulism and inhaled botulism. Clinically, neurological symptoms are the main clinical manifestations, and the mortality rate is high. basic knowledge The proportion of illness: 0.23% Susceptible people: no special people Mode of infection: non-infectious Complications: respiratory failure pneumonia

Cause of botulism

(1) Causes of the disease

Clostridium botulinum was first isolated from van Ermengen in a food poisoning incident in Belgium in 1897. The bacteria were 2 to 4 m long and 0.5 to 2 m wide. The bacteria had 4 to 8 flagella and could move. The capsule grows in an anaerobic environment and is easy to form spores. The young bacteria are positive for Gram staining, and the old bacteria are negative after the formation of spores. The bacteria are widely found in nature, and the soil, vegetables and fruits are in the form of spores. In cereals, it can also be found in animal feces. The spores are heat-resistant. They are still active after boiling for 6 hours. It takes 20 minutes to be killed after autoclaving at 120 °C. It can be killed after drying at 180 °C for 5 to 15 minutes. The agent is not sensitive, 5% phenol or 20% formaldehyde solution for 24h, 10h hydrochloric acid solution can kill in 1h, Clostridium botulinum toxin is an exotoxin secreted by Clostridium botulinum, its essence is polypeptide, according to the antigenicity of exotoxin Differently, it is currently divided into eight types: A, B, C (Ca, Cb), D, E, F, and G. The main causes of illness are A, B, E, F, and G. Type C, D type mainly causes wild water birds, cattle, horses, ducks, chickens and leeches. Known chemical poisons and biological poisons, Clostridium botulinum toxin is extremely toxic, and the lethal dose to humans is about 2 g, which is a neurotropic drug. The affinity for nerve tissue is the strongest, and the type E is the second, B. The type is weak, the toxin is resistant to stomach acid, but it is sensitive to heat. It can be destroyed at 80 °C for 30 min or 100 °C for 10 min. Under the condition of dry, sealed and dark and normal temperature, the toxin can be preserved for many years, so it is contaminated by Clostridium botulinum. The toxins in canned foods can maintain their toxicity for a long period of time. The toxins and their formaldehyde-treated toxoids are antigenic. Inoculated animals can produce anti-toxic serum and neutralize the same type of toxin.

(two) pathogenesis

Foods contaminated by human botulinum toxins cannot be destroyed by gastric acid and digestive enzymes. Since Clostridium botulinum toxin is present as a non-toxic precursor in the bacteria, it becomes active by its own activating enzyme. Toxin, enteric trypsin has an activation effect. Clostridium botulinum exotoxin is decomposed into small molecules by the proteolytic enzyme in the stomach and small intestine, and then absorbed into the blood circulation to reach the motor synapses and cholinergic nerve endings. It can be divided into two stages. In the first stage, the toxin reversibly binds to the surface of the nerve ending and can be neutralized by the corresponding antitoxin. In the second stage, the toxin is in the acetylcholine release site, and the adjacent receptor undergoes irreversible binding, thereby inhibiting the nerve. The release of the transmitter-acetylcholine makes the muscles unable to contract, causing the eye muscles, the pharyngeal muscles and the skeletal muscles of the body to remain in a state of paralysis. The pathological changes of botulism are non-specific, and the pathological changes may not reflect the degree of poisoning, because the poisoning is more Heavy, the faster the death, the tissue lesions are lighter, the autopsy occasionally sees the cerebral nucleus, the anterior horn of the spinal cord is degenerated, the meninges are congested, and the water Swelling, liver, spleen, kidney and other organs can be seen with congestion and small thrombosis. The age of onset of infant botulism is less than 6 months. The pathogenesis is different from the above, mainly because no toxins can be detected in foods consumed by infants. The faecal venom of the genus Clostridium and its toxins can be found in the children's feces, so it may be due to the inoculation of Clostridium botulinum spores or propagules. Although exotoxin is not contained, the bacteria in the intestines produce exotoxin and are absorbed by the intestinal mucosa. Symptoms appear afterwards.

Botulism prevention

1. Strictly implement the food management law. The preparation and preservation of canned food, ham and cured food should be carried out for hygiene inspection. For kippers, bacon and sausage, they must be steamed, cooked, fried, and eaten. Corrupted food, the top of the canned food may appear to be banned or sold.

2. It is forbidden to eat spoiled food.

3. Poisoning poisoning occurs in the same eater. Those who have not been diagnosed may consider taking multi-valent serum 1000-2000U for prevention and observation. Those who must eat canned food frequently in life may be vaccinated with Clostridium botulinum toxoid, 1ml. / time, subcutaneous injection, 1 time / week, a total of 3 injections.

4. During the war, the enemy may spread the botulinum toxin aerosol, or the botulinum toxin crystallizes the water source, and if necessary, the person concerned should be automatically immunized.

Botulism poisoning complications Complications, respiratory failure, pneumonia

Severe patients were not rescued in time for most deaths, and the mortality rate was 30-60%. The causes of death were mostly respiratory failure caused by medullary paralysis, cardiac insufficiency and secondary infection caused by aspiration pneumonia.

Symptoms of botulism poisoning Common symptoms Nausea, dizziness, sore throat, abdominal distension, fatigue, dizziness, diplopia, weakness, light reflex, disappearance, drooping, drooping

The length of the incubation period is related to the amount of toxins. It can be as short as several hours or as long as more than ten days. The shorter the incubation period, the heavier the disease, but the longer the incubation period can be severe, or the mild onset, then develop into a heavy, clinical The performance is different, the light is only mild discomfort, no treatment is needed, the severe one can be killed within 24 hours, the onset is rapid, the central nervous system symptoms are the main symptoms, early nausea, vomiting and other symptoms, general B type and E type than A Common types, followed by dizziness, headache, general malaise, blurred vision, diplopia, when the transmission of cholinergic nerves is impaired, visible constipation, urinary retention and decreased secretion of saliva and tears, physical examination found: mental stress, on The eyelids are drooping, the extraocular muscles are weak, and the eyeball function is reduced or disappeared. Some patients have unequal pupils on both sides of the pupil, and the light response is slow. In severe cases, the tongue, throat, and respiratory muscles are symmetric and flaccid, and chewing is difficult. Dysphagia, difficulty in language, difficulty in language, dyspnea and other cranial nerve damage, limb flaccid flaccid paralysis can be weakened and disappeared, but no pathological reflex, limb paralysis Less common, normal feeling, clear consciousness, no secondary infection, normal body temperature, botulism, once the symptoms appear, the disease progresses rapidly, the changes are obvious, severe cases may have respiratory failure, heart failure, or secondary pulmonary infection, if rescued If you don't arrive in time, you can die in 2~3 days. After the stabilization period, you will gradually enter the recovery period. Most of them will recover within 6-10 days. The elderly will be more than 1 month. Generally, breathing, swallowing and language difficulties will be relieved first, then the limbs will be relieved. The muscles gradually recover, the visual recovery is slow, sometimes it takes several months, the baby is poisoned by botulism: the age is 4 to 26 weeks, mostly mixed feeding, and there is also simple breastfeeding. The initial symptoms are constipation, no milk, whole body. Soft, crying low, neck soft can not look up, followed by cranial nerve palsy, rapid progress, can be caused by respiratory paralysis, but also lighter, only abdominal distension, or difficult to detect constipation, fatigue, it should be vigilant Missed diagnosis or misdiagnosis, traumatic botulism: the incubation period from wound infection to symptoms of poisoning is about 10 to 14 days, the performance is the same as food poisoning, but no nausea, vomiting, etc. Intestinal symptoms, may have fever, toxemia performance.

According to the history of special diet and the incidence of the same meal, combined with clinical manifestations of symptoms such as dry throat, constipation, blurred vision and central nervous system damage, it is generally not difficult to make a diagnosis. The detection of bacteria can only be used as an auxiliary basis. The diagnosis of toxins is confirmed by culture. The diagnosis of infant botulism is mainly based on the detection of Clostridium botulinum or Clostridium botulinum toxin in the feces of the children. The blood toxins may have been combined and are not easy to detect. Traumatic botulism , mainly to detect Clostridium botulinum or serum toxins.

Botulism poisoning check

1. Pathogen examination After heating suspected food, vomit or excrement for 20 minutes, inoculate blood agar for anaerobic culture, detect pathogenic bacteria, poisonous botulism, find toxins in serum or from wounds Isolation and culture of botulinum under anaerobic conditions can be clearly diagnosed. Infant botulism needs to be differentiated from sepsis, congenital muscular dystrophy, spinal muscular atrophy, hypothyroidism and benign congenital muscle tone. The botulinum toxin is found in the stool or the bacterium can be diagnosed.

2. Toxin test

(1) Animal test: The test specimen leaching solution is fed to the animal, or the guinea pig, the white mouse is injected intraperitoneally, and the control group is set at the same time, the specimen treated by heating at 80 ° C for 30 min or the mixed botulinum antitoxin is added to the specimen, such as The limbs of the experimental group died of limb paralysis, while the control group did not, the diagnosis of the disease was established.

(2) Neutralization test: 0.5 ml of each type of antitoxin serum was injected into the peritoneal cavity of the mouse, and then 0.5 ml of the specimen was inoculated, and a control group was set at the same time to judge the toxin and the stereotype.

(3) Avian eye inoculation test: The toxin containing toxin is injected into the lower eyelid of the poultry's eye from 0.1 to 0.3 ml depending on the size of the bird. The eyelids are closed, or paralytic convulsions and dyspnea appear. Death to several hours can be used as a quick diagnosis.

3. EMG examination has muscle fiber fibrillation, single stimulation response is reduced, multiple repeated stimulation potentials are increased, short-term duration wavelet amplitude multi-phase movement, increased potential and other characteristics, which is helpful for the diagnosis of this disease.

Diagnosis and identification of botulism

Botulism can be confused with Guillain-Barré syndrome, stroke, vaginal paralysis, and poisoning caused by arrow poison or belladonna alkaloids. EMG examination is helpful for diagnosis because in most patients Can produce a characteristic enhanced response to rapid repetitive stimuli, early due to dry throat, red, pain, should be differentiated from pharyngitis; vomiting, abdominal pain, constipation, should be differentiated from intestinal obstruction, intestinal paralysis; mucosal dryness, pupil dilation should be Atropine or mandala poisoning identification; also need to identify with food poisoning caused by pufferfish or grass mites, these two kinds of biological food poisoning can also produce symptoms of nerve paralysis, but puffer fish poisoning is finger numbness, heavy For quadriplegia, obvious weakness and needless differentiation with multiple neuritis, myasthenia gravis, diphtheria and nerve palsy, polio.

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