Tetanus

Introduction to tetanus Tetanus is an acute infectious disease characterized by invasive human body wounds by Clostridium tetani, which grows and breeds under anaerobic conditions and produces neurotropic exotoxin which causes muscle tonicness in the whole body. Severe patients may die from a sore throat or a secondary severe lung infection. Neonatal tetanus is caused by umbilical cord infection and has a high mortality rate. Although the World Health Organization is actively pursuing a global immunization program, it is estimated that there are nearly a million cases of tetanus in the world each year, and hundreds of thousands of newborns die from tetanus. basic knowledge The proportion of illness: 0.001% Susceptible people: no special people Mode of infection: non-infectious Complications: pneumonia, atelectasis, pulmonary edema, sepsis, shock

Cause of tetanus

Local wounds (30%):

Tetanus is widely found in soil and human and animal waste. Both bacilli and their toxins cannot invade normal skin and mucous membranes. Therefore, tetanus occurs after injury. All open injuries such as inflammatory lesions, open fractures, burns, and even Small wounds such as thorns or rust spikes may cause tetanus. Tetanus is also seen in unsterilized umbilical cord stumps and unsanitary abortions in newborns; and occasionally after gastrointestinal surgery After removing the foreign body left in the body for many years, there is a tetanus in the wound, which is not necessarily the disease; the occurrence of tetanus is not only related to the strong virulence of the bacteria, the quantity, or the lack of immunity, but also the hypoxia of the local wound. A disease-promoting factor, therefore, when the wound is narrow and deep, ischemic, necrotic tissue, poor drainage, and mixed, tetanus is easy to occur, the calcium chloride contained in the soil can have other infections requiring oxidative pus Causes tissue necrosis when the wound is partially hypoxic, which is beneficial to the breeding of anaerobic bacteria. Therefore, the stab of the rust nail or the forest thorn with soil may cause tetanus.

Other factors (30%):

Clostridium tetani is a genus of anaerobic spores, obligate anaerobic, 2 ~ 5m long, 0.3 ~ 0.5m wide, has flagella around, can be active, Gram stain positive, but in the breeding process When examined by wound smears, it can be negative for Gram staining. Clostridium typhimurium breeds under anaerobic conditions, forms propagules and produces toxins, but is easily killed by disinfectant and boil. When environmental conditions are unfavorable, The spores are formed at the end of the bacteria, which are shaped like drums. The tetanus spores have strong resistance to the external environment. They can survive in the soil for several years and must be autoclaved to kill them. Tetanus exotoxin can be used. It is decomposed into ,, components by trypsin treatment, and their different clinical effects are called tetanospasmin, tetanolysin, and fibrinolysin. In addition to hemolysin can cause hemolysis and may lead to local tissue necrosis, the main cause of clinical symptoms is scorpion toxin, which is encoded by a plasmid with a molecular weight of 160×103 (two peptide chains: heavy chain 105×1) 03; light chain 55 × 103), heat-resistant, destroyed at 65 ° C for 30 min, its light chain is the toxic part, zinc endopeptidase; heavy chain (H chain) has binding and transport functions, Hc and Nc, the former can specifically bind to nerve cell surface receptors, the latter is conducive to the internalization of cells, allowing toxins to enter nerve cells.

Sympathetic inhibition (25%):

Clostridium tetani has no invasiveness, does not invade the blood circulation, and only grows in local wounds. Its pathogenic effect is mainly caused by the produced exotoxin. Exotoxin mainly invades the spinal cord and brainstem motor neurons. Once combined with nerve cells, Can not be neutralized by tetanus antitoxin, after the invasion of local wounds by Clostridium typhimurium spores, generally does not grow and multiply, such as a suppurative infection with aerobic bacteria, local blood circulation caused by severe tissue trauma, or necrotic tissue And the retention of foreign matter to form a local anaerobic microenvironment is very beneficial to the propagation of Clostridium typhimurium. The bacteria proliferate in a large amount in the form of propagules and produce a large amount of scorpion toxin. The toxin first binds to the ganglioside of the nerve endings. The reverse nerve sheath passes through the spinal nerve root to transmit the anterior horn neurons of the spinal cord, and the brain stem cells are ascended. The toxin can also be absorbed by the lymph, and reaches the central nervous system through the blood. Under normal circumstances, when the flexor motor neurons are stimulated and excited, Impulsive also introduces inhibitory interneurons to release inhibitory transmitters (glycine and gamma-aminobutyric acid). The corresponding extensor motor neurons relax the extensor muscle and coordinate with the flexor contraction. At the same time, the excitatory state of the flexor motor neurons is also inhibited by the negative feedback of the inhibitory neurons, so that they are not overexcited, tetanus Scorpion toxin can selectively block inhibitory neurons, prevent the release of neurotransmitter inhibitors, and balance the contraction and relaxation of the flexor and flexor muscles while strongly contracting. In addition, tetanus toxin can inhibit nerves at the neuromuscular junction. The transmission of the neurites causes the acetylcholine to accumulate in the junction of the neurites, and frequently sends impulses to the periphery, resulting in sustained increase in muscle tone and muscle spasm, resulting in clinical closure of the jaws and angulation.

Tetanus prevention

Prevention of tetanus includes autoimmunity, passive immunization, and debridement and perinatal protection after injury.

1. Active immunization: China has already mixed the pertussis vaccine, diphtheria toxoid and tetanus toxoid into a triple vaccine, which is included in the children's plan immunization. The inoculation target is 3 to 5 months old children, and the first year is subcutaneous injection of 0.25 ml, 0.5 ml. A total of 3 times with 0.5ml, 4 weeks apart, 0.5ml subcutaneously in the second year, and once again in 1 year and a half to 2 years old, and then 1ml once every 2 years, until before enrollment Maintaining antibody levels, military personnel and vulnerable workers who have not been actively immunized with tetanus can use aluminum phosphate adsorption to purify tetanus toxoid for population immunization, which is economical and effective. The method is the first year of intramuscular. Inject twice a time, 0.5ml each time, 4 to 8 weeks apart, 0.5ml intramuscularly in the second year, and then boost the injection once every 5 to 10 years to maintain the effective antibody level. In order to achieve enhanced antibody levels, tetanus toxoid is highly immune, with a high success rate after vaccination, and rarely after vaccination.

In areas with high incidence of tetanus, pregnant women are encouraged to undergo tetanus immunization in the second trimester of pregnancy by intramuscular injection of 0.5 ml of tetanus toxoid for 3 times at intervals of 1 month. The last injection should be before delivery. In the month, this not only keeps the mothers with higher antibody levels during childbirth, but also has enough antibodies to pass on to the baby to achieve effective protection and prevention. The World Health Organization has widely promoted the global tetanus immunization program for children, hopefully in 2000. In the year, the world has basically eliminated tetanus. Unfortunately, this goal is still far from being achieved. The planned immunization monitoring reports from the United States, Britain and other countries show that tetanus protects antibodies and gradually decreases with age, only about 60% in adults. People have protective antibodies, so how to protect the elderly and further popularize tetanus immunization programs in developing countries remains a problem that remains to be worked out.

2, passive immunization: mainly used for those who have not been automatically immunized with tetanus, using tetanus antitoxin TAT, 1000 ~ 2000U, 1 injection, need to do a skin test before injection, such as skin test positive should be taken off Sensitive injection method can be administered in divided doses. After the injection, the protection period can be maintained for about 10 days. It can also be administered intramuscularly with human tetanus immunoglobulin HTIG5001000U, which can maintain the protection period of 3-4 weeks. To enhance the protective effect, it is best to start at the same time. After establishing active immunization and passive immunization, some people may still develop the disease, but usually have a long incubation period and a milder condition.

3, wound treatment: timely and thorough debridement and treatment of wounds, can effectively prevent the infection and reproduction of tetanus bacteria, including strict disinfection in maternal labor, have a positive preventive effect, in addition, such as deep wounds or pollution In severe cases, appropriate antibiotics should be used as early as possible to prevent and control infections. It is generally recommended to use the best within 6 hours of injury. The course of treatment is 3 to 5 days. The main purpose is to control the infection of pyogenic bacteria, thus avoiding the anaerobic microenvironment. Control and prevent the purpose of growth and reproduction of Clostridium tetani.

Tetanus complications Complications pneumonia atelectasis pulmonary edema septic shock

Complications: mainly pneumonia, atelectasis, pulmonary edema, other vertebral compression fractures, motor dysfunction caused by sustained muscle contraction, acne, sepsis, urinary retention and respiratory arrest.

1 suffocation: due to the throat, respiratory muscles, persistent paralysis and sticky phlegm blocked by the trachea.

2 pulmonary infection: throat sputum, poor airway, bronchial secretions, can not often turn over, etc., are the cause of pneumonia, atelectasis.

3 acidosis: poor breathing, lack of ventilation and respiratory acidosis, strong muscle contraction, body fat decomposition after fasting, so that acidic metabolites increase, resulting in metabolic acidosis.

4 Circulatory failure: due to lack of oxygen, poisoning, tachycardia can occur, heart failure can occur after a long time, and even shock or cardiac arrest, these complications are often an important cause of death, should strengthen prevention and treatment.

Tetanus Symptoms Common Symptoms Angular Arch Reversed Eyes Twitching Twitching Systemic Skeletal Muscle Spasm After Tetanus Abdominal Tonic Difficulty Muscle Soreness Coma Laughter Face

The incubation period for tetanus averages 6 to 10 days. It is also shorter than 24 hours or as long as 20 to 30 days, or even months, or only after removing foreign bodies such as bullets or shrapnel that have remained in the body for many years. Neonatal tetanus usually occurs around July after the umbilical cord is broken, so it is commonly called "seven-day wind." In general, the shorter the duration of the incubation period or prodromal symptoms, the more severe the symptoms and the higher the mortality rate.

The patient has pre-existing symptoms such as fatigue, dizziness, headache, biting muscles, soreness, irritability, and yawning. These prodromal symptoms usually last for 12 to 24 hours, followed by typical muscle contractions, initially masseter muscles, followed by facial muscles, neck muscles, dorsal and abdominal muscles, limb muscles, diaphragm and intercostal muscles. The patient began to feel chewed inconveniently, and it was difficult to open the mouth. Then the jaws were closed and the facial expression muscles were paroxysmal, which made the patient have a unique "chat smile" expression. When the neck tendon is present, the neck is stiff and the head is slightly tilted back. No nodding action can be made. The dorsal and abdominal muscles contract at the same time, but the back muscles are strong, so that the waist is lordotic, the head and the feet are bent, forming a dorsal arch, which is called "angular arch reversal". When the muscles of the extremities contract, due to the strength of the flexor muscles, the limbs may appear to bend, elbow, and semi-fist. On the basis of continuous tension, any slight irritation, such as light, sound, vibration or touching the patient's body, can induce convulsions and convulsions in the whole body muscles.

Each episode lasts for a few seconds to a few minutes, the patient's face is purple, shortness of breath, foaming at the mouth, flowing, grinding teeth, the head frequently back, the limbs twitching, the whole body sweating, very painful. During the interval of the attack, the pain is slightly reduced, but the muscles are still not completely relaxed. Strong tendons can sometimes break muscles and even fracture. The bladder sphincter can cause urinary retention. Persistent respiratory muscles and diaphragmatic spasm can cause respiratory arrest and death. During the disease, the patient's mind is always clear, and there is generally no high fever. The appearance of high fever often indicates the occurrence of pneumonia. The course of the disease is usually 3 to 4 weeks. Since the second week, the symptoms gradually decrease as the disease progresses. However, in a long period of time after recovery, some muscle groups sometimes have tension and hyperreflexia.

Tetanus check

Laboratory tests of tetanus patients are generally non-specific. When there is secondary infection in the lungs, white blood cells can be significantly increased. The corresponding pathogens can be found in sputum culture. The wound secretions are often separated into aerobic suppurative bacteria. Tetanus bacillus is isolated by anaerobic culture. Because the clinical manifestation of tetanus is more specific, especially when the symptoms are typical, it is not difficult to diagnose. Therefore, routine anaerobic culture and bacteriological evidence are not required for clinical diagnosis.

Diagnose based on:

1, the patient has a history of open injury infection, or neonatal umbilical cord disinfection is not strict, postpartum infection, surgical history.

2, the prodromal performance is weak, headache, hard tongue, swallow inconvenience and head and neck rotation is not comfortable.

3, the typical performance of muscle sustained tonic contraction and paroxysmal convulsions, initially chew inconvenience, masticatory muscle tension, painful rigidity, open mouth difficulties, bitter smile face, difficulty swallowing, neck stiffness, horn arch reversal, difficulty breathing, nervous And even suffocate.

4, mild stimulation (glare, wind, sound and vibration, etc.), can induce seizures.

5, local type tetanus, muscle tonic contraction is limited to the vicinity of the wound or injured limb, the general incubation period is longer, the symptoms are lighter, the prognosis is better.

Tetanus diagnosis

diagnosis

Diagnosis can be based on medical history, clinical symptoms, and laboratory tests.

Differential diagnosis

1. Although purulent meningitis has symptoms such as "angular arch reversal" and neck stiffness, there is no paroxysmal spasm. The patient has severe headache, high fever, jet vomiting, etc., and the mind is sometimes unclear. Cerebrospinal fluid examination has increased pressure and increased white blood cell count.

2, rabies has a history of bites by mad dogs and cats, mainly swallowing muscles. The pharyngeal muscles are more stressful. When the patient hears the sound of water or sees the water, the pharyngeal bone immediately sputum, severe pain, can not swallow when drinking water, and a lot of mouth licking.

3, other such as temporomandibular arthritis, eclampsia, rickets and so on.

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