meningococcal meningitis
Introduction
Introduction to epidemic cerebrospinal meningitis Epidemic cerebrospinal meningitis (epidemiccerebrospinal meningitis), referred to as meningitis, is a purulent meningitis caused by meningococcus. Pathogenic bacteria invade the blood circulation from the nasopharynx, forming sepsis, and finally confined to the meninges and spinal cord membrane, forming suppurative cerebrospinal meningeal lesions. The main clinical manifestations were fever, headache, vomiting, skin blemishes and neck stiffness and other meningeal irritation, cerebrospinal fluid showed suppurative changes. basic knowledge The proportion of illness: 0.02% Susceptible people: no special people Mode of infection: droplet spread contact spread Complications: pneumonia otitis media septic arthritis empyema myocarditis orchitis epididymitis vasculitis pericarditis hydrocephalus congenital hydrocephalus
Cause
The etiology of epidemic cerebrospinal meningitis
Pathogen infection (35%):
The pathogen invades the human body from the nasopharynx, and the child has a cold, sore throat, nasal congestion and other colds. If the human body is strong, it can quickly kill the pathogen or become a carrier state; if the body lacks specific bactericidal antibodies, or the bacteria have strong virulence, the bacteria can enter the blood from the nasopharynx mucosa and develop into sepsis. Then it involves the cerebrospinal membrane and forms suppurative encephalomyelitis. It is worth noting that the incidence of infants and young children is atypical, often misdiagnosed as a cold, increasing the difficulty of early identification.
Septicemia (30%):
Bacteria often invade the inner wall of the blood vessels of the skin, causing embolism, necrosis, hemorrhage and cell infiltration, resulting in defects or ecchymoses. Due to thrombosis, thrombocytopenia or endotoxin, the internal organs have varying degrees of bleeding.
Tyranny septicemia is a special type, formerly known as Hua-French syndrome, which was thought to be caused by acute adrenal insufficiency due to bilateral adrenal hemorrhage and necrosis. It has been proven that most of the adrenal cortical function has not been depleted and does not play a major role in the pathogenesis, and that lipopolysaccharide endotoxin of meningococcus can cause microcirculatory disorders and endotoxic shock, which in turn leads to disseminated intravascular coagulation. (DIC) is the main pathological basis.
The occurrence and development of fulminant meningoencephalitis is also related to endotoxin. Type III allergies may also play a role in the pathogenesis, such as the deposition of immunoglobulins, complement and meningococcal antigens in the damaged vessel wall.
Meningitis (20%):
The child continued to have high fever, severe headache, frequent vomiting and frequent sprays; irritability and unclearness. Later, he often died of toxemia and circulatory failure. The above three phases are not the process of patient experience. At each stage, some people's condition stops developing and gradually recovers.
The incidence of meningitis is fierce, and the disease develops rapidly. Most of the age of onset is under 15 years old, and the incidence of infants under 1 year old is the highest. The younger the age, the heavier the condition. The disease has sporadic people throughout the year, but generally begins in February and peaks in March and April. According to statistics, the incidence rate in spring accounts for about 80% of the total cases in the year. Therefore, if you find a suspicious individual, you must go to the hospital immediately. The sooner you treat, the better. If the diagnosis is delayed, it can lead to different levels of mental development and mental retardation. Neisseria meningus belongs to the genus Neisseria, which is a Gram-negative cocci, which is oval in shape and often arranged in pairs. The bacteria are only found in the human body and can be detected from the nasopharynx of the carrier, the blood, cerebrospinal fluid and skin defects of the patient. Bacteria in the cerebrospinal fluid are more common in neutrophils, and only a few are outside the cell. It is not easy to grow on ordinary medium, and grows well on medium containing blood, serum, exudate and egg yolk. It generally grows better in 5% to 10% of carbon dioxide. The bacteria are extremely sensitive to cold, dry and disinfectants. It is extremely easy to die in vitro, and the pathogen can form its own lytic enzyme, so it must be sent for inoculation immediately after collecting the specimen.
Prevention
Epidemic cerebrospinal meningitis prevention
1. Early detection of patients, early diagnosis, early reporting, isolation and treatment on the spot.
2. Escherichia coli is very resistant to sunlight, dryness, cold, damp heat and disinfectant, so pay attention to personal and environmental sanitation, keep indoors clean, wash clothes and bedding; keep indoor air circulation and freshness.
3. Do a good job in publicity during the popular period. Try to avoid large-scale gatherings and group activities. Don't take the children to the patient's house to go to the door. Try not to take the children to public places such as shops, theaters, parks, etc. If you can't, you should wear them. Upper mask.
4. In the epidemic peak season, if you find that your child has fever, sore throat, headache, vomiting, mental disorder, skin bleeding and other symptoms should go to the hospital for treatment.
5. Pay attention to keep warm and prevent colds. When a cold catches the patient's resistance, it is easy to be attacked by ECM. Therefore, it is necessary to increase or decrease clothes as the weather changes. After strenuous exercise or labor, you should dry your sweat and get dressed. Cover your quilt when you sleep at night, and pay more attention to this problem for children.
6. At each meal, you can eat a few cloves of raw garlic, which can kill the bacteria in the mouth. Salt water sputum after a meal is also conducive to preventing the occurrence of "flowing brain".
7. In the late fall and early winter, the children who are under 5 years old are vaccinated with cerebral vaccination. The protection rate can reach 80-90%, and the disease resistance can be maintained for about 1 year.
8. Drug prevention: Sulfonamides are still used in China. Those who are in close contact can use iodamine (SD), adults 2g/day, 2 times with the same amount of sodium bicarbonate, even for 3 days; children daily 100mg/ Kg. In the epidemic of meningitis, those who have: 1 fever with headache; 2 wilting; 3 acute pharyngitis; 4 skin, oral mucosal hemorrhage, etc., can be given a full range of sulfa drug treatment, which can effectively reduce Incidence and prevention of prevalence. Foreign use of rifampicin or minocycline for prevention. Rifampicin is 600 mg daily for 5 days, and the daily dose for children aged 1 to 12 is 10 mg/kg.
9. Vaccine prevention: At present, two groups of capsular polysaccharide vaccines of A and C are widely used at home and abroad. The protection rate of group A polysaccharide vaccine purified by ultracentrifugation was 94.9%, and the average antibody titer increased 14.1 times after immunization. In China, polysaccharide vaccines are also used as emergency preventers. If the incidence of meningitis in January-February is greater than 10/10 million, or the incidence rate is higher than the same period of the previous year, vaccination can be carried out in the population.
Complication
Complications of epidemic meningitis Complications Pneumonitis otitis septic arthritis empyema myocarditis orchitis epididymitis vasculitis pericarditis hydrocephalus congenital hydrocephalus
(1) Complications include secondary infections. Secondary infections are most common with pneumonia, especially in the elderly and infants. Others have hemorrhoids, corneal ulcers, and urinary tract infections.
(2) Suppurative lesions caused by scattered sepsis to other organs: purulent migratory lesions include total ophthalmia, otitis media, septic arthritis (often monoarthritis), pneumonia, empyema, endocardium Inflammation, myocarditis, orchitis, epididymitis.
(3) Damage caused by meningitis to the brain and surrounding tissues: Damage to the brain and surrounding tissues caused by inflammation or adhesions: ocular eye muscle paralysis, optic neuritis, auditory nerve and facial nerve damage, limb dyskinesia, aphasia, brain function Incomplete, epilepsy, brain abscess, etc. In chronic patients, especially infants and young children, hydrocephalus or subdural effusion may occur separately due to interventricular septum or subarachnoid adhesions and embolic phlebitis of the bridge between the meninges.
(4) allergic diseases: vasculitis, arthritis and pericarditis may occur in the later stages of the disease.
The sequelae can be caused by any complications, such as deafness (children develop hoarseness), blindness, oculomotor palsy, paralysis, mental or temperamental changes, mental disorders and hydrocephalus.
Symptom
Epidemic cerebrospinal meningitis symptoms common symptoms sore throat high fever pale pale lips herpes conscious disturbance appetite loss meningeal irritation acute face sepsis chill
Meningococcal bacteria mainly cause latent infection. According to statistics, about 30%-70% of asymptomatic carriers are deeply breathed to infection type and hemorrhage type, and 1% are typical epidemic patients. The incubation period is 1-10 days. For 2-3 days.
Epidemiology
1. Source of infection: carriers and patients, carriers and light patients are more important.
2. Routes of transmission: Pathogens mainly spread from the air by coughing, sneezing, talking, etc., and enter the respiratory tract to cause infection; for infants and young children, they can also be transmitted through arms, breastfeeding, kissing, and close contact.
3. Susceptibility to the population: Susceptibility is closely related to the level of antibody in the population. Newborns have antibodies from the mother and are less infected. The age of onset starts from 2 to 3 months, and the incidence of children from 6 months to 14 years is the highest. The disease has many invisible infections, and the antibody titer obtained after the disease can be reduced year by year, but the second time the patient is very few.
4. Popular season: can occur all year round, but the most common occurrence in winter and spring. In the epidemic season, high fever, headache, vomiting, accompanied by changes in consciousness, physical examination of the skin, mucous membranes, ecchymosis, ecchymosis, meningeal irritation positive, clinical diagnosis can be initially established. The diagnosis depends on cerebrospinal fluid examination and pathogen discovery. Immunological examination is conducive to early diagnosis.
Clinical symptoms
Meningococcal bacteria mainly cause latent infections. According to statistics, about 60%-70% of asymptomatic carriers are about 30% deep-inhaled to infectious and hemorrhagic, and 1% are typical epidemic patients. The incubation period is 1-10 days, usually 2-3 days. According to the severity of the disease and clinical manifestations, it is divided into four clinical types: light, common, explosive and chronic septic.
(1) Light type: more common in the epidemic, mild lesions, clinical manifestations of low fever, mild headache and sore throat and other upper respiratory symptoms, the skin may have a few small bleeding points and meningeal irritation. There is no significant change in cerebrospinal fluid, and throat swab culture may have pathogenic bacteria.
(2) Ordinary type: The most common, accounting for more than 90% of all cases. It is divided into 4 phases and its characteristics are:
A. The prodromal period (the upper respiratory tract infection period) is about 1-2 days, and may have symptoms of upper respiratory tract infection such as hypothermia, sore throat, and cough. Most patients do not have this performance.
B, sudden symptoms of septicemia or prodromal period, sudden chills and fever, accompanied by headache, muscle aches, loss of appetite and mental atrophy and other symptoms of toxemia. Young children are crying and uneasy, because of skin allergies and refusal, as well as horror. A small number of patients have joint pain and splenomegaly. The characteristic manifestation of this period is rash, usually sputum or ecchymosis, 70%-90% of patients have skin or mucous membrane spots or ecchymoses, diameter 1mm-2cm, starting with bright red, then purplish red, first seen in The conjunctiva and oral mucosa vary in size and size, and are unevenly distributed. The shoulders, elbows, and buttocks are more susceptible to pressure, and the color is bright red and then becomes purple. In severe cases, the ecchymosis rapidly expands and the center is necrotic due to thrombosis. In the center, due to thrombosis, purple-black necrosis or bullous formation occurs, and necrosis involving the subcutaneous tissue can leave scars. Most patients develop meningitis in 12 to 24 hours.
C, meningitis meningitis symptoms and septic symptoms at the same time. On the basis of the symptoms of the prodromal period, new severe headache, frequent vomiting, mania and meningeal irritation, blood pressure can be increased and the pulse is slowed down, severe convulsions, mental disorders and convulsions. Usually enters the recovery period after 2-5d.
D. After the recovery period, the body temperature gradually decreased to normal, and the skin spots and spots disappeared. The central necrotic area of the large plaque formed an ulcer, and the sputum became healed; the symptoms gradually improved and the nervous system examination was normal. About 10% of patients have herpes labialis. The patient usually recovers within 1-3 weeks.
(3) A small number of fulminant patients have a sudden onset of illness and a dangerous condition. If they are not treated in time, they can die within 24 hours. More common in children. The following types can be seen.
1, septic shock type in addition to the general type of sepsis must be a short-term appearance of extensive skin mucosal deposition or ecchymosis, and rapidly expand into a large piece, with central necrosis. Circulatory failure is a feature of this type. It is pale, with cold ends at the ends of the extremities, cyanosis, and variegated skin. The pulse can not be evenly fused, and blood pressure can not be measured. Can have shortness of breath, easy to concurrent DIC. However, most of the meningeal irritation signs are absent, and the foundation is mostly clarified, and the number of cells is normal or slightly elevated.
2, meningeal encephalitis type is mainly characterized by severe damage of brain parenchyma. In addition to high fever and ecchymosis, the patient's consciousness disorder deepens and quickly enters a coma; the convulsions are frequent and the pyramidal tract sign is positive. The blood pressure is increased, the heart rate is slowed down, the pupil is suddenly small or small, or the size of the brain is edema, and the ocular edema of the auditory edema is observed. Severe cases can occur cerebral palsy, the common is the occipital macroporous sputum due to cerebellar tonsil embedded in the occipital foramen magnum medulla, deepening coma, dilated pupils, increased muscle tone, upper extremity mostly internal rotation, lower extremity rigidity; and rapid breathing Depletion. A few are the occipital hiatus, causing the brain stem and the dynamic extension nerve to be compressed, showing coma, the ipsilateral pupil dilated and the light reflex disappears the fixation or abduction of the eyeball, and the contralateral limb is paralyzed. Both can die from respiratory failure.
3. The mixed type has the clinical manifestations of the above two types, and it appears at the same time or successively, the condition is extremely serious, and the mortality rate is high.
(4) Chronic septicemia.
[Characteristics of population]
Characteristics of infants and children with cerebral circulation: clinical manifestations are often atypical. In addition to high fever, refusal to eat, spit milk, irritability and crying, convulsions, diarrhea and cough are more common in adults, and meningeal irritation can be absent. The former halogen sinks.
Characteristics of the elderly brain:
(1) The immune function of the elderly is low, the lack of proper preparation of the Chinese medicine, and the increased sensitivity to endotoxin, so the incidence of fulminant is high;
(2) Clinical manifestations of upper respiratory tract infections are more common, disturbance of consciousness is obvious, and the incidence of ecchymosis in skin mucosa is high;
(3) The course of disease is long, about 10 days; complications and pods are more, the prognosis is poor, and the mortality rate is high. According to statistics, the case fatality rate is 17.6%, and the adult population is only 1.19%. 4 The number of white blood cells in the laboratory may not be high, indicating that the disease is heavy and the body response is poor.
Examine
Examination of epidemic cerebrospinal meningitis
(1) The total number of white blood cells in blood is obviously increased, generally around 20,000/mm3, the highest is 40,000/mm3 or more, and the neutrophils are 80% to 90%.
(two) cerebrospinal fluid examination
At the beginning of the disease, only the pressure increased, the appearance was normal, the typical meningitis period, the pressure was as high as 1.96 kPa, the appearance was cloudy or pus-like, the number of white blood cells reached several thousand to tens of thousands per cubic millimeter, mainly neutrophils, protein content Significantly improved, and the sugar content is significantly reduced, sometimes can not be detected completely, the chloride is reduced, if the clinical symptoms of meningitis and signs and early cerebrospinal fluid examination is normal, should be retested after 12 to 24 hours, the brain is treated with antibacterial drugs After that, cerebrospinal fluid changes can be atypical.
(three) bacteriological examination
1. Smear test Use a needle tip to pierce the skin, squeeze a little blood and tissue fluid, smear stained and microscopic examination, the positive rate is up to 80%, the positive rate of cerebrospinal fluid precipitation smear is 60% to 70%, cerebrospinal fluid is not suitable Leave it for too long, otherwise the pathogen will be easily dissolved and affect the detection.
2. Bacterial culture blood culture has a low positive rate in the flow of brain, but blood culture is very important for the diagnosis of common type of meningitis, fulminant sepsis and chronic meningococcal septicemia. Therefore, it is necessary to pay attention to the blood collection before the application of antibacterial drugs. Bacterial culture, and blood sampling should be carried out multiple times. The cerebrospinal fluid should be centrifuged in a sterile test tube, and the sediment should be directly inoculated on chocolate agar, and then injected into glucose broth and cultured in a 5% to 10% carbon dioxide environment.
(4) Immunological test
It is a rapid diagnosis method of meningitis in recent years. The detection of antigen in cerebrospinal fluid is beneficial to early diagnosis. It has high sensitivity and specificity. Currently, commonly used antigen detection methods include convective immunoelectrophoresis, latex agglutination and reverse indirect hemagglutination. Test, bacterial synergistic agglutination test, radioimmunoassay, enzyme-linked immunosorbent assay, etc., the positive rate of convective immunoelectrophoresis is above 80%, the positive rate of latex agglutination test is 85% to 93%, and the synergistic agglutination test detects group A and C. The positive rate of the group was also higher. The positive rate of reverse indirect hemagglutination test was 94.2% (cerebrospinal fluid) and 78.8% (blood). The sensitivity of enzyme-linked immunosorbent assay for detection of group A antigen was higher than that of reverse indirect hemagglutination test. Antibody detection can not be used as an early diagnosis method, and sensitivity and specificity are poor, so clinical application is decreasing. Convective immunoelectrophoresis, radioimmunoassay, indirect hemagglutination test, such as recovery period serum titer is greater than acute phase 4 More than double, there is diagnostic value.
Diagnosis
Diagnosis and identification of epidemic cerebrospinal meningitis
diagnosis
1. Epidemiological data: mainly found in children, mostly in winter and spring, local occurrence of meningitis or epidemics.
2. Clinical manifestations: acute onset, high fever, headache, vomiting, skin mucous membrane defects and meningeal irritation positive.
3. Laboratory examination: the total number of peripheral blood leukocytes increased, generally (15 ~ 40) × 109 / L, classified by neutrophils; cerebrospinal fluid showed purulent changes, but in the early stage of the disease, cerebrospinal fluid only pressure increased The appearance is normal, the turbidity is late, the number of cells is increased by >1000×106/L, the classification is mainly multinucleated cells, the protein is obviously increased, and the sugar and chloride are reduced. Skin smear or cerebrospinal fluid smear found Gram-negative cocci, cerebrospinal fluid or blood culture positive can be diagnosed.
Differential diagnosis
1. Other purulent meningitis can be initially differentiated according to the invasive route. Most of the pneumococcal meningitis is secondary to pneumonia. On the basis of otitis media, staphylococcal meningitis mostly occurs in the course of staphylococcal septicemia, and Gram-negative bacilli meningitis Prone to occur after craniocerebral surgery, influenza bacillus meningitis occurs in infants and young children, Pseudomonas aeruginosa meningitis often secondary to lumbar puncture, anesthesia, angiography or surgery.
2. The epidemic encephalitis season is mostly from July to September. The brain parenchymal damage is serious, coma, convulsions are common, the skin is generally flawless, the cerebrospinal fluid is clearer, the number of cells is mostly below 500/mm3, sugar and protein. The amount is normal or slightly increased, the chloride is normal, and immunological tests such as specific IgM, and the complement test are helpful for identification.
3. Virtual meningitis sepsis, typhoid fever, lobar pneumonia and other acute infection patients with severe toxemia, meningeal irritation may occur, but the cerebrospinal fluid except for a slight increase in pressure, the rest are normal.
4. Poisonous bacterial dysentery is mainly seen in children. The season is in summer and autumn. In the short term, there are symptoms such as high fever, convulsions, coma, shock, respiratory failure, but no symptoms, cerebrospinal fluid examination is normal, and the diagnosis depends on fecal bacteria culture.
5. Subarachnoid hemorrhage is more common in adults, sudden onset, mainly with severe headache, followed by coma in severe cases, body temperature often does not rise, meningeal irritation sign is obvious, but no skin and mucous membranes, ecchymosis, no obvious Symptoms of poisoning, cerebrospinal fluid is bloody, cerebral angiography can be found in aneurysms, vascular malformations and other changes.
