Meningococcal meningitis

Introduction to meningococcal meningitis Meningococcal meningitis is suppurative meningitis caused by Neisseria meningitis (Nm). Pathogenic bacteria invade the blood circulation from the nasopharynx, and finally confined to the meninges and spinal membrane, forming suppurative cerebrospinal meningeal lesions. The main clinical manifestations were fever, headache, vomiting, skin ecchymosis, sputum and neck stiffness, and cerebrospinal fluid showed suppurative changes. In addition, meningococcal bacteria can not invade the meninges and only manifest as sepsis. Among them, severe cases can be violent, and infection can also occur in the upper and lower respiratory tract, joints, pericardium and eyes. The disease is found throughout the world, with sporadic or large, small epidemics, with a high incidence of children. basic knowledge The proportion of illness: 0.069% Susceptible people: no special people Mode of infection: infection Complications: pneumonia, acne, corneal ulcer, urinary tract infection, septic arthritis, otitis media, epilepsy

Causes of meningococcal meningitis

(1) Causes of the disease

Meningococcus is one of the genus Neisseria, Gram-negative, kidney-shaped, about 0.6-0.8 m in diameter, arranged in pairs, adjacent, flat, sometimes four connected, freshly isolated strains have polysaccharide capsules, Under electron microscope, the bacteria has an outer membrane with a thickness of about 8 nm. The mucosal layer is between the outer membrane and the cytoplasmic membrane, or the periplasmic space is about 6 nm thick. The bacteria are only present in the human body and can be taken from the nasopharynx of the carrier. And the patient's blood, cerebrospinal fluid, skin defects were detected, the bacteria in the cerebrospinal fluid smear can be seen inside and outside the neutrophils, the bacteria are obligate aerobic, high requirements for the medium, usually with blood agar or chocolate The agar is separated and grows well at a concentration of 5% to 10% carbon dioxide. The optimum temperature is 35-37 ° C. It can not grow above 41 ° C or below 30 ° C. After 18-24 h, the colonies are colorless and translucent. Smooth and moist, shiny dew-like rounded uplift, the bacteria can form autolytic enzymes. If not transferred in time, it can die within a few days, is extremely sensitive to cold and dry, and is very easy to die in vitro, so after collecting specimens Must be vaccinated immediately and is extremely sensitive to general disinfectants. Fermentation reaction is an important method to identify Neisseria species. Meningococcal fermentation of glucose, maltose, but not fermented lactose, fructose and sucrose, can be distinguished from Neisseria gonorrhoeae and Neisseria lactis. The capsular polysaccharide of the bacterium is the basis of grouping. At present, the bacterium is divided into A, B, C, D, X, Y, Z, 29E, W135, H, I, K, L, 13 bacteria, in addition Some strains cannot be agglutinated by the above-mentioned bacterial antiserum, which is called undetermined group, which accounts for 20% to 50% of the meningococcal bacteria isolated by the carrier, and generally has no pathogenicity, and the B group and the C group are still acceptable. According to the protein antigen typing of the extracorporeal membrane, most of the clinically occurring patients are type 2 and type 15. The antigens of the type B and C are identical in chemical and serological terms. In recent years, seven types have been used in combination. Multi-locus electrophoresis (MLEE) of cytosolic enzymes and polypropylene gel electrophoresis of two outer membrane proteins were used to analyze the clonal type of group A meningococcus, and many sites were developed based on this. Multilocus sequence typing (MLST) method has high resolution and weight Good sex, can compare the data of different laboratories around the world (http:www.mlst.net) on the website, and become the "gold standard" of Nm classification. This method is especially suitable for epidemiological investigation and research on different epidemic strains. The genetic evolution of Pierre, Pierre used MLST study to find the A group 4 and P1-9 subtypes popular in Africa from 1988 to 1999, in fact, ST-5 and ST-7 two sequence types.

(two) pathogenesis

Pathogenesis

Pathogenic bacteria invade the human body from the nasopharynx. If the human body is healthy or immune, the pathogen can be quickly eliminated or become a carrier. It is estimated that 1000 to 5000 infections can cause a clinical infection, and the immunity is not strong, mainly due to lack of body. Specific bactericidal antibodies are the main factors causing clinical pathogenesis. The virulence of bacteria is also an important factor. The main virulence factors of Neisseria meningitidis are capsule, pili and endotoxin, and the capsule can resist phagocytosis. The pili can adhere to the surface of the pharyngeal mucosal epithelial cells, which facilitates further invasion. After the bacteria invade the body, the endotoxin is released due to autolysis or death. Endotoxin acts on small blood vessels and capillaries, causing necrosis and hemorrhage. Skin ecchymosis and microcirculatory disorders, severe sepsis, caused by a large amount of endotoxin release: DIC and toxic shock, A, B, C group virulence is stronger than other groups, B and C groups Types 2 and 15 are also more susceptible to disease than other types. Studies have shown that congenital or acquired IgM deficiency or reduction, a single congenital deficiency of complement C5 ~ C8 is causing clinical development Even the cause of recurrent or fulminant, due to other diseases, such as systemic lupus erythematosus, multiple myeloma, nephritis and post-hepatic disease, the complement is reduced, the incidence of meningococcal is also increased, and the congenital deficiency of properdin is also It can cause fulminant meningitis, but these factors only play a role in the pathogenesis of individual cases. In addition, the abnormal increase of specific IgA can be combined with a large number of pathogenic antigens. Since IgA cannot activate the complement system, complement-mediated lysis of IgM The bactericidal action acts as a blocking antibody, and may also be a factor causing clinical morbidity. It is also prone to the onset of viral infection in the upper respiratory tract. The meningitis seen in the clinic actually has sepsis at the same time, so other organs are also occasionally available. Migratory suppurative lesions, such as endocarditis, pericarditis, septic arthritis, etc., in addition, meningococcal can cause primary pneumonia from the respiratory tract, especially the Y group, 88 cases of Y group meningitis have been reported Among the cocci, 68 cases showed pneumonia without sepsis and meningitis, which was confirmed by the secretion culture of the trachea. The fulminant meningococcal septicemia, formerly known as Waterhouse-Friderichsen syndrome, was thought to be caused by bilateral adrenal hemorrhage and necrosis, causing acute adrenal insufficiency, and the adrenal cortex has been demonstrated. Most of the functions are not exhausted, and it does not play a major role in the pathogenesis, because: 1 patients with fulminant meningococcal septicemia also occur when there is no bleeding in the adrenal cortex; 2 serum cortisol levels are usually significantly increased rather than reduced 3) Addison disease does not occur after recovery from patients with fulminant meningococcal septicemia. The cause of outbreak shock in some patients with sepsis is due to the lipopolysaccharide endotoxin of meningococcal can cause systemic Schwarzman The reaction (Shwartzman reaction) activates the complement system and causes microcirculatory disturbance and endotoxin shock. The level of serum tumor necrosis factor is also increased, and the degree is directly proportional to the severity of the disease. Endotoxin causes skin defects and freckles. It is 5 to 10 times stronger than Gram-negative bacilli and is considered to be caused by a local Schwarzman reaction. Meningococcal endotoxin is more likely to activate the coagulation system than other endotoxins, so diffuse intravascular coagulation (DIC) can occur in the early stage of the outbreak of the episode, which aggravates purpura, hemorrhage and shock, and the outbreak of meningoencephalitis Development is also related to endotoxin. Animal experiments have shown that intraventricular injection of meningococcal endotoxin can cause meningoencephalitis syndrome, and type 3 allergies may play a role in pathogenesis, such as in damaged vessel walls. Immemia globulin, complement and meningococcal antigen deposition can be seen; complications of this disease such as arthritis and pericarditis can be diagnosed after sepsis and the culture medium is negative, but immune complexes containing specific antigens can be found. Things.

2. Pathology

In the period of sepsis, the main lesions are vascular endothelium damage, inflammation of the blood vessel wall, necrosis and thrombosis, as well as perivascular hemorrhage, focal hemorrhage of skin, subcutaneous tissue, mucosa and serosa, and shock anatomy A large number of Gram-negative diplococcus can be found in the vascular endothelial cells and in the lumen of the skin. The damage of the skin and visceral blood vessels is more serious and extensive. There are endothelial cell necrosis and shedding. There are fibrin-leukocyte-platelet thrombus in the lumen of the blood vessels. Lung, heart, gastrointestinal tract and adrenal gland have extensive hemorrhage. Myocarditis and small abscess are also common. There is a causal relationship between the presence of myocarditis and shock. The meningitis lesions are mainly soft meninges and early hyperemia. a small amount of serous exudation and focal small bleeding points, in the later period there are a large number of fibrin, neutrophils and bacteria, the lesions mainly in the skull base and the surface of the brain hemisphere, due to the adhesion of the skull base pus, and suppuration Direct invasion of sexual lesions can cause damage to the optic nerve, abduction and oculomotor nerves, facial nerves, auditory nerves, etc. Long-term, the surface of the brain has degenerative changes. In addition, inflammation can invade the brain tissue along the blood vessels, causing congestion, edema, focal neutrophil infiltration and hemorrhage. In cases of fulminant meningoencephalitis, the lesion is brain Mainly tissue, with obvious congestion and edema, intracranial pressure is significantly increased, edema brain tissue protrudes into the intracranial hole (occipital large hole and canopy hole), can form cerebral palsy, a small number of chronic patients due to ventricular occlusion and cerebrospinal fluid circulation Hydrocephalus occurs due to obstacles.

Meningococcal meningitis prevention

During the popular period, we will do a good job in publicity, carry out health campaigns, do a good job in indoor hygiene, pay attention to personal and environmental sanitation, avoid children in crowded public places, advocate less meetings, and less friends and relatives.

1. Early detection and isolation of patients

Do a good job in predicting and forecasting the disease to prevent the spread and expansion of the epidemic. Patients should be isolated from the respiratory tract. When there is an outbreak in a certain area, emergency vaccination can be given to the area and its surrounding areas.

2. ECM vaccine injection

The protection rate of group A polysaccharide vaccine is about 90% after inoculation, and the side effect is very small. The bactericidal antibody can be detected in the body of most affected people about 2 weeks after injection, and it lasts for more than 2 years, the dosage is 30g, the best immune The plan is to carry out a general breeding of susceptible populations before the arrival of the predicted epidemic, and the coverage rate is required to be 85% to 90%. After that, the infants of 6 months to 2 years old will be immunized once a year for a total of 2 needles. In one year, the incidence of low-age group can be reduced, the immune response of the population can be improved, and the effect of prolonging the epidemic period can be prolonged. The monovalent, C-group and ACY W135 group (CPS) polysaccharide vaccines have been developed abroad. Group A and Group C vaccines have an immune effect of about 90% for children over 4 years old, and the immune protection effect is about 3 years, but it has a poor immune effect on young children, and the protection time is short, probably because the vaccine is in the The age group can only cause specific, IgM antibody response and can not cause specific IgG antibody response. So far, no satisfactory B group Nm vaccine has been obtained at home and abroad, and the outer membrane protein (0MP)-based B group Nm vaccine is in Cuba, Chile, Norway and Brazil and other countries have done Observed, the tested group B OMP vaccine has about 70% immune protection effect on children aged 5 to 21 years old, has no obvious protective effect on children aged 1 to 4 years old, and has no preventive effect on children under 2 years old. A B-group Nm outer membrane protein complex (OMPC) has been coupled with a domestic group A meningococcal polysaccharide vaccine to construct a conjugate of ACPS-BOMPC. This conjugate not only enhances the immunogenicity of group A meningococcal polysaccharide, but also has the immunogenicity of group B NmOMPC, and its safety and stability are also better.

3. Drug prevention

Since the B group Nm vaccine has not been obtained at home and abroad, the group A vaccine has no preventive effect. When the number of cases caused by the B group Nm is increased, the close contact of the patient can be prevented. In the first case, close contact within 4 days after onset can cause the disease, so it is necessary to prevent the drug early, and rifampicin or minocycline can be used. The adult dose of rifampicin is 600mg, and the child is 10mg/kg body weight, 2 times/d. For a total of 2 days, minocycline is also effective, but there are side effects such as dizziness. In areas sensitive to sulfa drugs, sulfadiazine can still be used, adults 4-6g/d, children 100-200mg/(kg·d), Oral administration for 2 days, for a total of 3 days, during the epidemic, regardless of whether or not to receive drug prevention, medical contacts should be observed for close contacts, early detection of cases, active treatment.

Complications of meningococcal meningitis Complications pneumonia acne corneal ulcer urinary tract infection septic arthritis otitis media epilepsy

Complication

These include secondary infections, suppurative lesions caused by dissemination to other organs during sepsis, damage to the brain and its surrounding tissues by meningitis itself, and allergic diseases.

(1) secondary infection: pneumonia is the most common, especially in the elderly and infants, others have hemorrhoids, corneal ulcers, urinary tract infections caused by urinary retention.

(2) purulent migratory lesions: septic arthritis (often single joint), total ophthalmia, otitis media, pneumonia, empyema, pericarditis, endocarditis, myocarditis, orchitis, epididymitis.

(3) Damage caused by inflammation or adhesion of the brain and surrounding tissues: ocular eye palsy, optic neuritis, auditory nerve and facial nerve damage, limb dyskinesia, aphasia, brain dysfunction, epilepsy, brain abscess, etc., in chronic patients, Especially in infants and young children, due to interventricular ventricle or subarachnoid adhesion and meningitis caused by embolism phlebitis in the bridge vein, hydrocephalus or subdural effusion can occur separately, which can be confirmed by CT or MRI.

(4) allergic diseases: vasculitis, arthritis and pericarditis may occur in the later stages of the disease, arthritis is divided into early and late stages, early (2 to 3 days) allergic arthritis is common, multi-articular, joint There is acute inflammation, but the joint cavity is less or absent, often with the treatment and rapid improvement, late (4 ~ 10 days) often manifested as subacute monoarthritis, and there is joint cavity exudate, with recurrence of fever, Pleural pericarditis, exudate is a serum blood sample, treatment includes pumping and anti-inflammatory drugs.

2. sequelae

Common people are deafness, blindness, ocular paralysis, paralysis, mental and temperamental changes, mental disorders and hydrocephalus.

Meningococcal meningitis symptoms Common symptoms Anorexia lack of skin

The condition of the brain is complicated and variable, and it can be expressed in three clinical types, namely, common type, fulminant and chronic sepsis. In addition, there are still atypical manifestations, and the incubation period is 1 to 7 days, generally 2 to 2 3 days.

Normal type

About 90% of the incidence of meningococcal infection, according to the development of this disease, can be divided into three stages of upper respiratory tract infection, sepsis and meningitis, but clinically difficult to divide, and sometimes the disease ends in the sepsis period No meningitis occurs, while meningitis has sepsis at the same time, even the common type of disease is also different.

(1) Upper respiratory tract infection period: Most patients do not produce any symptoms. Some patients have sore throat, pharyngeal mucosal congestion and increased secretions. At this time, nasopharyngeal swabs can be used for culture to detect meningococcal bacteria, but even Positive culture, it is not certain that the upper respiratory symptoms are caused by meningococcal or by viruses.

(2) sepsis period: patients often have no prodromal symptoms, there are chills, high fever, headache, vomiting, malaise, muscle aches, loss of appetite and apathy and other symptoms of toxemia, young children have crying, irritability, skin allergies And convulsions, the pulse increased accordingly, the number of breaths increased slightly, the conjunctiva may have congestion, a small number of patients have joint pain, the main and significant signs of this period is rash, can be seen in about 70% of patients, rash soon after the disease Appears, mainly for sputum and ecchymosis, found in the skin and mucous membranes of the whole body, the size is 1 ~ 2mm to 1cm, in the sputum, before the appearance of ecchymosis, the systemic rose rash is visible, and the disease is severe, The plaque can be rapidly enlarged, and large skin necrosis occurs due to thrombosis. In addition, herpes, pustular rash, etc. are also visible. About 10% of patients may have herpes simplex around the lips and other parts, the latter usually about 2 days after the onset of the disease. Only appeared, but rare in the early days, a small number of patients can also swollen spleen, most patients develop meningitis within 1-2 days.

(3) meningitis period: the symptoms of meningitis can occur at the same time as sepsis, sometimes it appears later, most of them are obvious around 24h after onset, patients with high fever and toxemia continue, the body still has defects, ecchymosis, However, the symptoms of the central nervous system are aggravated, the headache is fibrillated due to increased intracranial pressure, vomiting is frequent, blood pressure can be increased, and the pulse is slowed down. There are often skin allergies, fear of light, mania and convulsions, and inflammation of the meninges is post-neck pain. Neck stiffness, angulation, Kernig and Brudzinski positive, after 1 to 2 days, the patient can enter a coma, the condition is already very serious, breathing may occur Circulatory failure or other complications, infantile attacks 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 may be absent, anterior or posterior Most of them are prominent, which is very helpful for diagnosis. Sometimes, due to frequent vomiting, loss of water, etc., the sag is sag, which makes the diagnosis difficult.

2. fulminant

A small number of patients have a sudden onset of illness, and the disease is dangerous. If they are not rescued in time, they can endanger life within 24 hours or even within 6 hours.

(1) Outbreak shock type: This type is more common in children, but it is not uncommon in adults. It starts with high fever, headache and vomiting, but the symptoms of poisoning are severe, the spirit is extremely wilting, and there may be disturbances of consciousness ranging from mild to severe, sometimes with convulsions. Often in the short term (within 12h), there are a wide range of sputum throughout the body, ecchymosis, and rapidly expanding, into a large subcutaneous hemorrhage, or followed by necrosis, shock is one of the important manifestations of this type, the appearance of pale gray, lips And fingertips, cold limbs, skin spots, pulse speed, blood pressure decreased significantly, pulse compression is small, many patients can drop blood pressure to zero, most of the meningeal irritation is absent, cerebrospinal fluid is mostly clarified, cell count is normal or light Increased degree, blood culture is mostly positive, most patients have DIC evidence in laboratory tests, thrombocytopenia, total white blood cells below 10 × 109 / L often indicate poor prognosis, erythrocyte sedimentation rate is mostly normal, the latter or fibrinogen Not increased but decreased as a result.

(2) fulminant meningoencephalitis type: this type is also more common in children, the clinical symptoms of brain parenchymal damage are obvious, the patient quickly falls into a coma, frequent convulsions, positive pyramidal tract signs and bilateral reflexes, ocular vein distortion can be seen in fundus examination Even nipple edema, blood pressure continues to rise, some patients develop cerebral palsy, occipital macroporous sputum (cerebellar tonsil) when the cerebellum of the cerebellum into the occipital foramen, compression medulla, the patient coma deepens, the pupil is significantly reduced or scattered Large, or suddenly small, the edge of the pupil is not neat, the muscles of both limbs are increased or stiff, the upper limbs are more internal rotation, the lower limbs are stretched and straight, the breathing is irregular, or fast, slow, deep, shallow, or Pause, or for soaking, nodding, or tidal breathing, often prompting that breathing will stop suddenly, sometimes the patient has no signs of a change in respiratory rhythm, or suddenly stop, the sacral sputum () is due to the temporal lobe The hook or hippocampus retracts into the canopy, compresses the diencephalon and the oculomotor nerve. The clinical manifestations are similar to the above. Only in the presence of respiratory failure, the ipsilateral pupil is enlarged by the pressure of the oculomotor nerve. The photoreaction disappeared, the eyeball was fixed or abducted, and the contralateral limb was paralyzed.

(3) Mixed type: This type has the clinical manifestations of the above two types of fulminant hair, often appearing at the same time or successively, and is the most serious type of this disease.

3. Chronic meningococcal septicemia This type is rare, more common in adults, the course of disease often lasts for several months, patients often have intermittent chills, chills, fever, each fever lasts about 12h and then fades, 1 to 6 apart There are seizures in the day, and the body temperature curve is similar to malaria. The fever-free period is generally good. After fever, rashes often appear in batches. The red rash is the most common. The sputum, subcutaneous hemorrhage, pustular rash can also be seen. Sometimes it can appear. Nodular erythematous rash, bleeding can occur in the center, rash is more common in the limbs, rash also subsides after fever, joint pain is more common, exacerbated when fever, can be migratory, often involving most joints, but joint cavity exudate Rarely, a small number of patients have splenomegaly. In the course of chronic sepsis, a small number of patients may sometimes have a sharp deterioration due to suppurative meningitis or endocarditis. Most patients with endocarditis die, other purulent complications such as Epididymitis, etc. can also be seen, white blood cells and neutrophils increased during fever, ESR increased, the diagnosis is mainly based on blood culture during the fever period, often need to be positive multiple times, already It is reported that the lack of congenital complement components can cause this type of clinical manifestations.

4. Atypical type of primary meningococcal pneumonia has been reported in recent years, mainly caused by Y group, clinical manifestations in addition to fever, mainly respiratory symptoms and signs, such as cough, cough, snoring, etc., X-ray Examination of visible segmental or lobary inflammation shadows, some patients have a small amount of pleural effusion, skin often no defects, blood culture is also often negative, sputum culture or secretion through the tracheal suction can be obtained meningococcal.

Examination of meningococcal meningitis

Blood picture

The total number of white blood cells increased significantly, generally around 20 × 109 / L, the highest can reach 40 × 10 ⁹ / L, or above, neutrophils in 80% to 90%.

2. Cerebrospinal fluid examination

Cerebrospinal fluid examination is an important basis for the diagnosis of meningococcal disease. However, in recent years, it is considered that because of lumbar puncture, it is easy to have cerebral palsy. Therefore, if the diagnosis is clear during the epidemic, it has been inclined to avoid lumbar puncture. If there is obvious increase of intracranial pressure, or short-term Patients who enter coma, especially suspected outbreaks of meningoencephalitis, need to be cautious. If the diagnosis is not clear, mannitol should be injected intravenously to reduce intracranial pressure and then lumbar puncture. All should be pulled out, but a small amount of cerebrospinal fluid should be slowly released for examination. If the pressure is significantly increased during lumbar puncture, the intravenous injection of mannitol should be repeated after puncture. Lumbar puncture should be used during emergency or after using antibiotics after admission. Execution, so as not to affect the results of the examination, after the lumbar puncture, the patient should be supine for 6 ~ 8h, do not raise your head to avoid cerebral palsy, when the disease is early, or for the outbreak type, cerebrospinal fluid is often clarified, cell number, protein and When the amount of sugar has not changed, the pressure tends to increase, and neutrophils are often seen in cell sorting. In the typical meningitis period, the pressure is often obvious. High, the appearance is turbid rice soup or even pus, the number of white blood cells is often significantly increased, the majority is neutrophils, protein is significantly increased, and the sugar content is often less than 2mmol / L, sometimes can not be measured at all, has accepted The amount of glucose in the cerebrospinal fluid of patients with glucose intravenous infusion and diabetes may be higher, but at this time, if blood glucose is measured at the same time, the blood sugar is often 1.5 times higher than that of cerebrospinal fluid. After the brain is treated with antibacterial drugs, the cerebrospinal fluid changes can be atypical. At this time, the appearance of cerebrospinal fluid is clear or slightly turbid, and the number of white blood cells is often below 1000×106/L. The classification is mainly neutrophils, or monocytes, mainly such changes and tuberculous meningitis or virality. Meningoencephalitis is quite difficult to distinguish.

3. Bacteriological examination

(1) Smear examination: including skin sputum and cerebrospinal fluid smear examination, when the skin is examined, use the needle tip to puncture the skin on the sputum, try not to cause bleeding, squeeze a small amount of tissue fluid, apply it on the glass slide, stain After the microscopic examination, the positive rate can be as high as 70%, and the cerebrospinal fluid precipitation smear is also higher than the cerebrospinal fluid culture, which is 60% to 70%. Therefore, the cerebrospinal fluid should not be put on hold for too long. Otherwise, the pathogen is easy to autolyze, sometimes the gelatin stains for too long, or the bacteria die. Gram-positive cocci can be mistaken for Gram-negative cocci, except for skin blemishes and cerebrospinal fluid, sometimes in the buffy coat or surrounding blood. Gram-negative cocci can also be found in the white blood cells of the tablets.

(2) Bacterial culture:

1 blood culture: blood culture in the flow of brain when the positive rate is about 30%, in the sepsis or fulminant 50% ~ 75%, must pay attention to the application of antibacterial drugs before the blood for bacterial culture, and choose a good medium.

2 Cerebrospinal fluid culture: Although the cerebrospinal fluid culture is lower than the cerebrospinal fluid smear positive rate, it is still necessary to check the procedure. The cerebrospinal fluid should be centrifuged in a sterile test tube, and the sediment should be directly inoculated into the chocolate agar, and the glucose broth is injected at 5%. Incubate at ~10% carbon dioxide concentration.

Regardless of blood or cerebrospinal fluid culture, if positive results are obtained, further biochemical reactions and serum agglutination should be performed to identify strains, and group A meningococcus can be used for multi-site enzyme electrophoresis for typing.

3 bacterial drug sensitivity test: culture-positive should be used as a reference for drug sensitivity test, sensitivity test should be carried on semi-solid medium containing different concentrations of sulfa drugs and antibiotics, while not containing the above drugs The medium was used as a control, and the sensitivity test was carried out by the paper method or the test tube method, and the results were often not reliable enough.

4. Immunological serology

(1) Immunological examination of antigens: including convective immunoelectrophoresis, reverse indirect hemagglutination test, enzyme-linked immunosorbent assay, synergistic agglutination of Staphylococcus aureus A protein, radioimmunoassay, etc., for detecting blood, cerebrospinal fluid or Urine meningococcal antigens are generally positive within 3 days of the disease course. Domestic reports are generally more positive than bacterial cultures, and are considered to be sensitive, specific, rapid and simple.

(2) Immunological examination of antibodies: indirect hemagglutination, bactericidal antibody assay, etc., if the serum titer of the recovery period is more than 4 times higher than the acute phase, it has diagnostic value. In addition, the antibody assay can be used to detect the immune level of the population. And in order to detect the antibody response after vaccination, the indirect hemagglutination test is more sensitive, and the presence of bactericidal antibodies is closely related to the protection of the disease, so it also has certain value.

5. Molecular biological diagnostic methods

PCR technology has been widely used as a diagnostic technique because of its sensitive, rapid and specific characteristics. This method can quickly detect a very small number of bacteria in different kinds of specimens, and its sensitivity can reach 10-12DNA/50l system, compared with serology. The test is much more sensitive, and the application of antibiotics has little effect on its detection. Three to four hours after the specimen is received, the diagnosis can be made. The clinical diagnosis can be assisted in the early stage of the disease, and the Nm-specific gene can be amplified by PCR. It can separate the meningitis from other bacterial meningitis, and can also Nm group, type and conduct drug resistance research, carry out PCR analysis on the epidemic types of specific areas, and provide information for vaccine research, although PCR Technology has many advantages over traditional diagnostic methods, but PCR itself has some problems. This is because PCR has a strong influence on inhibitory factors, pollution, and experimental conditions. There are many PCR inhibitors in clinical specimens, such as blood red. The gene can bind to Tag polymerase to inhibit its activity. The selection of the amplified gene and the design of the primer directly determine the sensitivity and specificity of the amplification. , A sensitivity and specificity of PCR experiments further specimens are preserved by the impact detection method of DNA extraction and PCR products.

6. Other

Blood, urea nitrogen, creatinine, blood gas analysis, blood pH, electrolytes, blood and urine routines, as well as central venous pressure and pulmonary wedge pressure during shock are helpful for estimating the condition and guiding treatment. If necessary, select the relevant items. For the determination of DIC, platelet, fibrinogen content decreased, prothrombin time prolonged, factor V, VII, VIII decreased, partial thromboplastin time prolonged, and increased fibrin degradation product concentration confirmed DIC diagnosis, cerebrospinal fluid In the determination of lactic acid, lactate dehydrogenase, etc., it is helpful to identify purulent meningitis and viral or tuberculous meningitis, but it is not possible to identify which purulent pathogen caused, blood and cerebrospinal fluid The test is often positive, but other Gram-negative bacterial meningitis can also be positive.

X-ray examination showed segmental or lobaric inflammation shadows, and some patients had a small amount of pleural effusion.

Diagnosis and differentiation of meningococcal meningitis

diagnosis

1. Epidemiological data The disease is prevalent in winter and spring. The patients are mainly children, but it is not uncommon in adults during the pandemic. It should be noted that if the disease is prevalent in the region, it should be especially vigilant.

2. Clinical data have high fever, headache, vomiting, skin mucous membrane defects, ecchymosis (especially in the course of disease, rapid expansion, other diseases are rare), neck stiffness and other meningeal irritation.

3. Laboratory data The total number of white blood cells is significantly increased, cerebrospinal fluid is purulent, skin sputum and cerebrospinal fluid sediment are found by Gram-negative diplococcus, and blood and cerebrospinal fluid are positive for bacterial culture. The latter is the main basis for diagnosis, blood and The cerebrospinal fluid is positive for antigen detection by immunological serum, and positive for PCR detection. It is helpful for early diagnosis. Due to the rapid development of the disease course, especially fulminant, during the epidemic, the patient has high fever and severe symptoms, accompanied by rapid skin. Mucosal defects, ecchymoses, with or without meningeal irritation, cerebrospinal fluid whether abnormal findings, should be actively treated according to the flow of brain immediately after the collection of specimens, for the above clinical symptoms accompanied by early shock, it should be divided into seconds According to the outbreak shock type rescue.

Differential diagnosis

1. Identification with other purulent meningitis and tuberculous meningitis.

2. Epidemic encephalitis

Patients are more common in children, but have strict seasonality, prevalent in July-August, high fever, convulsions, coma, no skin mucous membrane spots and oral herpes, cerebrospinal fluid clarification, white blood cell count rarely exceeds 1000 × 106 / L, The classification is mainly lymphocytes, but the early neutrophils may be slightly more than lymphocytes, the sugar content is normal or slightly higher, the blood complement fixation test has diagnostic value, and the blood specificity. IgM antibody positive can also be diagnosed.

3. Virtual meningitis

Severe systemic infections such as sepsis, typhoid fever, pneumonia, falciparum malaria, typhus and typhus often cause meningeal irritation due to high toxemia, but cerebrospinal fluid examination is generally normal except for increased pressure, and each of the above diseases has its own unique characteristics. Symptoms, signs and laboratory tests can be distinguished from the flow brain.

4. Poisonous bacterial dysentery

Mainly seen in children, the onset season is mainly in summer and autumn, short-term high fever, convulsions, coma, shock, respiratory failure and other symptoms, but no defects, cerebrospinal fluid examination is normal, cold saline enema after discharge or anal swab examination may have mucus pus Blood, microscopic examination has piles or a large number of pus cells and red blood cells, and the diagnosis depends on fecal bacteria culture.

5. Epidemic hemorrhagic fever

It is the peak of epidemic from November to December, but it is distributed all year round. The patients are mainly adults. There is a history of field operation in the infected area within 1 month before the disease. The initial bleeding is mild, and there are line-like bleeding spots on the skin. Mainly seen in the armpits, there is drunkenness, conjunctival congestion and edema, abnormal lymphocytes in the surrounding blood, urine routinely have a large amount of proteinuria and red, white blood cells, with the decrease in body temperature, the patient's condition is aggravated, can enter the shock phase and oliguria At this time, the bleeding phenomenon is aggravated, the renal function is obviously impaired, the meningeal irritation sign is not obvious, and the cerebrospinal fluid examination is also negative. The diagnosis depends on the antibody test in the blood of the patient.

6. Other

Others need to be diagnosed with viral meningitis or encephalitis caused by enteroviruses and other viruses, typhus, tsutsugamushi, etc. Chronic meningococcal septicemia should be associated with allergic purpura, vasculitis, rheumatism, subacute Identification of bacterial endocarditis.

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