measles
Introduction
Measles Introduction Measles (rubeola, morbilli) is an acute respiratory infection caused by measles virus. The main symptoms are fever, upper respiratory tract inflammation, conjunctivitis, etc., and it is characterized by red maculopapular rash on the skin and measles plaque on the buccal mucosa. The disease is highly contagious and is prone to epidemic in areas with dense populations and no vaccines. A pandemic occurred in about 2 to 3 years. Since 1965, China began to control the pandemic after a live attenuated measles vaccine. basic knowledge The proportion of illness: 0.002% Susceptible people: no special people Mode of infection: respiratory transmission Complications: respiratory syncytial virus infection Staphylococcus aureus pneumonia empyema lung abscess pericarditis bronchiectasis acute laryngitis otitis media myocarditis dehydration
Cause
Measles cause
Infection (35%):
The measles virus belongs to the family Paramyxoviridae and the morbillivirus. Unlike other paramyxoviruses, there is no special neuraminidase activity. The measles virus is a single-stranded negative-strand-ribonucleic acid (RNA) virus. For larger, the mirror is generally spherical, with a diameter of 150-300 nm, and the shape is variable, sometimes it can be filamentous. The center of the virus is composed of ribonucleic acid and a symmetrical spiral capsid, and the outer cover lipoprotein envelope has short protrusions. With hemagglutinin, it can agglutinate monkey red blood cells, and sequence the earliest isolated measles virus Edm strain. It is known that its genome is not segmented and has a length of about 15893 bp. There are six structural genes encoding six structural proteins, starting from the 3 end. In order: nucleoprotein (N) molecular weight 60 × 10 3 , phosphoprotein (P) molecular weight 72 × 10 3 , membrane protein (M) molecular weight 37 × 10 3 , blood lysin (F) molecular weight 60 × 10 3 , blood coagulation Protein (H) has a molecular weight of 78×10 3 to 80×10 3 and an RNA-dependent RNA polymerase-macroprotein (L) with a molecular weight of 210×10 3 , wherein the N, P, L proteins are combined with viral RNA, and the other three M, H, F proteins bind to the viral envelope, and N protein is measles The main protein of toxic, in the form of phosphorylation, plays a major role in gene packaging, replication and expression, and also participates in the binding of RNA, the formation of nuclear membrane structure, etc. The P gene can encode three proteins of different lengths, namely P. C, V protein, P protein is a phosphorylated polymerase binding protein, which binds to N and mRNA to form a complex, participates in the envelope of RNA and regulates the cellular localization of N protein. V and C proteins may regulate replication and transcription. Function, the protein encoded by the L gene is the same as the RNA-dependent RNA polymerase. The P protein and the nucleocapsid form a nuclear protein complex. The membrane protein encoded by the M gene is located between the viral envelope and the nucleocapsid. A non-glycosylated protein that forms the inner layer of the viral envelope, maintains the integrity of the viral particle, acts on the propagation of the virus, and is involved in viral assembly and germination. The F gene encodes a fusion protein, which is a glycosylated protein. The surface of the envelope, the precursor F0 is not biologically active, and is active when cleavage into F1 and F2 proteins. The F protein is related to the blood-soluble activity of the virus and the cell membrane fusion activity. When the virus spreads, the cells are fused with the cells. The H gene encodes a hemagglutinin, a glycosylated surface protein with hemagglutination, which is a hemagglutinin, which acts when the virus adheres to the host cell. It is known that the H protein contains a cell receptor binding site. It can bind to the measles virus receptor (CD46) present on the surface of the host cell to initiate the infection process of the virus in the host. When the measles is infected, the human body can produce antibodies against the three envelope complex proteins, F protein and H protein. It is the main viral antigen that the measles virus contacts the human immune system and causes the body to produce an antibody response. It is believed that the lack of antibodies to the F protein can cause atypical measles in the clinic, while the lack of antibodies to the M protein is associated with the measles subacute sclerosing whole brain. The onset of inflammation (SSPE).
The measles virus can be adapted to the tissue culture of human, monkey and dog. It is also easy to culture and pass through in chicken embryo cells. The virus is isolated from the patient specimen. The primary human embryonic kidney or monkey kidney cells are generally most successful, and the cell culture can be used. Two kinds of lesions appear: one is the formation of cell fusion, forming a huge fusion cell, which may contain more than 10 to 130 nuclei and have intranuclear inclusion bodies; the other pathological change is that the cells become fusiform or linear, and humans are measles The only natural host of the virus, the monkey can also be infected, the symptoms are mild, the measles virus wild strain can not infect small animals in the laboratory, but the vaccine strain measles virus can be injected into the newborn suckling mice by intracerebral injection.
Measles virus is unstable in vitro, easy to inactivate, sensitive to heat, dryness, ultraviolet light and fat solvents such as ether, chloroform, etc., so boiling, sunshine and general disinfectants are easy to inactivate, can be inactivated at 56 ° C for 30 min At pH 7, the virus survives well, and pH<5 or >10 cannot survive. The measles virus excreted with the patient's droplets can maintain its viability for at least 34 hours at room temperature, if the virus is suspended in a protein-containing substance such as mucus. In the middle, the survival time can be prolonged, because the protein can protect the virus from heat and light, and the protein-protected measles virus can be stored at -70 ° C for more than 5 years.
Genetic factors (20%):
The measles virus has long been considered to be a hereditary, antigenically stable virus with only one serotype, but the measles virus wild strain isolated from all over the world since the 1980s is compared with the 1950s and 1960s. There are many differences in biological characteristics and antigenicity, mainly manifested by the disappearance of hemagglutination and blood adsorption, the narrow range of cell culture sensitivity and the occurrence of antigenic drift. By measuring the genetic sequences of the wild measles virus strains in various places, it is found that there exists Various genetic variants, which were divided into eight genomes (A, B, C, D, E, F, G, H) and more than 20 genotypes in 2001 (A, B1-3, C1-3, D1). -9, E, F, G1-3, H1-2), type A was first isolated in 1954. It is widely distributed throughout the world and contains almost all vaccine strain viruses. Type B 1983 was first isolated in Africa, type C. It was isolated in the United States in the 1970s and later in Europe. In recent years, it has caused several outbreaks in high-immunity areas. The D1 type was first discovered in the United Kingdom in 1974, and the D3~D5 type was popular in Asia, Taiwan. Also isolated to the D3 type, in South Africa, the Americas have D3, D in recent years Type 6 is prevalent, E-type 1971 is found in the United States, Germany is also present, and is no longer popular. Type F 1979 was found in SSPE patients in Spain, G-type 1983 was found in the United States, and in 1998, China first reported molecular epidemiology of measles wild strains. The situation confirmed that the H1 type was isolated in 1993 and 1994, and the H1 type was isolated in Hunan, Shandong, Hebei, Beijing, Hainan, Anhui and other places. After the H2 type was isolated in Vietnam, the molecular epidemiology of the above-mentioned measles wild strains was It is important to find the factors that cause the measles virus to mutate; to identify the mutant strains and their origins, and the epidemic pathways, etc., to improve the existing measles vaccine, and to achieve the world goal of eliminating measles better and faster.
Immune response (20%):
(1) Elevation of specific antibodies: 4 to 10 days after measles virus infection, hemagglutination inhibitory antibodies and neutralizing antibodies begin to rise in the blood, and reach a peak at 4 to 6 weeks, and fall to 1/4 after 1 year. However, it is stored for a certain level for almost a lifetime. If the measles virus is no longer exposed, the antibody level can be reduced to 1/16 after 15 years. There is still some immunity. The complement-binding antibody appears late and lasts for a short time. The antibodies are basically present in IgM and IgG. The IgM antibody can be detected in the blood 2 to 3 days after the fever, and rises rapidly. It reaches a peak in about 10 days, and its level can reach 1:100,000, gradually after 30 to 60 days. The decline disappeared, the positive indicates the recent infection, the IgG antibody can appear at the same time or later than IgM, and reaches a peak at 25 to 30 days. After that, the antibody level gradually decreases, and falls to 1/4 to 1/2 within 6 months, and then decreases slowly. Maintained at a low level, positive often indicates past infection, and sIgA secretion can be detected in the respiratory tract. Generally, IgG antibody can be as high as 1:100,000 after hemorrhage, hemagglutination inhibition antibody 1:512, suffering from measles Can preserve the immunity against measles virus for a long time, the mechanism It is still not very clear today. Some people think that it is related to repeated exposure to measles virus after illness. After exposure to measles virus, there is often no obvious symptoms and recessive infection, but the antibody titer in the body can rise again and enhance specific immunity. In addition, it is believed that the cellular immunity produced by measles virus plays an important role in preventing measles reinfection, even if the antibody level is reduced to a minimum, it can protect the body from reinfection, and observe various viruses from the molecular biological analysis of measles virus. The structural proteins encoded by the genes can cause their respective antibodies after infection in the body, and their growth and dynamics are also different. For example, anti-N, P protein antibodies can be detected when the measles is rash, and the titer rises very quickly. That is, high levels of anti-H protein antibodies can prevent the virus from being adsorbed on sensitive host cells, and can be detected when the rash appears. The titer increases significantly within 2 to 3 weeks. Anti-F protein antibodies can prevent the virus from spreading between cells. The antibody titer in the blood is always stable at a low level, and the H hemagglutination inhibitor antibody and the F blood-suppressing antibody all play a role in neutralizing the virus. The main antibody to reinfection, the latter is more important than the former, M membrane protein antibodies can only be positive in 50% of patients within 3 weeks of the disease, and antibody levels are also low.
(2) Specific cellular immune response: Measles virus infection can cause host cell immune response, sensitize T cells, and can produce cytotoxic T cells specific to measles virus, class I and II, which can cause cytopathic and release lymphocytes. Cellular activity factors, leading to monocyte infiltration, multinucleated giant cell formation and necrosis of invaded cells, and also termination of viral infection. During measles infection, CD8+ and CD4+ T cells are activated, involved in virus clearance and rash. process.
(3) The role of interferon: Interferon levels may increase in serum 6 to 11 days after infection with measles virus or live measles vaccine, and disappear after 30 days. This interferon caused by measles virus has a protective effect.
(4) Restoration of measles and recovery from anti-re-infection Measles virus infection mainly relies on cellular immunity, specific antibodies and interferon production, and the three interact at the same time in the early, middle and late stages of the disease. If you have measles, the disease process is still normal, and there is no repeated infection after recovery; while those with low cellular immunity suffer from measles, even if they are treated with high-dose immunoglobulin, the course of measles is often serious, and it is often unhealed. Therefore, it is fatal, so it is believed that the role of cellular immunity in measles recovery may be more important than humoral immunity. However, serum antibodies play an important role in preventing measles infection. Therefore, the mechanism of passive immunization is here. The immune response to the measles virus should be the body's comprehensive immune function.
(5) Non-specific immune response: There are other non-specific immune reactions in the measles process: such as weakened neutrophil migration in the acute phase, decreased total number of white blood cells (including neutrophils and lymphocytes), thrombocytopenia, and complement system Inhibited, C3, C4, C1q and C5 decreased, lymphocyte transformation reaction was inhibited, T cells and B cells decreased, serum immunoglobulin IgA decreased, IgM increased, and IgG did not change much, skin delayed hypersensitivity It can be attenuated after natural infection and vaccination, which may be related to cellular immune response in measles, often caused by the rise of the inhibitory cytokine interleukin-4, due to the significant decline in various immune responses during measles infection. Therefore, the patient's original eczema, asthma, nephrotic syndrome and other diseases are temporarily relieved, but the patient is prone to secondary infection of the lungs, the original tuberculosis lesions may appear to deteriorate, the tuberculin reaction was originally positive, measles Or it may be temporarily negative, and the wound healing is often slow and other adverse consequences.
Pathogenesis:
Pathogenesis
Through animal experiments and pilot infections, there is a relatively complete understanding of the uncomplicated measles virus infection process. The measles virus injects droplets of droplets from the patient to the nasopharynx of the susceptible person and other parts of the respiratory tract or eye. The membrane enters the human body, and the virus grows and multiplies in the epithelial cells, causing infection. On the first 1-2 days after infection, the virus rapidly multiplies in the invading local lesion mucosal cells, invades the local lymphoid tissue, enters the white blood cells, and causes the first viremia (1 to 3 days). The virus follows the blood circulation by the single nucleus. White blood cells are carried and spread to the liver tissues of the liver, spleen, bone marrow, lymph nodes and other lymphoid tissues of other organs, and the second large amount of viremia occurs on the 3rd to 7th day, and the blood is invaded by viruses. Mainly mononuclear leukocytes, the virus also proliferate well in both T cells and B cells. Both epithelial cells and endothelial cells of the body can be infected by viruses, causing inflammation and necrosis. The infected tissues are extensive, including liver, spleen and thymus. Lymph nodes, skin, eye-bound membrane, the entire respiratory system from the upper respiratory tract to the lungs, etc., at this time the clinical symptoms peak (precursor period), after 1 to 3 days with the symptoms of respiratory catarrh, the oral mucosa appears Coriolis (Koplik' Spot), and then the skin develops a maculopapular rash. At this time, the measles virus proliferates in the invading cells, destroys the cells, causes inflammation, and causes clinical symptoms (11th to 14th days). There are three explanations for the mechanism of rash and Coriolis plaque due to allergies caused by inflammatory products:
1 virus directly damages the vascular endothelial cells of mucosal skin;
2 The viral antigen in the skin vascular endothelial cells interacts with the body antibody to activate different reactions to cause skin damage;
3 T-cells in skin vascular endothelial cells induce delayed hypersensitivity of viral antigens. Clinically, patients with T-cell deficiency often do not develop rash after infection with measles virus, and patients with no gamma globulinemia are infected with measles virus. On the 15th to 17th day, the amount of measles virus in the blood decreased rapidly with the increase of specific antibodies in the body until it disappeared, and basically entered the recovery period.
2. Pathological changes
When measles virus invades various tissues and cells, it mainly causes inflammation, extensive mononuclear cell infiltration and cell necrosis, and fusion forms multinucleated giant cells. These giant cells vary in size and shape, and may contain more than 100 nuclei. Eosinophilic inclusion bodies can be seen in the cytoplasm and in the nucleus, and the polymerized virus coats can also be seen, especially in the cytoplasm. The multinucleated giant cells seen in the mononuclear macrophage system are called Warthin-Finkeldey cell, widely found in lymphoid tissue of the pharynx, tonsils, parabrachial and mesenteric lymph nodes, lymphoid tissue in the appendix and intestinal wall; fusion found in tissues of the respiratory and intestinal mucosa, epithelial surface of the skin Multinucleated giant cells are called epithelial giant cells. When the symptoms of respiratory catarrh are obvious, the giant cells of the respiratory epithelium often fall off the surface and can be found in respiratory secretions, which has certain diagnostic significance.
Typical epithelial giant cells can be found in measles rash biopsy, skin epithelial cells are swollen, vacuolar degeneration, necrosis, keratinized desquamation, dermal dermal endothelial capillary swelling, hyperplasia, lymphocyte and histiocyte infiltration, Vasodilatation, also found viral antigens in the rash, Coriolis plaque lesions and rash similar, can be necrotic into small ulcers, mostly viremia results, rather than the primary lesion.
In the process of simple measles, the pathological damage is mainly respiratory, lymphoid and mucosal skin. The whole respiratory system is more obvious. The mucosa has congestion and edema, mononuclear cell infiltration, even mucosal necrosis, ulcer formation, and interstitial pneumonia in the lung. , mainly multinucleated giant cell lesions, called measles giant cell pneumonia (Hacht giant cell pneumonia), especially in patients with low immune function, when concurrent bacterial infection, there may be pulmonary parenchymal purulent inflammation, in the intestinal wall and small intestine The multinucleated giant cells containing inclusion bodies and inflammatory changes can be seen in the lymphocytes of the appendix. The brain and spinal cord of patients with measles encephalitis can be swollen and congested. It can be seen in the hemorrhagic foci, perivascular oozing and lymphocytic infiltration. Later, the central nervous system is widely seen. Demyelinating lesions.
Prevention
Measles prevention
Improving the immunity of the population is the key to preventing measles. Therefore, it is very important to carry out planned immunization for susceptible populations. If measles patients are found, comprehensive measures should be taken to prevent transmission and epidemic.
(1) Autoimmune
Susceptible persons should be vaccinated against measles live attenuated vaccine, the initial age should not be less than 8 months, due to the fear of antibodies from the mother to neutralize the vaccine virus, making it invalid. China is currently scheduled to start at 8 months, when 4 years old Strengthen once, foreign countries advocate that the first vaccination is more insurance at 15 months, and believe that those who are vaccinated within 1 year of age should be strengthened once after 1 year, the vaccine should be kept in the dark at 2 ~ 10 °C, each time subcutaneous injection of 0.2ml 1 time, all ages are the same, the best inoculation in the first month of the measles epidemic season, susceptible people within 2 days after contact with measles patients, if the emergency immunization against measles vaccine, can still prevent the onset or reduce the disease, popular time 80% of the vaccination is vaccinated, and the epidemic can be controlled within 2 weeks. After the vaccination, the reaction is mild. After 5 to 14 days, there may be a few days of low fever, occasionally a sparse red rash.
Those with fever and urgency, chronic diseases should be suspended for automatic immunization; those with allergies, active tuberculosis, malignant tumors, leukemia and immunosuppressive agents or radiation therapy and congenital immunodeficiency should not be vaccinated with measles live attenuated vaccine; Those who have received blood transfusion or blood products and passive immunization preparations within 8 weeks, and those who receive other live attenuated vaccines within 4 weeks should delay the vaccination to avoid affecting the effect.
After vaccination with live attenuated measles vaccine, serum antibodies have increased, the positive rate can reach 95% to 98%, and antibodies such as hemagglutination inhibition can appear in the blood at the earliest 12 days, reaching a peak at 1 month, and the antibody titer is 1 : 16 ~ 1:128, after 2 ~ 6 months, gradually decline, generally still maintain a certain level, some vaccinates can disappear after 4 to 6 years, so the age of multiple cropping can be 4 to 6 years old, the baby's active immunization coverage When it reaches 90% or more, a disease-free area can be formed.
In some countries, the measles vaccine is vaccinated with the rubella vaccine and the mumps vaccine, and the immune effect is not affected.
(two) passive immunization
Young and weak and sick people who are exposed to measles, passive immunization within 5 days can be prevented from onset, and can only be relieved within 5 to 9 days. Intramuscular injection of gamma globulin (10%) 0.2ml/kg, or placenta Globulin 0.5 ~ 1.0ml / kg, or adult plasma 20 ~ 30ml, passive immunity can only be maintained for 3 to 4 weeks, 3 weeks later contact with measles patients need to be injected.
(3) Comprehensive preventive measures
Patients with measles should be reported immediately for epidemic situation and 5 days after the isolation of the respiratory tract to the rash. Those with complications should be extended to 10 days. All susceptible children who are exposed to the patient should be quarantined for 3 weeks and given automatic or passive immunity according to the situation. For immunization preparations, the quarantine should be extended to 4 weeks. During the measles epidemic, patients should be vigorously promoted not to go out, medicines are delivered to the door, and susceptible children do not suffer from the door. Collective institutions strengthen morning inspections, and suspicious persons should be isolated and observed.
Complication
Measles complications Complications Respiratory syncytial virus infection Staphylococcus aureus pneumonia, empyema, lung abscess, pericarditis, bronchiectasis, acute laryngitis, otitis media, myocarditis, dehydration
In the process of measles infection, due to low immunity in the body, it is easy to be secondary to other viral or bacterial infections, especially in young and weak and malnourished patients. It can also be caused by poor environment and improper care. Secondary respiratory infections are the most common. It is caused by Staphylococcus aureus, hemolytic streptococcus, Streptococcus pneumoniae, influenza bacillus or Escherichia coli; secondary viral infection is infected with adenovirus and respiratory syncytial virus, and bacterial virus infection can also occur.
Respiratory complications
(1) pneumonia: measles virus infection often affects the lungs. About half of measles patients have lung lesions. Most of the pneumonia caused by measles virus occurs in the early stage of the disease. Patients may have mild shortness of breath and a voice in the lungs. X-ray examination of hilar lymph node enlargement, thickening of lung texture, hyperinflation of both lungs, infiltration of small lungs, rapid disappearance of shadow after rash, secondary pneumonia caused by bacteria or other viruses is the most common complication of measles, more common in In the rash period, the infants and young children are seriously ill. Clinically, after the rash is released, the fever does not decrease, the symptoms of dyspnea and hypoxia are aggravated, the lungs are increased, the symptoms of poisoning are intensified, and vomiting, diarrhea, dehydration, acidosis, etc. may occur. Metabolic disorders, even coma, convulsions, heart failure and other critical symptoms, large X-ray films of the lungs can be seen, large-scale fusion lesions, Staphylococcus aureus pneumonia easily with empyema, lung abscess, pericarditis, etc., the course of repeated delays, long-term Bronchiectasis can be left behind, and most of the hospitalized measles patients have pneumonia, which is the main cause of measles death.
(2) laryngitis: measles process mild laryngitis, bronchitis is quite common, sometimes developed into severe acute laryngitis or laryngotracheal bronchitis, mostly secondary infections of bacteria, hoarseness, croup, cough, breathing Difficulties, hypoxia and chest recession, etc., when the respiratory tract is severely blocked, tracheotomy or intubation must be performed as soon as possible to rescue.
(3) otitis media: a common complication of measles, mostly occurs in young children, for secondary bacterial infections, children crying and uneasy, pay attention to the secretion of the external auditory canal.
2. Cardiovascular complications
Measles rash symptoms are severe, high fever, shortness of breath, hypoxia, dehydration, etc. often lead to cardiac insufficiency, patients often manifest as shortness of breath, pale, nasal cyanosis, irritability, cold limbs, pulse speed, heart sound Low blunt, rash darkening or sudden retreat, liver sharply increased, critical illness, low voltage on ECG, T wave inversion, abnormal conduction, etc., a small number of patients with signs of myocarditis or pericarditis.
3. Nervous system complications
Encephalitis is a common complication of measles. According to statistics, the pre-vaccination prevalence rate is 0.01% to 0.5%. Even in patients without obvious neurological symptoms, EEG examination is 50% abnormal. Most of them think that measles encephalitis Mostly caused by measles virus directly invading brain tissue, measles virus or its antigen has been detected from brain tissue or cerebrospinal fluid many times, but the role of immune response caused by virus in the pathogenesis can not be excluded, most of measles encephalitis occurs. The rash period, occasionally before the rash or after the rash, often has high fever, headache, vomiting, lethargy, confusion, convulsions, tonic spasm, cerebrospinal fluid with mononuclear cells, increased protein, not low sugar, large Most patients can recover, but a small number can leave mental dysfunction, limb paralysis, epilepsy, blindness, deafness and other sequelae.
4. Other complications
Improper care, poor diet, dark and humid environment often cause complications in patients, long-term taboos, avoid oil causing malnutrition, vitamin A deficiency, etc., so that the body's immunity is reduced, severe cases of corneal softening or even perforation caused blindness, neglecting oral hygiene Stomatitis, and even serious complications such as walking horses, measles may cause skin purple spots due to increased capillary permeability, mucosal bleeding, secondary infection may cause local lymphadenitis, suppurative ocular membrane inflammation, enteritis, appendicitis, Meningitis, etc., after the measles, the body's immunity is prone to pertussis, diphtheria and other respiratory infections, and it is easy to relapse the original tuberculosis lesions, causing miliary tuberculosis and tuberculous meningitis.
Symptom
Measles Symptoms Common symptoms High fever pale pale fever convulsions runny ecchymosis papules irritability eyelid edema swollen conjunctiva congestion fever with rash
1. Typical measles
(1) Incubation period: generally 10 days ± 2 days (6 to 21 days), the infection period is severe or the infection can be as short as 6 days after receiving the blood transfusion, and the immunological preparation (whole blood, serum, immunoglobulin, etc.) or When the measles vaccine has been vaccinated, the incubation period can be extended to 3 to 4 weeks. The measles virus can be discharged from the upper respiratory secretions at the end of the incubation period of 1 to 2 days. Some patients may appear after several hours of contact with measles. Temporary mild upper respiratory symptoms and low fever, even a transient rash, but very rare, the typical course of measles can be divided into three stages: the prodromal phase, the rash phase and the recovery phase.
(2) prodromal period: generally lasts for 3 to 5 days, frail and severe cases can be extended to 7 to 8 days, and those who have been vaccinated with measles or have passive immunity can be as short as 1 day. For the symptoms of catarrhal inflammation of the upper respiratory tract (including the ocular membrane), there are fever, cough, runny nose, tears, photophobia, etc., accompanied by varying degrees of general malaise, fever often low and high night, rising day by day, Up to 39 ~ 40 ° C, infants and young children can have febrile seizures, older children or adults often complain of headache, dizziness, fatigue, lethargy, coughing is getting worse, mostly dry cough, because the upper respiratory tract mucosal inflammation often extends to the throat, trachea, Bronchial, cough often with hoarseness, young children even have shortness of breath and difficulty, often with decreased appetite, and even vomiting, diarrhea and other gastrointestinal symptoms, physical examination can be seen in the oral and pharyngeal mucosal congestion, 2 to 3 days after onset Coriolis plaque can appear on the buccal mucosa opposite the first molar, which is a characteristic sign of the measles prodromal period, and has early diagnosis value of measles. This small oral rash is white, 0.5~1mm tip size, scattered in bright red Wet On the buccal mucosa, only a few at the beginning, quickly increased, and can be fused, spread to the entire buccal mucosa, as well as the inside of the lips, gums, etc., and occasionally on the orbital membrane, rarely occurring in hard, soft palate, When the number of spots is small, it is easy to see small white spots in the daylight, and the surrounding area is red. When the number is large, it can be fused into a piece. Only the bloody buccal mucosa has fine salt-like protrusion particles. The Coriolis spot generally lasts for 2 to 3 days and disappears rapidly. Sometimes it can be seen 1 to 2 days after the rash. Individual patients see a rubella-like or scarlet-like fever or urticaria-like rash on the neck, chest, and abdomen at the beginning of the prodromal period. It disappears within a few hours and is called a precursor rash. Sometimes in the sag (also known as uvula), tonsil, posterior pharyngeal wall, soft palate can be found brown red spots, the early rash period quickly disappeared.
(3) rash period: 3 to 5 days after onset, when the symptoms of respiratory tract catarrh and fever peaked, rash began to appear, often 1 to 2 days after seeing Coriolis, first appearing reddish from behind the ear The maculopapular rash gradually spreads to the forehead of the head, face, neck, and extends from top to bottom to the chest, abdomen, back, and finally reaches the limbs until the soles of the palms. It spreads to the whole body in 2 to 3 days. The rash is mainly based on maculopapular rash. The color is bright red, the color is faded, the size is different, the average diameter is 2~5mm, the distribution is sparse and distinct, and the number of rashes increases when the rash peaks, and the aggregates are merged into pieces, and the color is gradually turned dark, but the skin between the rashes is still normal. Occasionally, herpes simplex or small hemorrhagic rash, when the condition is serious, especially with cardiopulmonary failure, the color of the rash can suddenly turn dark, and quickly retreat, with the rash reaching the peak, the symptoms of systemic poisoning are aggravated, and the body temperature is further increased. Above 40 °C, mental euphemism, lethargy, or irritability all day long, cough aggravation, dry lips, extremely swollen throat, swollen eyelids, excessive secretions, cervical lymph nodes and hepatosplenomegaly, lungs often dry, wet Arpeggio, chest X-ray Examination, it can be seen that the mediastinal lymph nodes are enlarged, the lung texture is thickened, and the adult is less likely to suffer from the natural infection caused by the measles virus in the pre-vaccination period. The symptoms of poisoning during the rash period are often more serious than those of children, and the rash is also dense, but Concurrent bacterial infections appear to be less than infants.
(4) Recovery period: In patients with measles alone, when the symptoms of rash and poisoning develop to a peak, the body temperature usually decreases rapidly within 12 to 24 hours, and the patient's spirit improves, the respiratory symptoms are relieved, but the cough can often last longer. The appetite is greatly improved. After 2 to 3 days of general body temperature decline, the rash disappears in the order of rash, leaving light brown pigmentation spots, with small bran-like desquamation, with more trunks, and retreat within 2 to 3 weeks. Complications, simple measles from onset to rash retreat generally 10 to 14 days.
2. Atypical measles
According to the genetic difference of measles virus, the virulence, the number of people entering the body, the age of the patient, the health status, the nutritional quality, the immunity, etc., the clinical development process of measles is mostly typical measles, in some cases still The following atypical performance can be presented.
(1) heavy measles: mostly due to weak constitution, other diseases, malnutrition, low immunity or secondary bacterial infections, such as measles, such as toxic measles, severe measles infection, onset Soon there will be high fever above 40 °C, accompanied by severe symptoms of poisoning, often unconscious, repeated convulsions, shortness of breath, cyanosis, rapid pulse, dense rash, dark red, fused into a piece, rash can be hemorrhagic, Forming purple spots, even accompanied by visceral hemorrhage, hematemesis, hemoptysis, blood in the stool (hemorrhagic measles), sometimes rash-like herpes-like fusion can form a bullous (herpes-like measles), some young and weak children with measles rash rash, failed to produce Through, no hand and foot, or rash suddenly hidden, body temperature dropped below normal temperature, pale or blue gray (Chinese medicine called white noodles), cold limbs, mostly due to cardiac insufficiency or circulatory failure (shock measles), heart rate Rapid, weak pulse, irregular breathing or difficulty, complicated with severe bacterial (Staphylococcus aureus) pneumonia or other viral pneumonia (adenoviral pneumonia) are also often heavy , Heart failure often occurs in critical illness and high mortality.
(2) Light measles: Most of them are caused by certain immunity to measles virus in the body. For example, 6 months ago, the baby still has passive immune antibodies from the mother, or recently injected passive immunization, or has been vaccinated against measles in the past. And the second infection can be manifested as mild, the light measles latency can be extended to 3 to 4 weeks, the incidence is mild, the prodromal period is short and not obvious, the respiratory catarrhal symptoms are mild, the Coriolis spot is not typical or Does not appear, systemic symptoms are mild, no fever or only moderate to moderate heat, rash is sparse and pale, with a short course of disease, few complications, but the immunity obtained after the disease, the specific antibody rise titer and the basic measles Similarly, it has been confirmed that measles also has a lot of latent infections or no rash-type measles, which can only be confirmed by an increase in serum-specific antibodies after the disease.
(3) Heterotypic measles: mainly occurs in patients who have been inoculated with measles inactivated vaccine in the past. When they are exposed to measles in the acute phase after 4-6 years of inoculation, they can cause heterotypic measles. The incubation period is 7 to 14 days, and the prodromal period can be sudden. High fever, up to 39 ° C, with headache, myalgia, abdominal pain, fatigue, etc., and the upper respiratory tract catarrhal symptoms are not obvious, may have dry cough, most of which have no runny nose, tears, ocular membrane inflammation, etc., most patients have no typical Coriolis Spot, rash occurs 2 to 3 days after onset, from the distal wrist of the extremities, the sacral part, the centripetal spread to the proximal extremities and trunk, the lower body is more, rarely spread to the nipple line above, occasionally in the head Facial, rash is generally yellow-red maculopapular rash, sometimes 2 ~ 3mm size herpes, itchiness, no crusting when regressing, rash even sputum, ecchymosis or urticaria, often accompanied by edema of limbs, respiratory symptoms Although not serious, the lungs sometimes smell snoring, X-ray examination shows hilar lymphadenopathy and flaky shadows in the lungs. This kind of pneumonia can be repeated for 1 to 2 years. Some patients can show liver and splenomegaly. Limb numbness, weakness and paralysis, Can also be clinically no obvious rash, and other symptoms of the disease, the most important diagnosis of this disease is the recovery of measles hemagglutination inhibition antibody and complement-binding antibody titer rose sharply, there are reports of heterotypic measles patients have not found The measles virus of the disease, epidemiological data also pointed out that the disease is not contagious.
The pathogenesis of this disease is currently thought to be caused by the hypersensitivity reaction to measles virus on the basis of partial immunization of the host. Studies have indicated that the inactivated measles vaccine lacks the F protein antigen (the formaldehyde used in the inactivated vaccine destroys the F protein), so it cannot Induction of anti-F protein antibodies in humans results in a lack of function to prevent measles virus invasion and spread in host cells, but only H protein hemagglutination inhibitory antibody (HI), inoculated inactivated vaccine several years later HI The antibody gradually decreased. When the measles virus was re-adsorbed, the HI antibody rose rapidly in the early stage, and it could reach 1:1280 in 10 days. However, the lack of F antibody could not prevent the virus from spreading between cells and cause atypical measles.
(4) Pregnant women and neonatal measles: Susceptible pregnant women suffering from measles are relatively serious. It is reported that 54% are hospitalized for primary measles pneumonia and other respiratory complications. Although pregnant women with measles are not as susceptible to rubella, they may cause fetal distortion. Often caused by stillbirth in early pregnancy, may cause spontaneous abortion or stillbirth and premature birth later, pregnant women with measles can pass the placenta to the fetus before delivery, so that newborns can also develop measles, the severity of the disease, However, there are often no obvious prodromal symptoms and more rashes. Therefore, it is recommended that newborns born to measles mothers be passively immunized after birth and injected with specific immunoglobulins.
Fetus can obtain measles antibodies from pregnant mothers through the placenta, and obtain passive immunity. Since the measles vaccine was widely used internationally in the mid-1960s, most women of childbearing age are immune to measles virus and are induced by vaccines. The titer is mostly lower than the antibody titer obtained after natural measles. After pregnancy, the antibody transmitted to the fetus through the placenta is also less. After birth, the measles antibody titer of the infant quickly drops below the protective level, so the newborn and the baby The prevalence of measles has increased compared with the pre-vaccination vaccine, and the general condition is not serious.
(5) Immunization is low in people with measles: regardless of congenital immunodeficiency or secondary immunodeficiency (such as cancer patients, adrenal corticosteroids, malnutrition immunity, etc.), if measles often suffers from severe illness, the mortality rate is also Higher, there are reports of cancer patients with measles often no rash, and more than half can occur measles giant cell pneumonia, and easy to develop encephalitis, clinically difficult to get a clear diagnosis of measles, can only rely on the measles virus antigen found in infected tissues Those who have not had measles in the past, especially those with low cellular immunity, such as patients with measles during infection, should use a specific immunoglobulin for passive immunization, the sooner the better, to prevent measles or at least reduce The condition, even if you have received measles vaccine, should be the case.
Examine
Measles check
1. Cytology and viral antigen examination. Exfoliated cell smears of nasopharyngeal aspirate or nasopharyngeal swab or urine sediment were stained with Gemsa or HE. Under normal light microscope, multinucleated giant cells were formed and distributed in the epithelium. The eosinophilic inclusion bodies in the nucleus and cytoplasm can be as high as 90% in the first week of the disease course, and have important reference value for the diagnosis of measles. If the above smear specimens are stained with specific antibody markers, they can be further examined. Measles virus antigen.
2. Serum antibody detection Serum-specific IgM antibody is a marker of recent infection. The detection of measles IgM antibody by immunofluorescence or capture ELISA is a commonly used specific diagnostic method. Only a single serum sample is needed, 3 days after onset. It can be detected from left to right (the highest positive rate is detected 5 to 20 days after the onset), and it is not interfered by rheumatoid factor. If the vaccine is not vaccinated within 1 month, and the serum measles IgM antibody is positive, the diagnosis can be confirmed. Double serum from the acute phase and recovery phase (2 to 4 weeks after the disease), total antibody detected by hemagglutination inhibition (H1) test and micro-neutralization test, or measles IgG antibody by ELISA, IFA, recovery period Serum antibody titer 4 times increase, has diagnostic value, can be used as a retrospective diagnosis.
Nasopharyngeal swabs were isolated from measles virus, and large X-ray films of the lungs showed large fusion lesions. Electrocardiogram showed low voltage, T wave inversion, conduction abnormality, etc., and EEG examination showed 50% abnormality.
Diagnosis
Measles diagnosis
diagnosis
Typical measles is not difficult to diagnose according to epidemiological history and clinical manifestations. Susceptible people have a history of measles exposure within 3 to 4 weeks, showing fever, runny nose, cough, eye conjunctival congestion, photophobia, tearing and other symptoms of upper respiratory tract. That is suspected and measles, if the Coriolis spot is found, it can be basically diagnosed. According to the characteristics of the rash after the rash, the distribution is easy to make a diagnosis. After the rash, there is desquamation and pigmentation to help diagnose, peripheral blood in the rash period. The total number of white blood cells is reduced to measles. The epithelial giant cells can be found in the nasopharyngeal secretions, sputum and urine sediments of the prodromal patients. The measles antigen can also be detected by immunofluorescence. It can be used as an early diagnosis basis to separate measles from tissue culture. The positive rate of virus is not high, serum hemagglutination inhibitory antibody, neutralizing antibody and complement-binding antibody detection, the titer of recovery period is more than 4 times higher than the initial stage of disease or the early specific IgM increase has diagnostic value. The clinical diagnosis of atypical measles is not easy, most of them Diagnosis can be established by means of antibody assays or molecular biological genetic tests.
Differential diagnosis
Measles should be differentiated from common rash diseases, as described below:
1. The main focus of rubella should be differentiated from light measles. The characteristics of rubella are: more common in young children and preschool children, rare in adults, short in prodromal period and mild symptoms, no heat or low fever, mild cough, runny nose, less conjunctivitis There is no Coriolis spot, and the rash occurs after 1 to 2 days of onset. It is quickly seen in the whole body. The rash is a sparse blemish, and the papules disappear after 1 to 2 days. No scaling, no marks, and at the same time, behind the pillow. , cervical lymph nodes, few complications, good prognosis, serum specific antibodies can help identify.
2. Children's acute rash is more common in infants and young children. It is mainly within 1 year old, and it is high fever for 3 to 5 days. Sudden decline can be accompanied by febrile seizures. The symptoms of respiratory tract are not obvious. When retreating or after retreating12
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