Pediatric Adenoviral Pneumonia
Introduction
Introduction to pediatric adenoviral pneumonia Adenovirus pneumonia is a pneumonia caused by adenovirus infection and is one of the more common diseases in children in China. Adenovirus infection can cause pharyngeal-binding membrane fever, pneumonia, encephalitis, cystitis, enteritis, etc. Adenovirus pneumonia is one of the most serious types of pneumonia in infants and young children, and is more common in infants from 6 months to 2 years old. basic knowledge The proportion of sickness: 0.01% Susceptible people: children Mode of infection: respiratory infection Complications: abdominal pain, diffuse intravascular coagulation, chronic pneumonia, atelectasis, bronchiectasis, edema
Cause
The cause of adenoviral pneumonia in children
(1) Causes of the disease
The pathogen is adenovirus. It is known that there are 41 serotypes of adenovirus, many of which are closely related to human upper and lower respiratory infections. Most of the adenovirus pneumonia in China is caused by type 3 and type 7, but 11,5,9, Types 10 and 21 have also been reported. Clinically, type 7 is heavier than type 3, and the etiology of inpatients from northern and southern parts of China (Changchun Institute of Biological Products and Bethune Medical University, 1962. Institute of Pediatrics, Chinese Academy of Medical Sciences and Virus Institute, 1962-1967, 1974-1977. Shanghai First Medical College, 1962-1964. Guangzhou People's Hospital, 1973-1983. Hubei Medical College, 1973-1980, etc.) have proved that type 3 and type 7 adenoviruses are glandular The main pathogen of viral pneumonia, from the throat swab, feces or post-mortem lung tissue can be isolated from the virus, the serum antibody titer in the recovery period is more than 4 times higher than the early (onset 5 to 10 days or earlier), in part of measles complicated with pneumonia In the severe cases, the same pathogen test results were obtained. The adenovirus type 11 was also found to be a common pathogen of pneumonia and upper respiratory tract infections in Beijing and other places (Pediatric Research Institute, 1964-1966). In addition, 21, 14 and 1 2,5,6 and so on are also gradually appearing in mainland China. Taiwan is mainly type 1,2,5,6. Bethune Medical University carried out genomic type of adenovirus type 3,7 isolated from 1976 to 1988. Analysis, it is proved that type 7 causes severe pneumonia.
(two) pathogenesis
Adenovirus is a DNA virus that mainly propagates in the nucleus. It is resistant to temperature, acid, and lipid-resistant solvents. In addition to pharynx, combined with membrane and lymphoid tissue, it is also intestines, which can be agglutinated according to its special animal red blood cells. The ability is divided into 3 groups, 3,7,11,14,21, which are easy to cause pneumonia in infants and young children, can agglutinate monkey red blood cells, adenovirus pneumonia lesions are extensive, manifested as focal or fusion, necrotic lung infiltration and Bronchitis, both lungs can have large solid necrosis, mainly in the lower leaves, lung tissue other than consolidation can have obvious emphysema, bronchus, bronchioles and alveoli with monocytes and lymphocytes infiltration, epithelial cell damage The wall of the tube is necrotic, hemorrhagic, alveolar epithelial cells are significantly proliferated, and there are inclusion bodies in the nucleus.
Prevention
Prevention of adenoviral pneumonia in children
The oral attenuated live vaccine of adenovirus type 3,4,7 has been proven to have a preventive effect by small-scale application abroad, but it has not been produced and applied on a large scale. During the epidemic, especially in the ward, it should be isolated as much as possible to prevent cross-infection; In the work, more family treatments for infants and young children should be done. In child care institutions, special attention should be paid to early isolation and avoidance of nurses with colds to continue their nursing work to reduce the chance of transmission. It is reported that the incidence of adenovirus cross infection is 60%. ~ 85%, the contact time is short, 20 minutes can cause disease, the incubation period is 4 to 6 days, therefore, children with adenovirus infection can not be in the same room as other children to avoid cross-infection.
Complication
Pediatric adenoviral pneumonia complications Complications abdominal pain diffuse intravascular coagulation chronic pneumonia atelectasis bronchiectasis edema
In the course of adenovirus pneumonia, Staphylococcus aureus, Escherichia coli, Streptococcus pneumoniae, Klebsiella pneumoniae, Pseudomonas aeruginosa and other infections may occur, resulting in more serious disease. In the later stage of adenovirus pneumonia, the following points are often Prompt there are secondary bacterial infections:
1. The condition does not improve after about 10 days of onset, or it is once again relieved and worsened.
2. turns yellow or Taomi water color.
3. There are suppurative foci in other parts of the body.
4. There is a empyema.
5. X-ray inspection has a new shadow.
6. Increased white blood cell count and increased neutrophil ratio or left shift of the nucleus.
7. The neutrophil alkaline phosphatase or tetrazolium blue staining value increased, in the extreme stage of severe adenovirus pneumonia (6th to 15th day), a few cases can be complicated by diffuse intravascular coagulation (DIC), Especially prone to secondary bacterial infections, there are microcirculatory dysfunction before DIC, initially limited to a small amount of bleeding in the respiratory tract and gastrointestinal tract; later, there may be extensive lung, gastrointestinal and skin bleeding, the disease The primary screening test, screening test and confirmatory test can confirm the diagnosis. Changchun Bethune Medical University found severe cases or complicated type 7 or type 3 adenovirus myocarditis. It is characterized by acute onset and rapid recovery. It is generally seen in the early 2nd week of the disease course. Cardiac hypoxia, edema elimination, its recovery is faster, but due to combined heart failure, often missed diagnosis of myocarditis; so should pay attention to sudden appearance of pale, sweating, vomiting, abdominal pain, heart expansion, heart rate faster or slower, and Liver and other diseases, routine electrocardiogram and myocardial enzyme examination to determine the diagnosis, severe pneumonia often accompanied by pulmonary fibrosis, chronic pneumonia, atelectasis and bronchiectasis.
Symptom
Symptoms of adenoviral pneumonia in children Common symptoms High fever diarrhea, bloating, irregular heat, wheezing, pale pharyngeal congestion, tachycardia, fistula, respiratory breath
According to the analysis of 245 cases of virologically confirmed infantile adenovirus pneumonia in Beijing from 1959 to 1963, the clinical features can be summarized as follows.
1. General performance
The incubation period is 3 to 8 days. The onset is usually acute and the adenovirus pneumonia is inconsistent. The high fever above 39 °C occurs from the first 1-2 days. Most of the retention is above 39~40 °C. The next is irregular. Fever, relaxation heat is less common, the highest body temperature of more than 3/5 cases exceeds 40 ° C, mild symptoms generally fall 7 to 11 days, other symptoms quickly disappear, infants and young children are more serious, the recovery is On the 10th to 15th day, the fever subsided, and the retreat and the retreat accounted for half of each. Sometimes there was fever after the sudden retreat. After 1 to 2 days, it fell to normal. If there were complications, the heat continued to retreat.
2. Respiratory symptoms and signs
Most sick children have coughing from the onset of symptoms, often manifested as frequent cough or cough, and at the same time, pharyngeal congestion, but nasal symptoms are not obvious, breathing difficulties and cyanosis mostly begin on the 3rd to 6th day, gradually worsening . Severe cases of nasal wing fan, three concave signs, wheezing (with wheezing and hernia obstructive dyspnea) and lips, nail bed bruising, percussion is easy to get dull voice; voiced parts with respiratory sound reduction, sometimes can hear tubular breath sounds Most of the initial auscultation has a rough or dry snoring sound. The wet snoring sounds signs of emphysema after the third to fourth days of onset. In severe cases, there may be pleural reaction or pleural effusion (more common in the second week). The exudate of the secondary infected person is grass yellow and not turbid; when there is secondary infection, it is a turbid liquid, and the number of white blood cells exceeds 10×109/L.
3. Nervous system symptoms
Generally, after 3 to 4 days of onset, drowsiness, wilting, etc., sometimes alternating irritability with wilting, semi-coma and convulsions may occur in the middle and late stages of severe cases, some of the sick children head backwards, the neck is stiff, except for toxic encephalopathy In addition, there are still some encephalitis caused by adenovirus, so sometimes need to do the waist through the identification.
4. Circulatory system symptoms
Pale pale is more common, heavy face gray, heart rate increased, mild generally no more than 160 times / min, severe cases more than 160 ~ 180 times / min, sometimes up to 200 times / min, 35.8% of severe cases can be Heart failure occurred on the 6th to 14th day after the onset, and the liver gradually enlarged, reaching 3 to 6 cm below the rib. The quality was hard, and a few may have splenomegaly.
5. Digestive symptoms
More than half of the patients have mild diarrhea and vomiting. In severe cases, they often have abdominal distension. Diarrhea may be related to the reproduction of adenovirus in the intestine. However, in some cases, digestive function may also be affected by high fever and high fever.
6. Other symptoms
There may be catarrhal conjunctivitis, red papules, maculopapular rash, scarlet fever-like rash, the appearance of lime-like white spots on the tonsils is not high, but also a special sign in the early stage of the disease.
7. Course of disease
According to the respiratory system and symptoms of poisoning, the disease is divided into mild and severe cases. The mildness usually decreases in 7 to 14 days, and other symptoms begin to improve. However, the lung shadow takes 2 to 6 weeks to fully absorb, and the severe case is in the 5th. After ~6 days, every time there is obvious lethargy, pale and gray, hepatomegaly is obvious, wheezing is obvious, the lungs have large consolidation, some children have heart failure, convulsions, semi-coma, and the recovery period of lung lesions is longer. It takes 1 to 4 months, and after 3 to 4 months, there is still a lot of atelectasis. It may develop into bronchiectasis in the future. We have followed up for 3 to 7 years of adenovirus type 3,7. 30.1% had chronic pneumonia, atelectasis and individual bronchiectasis. Later, 109 cases of type 3,7,11 adenovirus pneumonia were followed up for 10 years. X-ray plain film showed 45.3% of pulmonary interstitial thickening, fiber Chronic bronchitis, chronic pneumonia with bronchiectasis accounted for 3.8%, bronchiectasis and chronic pneumonia accounted for 4.7%, adrenal pneumonia in preschool and school-age children, generally mild, often persistent high fever, but respiratory tract Symptoms and nervous system symptoms are not heavy, hemp When the rash is complicated by or secondary adenovirus pneumonia, all the symptoms are serious, and the condition often suddenly deteriorates. We have observed the clinical manifestations of 34 cases (1964-1980) type 11 adenovirus pneumonia and found it with type 3,7 adenovirus. There were no significant differences in the symptoms of pneumonia, but severe and death were similar to those of type 3, but significantly less than type 7. We have observed 38 cases of infants with adenovirus pneumonia in 1 to 5 months (type 3, type 20, type 7 12) For example, 6 cases of type 11 (1981 to 1983), 8 cases of bronchiolitis, 30 cases of pneumonia, the clinical features are: low or moderate fever, short heat history, no signs of lung consolidation, chest X-ray Small pieces of shadow-based, wilting, lethargy and other neurological symptoms occur less than 6 months of infants and young children, clinically unable to distinguish from respiratory syncytial virus or parainfluenza virus pneumonia, resulting in no case of this group of cases before the etiology report Clinical diagnosis of adenovirus pneumonia.
Examine
Examination of pediatric adenoviral pneumonia
1. The total number of leukocytes in the blood: in the early stage (1st to 5th day), most of them are reduced or normal, about 62% of cases are below 10×109/L, and 36% are (1015)×109/L. Change, the late white blood cell values are similar to those in the early stage, only increased after secondary bacterial infection, blood smear examination, neutrophil alkaline phosphatase and tetrazolium blue staining, generally compared with children with normal children or bacterial pneumonia Low, although the total number of white blood cells is as high as 15 × 109 / L, but the white blood cell alkaline phosphatase index is still significantly reduced.
2. Pathogen examination: The diagnosis should be based on the isolation of nasopharyngeal lotion virus, double serum antibody determination, some patients with serum condensation test can be positive, currently using immunofluorescence (indirect method is more suitable than direct method), enzyme Combined immunosorbent assay and specific IgM assay, rapid diagnosis of immune enzyme technology can help diagnose in time, but can not classify adenovirus, while conventional throat swab virus isolation and double serum antibody test are only suitable for laboratory As a retrospective diagnosis.
3. Urine test: During the fever, some cases have a small amount of protein in the urine test.
4. Cerebrospinal fluid examination: In children with meningeal irritation, cerebrospinal fluid examination is generally normal.
5. X-ray examination: X-ray morphology and disease, the disease period is closely related, the lung texture is thickened, and the blur is the early manifestation of adenovirus pneumonia. The lung lesions start to appear on the 3rd to 5th day of the onset, and may vary in size. The flaky lesions or fusion lesions are more common in both the lower lung and the right upper lung. After 6 to 11 days after the onset, the lesion density increases with the development of the disease, the lesions also increase, the distribution is wider, and they are integrated with each other. The difference is that the lesion of this disease is not limited to a certain lung lobe. Most of the lesions are absorbed after the 8th to 14th day. If the lesion continues to increase and the condition is aggravated, there should be a mixed infection, and the emphysema is quite See, there is no significant difference between the early and the extreme, bilateral diffuse emphysema or emphysema around the lesion, 1 / 6 cases may have pleural changes, more pleural reaction in the extreme stage, or pleural effusion
6. B-ultrasound: Abdominal B-ultrasound has hepatosplenomegaly; chest B-ultrasound has pleural effusion.
7. Electrocardiogram: myocardial damage, electrocardiogram is generally sinus tachycardia, severe cases have increased right heart load, T wave, ST segment changes and low voltage, individual I ° ~ IIo atrioventricular block, occasionally Pulmonary P waves appear.
Diagnosis
Diagnosis and diagnosis of adenoviral pneumonia in children
diagnosis
According to the prevalence, combined with clinical diagnosis, the typical early stage of adenoviral pneumonia in infants and young children is different from general bacterial pneumonia:
1. High fever: Most cases have persistent high fever at the onset or shortly after onset, and are not treated with antibiotics.
2. Multiple system involvement: From the 3rd to 6th day of the disease, there are symptoms such as lethargy and wilting, and sleepiness sometimes appears alternately with irritability. The complexion is pale and gray, and the liver is markedly obvious. Later, heart failure, convulsions and other complications are easily seen. It is suggested that adenovirus pneumonia not only involves the respiratory tract, but other systems are also affected.
3. Lung signs appear late: lung signs appear later, usually in the 3rd to 5th day after the occurrence of wet voice, the lesion area gradually increases, easy to have percussion dullness and respiratory sounds, wheezing in the disease 2 weeks getting worse.
4. Characteristics of blood picture: The total number of white blood cells is low, the majority of sick children do not exceed 12 × 109 / L, neutrophils do not exceed 70%, neutrophil alkaline phosphatase and tetrazolium blue staining is more purulent The number of bacterial infections is significantly lower, but as a result of concurrent purulent bacterial infections, it rises again.
5. Features of chest X-ray: X-ray examination of the lungs can have a large flaky shadow, the most common in the lower left. In short, in the epidemic season, infants and young children have severe pneumonia, and the X-ray and blood picture are also consistent. At the time, a preliminary diagnosis can be made. A conditional unit can perform rapid diagnosis of the virus. Currently, immunofluorescence technology can be performed (indirect method is more suitable than direct method), enzyme-linked immunosorbent assay and specific IgM assay. The three methods can not classify adenovirus, which is the shortcoming, and the conventional throat swab virus isolation and double serum antibody test are only suitable for laboratory diagnosis.
Differential diagnosis
Special attention should be paid to preschool and school-age children. The clinical manifestations of adenovirus and mycoplasmal pneumonia are almost the same. There are high fever, dyspnea and drowsiness. The symptoms of adenovirus pneumonia are common. Mycoplasma pneumonia has only X-ray shadow without snoring can help identify, but ultimately can only rely on laboratory-specific diagnosis, the clinical manifestations of adenoviral pneumonia in infants less than 5 months are significantly lighter than infant adenoviral pneumonia, and respiratory syncytial virus Pneumonia caused by parainfluenza virus can not be identified, only by rapid diagnosis or pathogen diagnosis.
