Symptoms and signs of bronchopneumonia

Bronchopneumonia (bronchopneumonia), also known as lobular pneumonia, is the most common pneumonia in children. It is inflammation of the lungs involving the bronchioles, terminal bronchioles, and distal alveoli. It is more common in clinical practice, mostly caused by bacterial and viral infections, and pathogens often invade by the respiratory tract, and a few enter the lungs through blood. It is common in infants and frail elderly people. It can occur all year round, and it mostly occurs in the cold season of winter and spring and when the climate changes abruptly in the north, and the main clinical manifestations are fever, cough, shortness of breath, etc. The disease is diagnosed by clinical symptoms, auscultation of the lungs, and chest imaging, and the prognosis is generally good with aggressive treatment.

Pathological etiology

Pediatric pneumonia in developed countries is mainly caused by viral pathogens, and pediatric pneumonia in developing countries is mainly bacterial pathogens, and in general, bronchopneumonia is caused by bacteria, Haemophilus influenzae and Streptococcus pneumoniae account for more than 60% of bacterial pneumonia.

Staphylococcus is also an important pathogenic bacteria, streptococcus, Escherichia coli, pneumobacterium, Pseudomonas aeruginosa is less common in infantile pneumonia, bacterial virulence is related to the structure of bacteria, capsular bacteria can resist bacteriophage, virulence is larger, the same bacteria are classified into several serotypes according to different capsular components, different types of bacteria have different capsules, and the virulence is also different, Haemophilus influenzae is divided into six serotypes A-F, of which type B is the most virulent, and is one of the main pathogenic bacteria for pediatric sepsis, meningitis and pneumonia, Capsular polysaccharide is ribose phosphoric acid, pediatric pneumonia caused by Haemophilus influenzae is often secondary to bronchitis, bronchiolitis or sepsis, more common before the age of 3, Haemophilus influenzae without capsular is amorphous, less virulent, generally only causes upper respiratory tract infection, β hemolytic streptococcus can appear as a secondary infection in the course of measles or pertussis, but it is rare, and group B hemolytic streptococcus is a common pathogen of neonatal pneumonia abroad, which has not attracted enough attention in China, Coagulase-positive Staphylococcus aureus is also a common pathogen of severe pneumonia in children, coagulase-negative staphylococcus (mainly referring to Staphylococcus epidermidis) has been isolated more in China in recent years, but because it is a conditional pathogenic bacteria, it is easy to be polluted during the culture process, and it must be combined with clinical judgment whether it is indeed the pathogen of pneumonia, pneumonia caused by Escherichia coli is mainly seen in newborns and malnourished infants, and can also be secondary to other serious diseases.

Interstitial bronchopneumonia is mostly caused by viruses, mainly adenovirus, influenza virus, parainfluenza virus, respiratory syncytial virus and measles virus, etc., interstitial bronchomyositis can also be caused by Haemophilus influenzae, pertussis, streptococcus and some types of Mycoplasma pneumoniae.

Pathological morphology

Generally, the main lesions of bronchopneumonia are scattered in the alveoli near the bronchial wall, the bronchial wall is only mucosal inflammation, alveolar telangiectasia and congestion, edema and inflammatory exudation in the alveoli, serous fibrinous exudate contains a large number of neutrophils, red blood cells and germs, the lesion spreads to the surrounding adjacent lung tissue through the interalveolar passage and bronchioles, showing small spots of focal inflammation, and the interstitial lesions are mostly insignificant, and sometimes the small lesions are fused together to become bronchopneumonia. However, the pathological changes are not as uniform and dense as lobar pneumonia, and in the later stage, macrophages increase in the alveoli, and a large number of bacteria and cell debris are engulfed, which can cause the dissolution and absorption of fibrinous exudate in the alveoli, the dissipation of inflammation, and the re-inflation of the alveoli.

The main lesions of interstitial pneumonia are inflammation of the bronchial wall, bronchiole wall and alveolar wall, edema and inflammatory cell infiltration, bronchiolitis, bronchiolitis and pneumonitis changes, spreading widely, when the cells on the bronchiole wall are necrosis, the lumen can be blocked by mucus, cellulose and broken cells, and localized emphysema or atelectasis occurs, viral pneumonia is mainly interstitial pneumonia, but sometimes focal inflammation invades the alveoli, resulting in the formation of a transparent membrane in the alveoli, and chronic interstitial fibrosis occurs in a few cases in the late stage, which can be seen in adenovirus pneumonia.

Symptoms and signs

According to the acute onset, respiratory symptoms and signs, it is not difficult to make a general clinical diagnosis, if necessary, X-ray, chest x-ray, or pharyngeal specimens, tracheal secretions bacterial culture or virus isolation, other etiological tests including antigen and antibody testing, leukocytes are significantly elevated and granulocytosis, serum C-reactive protein is elevated to help the diagnosis of bacterial pneumonia, leukopenia or normal, it is mostly viral pneumonia.

1. General symptoms

The onset is acute or slow, there are sudden symptoms such as fever, refusal to eat or vomiting, drowsiness or irritability, wheezing and other symptoms, there can be a mild upper respiratory tract infection for several days before the onset of the disease, and the early body temperature is mostly 38~39 °C, but also as high as about 40 °C, most of which are galloping or regular fever.

Most of the young infants have a slow onset, low fever, cough and pulmonary signs are not obvious, and refusal to eat, choking on milk, vomiting, or dyspnea are common.

2. Respiratory symptoms and signs

Cough and pharyngeal phlegm sound, generally early obvious, rapid breathing, up to 40~80 times per minute, so that the ratio of breathing and pulse rises from 1:4 to about 1:2, common dyspnea, severe cases have moaning sound when exhaling, nasal wings, three recesses, perioral power batch nail bruising, some children tilt their heads back to make breathing smooth, if the child passively bends the neck forward, the resistance is obvious, this phenomenon should be different from cervical muscle rigidity.

Chest signs are often subtle in the early stages, or only the breath sounds become coarse or slightly reduced, medium and coarse crackles may be heard later, with slight dullness to percussion, after a few days, fine crackles or crepitations may be heard, tubular breath sounds may be heard when the lesion is enlarged, and dullness to percussion may be heard, and if a solid percussion sound or/and absent breath sounds are found in one lung, a combined pleural effusion or empyema should be considered.

The WHO Programme for the Prevention and Control of Acute Respiratory Tract Infection in Children particularly emphasizes that rapid breathing is the main manifestation of pneumonia, and shortness of breath refers to: young infants < 2 months old, with 60 breaths ≥; Under 2~12 months of age, 50 breaths ≥; Under 1~5 years old, ≥ 40 breaths, severe pneumonia is indicated as irritability or drowsiness, refusal to eat, depression of the lower chest wall and cyanosis, which provides a simple and feasible diagnostic basis for primary medical personnel and primary health care workers, and is worthy of promotion.

3. Symptoms and signs of other systems are more common in severe patients.

(1) Gastrointestinal symptoms: when infants and young children suffer from pneumonia, they are often accompanied by vomiting, diarrhea, abdominal pain and other digestive symptoms, vomiting often occurs after a strong cough, and when the abdominal distension is severe, the diaphragm rises, compresses the chest, and makes it more difficult to breathe, and sometimes pneumonia in the lower lobe can cause acute abdominal pain, which should be distinguished from abdominal dysentery.

(2) Circulatory system symptoms: children with severe pneumonia may have an accelerated pulse, 160~200 beats per minute or more, which is not commensurate with the increase in body temperature and dyspnea, the liver is significantly enlarged or enlarged in a short period of time, pale, cyanotic lips, or face, swollen limbs, and less urine, which is a sign of congestive heart failure, and sometimes the limbs are cold, the perioral area is gray, and the pulse is weak, which is peripheral circulatory failure.

(3) Nervous system symptoms: common irritability, drowsiness, or alternating between the two, young infants are prone to convulsions, mostly due to high fever or calcium deficiency, such as convulsions at the same time with obvious drowsiness or irritability, and persistent coma, and even the occurrence of tonic muscle spasm, hemiplegia or other brain signs, it may be complicated by central nervous system lesions such as meningoencephalitis, toxic or hypoxic encephalopathy.