The classification of neonatal pneumonia is complex. Generally, we can classify neonatal aspiration pneumonia and neonatal infectious pneumonia according to infectious and chemical irritation or according to the etiology. Inhalation pneumonia can be divided into amniotic fluid aspiration pneumonia, meconium aspiration pneumonia, and lactation aspiration pneumonia.
I. Examination methods
1, neonatal aspiration pneumonia
(1) amniotic fluid aspiration pneumonia: X-ray examination can be a light density patchy shadow, can be accompanied by mild or moderate emphysema.
(2) Meconium aspiration pneumonia
(1) X-ray examination: X-ray changes are more obvious 12-24 hours after birth. The typical manifestations are coarse granular or lamellar or cloudy shadows with increased density in both lungs, or segmental atelectasis and emphysema, which may be complicated by pneumothorax and/or mediastinal pneumothorax; in combination with PPHN (persistent pulmonary hypertension in newborns), the bronchial shadow is reduced and the lung permeability is increased; in combination with ARDS (adult respiratory distress syndrome), the characteristic X-ray changes of pulmonary hyaline membrane disease are seen. The severity of chest X-ray and clinical manifestations may not be proportional to each other.
②Blood gas analysis: Arterial blood gas shows hypoxemia, hypercapnia and metabolic or mixed acidosis. If hypoxemia is significant and disproportionate to the degree of pulmonary pathology or dyspnea, note the presence of concomitant persistent pulmonary hypertension.
(3) Lactic aspiration pneumonia: X-ray examination may be a widened hilar shadow, thickened lung texture or patchy shadow, which may be accompanied by emphysema or pulmonary atelectasis. Interstitial pneumonia and even fibrosis may occur in those with repeated inhalation.
Second, the diagnosis method
1, aspiration pneumonia in newborns
(1) amniotic fluid aspiration pneumonia
① history: history of intrauterine distress or postnatal asphyxia.
② clinical manifestations.
(3) X-ray examination.
(2) Meconium aspiration pneumonia
①History: there is often a clear history of hypoxia, such as intrauterine distress (fetal movement and/or abnormal fetal heartbeat), intrapartum asphyxia or a history of chronic intrauterine hypoxia; there is evidence of meconium contamination of amniotic fluid, such as meconium mixed with amniotic fluid, placenta and the child’s fingernails, skin, umbilical cord fecal staining, and meconium in oral and nasal aspirates; meconium is visible at the voice box or endotracheal aspirates during tracheal intubation.
②Clinical manifestations.
(3) Relevant examination.
(3) Lactation aspiration pneumonia
①History: there is often a causative factor. Premature infants are more common, especially those with combined bronchopulmonary dysplasia have swallowing coordination dysfunction, gastroesophageal reflux; esophageal atresia or tracheoesophageal fistula; those with severe cleft lip and palate.
②Clinical manifestations.
③X-ray manifestations.
2. Neonatal infectious pneumonia
①History: Pay attention to asking about high-risk factors. Such as intrauterine – history of maternal infection during pregnancy (early viral-based, late bacterial-based), amniocentesis operation, chorioamnionitis and premature rupture of membranes; intrapartum – intrauterine distress, prolonged labor, foul-smelling amniotic fluid or placental spoil; postnatal – history of contact with patients with respiratory tract infection, umbilicitis, skin infection and high-risk factors for nosocomial infection such as birth weight <1500g, prolonged hospitalization, mechanical ventilation more than 72 hours, invasive operations, long-term intravenous nutrition, etc.
Clinical manifestations: intrauterine infections tend to develop within 3 days after birth, while intrapartum or postpartum infections tend to develop 3 days after birth. Clinical severity varies. In mild cases, there is only increased respiration; in severe cases, there is marked respiratory distress with moaning, spitting, irregular respiratory rhythm or apnea. It may be accompanied by fever or hypothermia, poor response, poor milk intake and other signs of infection toxicity. Wet rales may be heard in the lungs. Severe cases are often complicated by heart failure, DIC, shock, persistent pulmonary hypertension, pulmonary hemorrhage, etc.
X-ray examination is an important diagnostic basis: X-ray features vary depending on the pathogen. In viral infection, only coarse texture or scattered patchy shadows are shown in both lungs; in bacterial infection, there are patchy hyperdense shadows in both lung fields, which may be accompanied by pulmonary blister and pus pneumothorax. Early-onset group B hemolytic streptococcal infection pneumonia chest film changes and RDS are not easily distinguished.
④Blood tests: neutrophils increase in bacterial infection, the nucleus shifts left, and platelets may decrease. Cord blood IgM may be elevated. Blood CRP (C-reactive protein) is mostly elevated in bacterial infections.
⑤ Detection of pathogenesis: smear and culture of tracheal secretions, blood culture if necessary. Gastric fluid within 1 hour after birth and tracheal secretion smear and culture within 8 hours after birth can suggest the causative agent of intrauterine infection. Serum specific IgM as well as pathogenic PCR (polymerase chain reaction) testing.
(vi) Blood gas analysis: to determine respiratory failure and type.