Expert Consensus on Diagnosis and Treatment of neonatal Mycoplasma pneumoniae pneumonia (2024)
Mycoplasma Pneumoniae Pneumonia (MPP) is the most common community acquired pneumonia in children over 5 years of age in China. As an important atypical respiratory pathogen, the clinical manifestations of MPP infection in children are complicated and uncertain. Especially in newborns whose immune system is not fully developed, MP has attracted wide attention in the pediatric medical community worldwide in recent years.
I. Characteristics of Neonatal MPP
Neonatal MPP is more common in late newborns more than 2 weeks after birth, mainly through direct contact between newborns and infected people. The clinical manifestations of neonatal MPP are relatively hidden and diversified, and special attention should be paid to the following cases:
1) Fever is irregular or lasts for a long time, and fever does not significantly improve or repeat after routine antibiotic treatment.
2) Respiratory symptoms are complex and diverse, including intermittent cough (especially paroxysmal, spastic cough or dry cough without phlegm), increased respiratory rate, wheezing, and even dyspnea, nasal flapping, and aspiratory trispleura sign, etc. Physical examination can be heard and lung rales or chest X-ray abnormalities, such as unilateral or bilateral patchy shadows, interstitial changes or lung compactification.
In addition, extra-pulmonary manifestations should also be vigilant: 1) Digestive symptoms, such as decreased milk intake, feeding difficulties, vomiting and diarrhea, are the most common extra-pulmonary manifestations of MPP; 2) Neurological symptoms, such as drowsiness, irritability, and convulsions; 3)Manifestations of cardiovascular system involvement, such as arrhythmia, myocardial damage, pericarditis, etc.; 4) Manifestations of blood system involvement, such as hemolysis, thrombosis, disseminated intravascular coagulation, etc.; 5) skin mucosal damage and other manifestations.
Recommendation 1:
Pay attention to the early identification and evaluation of neonatal MPP, MP testing is recommended for those with the following indications.
1) The mother had a history of respiratory tract infection during pregnancy, the placental pathology examination suggested chorioamniotitis or vasculitis, and the imaging findings of multifocal pulmonary infiltration and consolidation occurred within 2 weeks after birth.
2) Contact with patients with respiratory infection and have the respiratory symptom after newborn, respiratory symptoms such as cough (especially paroxysmal, spasmodic cough or dry cough without phlegm), increased respiratory rate, wheezing, and even dyspnea, nasal flapping, and aspiratory trifossa sign, chest imaging confirmed pneumonia, accompanied by irregular fever or a long duration of fever. There was no improvement in clinical symptoms or imaging after conventional antimicrobial treatment.
Recommendation 2:
The clinical manifestations of neonatal MPP are diverse, and there are many extrapulmonary concomitant symptoms, so it is necessary to identify and determine whether MP-related tests should be performed in time.
II. Laboratory testing methods of neonatal MPP
1. The clinical symptoms of neonatal MPP are not typical, and laboratory detection is of great significance for the diagnosis and treatment of neonatal MPP.
1) MP pathogen culture is still the "gold standard" for the diagnosis of neonatal MP infection. Test specimens include throat swabs, sputum, bronchoalveolar lavage fluid, etc. However, MP culture requires special conditions, long culture time, and delayed results, so it is not the first choice for detection of neonatal MP infection.
2) Conventional methods also include detection of serum antibodies, such as MP-IgM, IgG, and IgA antibodies. IgM antibodies generally appear 4 to 5 days after infection and reach a peak 3 to 4 weeks later, Positive results indicate recent infection.The detection of MP-IgM antibody requires a small amount of blood and can produce a quick result, but a negative test result cannot exclude MP infection.
3) In addition, direct detection of MP antigen is also an important methods to detect MP infection, which has high specificity but low sensitivity, and is prone to false negative results.
2. Peripheral blood MP-IgM test or throat swab MP antigen test are recommended as the first choice for outpatient children with disease duration less than 7 days and a history of exposure to MP infection. In addition, the application of modern molecular biology techniques has greatly improved the diagnosis efficiency:
1) MP nucleic acid detection: including DNA or RNA, with high sensitivity and high specificity, when hospitalized children suspect MPP, it is recommended to use throat swab or sputum MP nucleic acid detection as the first choice.
2) Metagenomics next-generation sequencing (mNGS) : The presence of MP can be identified from mixed pathogen samples through microbial metagenomics analysis, suitable for children with negative test result of routine microbial testing (culture or nucleic acid testing) and no response to 3 days of empiric therapy, bronchoalveolar lavage fluid was chosen as the preferred sample type, followed by sputum or nasopharyngeal swab samples obtained under tracheal intubation.
Recommendation 3:
The laboratory pathogen detection method for neonatal MPP should be correctly selected.
1. For hospitalized children, when MP infection is clinically suspected, throat swab or sputum MP-DNA test or MP culture is recommended for the diagnosis of neonatal MPP.
2. For outpatient children with a history of exposure to MP infection, peripheral blood MP-IgM antibody or throat swab MP antigen are recommended as the preferred methods of detection. A positive result can indicate recent MP infection, while a negative result cannot completely rule out MP infection, and a comprehensive analysis of the detection results should be combined with clinical and imaging characteristics. If necessary, MP-DNA detection of throat swabs can be further involved.
Xiamen Wiz Biotech Co., Ltd has developed a rapid MP-IgM test for physician use, which will help in diagnosis process.
