(Disclaimer: This article is for general science purposes only. To protect patient privacy, the relevant information in the following content has been processed.) Abstract: Pediatric fever is mostly related to infection. The presence of persistent pediatric fever is recommended for Mycoplasma pneumoniae antibody testing because Mycoplasma pneumoniae infection is very common. In this case, the child came to the clinic with cough and fever, and the clinical diagnosis was upper respiratory tract infection, and the symptoms did not improve after treatment. Later, the diagnosis of Mycoplasma pneumoniae infection was confirmed by relevant tests, and the treatment plan was quickly adjusted, i.e., intravenous azithromycin with nebulized inhalation, etc. The child’s body temperature returned to normal and the cough was significantly relieved. [Basic information] Male, 5 years old [Disease type] Mycoplasma pneumoniae infection (cough + fever) [Attending hospital] Fudan University Pediatric Hospital [Attending time] May 2021 [Treatment plan] Nebulized inhalation + medication (azithromycin intravenous, oral erythromycin, oral azithromycin) [Treatment cycle] Inpatient treatment for 3 days, outpatient follow-up after 2 days [Treatment effect] After 5 days of medication, the The child’s temperature was normal, the lung rales disappeared, and the cough was significantly relieved. The child started to cough 5 days ago and came to our outpatient clinic with a temperature of 38.5℃, no abnormal abdominal auscultation, and 13×10^9/L peripheral blood leukocytes, and was clinically diagnosed with upper respiratory tract infection. However, the child’s symptoms did not improve after medication, and the fever persisted, reaching a maximum of 40℃ yesterday. The cough has instead worsened in the past 2 days, manifesting as an irritating dry cough with mild symptoms of shortness of breath. Today, the child came to our hospital again. Outpatient examination of peripheral blood leukocytes 15×10^9/L, weakly positive for Mycoplasma pneumoniae, small vesicular sounds on the left side of the back on auscultation, and immediate x-ray confirmation of bronchopneumonia. After the diagnosis of pneumonia was clear and Mycoplasma pneumoniae infection was considered, the clinical treatment plan was adjusted by discontinuing cefdinir and switching to intravenous azithromycin, together with cough and sputum relief and nebulizer inhalation and other comprehensive treatment. In view of the child’s clinical high fever and mild shortness of breath, he was kept in the hospital for observation. After targeted anti-infection treatment, the child’s clinical symptoms improved on the 2nd day of medication, the high fever decreased to 38.8℃, and the cough symptoms were also relieved. The clinician recommended 2 days of azithromycin and followed up with the clinic. At present, the child’s body temperature is completely normal and the cough has improved significantly after 5 days of regular medication for pneumonia. The reason for the unsatisfactory effect of cefdinir treatment for the child’s initial respiratory infection was that the causative agent of the child’s respiratory infection was Mycoplasma pneumoniae, so the infection was not effectively controlled, but led to the spread of the infection to the lungs. Once the pneumonia was confirmed by laboratory tests and X-rays, the child’s pneumonia symptoms improved significantly once the treatment was adjusted and azithromycin was administered intravenously. We are glad that the child’s condition is under control and the discomfort has improved. It is recommended that during the home medication and follow-up period, you should follow the doctor’s instructions for regular medication use. Keep the air in the living room, try to eat a nutritious and light diet, get enough sleep every day, exercise appropriately, but do not go to crowded places to avoid cross-infection. V. Personal insight Pediatric Mycoplasma pneumoniae infection can mostly present symptoms of fever, dry cough, coughing significantly worse at night, some infants and children can also appear shortness of breath, respiratory distress and other manifestations. Mycoplasma pneumoniae infection is relatively common in clinical practice, and antibodies to mycoplasma are sometimes not always evident in the early stages of the disease, which requires a comprehensive analysis by the physician based on the clinical condition of the child, as well as laboratory tests, in order to make the right choice and achieve the goal of cure.