Mycoplasma pneumoniae Pneumonia with Pleural Effusion in a 2-Year-Old Girl

A report describes a case of a previously healthy 2-year-old girl who presented with six days of productive cough, high fever, and poor appetite. She was fully immunized and had no recent travel or sick contacts. On examination, the patient was febrile (39.2°C), tachypneic (respiratory rate: 42 breaths/min), mildly hypoxemic (SpO₂ 92–93%), and tachycardic (heart rate: 124 beats/min) with normal blood pressure (90/60 mmHg). Her weight was 11.9 kg and her height was 93.5 cm. Lung auscultation was done, and reduced breath sounds in the 1/3 right lower lung were observed, with no additional adventitious sounds. Upon physical examination, no notable observations were seen.

White blood cell count (7.9 × 10⁹/L) with 78.7% neutrophils, hemoglobin within normal limits at 12.1 g/dL, and a reduced platelet count of 137 × 10⁹/L. C-reactive protein was elevated at 215.6 mg/L while electrolytes, liver function, blood urea nitrogen, and creatinine were all normal. Chest X-ray revealed right lower lobe consolidation, while thoracic ultrasound showed no pleural effusion. The patient needed oxygen via nasal cannula for hypoxemic respiratory failure, and cefotaxime was started empirically for community-acquired pneumonia.

Over the next three days, she remained febrile (up to 40.1°C) with rising CRP (280 mg/L) and worsening respiratory effort, including subcostal and intercostal retractions and oxygen saturations of 92–96% on nasal cannula. Blood cultures were negative. Repeat chest X-ray showed progression of right lower lobe opacification, and ultrasound detected a small right pleural effusion. Empiric vancomycin and amikacin were added due to concern for empyema.

Ultrasound-guided thoracocentesis drained 40 mL of serosanguineous fluid. Analysis confirmed an exudative fluid with a pleural-to-serum protein ratio of 0.7, a pleural-to-serum lactate dehydrogenase (LDH) ratio of 1.6, a pleural pH of 7.7, and a glucose of 82 mg/dL. Cell counts showed 60 WBC/mm³ (90% lymphocytes) and 9,000 RBC/mm³.

PCR detected 295,000 copies/mL of Mycoplasma pneumoniae (M. pneumoniae). Blood cultures did not reveal any growth, and M. pneumoniae IgM titers rose from 19.9 U/mL on day 3 post-admission to >150 U/mL within five days. Intravenous levofloxacin was administered for complicated M. pneumoniae infection; cefotaxime and amikacin were discontinued, while vancomycin was continued for seven days. Fever initially subsided but recurred three days later with increased respiratory distress.

A chest ultrasound revealed a moderate-to-large right pleural effusion. Later, 170 mL of serosanguineous fluid was drained via pleural effusion, followed by chest tube placement, which drained an additional 360 mL over 24 hours. Pleural fluid PCR remained positive for M. pneumoniae. Following chest tube drainage, her respiratory status improved, oxygen supplementation was discontinued, and her fever resolved over the next five days. The chest tube was removed after three days without recurrence of effusion on ultrasound. The patient completed a 14-day course of levofloxacin and was discharged after a 16-day hospitalization. At the two-month follow-up, the patient was doing well, and the chest X-ray showed near-complete resolution of right lower lobe consolidation.

https://www.ijcripediatrics.com/archive/article-full-text/100012Z19MD2021