A previously well 6-year-old girl presented with cough, fever and difficulty in breathing for a week with no response to oral amoxicillin. She had spent 5 weeks in China and became unwell within 3 weeks of return to Australia. Her grandfather had been admitted with respiratory illness in China for a month and recovered.On presentation, she was tachypnoeic (respiratory rate: 60/min), febrile (temperature: 40.2 C) and tachycardic (pulse rate: 136 beats/min). Her chest examination revealed reduced air entry with stony dullness on the left side, suggestive of a pleural effusion. She had leukocytosis of 21 × 10 9 /L of mainly neutrophils and a very high C-reactive protein of 316 mg/dL. Chest radiograph showed diffuse opacification on the left lung (Fig. 1a), and a large pleural effusion was observed on ultrasound. She was commenced on broad-spectrum antibiotics (azithromycin, cefotaxime and vancomycin) for severe pneumonia. She required intubation and ventilation on day 2 of admission. Pleural fluid analysis showed protein of 30 g/L, albumin of 19 g/L, lactate dehydrogenase of 4807 U/L and lymphocyte predominance. Bacterial cultures from blood, endotracheal aspirates and pleural fluid were negative, and viral testing (Seegene Seeplex RV 15) on endotracheal aspirates was negative. Mycoplasma pneumoniae IgM (ELISA) returned positive on day 3. She was very slow to improve and required invasive and then non-invasive (CPAP)Severe Mycoplasma pneumoniae pneumonia LS Al Yazidi et al.