A 44-year-old woman with a medical history of systemic arterial hypertension, type 2 diabetes mellitus and stage 3 chronic kidney disease, was admitted to the Emergency Department (ED) with complaints of asthenia, adynamia, dyspnea and orthopnea. On initial examination, blood pressure was 140/100 mmHg, pulse rate 92 bpm, a respiratory frequency of 24 bpm, a temperature of 37.9 °C (100.2 °F), and an oxygen saturation 88% at room air. The physical examination was remarkable for a decrease in breath sounds and medium crackles with predominance in both bases of the lung. The laboratory tests reported a Hemoglobin of 9.37 g/dL, white blood cells of 11,800 CC3 with neutrophilia of 9700 CC3, serum glucose of 140 mg/dL, creatinine of 3 mg/dL, blood urea nitrogen of 75 mg/dL, and an elevated C reactive protein (15.4 mg/dL). A chest X-ray study was made, and it was reported that there was a round opacity with an air bronchogram in the superior lobe of the left lung with measurements of 8.6 cm × 5.6 cm. Additionally, there was an image compatible with bilateral pleural effusions and a radio lucid area localized in the apex of the left lung compatible with a pneumothorax (Fig. 1a). Because of this, we decided to perform a thorax computed tomography (thorax CT) that eliminated the possibility of a pneumothorax in the left lung apex (Fig. 1b). We started empirical therapy with ceftriaxone 2 g per day and clarithromycin 1000 mg per day with clinical improvement, and a room air saturation 95% at the 7th day of treatment. Gram’s stain and sputum culture were negative, and the patient was discharged after 7 days of hospital stay.