Spontaneous pneumothorax and subpleural bullae in a patient with COVID-19: a 92-day observation.

This report describes a patient with COVID-19 who developed spontaneous pneumothorax and subpleural bullae during the course of the infection. Consecutive chest computed tomography images indicated that COVID-19-associated pneumonia had damaged the subpleural alveoli and distal bronchus. Coughing might have induced a sudden increase in intra-alveolar pressure, leading to the rupture of the subpleural alveoli and distal bronchus and resulting in spontaneous pneumothorax and subpleural bullae. At the 92-day follow-up, the pneumothorax and subpleural bullae had completely resolved, which indicated that these complications had self-limiting features.

INTRODUCTION

The coronavirus disease-2019 (COVID-19) pandemic is an ongoing global pandemic [1]. More and more evidence is emerging to explain its complicated pathogenesis, such as the ‘cytokine storm’, multi-organ impairments and pulmonary embolization, and acute respiratory distress syndrome [2]. This report describes the complete clinical course in a patient with COVID-19, who developed spontaneous pneumothorax and subpleural bullae simultaneously. In addition, we attempted to explain the potential mechanism of development of these rare complications based on consecutive chest computed tomography (CT) images.

CASE REPORT

A 32-year-old male medical staff worker at a biosafety level-3 hospital facility developed a dry cough on 27 January 2020, without a known source of COVID-19 exposure (day 1). The patient did not have a history of smoking, pulmonary disease or surgery. The concise clinical course is illustrated in Fig. 1. On day 5–6, the chest CT scan demonstrated typical signs of viral pneumonia with multiple ground-glass opacities in both lungs and the laboratory nucleic acid test of COVID-19 from throat swabs was positive. Hence, the diagnosis of COVID-19 was confirmed on day 6. After admission, moxifloxacin (0.4 g, iv drip, pd), arbidol (0.2 g, po, tid) and thymalfasin (1.6 mg, ih, biw) were administrated empirically. On day 17, the patient recovered and had a good mental status and normal body temperature, while the transient cough and expectoration remained. On day 21, sudden chest distress with severe dry cough occurred and an emergency chest CT scan showed massive pneumothorax with a giant subpleural bulla on the left side (Fig. 2A). Imperative closed thoracic drainage and nasal cannula oxygen therapy (5 l/min) were conducted and the symptoms improved. The patient was discharged on day 57 and was followed up in the outpatient department. Consecutive chest CT scans demonstrated an eventual resolution of the pneumothorax and subpleural bullae on day 92, after recovery from pneumonia (Fig. 2B).

Figure 1:

Timeline of the clinical course. AST: aspartate aminotransferase; COVID-19: coronavirus disease-2019; CT: computed tomography; IL: interleukin; LDH: lactate dehydrogenase.

Figure 2:

Typical chest computed tomography manifestations at different time points. Day 21, pneumothorax was found on the left side with a subpleural giant bulla (A), which was completely absorbed on day 92 (B). Day 21, a subpleural hypodense line (B, black arrows) was noticed in the right upper lung attaching to a branch of a peripheral bronchus (C, white arrowhead) surrounded with consolidation; day 24, the previous subpleural hypodense line became a localized pneumothorax (D, black arrow); day 92, the localized pneumothorax was completely absorbed (E). All images have the same window level of −600 and window width of 1600.

Despite the spontaneous pneumothorax, the clinical course of this patient generally conformed to the typical patterns of mild pneumonia caused by COVID-19 [3]. Spontaneous pneumomediastinum and pneumothorax were recently reported but the detailed mechanism of development is still unclear [4, 5]. A retrospective review of the consecutive CT images in this patient revealed a clue to explain how these complications developed. On day 21, a subpleural hypodense line was noticed in the right upper lung attached to a branch of a peripheral bronchus surrounded by consolidation (Fig. 2C). On day 24, this subpleural hypodense line became a typically localized pneumothorax (Fig. 2D). However, it was completely absorbed with the resolution of pneumonia on day 92 (Fig. 2E). These dynamic findings suggested that the subpleural consolidation caused by COVID-19 could destroy the subpleural pulmonary alveoli and erode the distal bronchus. In the presence of a persistent cough, this might trigger a sudden increase in the intra-alveolar pressure, inducing the formation of subpleural bullae or pneumothorax, if the alveoli rupture. In a previous report, similar explanations were presented [5]. However, this report revealed that subpleural bullae and pneumothorax could completely resolve after recovery from COVID-19.

CONCLUSIONS

This report described the complete radiological and clinical course of a COVID-19 patient with spontaneous pneumothorax and subpleural bullae. It indicated subpleural consolidation with a persistent cough might be a risk factor of spontaneous pneumothorax and subpleural bullae in COVID-19 patients. However, in our patient, these complications completely resolved after recovery from pneumonia.