The Indian Journal of Chest Diseases and Allied Sciences
Volume 65 | Issue 3 | Year 2023

Spontaneous Alveolar Air Leak Syndromes in COVID-19 Patients: A Case Series

Pradeep Ravi1, Deepak Amalnath2

1,2Department of Medicine, JIPMER, Puducherry, India

Corresponding Author: Pradeep Ravi, Department of Medicine, JIPMER, Puducherry, India, Phone: +91 8220028037, e-mail:

How to cite this article: Ravi P, Amalnath D. Spontaneous Alveolar Air Leak Syndromes in COVID-19 Patients: A Case Series. Indian J Chest Dis Allied Sci 2023;65(3):163–166.

Source of support: Nil

Conflict of interest: None

Patient consent statement: The author(s) have obtained written informed consent from the patient for publication of the case report details and related images.

Received on: 22 November 2023; Accepted on: 13 January 2024; Published on: 05 February 2024


The spectrum of spontaneous alveolar air leak (AAL) syndromes (AAS) includes pneumomediastinum, pneumothorax, and subcutaneous emphysema. These syndromes have been recently reported to be an uncommon complication in patients with coronavirus disease-2019 (COVID-19) pneumonia. These syndromes were found in patients with other viral respiratory diseases, such as SARS, MERS, and H1N1. The pathophysiology of which is mostly unknown but has been attributed to the diffuse alveolar injury which leads to alveolar rupture and air leak. Here, we present a case series of 11 patients with COVID-19 pneumonia who had alveolar air leak syndromes. All 11 patients had severe COVID and raised inflammatory markers. Most of them developed air leak syndromes when they were not on invasive or noninvasive ventilation. About 7 out of 11 patients expired. This case series is hereby presented because of the rarity of these complications, that is, on an extensive search of the literature, less than 20 cases of alveolar air leak syndromes in COVID-19 have been reported.

Keywords: Alveolar air leak syndromes, Coronavirus disease-2019, Pneumothorax, Pneumomediastinum, Subcutaneous emphysema.


AAL = Alveolar air leak; AAS = Alveolar air leak syndrome; ARDS = Acute respiratory distress syndrome; CRP = C-reactive protein; DIC = Disseminated intravascular coagulation; MODS = Multiorgan dysfunction syndrome; NIV = Noninvasive ventilation.


Coronavirus disease-2019 (COVID-19) has emerged as the most common health issue in the last 2 years affecting almost 200 million people worldwide with more than 32 lakhs people getting affected in India alone. It is a multisystem disorder causing various life-threatening complications.1 Pneumothorax, subcutaneous emphysema, and pneumomediastinum together called alveolar air leak syndromes are found to be a very rare spontaneous complication of COVID-19 disease. A study in India has found the incidence of these to be 2.9%.2 Another study in the united kingdom showed an incidence of these syndromes to be almost 9% in patients with severe COVID-19.3

In the literature review, there were less than 20 cases with spontaneous air leak syndromes, that is, not related to trauma during intubation or barotrauma secondary to invasive and noninvasive ventilation in patients were found. Here, we report a case series of 11 patients with spontaneous air leak syndromes secondary to COVID-19 infection. All the patients had severe COVID and 8 out of 11 patients succumbed to either the disease or its complication.


Cases 1–11

Out of the 11 patients, most of them were between 40 and 60 years, with the oldest patient being 78 years and the youngest patient was 20 years. Seven patients were male and four were female. Seven patients had no comorbidities, two had type 2 diabetes and two had hypertension. Only three patients had received COVID-19 vaccine during admission. All the patients presented to the hospital within 4 days of onset of symptoms except patient 11 who presented after 10 days of onset of symptoms. All the 11 patients had severe COVID-19 clinically at admission (room air saturation was less than 90% and respiratory rates were more than 30). All the patients had a computed tomography (CT) scan severity of more than 17 at admission with maximum severity of 22 in three patients (patients 1, 2, and 3). All the patients had pneumomediastinum except one patient (patient 11). Four patients had a pneumothorax (Fig. 1) (patients 1, 3, 8, and 10) and four patients had subcutaneous emphysema (Fig. 2A) (patients 1, 4, 10, and 11).

Figs 1A to D: (A) Chest X-ray image showing pneumothorax; (B) CT image showing pneumomediastinum; (C) CT image showing pneumopericardium; (D) CT thorax showing pneumomediastinum (Images from different patients and not the same patient)

Figs 2A to D: (A) Chest X-ray showing subcutaneous emphysema; (B) CT image showing subcutaneous emphysema with pneumomediastinum; (C and D) CT image showing massive subcutaneous emphysema (Images from different patients and not the same patient)

Six of the patients were found to have alveolar air leak syndromes in the first week of illness (patients 2, 4, 6, 7, 8, and 10). One patient presented with pneumomediastinum and subcutaneous emphysema to the hospital (patient 10) (Figs 2B to D). Two patients had alveolar air leak syndrome in the second week of illness (patients 3 and 9). Two patients were found to have AAS in the third week of illness (patients 5 and 11) and one patient was found to have on day 25 of illness (patient 11). When the air leak syndrome was identified, 6 patients were on NRBM masks requiring oxygen of more than 10 liters per minute, 4 patients were on noninvasive ventilation (NIV) with a maximum PEEP of 12 and maximum pressure support of 12, two patients were intubated and were on mechanical ventilation. The intubated patients were on the volume control mode of ventilation with both of them on 6 mL/kg tidal volume with a PEEP of 10–12. All the patients were treated with dexamethasone and low-molecular-weight heparin. Along with these drugs, two patients had received antiviral drug remdesivir (patients 3, 8, and 11) and two patients had received tocilizumab (anti-IL-6). Investigations have shown raised TLC counts in all 11 patients when the alveolar air leak syndrome was identified. Furthermore, inflammatory markers like CRP were elevated in all 11 patients. Coagulation markers like D-dimer were elevated in nine patients, in two patients D-dimer was not done due to practical reasons.

All cases of pneumothorax had worsening hypoxemia and hemodynamic instability and thus they were treated with intercostal drainage tubes. Out of four patients with pneumothorax two had a bilateral pneumothorax. A cardiovascular surgeon’s consult was asked for all pneumomediastinum and subcutaneous emphysema patients and all of them were conservatively managed. Mortality was high in patients with alveolar air leak syndromes (7/11). All of them succumbed to secondary bacterial infection or worsening COVID pneumonia. Table 1 presents the summary of all 11 patients.

Table 1: Summary of clinical, laboratory, and radiological findings of eleven patients
Patient number 1 2 3 4 5 6 7 8 9 10 11
Age and sex 75/M 45/M 35/M 58/M 54/F 20/M 60/F 42/M 54/F 43/M 56/M
Day of AAL from onset of symptoms 25 4 14 2 20 4 3 7 14 1 17
Comorbidites DM Hypertension Hypertension Nil Nil Nil Nil Nil   DM Nil Hypertension
Maximum PEEP 12 10 12 12 12 12
CT severity 22/25 22/25 22/25 20/25 19/25 20/25 19/25 19/25 19/25 21/25 17/25
Alveolar air leak syndrome present PM, PT, SCE PM PM, PT, SCE PM PM PM PM, PT PM PM PM, PT, SCE SCE
TLC 14000 12370 15423 22000 14678 11234 16720 15270 17121 19262 18000
CRP 11.4 24 22 18 16 16.1 12 22 24.1 12 18
D-dimer Not done 1.871 2.321 1.123 2.261 2.479 3.929 Not done 1.180 2.370 2.1
Vaccination status Not vaccinated One dose Not vaccinated Not vaccinated Not vaccinated Not vaccinated Not vaccinated One dose Not vaccinated Not vaccinated One dose
Outcomes Expired Improved Expired Expired Improved Improved Expired Improved Expired Expired Expired
MV, mechanical ventilation; NRBM, non re-breather mask; PM, pneumomediastinum; PT, pneumothorax; SCE, subcutaneous emphysema


Common complications of COVID-19 disease include ARDS, arterial and venous thrombosis secondary to disseminated intravascular coagulation (DIC), acute and chronic renal disease, acute liver injury, multiorgan dysfunction syndrome (MODS) secondary to cytokine storm.1,4 One of the rare complications, that is now becoming more evident is alveolar air leak syndromes, that is, pneumothorax, pneumomediastinum, and subcutaneous emphysema. These complications are also seen in patients with other viral respiratory diseases such as MERS and SARS.5,6 Initial studies showed that these syndromes are secondary to barotrauma and trauma caused secondary to intubation.7 But then, in few other case reports and small studies, alveolar air leak syndromes are found in patients who were never on invasive or noninvasive ventilation.2,810 Most of the case reports showed that mortality is high in these patients. In a study done in North India, the incidence of alveolar air leak syndrome in patients with COVID-19 was 2.9%, the same study showed that in severe COVID, the incidence was almost 8% and 6 out of 10 patients with alveolar air leak syndrome succumbed to either the disease or the complications of the disease.2 There are two proposed mechanisms for alveolar air leak syndromes in COVID-19 disease, they are:

In our case series, only two patients were on mechanical ventilation and four were on noninvasive ventilation out of 11 patients contrast to old studies where most of the patients were on mechanical ventilation. The patients who were on ventilatory support required higher PEEP-12. Earlier studies have mentioned these complications in elderly patients. But in our case series, the age group of the affected patients was so varied, including a 20 years old patient with no comorbidity who developed this complication. All the patients had severe COVID clinically and radiologically with features like raised leukocyte counts with neutrophilia and raised CRP which was indirectly indicating ongoing severe inflammation. Earlier studies and case reports have also demonstrated that these complications occur in patients with severe COVID with elevated inflammatory markers.2,8 Most of the patients in our study had grossly elevated D-dimer values which were indirect evidence of microthrombi in the lung vasculatures. CT findings like cystic changes and bleb formations in the lung parenchyma were found to increase the incidence of air leak syndromes in earlier studies.2,8 None of our patients had these changes. Radiographically all our patients had subpleural consolidations and ground glassing.


Our case series showed that the incidence of air leak syndromes is increased in patients with non-ventilated severe COVID infection. It has to be promptly anticipated and treated accordingly due to increased mortality in these patients. Routine imaging, low PEEP, and using cough suppressants might have a role in preventing or identifying these complications early. Further studies are needed to know about the exact pathogenesis and preventing mechanisms of these complications of COVID-19.


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8. Sabharwal P, Chakraborty S, Tyagi N, et al. Spontaneous air-leak syndrome and COVID-19: A multifaceted challenge. Indian J Crit Care Med 2021;25(5):584–587. DOI: 10.5005/jp-journals-10071-23819.

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10. Wang W, Gao R, Zheng Y, et al. COVID-19 with spontaneous pneumothorax, pneumomediastinum and subcutaneous emphysema. J Travel Med 2020;27(5):taaa062. DOI: 10.1093/jtm/taaa062.

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