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This young female was brought in by EMS due to severe dyspnea. She reported one week of dry cough, malaise, and myalgias. The patient was triaged as a rule-out COVID patient. She reported remote history of lymphoma and DVT.
She was from a region with a high level of active COVID-19 infection but denies known contact with any COVID-positive patients. No history of prior reactive airway disease or e-cigarette use.
Physical exam reveals an anxious, tachycardic, and tachypneic female sitting in bed in a tripod position with an oxygen saturation of 92% on room air. Lung auscultation revealed diminished air movement but no wheezing. Cardiac auscultation was unremarkable.
Lung Ultrasound
Cardiac Ultrasound (Subcostal Window)
Cardiac ultrasound was attempted along parasternal and apical windows; only diffuse A-lines were seen. Subcostal window revealed normal cardiac anatomy and function. Note: The above image is not from the patient but is an example of cardiac A-lines (Md Noor & Eddie).**
Laboratory Findings
Initial Management
Patient was treated with handheld beta-agonist and ipratropium inhalers, and intravenous solumedrol, ceftriaxone, and azithromycin. No nebulized agents were ordered due to pathogen aerosolization risk. Patient underwent CT angiography to exclude PE and better delineate thoracic anatomy, given her severe dyspnea and history of DVT.
CT scans showed no evidence of PE but revealed moderate pneumomediastinum with air dissecting into fascial planes of the neck and extrathoracic subcutaneous tissue, a small right apical pneumothorax, and small degree of pneumopericardium. Additionally, multifocal ground-glass opacities (consistent with COVID-19) as well as increased bronchial wall thickening and occlusive secretions (consistent with chronic lung disease with superimposed infectious bronchitis) were also identified.
Patient Disposition & Hospital Course
The CT angio chest did not reveal a PE. However, a moderate-sized pneumomediastinum, small pneumopericardium, and small right apical pneumothorax were noted. Other findings, some consistent with COVID-19 while others were more consistent with chronic underlying lung disease, were also seen.
The patient was admitted to a monitored bed with enhanced droplet precautions as a possible COVID-19 patient. She was treated with a 100% non-rebreather mask for nitrogen washout of pneumomediastinum, pneumothorax, and pneumopericardium while concurrently being treated for reactive airway disease and bronchitis with possible bacterial superinfection.
The patient’s initial COVID PCR test returned negative for infection. After receiving supportive care, she returned to her baseline level of health by day 3 of hospitalization and was discharged. She was instructed to continue to practice physical distancing for 14 days and undergo follow-up COVID-19 testing as an outpatient.
A chest x-ray taken on hospital day 3 revealed resolution of the pneumothorax, small amount of residual pneumomediastinum, and patchy linear atelectasis vs. infiltrate in left lower lung field.
Integrating Ultrasound Findings into Medical Decision-Making
Bedside ultrasound revealed lung findings consistent with those seen in COVID-19 patients, including pleural irregularities, focal subpleural consolidations, and a shred or fractal sign (Biswas et al., Huang Y et al., Peng et al.). Non-specific B-lines were also noted. Given the clinical context, a moderate-to-high suspicion for COVID-19 was appropriate. The patient’s initial laboratory results were also consistent with COVID-19 infection, including a leukocytosis with lymphopenia, moderately elevated AST and ALT values, and an elevated D-Dimer value (Huang C et al., Luo et al.).
The CT finding of pneumomediastinum was surprising. The underlying pathophysiology in this case was likely alveolar rupture with dissection of air into lung interstitium and dissection of gas into the hilum and then mediastinum and contiguous structures (Zylak et al.). In retrospect, more diligent palpation of subcutaneous tissue may have detected crepitus (Hamman’s sign) on initial physical examination.
The inability to visualize the heart using parasternal and apical cardiac windows was likely the result of pneumomediastinum and pneumopericardium blocking sound wave transmission. Visualization of the heart using the subcostal view in the setting of pneumomediastinum has been described (Zachariah et al.). Specific sonographic findings seen with pneumomediastinum and/or pneumopericardium include an “air gap sign,” also termed “cardiac A-lines” (Md Noor & Eddie., Reid et al.). These signs result from trapped air interfering with ultrasound beam transmission in a cyclical manner corresponding to cardiac systole and diastole, which results in air displacement due to chamber size variation (Reid et al.).
The trace right-sided apical pneumothorax eluded sonographic detection as result of the linear-array ultrasound transducer being placed inferior to the apical air pocket. Small apical or loculated pneumothoraces can easily be missed if the ultrasound transducer is not positioned over the focal air pocket. Assuming optimal technique, transducer selection, and positioning of the ultrasound transducer directly over the pneumothorax air collection, ultrasound detects 86% to 100% of pneumothoraces (Blaivas et al., Lichtenstein & Menu, Wilkerson & Stone). Inability to acquire an imaging window due to subcutaneous gas or other signal transmission impediment results in the occasional miss.
Key Points
- Patients with COVID-19 may present with symptoms that overlap with many alternative, commonly encountered medical conditions.
- Focal subpleural consolidation with adjacent overlying pleural thickening and pleural line discontinuity may be an early finding with COVID-19 infection.
- Always consider and screen for an air gap sign/cardiac A-lines when you are unable to acquire a cardiac window, as this finding may indicate underlying pneumomediastinum and/or pneumopericardium.
- Small apical or loculated pneumothoraces can easily be missed if the ultrasound transducer is not positioned over the focal air pocket.
- If clinical signs and symptoms are highly suggestive of COVID-19 infection and an alternative etiology has not been definitively established, continuing to maintain patients on enhanced droplet precautions and performing repeat testing is prudent.
Biswas A, Lascano JE, Mehta HJ, et al. the utility of the “shred sign” in the diagnosis of acute respiratory distress syndrome resulting from multifocal pneumonia. Am J Respir Crit Care Med. 2017 Jan 15;195(2):e20-e22. doi: 10.1164/rccm.201608-1671IM.
Blaivas M, Lyon M, Duggal S. A prospective comparison of supine chest radiography and bedside ultrasound for the diagnosis of traumatic pneumothorax. Acad Emerg Med. 2005 Sep;12(9):844-849.
Huang C, Wang Y, Li X, et al. Clinical features of patients infected with 2019 novel coronavirus in Wuhan, China. Lancet. 2020 Feb 15;395(10223):497-506. doi: 10.1016/S0140-6736(20)30183-5. Epub 2020 Jan 24.
Huang Y, Wang S, Liu Y, et al. A preliminary study on the ultrasonic manifestations of peripulmonary lesions of non-critical novel coronavirus pneumonia (COVID-19). [Prepint]. 2020 [cited 2020 Mar 23]: [14 p.]. Available from: https://ssrn.com/abstract=3544750 or http://dx.doi.org/10.2139/ssrn.3544750
Lichtenstein DA, Menu Y. A bedside ultrasound sign ruling out pneumothorax in the critically ill: lung sliding. Chest. 1995;108:1345-1348.
Luo S, Zhang X, Xu H. Don’t overlook digestive symptoms in patients with 2019 novel coronavirus disease (COVID-19). Clin Gastroenterol Hepatol. 2020 Mar 20. pii: S1542-3565(20)30401-8. doi: 10.1016/j.cgh.2020.03.043. [Epub ahead of print]
Md Noor J, Eddie EA. Cardiac A-lines in fast scan as a sign of pneumopericardium. Ultrasound J. 2019 Apr 25;11(1):7. doi: 10.1186/s13089-019-0123-x.
Peng, QY, Wang XT, Zhang LN; Chinese Critical Care Ultrasound Study Group. Findings of lung ultrasonography of novel corona virus pneumonia during the 2019–2020 epidemic. Intensive Care Medicine. 2020 Mar: 1-2. doi: 10.1007/s00134-020-05996-6. [Epub ahead of print]
Reid CL, Chandraratna AN, Kawanishi D, et al. Echocardiographic detection of pneumomediastinum and pneumopericardium: the air gap sign. J Am Coll Cardiol. 1983;1:916-921.
Wilkerson RG, Stone MB. Sensitivity of bedside ultrasound and supine anteroposterior chest radiographs for the identification of pneumothorax after blunt trauma. Acad Emerg Med. 2010 Jan;17(1):11-17.
Zachariah S, Gharahbaghian L, Perera P, et al. Spontaneous pneumomediastinum on bedside ultrasound: case report and review of the literature. West J Emerg Med. 2015 Mar;16(2):321-324. doi: 10.5811/westjem.2015.1.24514. Epub 2015 Mar 13.
Zylak CM, Standen JR, Barnes GR, et al. Pneumomediastinum revisited. Radiographics. 2000;20(4):1043-1057
*Information from this website is for informational and learning purposes. It is not a substitute for professional medical advice, diagnosis, or treatment, but is intended to share real-time case studies and academic articles within the medical education community.
**The cardiac A-lines image was provided for use under the terms of the Creative Commons Attribution 4.0 International License (http://creativecommons.org/licenses/by/4.0/).