Case vignette
Otherwise healthy 19yoM presents with 12 hours of left-sided chest pain. Sudden onset while eating dinner the night before. Worse with ambulation. No fevers, cough, leg pain, dizziness, or syncope.
VS: HR 74, BP 160/102, RR 23, SpO2 99%, T 37.1
Exam: Normal breath sounds. Normal work of breathing. Normal pulses.
Differential includes viral URI, pneumonia, pneumothorax, musculoskeletal chest pain, acid reflux, among others. A medical student performs a cardiac and lung US, and a chest x-ray is obtained.
What do you see?
Right lung US (below): normal lung sliding
Left lung US (below): normal lung sliding is seen on the right side of the image with a transition point that comes into view with respirations. There is no visible lung sliding adjacent to this (“lung point”)
CXR: moderate left pneumothorax.
What do you do next?
You have identified a pneumothorax with US and confirmed with CXR. Given the moderate size of the pneumothorax, you determine that procedural re-expansion with a chest tube is indicated. You elect to use a smaller chest tube (14Fr pigtail catheter) in order to minimize pain and discomfort. Following successful placement, you obtain a repeat CXR showing appropriate chest tube position and near-resolution of the pneumothorax. You consult cardiothoracic surgery, who accepts the patient for admission to the hospital for further management.
The chest tube is removed on HD3 without complication. The post-pull CXR shows stable trace left pneumothorax. The patient is doing well and is discharged home later that day.
Teaching points: Diagnostics
Many studies have shown that bedside ultrasound can rapidly detect pneumothorax (read more here). Key diagnostic findings include lack of lung sliding and presence of a “lung point” or “transition point” (as seen above). Lung sliding refers to the back-and-forth movement of the parietal and visceral pleura sliding against each other during normal respiration. In contrast, a “lung point” is the transition point between normal sliding lung and absent lung sliding at the border of a pneumothorax.
In multiple studies of ultrasound for detection of pneumothorax in non-trauma settings, all proven pneumothoraces had absent lung sliding visible on ultrasound. However, absent lung sliding was sometimes a false positive for pneumothorax, particularly in critically ill patients. If lung sliding is absent, visible B lines or “comet tails” (read more here) can rule out pneumothorax. Other reasons for absent lung sliding include conditions with hypoventilation that cause decreased movement of the pleural interface (e.g. breath holding in intubated patients, mainstem intubation, asthma/copd) as well as conditions that result in adhesions of the pleural interface (e.g. history of VATS, pleurodesis) If lung sliding, B lines, and comet tails are all absent, the presence of a lung point has been found to have nearly 100% specificity for pneumothorax.
Teaching points: Management
Regarding the management of this patient’s pneumothorax, is a chest tube always necessary, specifically in patients with only mild symptoms and normal vital signs? In the Primary Spontaneous Pneumothorax trial, traditional interventional management of pneumothorax (i.e. chest tube placement) was compared with conservative management including at least 4 hours of observation and repeat CXR prior to discharge to home for clinically stable patients.
The trial included patients aged 14-50 with CXR demonstrating a first episode of spontaneous moderate-to-large pneumothorax. The primary end-point was successful lung re-expansion within 8 weeks. This end-point was seen in 98.5% of patients in the group receiving interventions and 94.4% of patients in the conservative management group, demonstrating a non- inferior outcome with conservative management. It is important to recognize that many patients will not be clinically appropriate for conservative management: there were over 2600 patients assessed for eligibility in this trial with only 316 patients meeting criteria to undergo study randomization. Yet, this trial provides modest evidence that conservative management was non-inferior to interventional management, laying the foundation for a potential shift in the management of spontaneous pneumothorax. This is especially relevant in patients with contraindications to chest tube placement (i.e. anticoagulation, high risk procedural sedation, etc.) Caution should be used for patients who do not have reliable follow up or ready access to medical care.
Sources:
1. Staub LJ, Biscaro RRM, Kaszubowski E, Maurici R. Chest ultrasonography for the emergency diagnosis of traumatic pneumothorax and haemothorax: A systematic review and meta-analysis. Injury. 2018;49(3):457-466. doi:10.1016/j.injury.2018.01.033 (https://pubmed.ncbi.nlm.nih.gov/29433802/)
2. Ultrasound for detection of pneumothorax. Angela Cirilli. Rebel EM. June 16, 2014. https://rebelem.com/ultrasound-detection-pneumothorax/. Accessed 10/9/22.
3. Lichtenstein DA. Lung ultrasound in the critically ill. Ann Intensive Care. 2014;4(1):1. Published 2014 Jan 9. doi:10.1186/2110-5820-4-1 (https://pubmed.ncbi.nlm.nih.gov/24401163/)
4. Comet tail artefact. James Rippey. Life in the Fast Lane. Aug 23, 2022. https://litfl.com/comet-tail-artefact/. Accessed 10/9/22.
5. Spontaneous pneumothorax: stand there and do nothing? Tarlan Hedayati. Rebel EM. March 12, 2020. https://rebelem.com/spontaneous-pneumothorax-stand-there-and-do-nothing/. Accessed 10/9/22.
6. Brown SGA, Ball EL, Perrin K, et al. Conservative versus Interventional Treatment for Spontaneous Pneumothorax. N Engl J Med. 2020;382(5):405-415. doi:10.1056/NEJMoa1910775 (https://pubmed.ncbi.nlm.nih.gov/31995686/)
Author: Lillian Lazenby MS4 with contributions from Drs. Nikolai Schnitkke, Bryson Hicks, Ryan Doumani
Images obtained by Lillian Lazenby, MS4