March 2023 Medical Image of the Month: Spontaneous Pneumomediastinum as a Complication of Marijuana Smoking Due to Müller's Maneuvers

Figure 1. PA chest radiograph obtained at the time of admission (A) demonstrating gas densities (arrows) along left heart border, left paratracheal stripe, upper mediastinum and neck extending into the right supraclavicular fossa in keeping with pneumomediastinum. Follow-up PA chest radiograph performed just before discharge (B) demonstrates resolution of pneumomediastinum.

Figure 2. Two axial images through the anterior mediastinum obtained from a contrast-enhanced chest CT demonstrating gas densities (arrows) in the mediastinum anterior to the heart and around the esophagus in-keeping with pneumomediastinum.

A 35-year-old woman with a medical history notable for celiac disease, ulcerative colitis, and bipolar disorder presents to the Emergency Department for evaluation of a strange sensation in the chest and neck associated with nausea and vomiting for one day. The patient also reports persistent nausea and markedly decreased oral intake for the last four days. She reported no concomitant symptoms such as shortness of breath, wheezing, fever, or chills. She denies diarrhea or constipation. Socially, she admits to smoking marijuana daily, and alcohol occasionally.

Vital sign shows blood pressure 147/97 mmHg, pulse 92 BPM, temperature 37.3°C, SpO2 96% breathing ambient air. She appears nontoxic and well-nourished, and the lungs are clear to auscultation bilaterally without any wheezes, rales, or rhonchi. The heart examination reveals a regular rate and rhythm, with normal S1 and S2 heart sounds and no murmurs, rubs, or gallops. The abdomen is soft, non-tender, and not distended. Her extremities do not exhibit any clubbing, cyanosis, or edema. CBC and CMP were unremarkable, and the drug screen test was positive for THC. An ECG is obtained (not shown here), which reveals a normal sinus rhythm with a heart rate of 55 beats/min and no ST-segment or T-wave abnormalities. Chest x-ray and CTA chest, CT abdominal with oral contrast were obtained (Figures 1 and 2). Upon further questioning of the patient’s social history, it was discovered that she smokes marijuana daily using water pipes, and while utilizing a water pipe she attempted a full inspiration against a closed mouth and nose, a technique known as the Müller’s maneuver.

Spontaneous pneumomediastinum (SPM) is a rare condition in which air escapes from the lungs and collects in the mediastinum, the space between the lungs. SPM is almost always a benign, self-limited condition. While SPM can be caused by a variety of factors, including coughing, vomiting, and physical trauma, this case report presents a rare instance of SPM caused by marijuana smoking. Spontaneous pneumomediastinum (SPM) was reported in 1939 by Johns Hopkins clinician Louis Hamman for whom the Hamman sign is named. It is defined as free air or gas contained within the mediastinum, which almost originates from the alveolar space or the conducting airways. Many authors distinguish spontaneous pneumomediastinum as a form of pneumomediastinum that is not associated with blunt force or penetrating chest trauma, endobronchial or esophageal procedures, neonatal lung disease, mechanical ventilation, chest surgery, or other invasive procedures.

The mechanism by which marijuana smoking leads to pneumomediastinum is not well understood, but it is thought to involve increased intra-alveolar pressure and alveolar rupture. This can result in the escape of air into the mediastinum, leading to the development of pneumomediastinum. SPM has been associated with the inhalation of drugs such as cocaine, amphetamines, and marijuana (1-4). Attempted inspiration through a closed glottis or Muller’s maneuver results in a drop in intrathoracic pressure, which increases alveolar air volume, causing alveolar distension and rupture which can cause shear damage and air leakage along a bronchovascular bundle into the mediastinum.

The patient, in this case, was a 35-year-old woman with a history of marijuana smoking who presented with symptoms of chest pain, shortness of breath, and dysphagia. Physical examination revealed subcutaneous emphysema and a chest x-ray confirmed the presence of SPM. This case highlights the potential respiratory complications associated with marijuana smoking, which can lead to SPM and other adverse outcomes. While marijuana use is becoming increasingly common and accepted, it is important for healthcare providers to be aware of the potential risks and to educate their patients about the potential consequences of marijuana use. Further research is needed to understand the full extent of the respiratory effects of marijuana smoking and to develop appropriate interventions and treatments.

Mohammad Abdelaziz Mahmoud DO

Doctors Medical Center of Modesto and Emanuel Medical Center

Modesto and Turlock, CA USA

References

1. Weiss ZF, Gore S, Foderaro A. Pneumomediastinum in marijuana users: a retrospective review of 14 cases. BMJ Open Respir Res. 2019 Feb 12;6(1):e000391. [CrossRef] [PubMed]
2. Al-Mufarrej F, Badar J, Gharagozloo F, Tempesta B, Strother E, Margolis M. Spontaneous pneumomediastinum: diagnostic and therapeutic interventions. J Cardiothorac Surg. 2008 Nov 3;3:59. [CrossRef] [PubMed]
3. Puri C, Rhee K, Harish VK, Slack D. Marijuana induced spontaneous pneumomediastinum. J Community Hosp Intern Med Perspect. 2021 Jun 21;11(4):516-517. [CrossRef] [PubMed]
4. Motes A, Laoveeravat P, Thongtan T, Nugent K, Islam S, Islam E. Marijuana use-induced spontaneous pneumomediastinum. Proc (Bayl Univ Med Cent). 2020 Dec 7;34(2):274-275. [CrossRef] [PubMed]

Cite as: Mahmoud MA. March 2023 Medical Image of the Month: Spontaneous Pneumomediastinum as a Complication of Marijuana Smoking Due to Müller's Maneuvers. Southwest J Pulm Crit Care Sleep. 2023;26(3):31-33. doi: https://doi.org/10.13175/swjpccs058-22 PDF 

April 2016 Imaging Case of the Month

Michael B. Gotway, MD

Department of Radiology

Mayo Clinic Arizona

Scottsdale, AZ USA

Imaging Case of the Month CME Information  

Members of the Arizona, New Mexico, Colorado and California Thoracic Societies and the Mayo Clinic are able to receive  0.25 AMA PRA Category 1 Credits™. Completion of an evaluation form is required to receive credit and a link is provided on the last panel of the activity.

0.25 AMA PRA Category 1 Credit(s)™

Estimated time to complete this activity: 0.25 hours

Lead Author(s): Michael B. Gotway, MD. All Faculty, CME Planning Committee Members, and the CME Office Reviewers have disclosed that they do not have any relevant financial relationships with commercial interests that would constitute a conflict of interest concerning this CME activity. 

Learning Objectives:
As a result of this activity I will be better able to:    

1. Correctly interpret and identify clinical practices supported by the highest quality available evidence.
2. Will be better able to establsh the optimal evaluation leading to a correct diagnosis for patients with pulmonary, critical care and sleep disorders.
3. Will improve the translation of the most current clinical information into the delivery of high quality care for patients.
4. Will integrate new treatment options in discussing available treatment alternatives for patients with pulmonary, critical care and sleep related disorders.

Learning Format: Case-based, interactive online course, including mandatory assessment questions (number of questions varies by case). Please also read the Technical Requirements.

CME Sponsor: University of Arizona College of Medicine at the Arizona Health Sciences Center.

Current Approval Period: January 1, 2015-December 31, 2016

Financial Support Received: None.

Clinical History: A 19 year-old man with no previous medical history was vacationing when he was found down, intoxicated, surrounded by vomit. He went into cardiac arrest, and, after several minutes, cardiopulmonary resuscitation was initiated. He was intubated in the field, and epinephrine was administered.

Once at the hospital, frontal chest radiography (Figure 1) was performed.

Figure 1. Frontal chest radiograph.

Which of the following statements regarding the chest radiograph is most accurate?

1. The frontal chest radiograph shows central venous catheter malposition
2. The frontal chest radiograph shows focal consideration
3. The frontal chest radiograph shows pleural fluid loculated within the major fissures
4. The frontal chest radiograph shows pneumomediastinum
5. The frontal chest radiograph shows pneumothorax

Cite as: Gotway MB. April 2016 imaging case of the month. Southwest J Pulm Crit Care. 2016 Apr;12(4):137-46. doi: http://dx.doi.org/10.13175/swjpcc035-16 PDF

Medical Image of the Week: Spontaneous Pneumomediastinum

Figure 1. Upright chest radiograph showing pneumomediastinum tracking into neck and small right apical pneumothorax (arrows).

Figure 2. Coronal slice of CT chest showing extensive pneumomediastinum and subcutaneous emphysema (arrows).

Figure 3. CT scan of chest showing the Macklin effect with air tracking along the bronchovascular sheath in the left lower lobe.

A 24-year-old man with a past medical history significant for type I diabetes mellitus presented to the emergency department with complaints of nausea and vomiting for several days. He reported he had been on drinking alcohol heavily 4 days prior to presentation and subsequently had multiple episodes of vomiting. Initial laboratory evaluation was consistent with diabetic ketoacidosis (DKA). A routine chest x-ray was obtained to evaluate for an infectious etiology of his DKA and revealed pneumomediastinum and a small right apical pneumothorax (Figure 1). A CT scan of the chest was done and showed extensive pneumomediastinum as well as air tracking along the bronchovascular sheaths in the left lower lobe (Figure 2 and 3). It did not reveal evidence of esophageal injury.

Spontaneous pneumomediastinum (SPM) refers to pneumomediastinum that is not associated with noticeable cause such as esophageal rupture or trauma. It is typically a benign condition thought to be due to alveolar rupture and subsequent air tracking along the bronchial tree (1). It has been associated with a number of conditions including asthma, DKA, anorexia nervosa, and other conditions that lead to excessive coughing or vomiting. The radiographic appearance of air dissecting through the pulmonary intersitium along the bronchovascular sheath is known as the Macklin effect and can be seen in Figure 3.

Spontaneous pneumomediastinum typically resolves without complications but must be differentiated from the much more serious diagnosis of esophageal rupture, or Boerrhaave’s syndrome. Boerrhaave’s syndrome is more likely to present with fever, hemodynamic instability, and hydropneumothorax. All patients presenting with suspected SPM should be evaluated for esophageal perforation with a radiographic contrast swallow (2). In our case it was negative for evidence of esophageal disruption and the patient recovered completely.

Lucie Griffin DO and Erik Kraai MD

Division of Pulmonary, Critical Car, and Sleep Medicine

University of New Mexico Health Sciences Center

Albuquerque, NM USA

References

1. Murayama S, Gibo S. Spontaneous pneumomediastinum and Macklin effect: Overview and appearance on computed tomography. World J Radiol. 2014 Nov 28;6(11):850-4. [CrossRef] [PubMed]
2. Kelly S, Hughes S, Nixon S, Paterson-Brown S. Spontaneous pneumomediastinum (Hamman's syndrome). Surgeon. 2010 Apr;8(2):63-6. [CrossRef] [PubMed] 

Cite as: Griffin L, Kraai E. Medical image of the week: spontaneous pneumomediastinum. Southwest J Pulm Crit Care. 2016 Mar;12(3):115-6. doi: http://dx.doi.org/10.13175/swjpcc015-16 PDF

Medical Image of the Week: Pneumomediastinum

Figure 1. Chest X-ray PA view.

Figure 2. CT scan of chest.

A 38-year-old gentleman was flown to the emergency room after being involved in a motor vehicle accident. In the field, he had a Glasgow Coma Scale of about 7 and cricothyrotomy was performed to establish an airway. He sustained severe head and chest injuries, with extensive subcutaneous emphysema.  Chest X-ray (Figure 1) and CT scan (Figure 2) revealed pneumomediastinum with classical “continuous diaphragm sign” (red arrows), lucent streaks outlining the ascending aorta (blue arrows) and extensive subcutaneous emphysema (block arrows). Subdural and subarachnoid hemorrhage was detected on CT scan of head. His neurological status worsened over next 24 hours and he was confirmed brain dead.

Ramasubramanian Baalachandran MD, Naser Mahmoud MD, and Laura Meinke MD

Department of Medicine

University of Arizona

Tucson, Arizona

References

1. Bejvan SM, Godwin JD. Pneumomediastinum: old signs and new signs. AJR Am J Roentgenol. 1996;166:1041-8. [CrossRef] [PubMed]
2. Levin B. The continuous diaphragm sign. A newly-recognized sign of pneumomediastinum. Clin Radiol.1973;24(3):337-8. [CrossRef] [PubMed]

Reference as: Baalachandran R, Mahmoud N, Meinke L. Medical image of the week: pneumomediastinum. Southwest J Pulm Crit Care. 2014;9(3):189-90. doi: http://dx.doi.org/10.13175/swjpcc123-14 PDF

Medical Image of the Week: Pneumomediastinum

Figure 1.  Chest x-ray (CXR) shows subtle evidence of pneumomediastinum with air outlining left cardiac border and trachea (arrows).

 

Figure 2. Chest computerized tomography (CT) showing pneumomediastinum (Panel A) extending into lower neck (Panel B) without evidence of pneumothorax.

A 65 year old man presented with mild increase in shortness of breath. He had a past medical history of diabetes mellitus, hypertension, and severe malnutrition with percutaneous endoscopic gastrostomy (PEG) placement after a colectomy and end ileostomy for sigmoid volvulus. CXR (Figure 1) suggested a pneumomediastinum with subsequent chest CT (Figure 2) confirming moderate sized pneumomediastinum. He had a chronic cough from chronic obstructive pulmonary disease (COPD) as well as aspiration and chest CT also demonstrated emphysema with small blebs. He denied any significant chest pain. He was followed conservatively with imaging and discharged in stable condition.

Pneumomediastinum can be caused by trauma, esophageal rupture after vomiting (Boerhaave’s syndrome) and can be a spontaneous event if no obvious precipitating cause is identified (1). Valsalva maneuvers such as cough, sneeze, vomiting and childbirth, can all cause pneumomediastinum. Risk factors include asthma, COPD, interstitial lung disease and inhalational recreational drug use. Hamman's sign (a crunching sound in time with the heartbeat) can occasionally be heard.  More commonly, subcutaneous emphysema is felt on exam (crepitus). Complications can include single or bilateral pneumothorax, tension pneumothorax and pleural effusion. CXR often does not identify mediastinal air and CT imaging is highly sensitive and confirmatory. Conservative management is recommended with close clinical follow up for possible complications.

Rene Franco, Jr MD, Mohammad Dalabih MD, Janet Campion MD

University of Arizona Medical Center, Tucson AZ

Reference

1. Newcomb AE, Clarke CP. Spontaneous Pneumomediastinum. Chest. 2005;128:3298-3302. [CrossRef] [PubMed] 

Reference as: Franco R Jr, Dalabih M, Campion J. Medical image of the week: pneumomediastinum. Southwest J Pulm Crit Care. 2014:8(1):46-7. doi: http://dx.doi.org/10.13175/swjpcc160-13 PDF