Multidetector computed tomography of spontaneous versus secondary pneumomediastinum in 89 patients: can multidetector computed tomography be used to reliably distinguish between the 2 entities?

Spontaneous pneumomediastinum: A comprehensive review of diagnosis and management

Pneumomediastinum is a rare condition defined by the presence of air in the mediastinum. In the absence of traumatic injury, iatrogenic injury, or clear etiology, it is called spontaneous pneumomediastinum (SPM). Spontaneous pneumomediastinum most commonly occurs in younger individuals and has a self-limiting course with a good outcome. The purpose of the present manuscript is to systematically review the existing literature on SPM evaluation and management for updated clinical understanding of this condition. A literature search was conducted of publications about SPM on MEDLINE/PubMed and Google Scholar by identifying all the articles with key search terms "pneumomediastinum" and "spontaneous pneumomediastinum". Inclusion criteria were case series published in English between 1980 and 2023. In total, 24 case series were selected and reviewed to determine presenting symptoms, clinical signs and predisposing factors associated with spontaneous pneumomediastinum. Most patients were male; the average age at diagnosis was 26.3 years. The most common presenting symptoms were chest pain and dyspnea. The most common exam finding was subcutaneous emphysema, in 35.4% of patients. Only 5.9% had the classic Hamman's sign. Risk factors include history of asthma, history of smoking, and recent physical activity. This manuscript presents an extensive review of relevant literature highlighting the diagnosis and essential management of spontaneous pneumomediastinum.

CT esophagogram in the emergency setting: typical findings and suggested workflow

PURPOSE

Esophageal perforation (EP) can be a diagnostic challenge. Computed tomography (CT) and CT esophagography (CTE) are often used to rule out EP in the emergency setting with promising diagnostic performance, but the standard of care remains fluoroscopic esophagography (FE). We assess the diagnostic performance of CT and CTE when interpreted by expert and generalist radiologists and created an imaging workflow guide.

METHODS

Retrospective study of patients presenting with suspected EP. Two expert radiologists independently reviewed blinded CT/CTE studies, recorded CT findings, and assigned an esophageal injury grade. We also collected initial (general radiologist) CT findings and interpretation and FE diagnoses. We assessed inter-reader reliability and diagnostic performance.

RESULTS

EP was diagnosed in 46/139 (33%) encounters. The most common CT/CTE findings in EP were esophageal wall thickening (46/46, 100%), pneumomediastinum (42/46, 91%), and mediastinal stranding (39/46, 85%). CT and CTE sensitivity for detecting EP was 89% and 89% for expert radiologists, respectively, and 79% and 82% for general radiologists, compared with 46% for FE. Inter-reader agreement for detecting EP by CT and CTE was kappa 0.35 and 0.42 (both p < .001) between expert and generalist radiologists. We present radiographic images for key CT/CTE findings and a suggested workflow for the evaluation of possible EP.

CONCLUSION

CT and CTE are more sensitive than FE for EP in the emergency setting. Due to the rarity of EP and current wide variability in imaging interpretation, an imaging workflow and injury grading system based on esophageal and mediastinal CT findings are offered to help guide management.

Pneumothorax and pneumomediastinum in children

Pneumothorax is a condition that describes the presence of air between the visceral and parietal pleura sheets and the consequent collapse of the lungs. The collapse of the lungs can be partial or total and can present in different clinical stages, such as a high-pressure pneumothorax that can cause a mediastinal shift. Pneumomediastinum is the presence of free air between the mediastinal tissues due to various causes. It can manifest spontaneously and be minimally symptomatic but can also develop due to severe complications. Its etiology includes numerous iatrogenic and traumatic factors. Although spontaneous pneumothorax and pneumomediastinum that develop in childhood are similar to adult patients, it is important to determine the appropriate treatment strategy in addition to the age group, the effectiveness of the treatment, the role of the applied treatment in reducing recurrence, and the etiologyoriented treatments if there is an underlying pathology.

Pneumomediastinum complicating diabetic ketoacidosis

Pneumomediastinum is an uncommon finding in patients with diabetic ketoacidosis (DKA) and may occur spontaneously or secondary to an effort rupture of the oesophagus. Excluding oesophageal rupture is important, as delaying treatment increases the risk of mortality. We discuss a case of DKA complicated by vomiting, pneumomediastinum, pneumopericardium and air in the epidural space. Instead of fluoroscopic oesophagography, chest CT was used to investigate oesophageal rupture. We present an overview of case reports and retrospective studies illustrating the utility of chest CT in the investigation of oesophageal rupture over fluoroscopic oesophagography.

Severe non-cardiovascular thoracic trauma: diagnostic clues on computed tomography

OBJECTIVE

About 60% of multiple trauma patients have thoracic trauma, and thoracic trauma results in the death of 10% of these patients. Computed tomography (CT) is the most sensitive and specific imaging modality for the diagnosis of acute disease, and it helps in the management and prognostic evaluation of patients with high-impact trauma. This paper aims to show the practical points that are key for diagnosing severe non-cardiovascular thoracic trauma by CT.

CONCLUSION

Knowing the key features of severe acute thoracic trauma on CT is crucial to avoid diagnostic errors. Radiologists play a fundamental role in the accurate early diagnosis of severe non-cardiovascular thoracic trauma, because the patient's management and outcome will depend largely on the imaging findings.

[Spontaneous pneumomediastinum]

INTRODUCTION

Pneumomediastinum, which can be spontaneous or secondary, is defined by the presence of free air in the mediastinum as shown on a chest X-ray and/or chest CT, with or without subcutaneous emphysema. Secondary pneumomediastinum develops in various contexts (thoracic traumatism, perforation of central airway or digestive tract, pneumothorax, barotraumatism complicating mechanical ventilation…). Spontaneous pneumomediastinum , which will be the focus of this review, develops without any of the above-mentioned conditions.

STATE OF ART

Spontaneous pneumomediastinum is a rare entity which usually occurs in young people either without medical history or with an history of asthma. A trigger event is detected in 40% to 60% of cases. Positive diagnosis is made on chest radiographt but thoracic CT is more sensitive. Distinction between spontaneous pneumomediastinum and secondary pneumomediastinum is in general easy but may sometimes be more difficult, particularly in case of oesophageal perforation. The evolution of spontaneous pneumomediastinum is most often benign but, rare complications may occur. Management is most often conservative.

PERSPECTIVES

There is no consensual management of spontaneous pneumediastinum because of the lack of randomized prospective studies. This may be explained by the rarity of the disease. The actual trend is to offer to the patients a conservative treatment, which could be ambulatory in some cases.

CONCLUSIONS

Spontaneous pneumomediastinum is a rare entity developing mainly in young subjects. The evolution is in general benign, justifying a conservative approach.

Imaging Manifestations of Chest Trauma

Trauma is the leading cause of death among individuals under 40 years of age, and pulmonary trauma is common in high-impact injuries. Unlike most other organs, the lung is elastic and distensible, with a physiologic capacity to withstand significant changes in contour and volume. The most common types of lung parenchymal injury are contusions, lacerations, and hematomas, each having characteristic imaging appearances. A less common type of lung injury is herniation. Chest radiography is often the first-line imaging modality performed in the assessment of the acutely injured patient, although there are inherent limitations in the use of this modality in trauma. CT images are more accurate for the assessment of the nature and extent of pulmonary injury than the single-view anteroposterior chest radiograph that is typically obtained in the trauma bay. However, the primary limitations of CT concern the need to transport the patient to the CT scanner and a longer processing time. The American Association for the Surgery of Trauma has established the most widely used grading scale to describe lung injury, which serves to communicate severity, guide management, and provide useful prognostic factors in a systematic fashion. The authors provide an in-depth exploration of the most common types of pulmonary parenchymal, pleural, and airway injuries. Injury grading, patient management, and potential complications of pulmonary injury are also discussed. ^©RSNA, 2021.

Clinical analysis of 71 spontaneous pneumomediastinum cases: an observational study from a tertiary care hospital in Japan

BACKGROUND

Spontaneous pneumomediastinum is characterized by the presence of interstitial air in the mediastinum without any underlying disease. Some cases of spontaneous pneumomediastinum have been reported in the past, although only few reports are available, and its management remains uncertain. This study reviewed our experience in the diagnosis and treatment of spontaneous pneumomediastinum.

METHODS

A retrospective study of 71 cases treated for spontaneous pneumomediastinum at the Yodogawa Christian Hospital between April 2005 and March 2020 was conducted.

RESULTS

The patients' mean age was 19.3 years (range, 7-48 years). A triggering event was noted in 69% of the cases. Seventy-six percent of the patients were admitted to the hospital, and 24% were outpatients. Treatment included analgesia, rest, antibiotics, and/or oxygen therapy. Thirty-six patients (51%) were treated with antibiotics. None of the cases presented any complications, including mediastinitis or worsening respiratory condition. Two patients (3%) had a recurrence of spontaneous pneumomediastinum.

CONCLUSIONS

All the patients, with or without antimicrobial treatment and hospitalization, had favorable outcomes. We should therefore reconsider the need for hospitalization and antimicrobial therapy for patients with mediastinitis prophylaxis.

Spontaneous primary pneumomediastinum: is it always benign?

BACKGROUND

Spontaneous Pneumomediastinum is a rare disease. It could be a simple and self-limited condition or be a life-threatening complication of underlying diseases. The therapeutic options also differ by the cause. This systematic review was done to provide, as far as we know, the first attempt to broadly assess the clinical feature, predisposing factors, possible management, and outcome of spontaneous primary pneumomediastinum.

METHODS

In addition to the two patients treated at our hospital, a Pub Med Search for literature on case reports of spontaneous pneumomediastinum published in English up to November 2018 was done. We extracted data on patients' demographic characteristics, symptoms, timing, diagnosis, management, and outcome of the treatment were analyzed based on the preferred Reporting Items for Systematic reviews and Meta-analysis (PRISMA) RESULT: A total of 339 cases were reviewed. 71.7% of them were male. The Mean age affected was 22.4 ± 11.3 years. Chest pain, 196 (57.8%), is the most common presenting symptom, followed by dyspnea, 156 (46%), cough 95 (28%), neck swelling 92 (27.13%), cervical pain 88 (25.9%), dysphagia 39 (11.5%), odynophagia 37 (10.9%), and Dysphonia 14 (4.1%). Fifty-seven patients (16.8%) had a prior history of Asthma, 19 (5.6%) had Connective Tissue Disorders, and 12 (3.5%) had associated malignancy as an identified risk factor. In 35 (10.3%) patients, spontaneous pneumomediastinum was found incidentally. The mean number of days before the clinical resolution of spontaneous pneumomediastinum was 6.65 ± 11.8 days and the average hospital stay was 4.15 ± 1.93 days. Nineteen (5.6%) patients have died as a result of the underlying disease not related to SPM.

CONCLUSION

Spontaneous pneumomediastinum is uncommon, usually benign, a self-limited disorder that commonly occurs in a young adult without any apparent precipitating factor or disease. Spontaneous pneumomediastinum usually responds very well to conservative treatment without recurrence. However, secondary causes should be ruled out to minimize the unfavorable outcome.

Diagnostic Utility of CT and Fluoroscopic Esophagography for Suspected Esophageal Perforation in the Emergency Department

OBJECTIVE. We evaluated the diagnostic utility of CT in emergency department (ED) patients with suspected esophageal perforation and assessed whether subsequent fluoroscopic esophagography is necessary. MATERIALS AND METHODS. This retrospective study included consecutive adult patients presenting to an urban academic tertiary care ED from January 1, 2000, to August 31, 2017, who underwent CT and fluoroscopic esophagography within 1 calendar day (< 27 hours) of each other for suspected esophageal perforation. The use of oral or IV contrast material and the CT findings (i.e., pneumomediastinum, pleural effusion, pneumothorax, unexplained mediastinal fluid or stranding, esophageal wall air or frank esophageal wall disruption, or extraluminal oral contrast material) were documented. Sensitivity, specificity, positive predictive value (PPV), and negative predictive value (NPV) were calculated. Surgical or procedural intervention results or clinical follow-up results were the reference standard. RESULTS. One hundred three patients met the inclusion criteria. Sensitivity, specificity, PPV, and NPV for diagnosing esophageal perforation were 100.0%, 79.8%, 32.1%, and 100.0%, respectively, with CT and 77.8%, 98.9%, 87.5%, and 97.9% with fluoroscopic esophagography. Combining CT and fluoroscopic esophagography did not improve sensitivity, specificity, PPV, or NPV relative to using CT alone. The true-positive esophageal perforation rate was 8.7% for CT and 6.8% for fluoroscopic esophagography. When CT showed only pneumomediastinum (n = 51) or no pneumomediastinum (n = 14), the NPV of CT was 100.0%. CT with oral contrast material had a PPV of 38.5%, whereas CT without oral contrast material had a PPV of 26.7%. CONCLUSION. CT has a high NPV similar to that of fluoroscopic esophagography and has greater sensitivity than fluoroscopic esophagography for diagnosing suspected esophageal perforation. Fluoroscopic esophagrams do not provide additional information that changes clinical management beyond the information that CT provides. In ED patients with suspected esophageal perforation, CT with oral contrast material should be considered the initial imaging examination and can obviate fluoroscopic esophagography.

Pneumomediastinum revisited: we should reconsider usual classification

Pneumomediastinum work-up should focus on differentiating mediastinal organ injuries from alveolar rupture since these two causative mechanisms have a different management and prognosis. After an admission at our Emergency Department, we wanted to challenge the current classification into 'spontaneous' or 'secondary' pneumomediastinum, which reflects the clinical rather than the pathophysiological circumstances and is therefore confusing and inappropriate to our view. We propose a new work-up algorithm based on clinical risks factors and chest CT findings.

Diagnosis and treatment of spontaneous pneumomediastinum: experience at a single institution for 10 years

OBJECTIVE

The aim of this study was to identify appropriate method of diagnosis and treatment of spontaneous pneumomediastinum (SPM) based on our experience.

METHODS

The medical records of patients who were diagnosed with SPM and treated at our hospital between April 2006 and July 2015 were, retrospectively, analyzed. The data included characteristics of the patients, method of diagnosis, treatment and clinical course.

RESULTS

Forty-five patients were diagnosed with SPM and treated at our hospital. The mean age of patients was 18.96 ± 4.65 years and 35 patients were male. The main symptoms expressed by these patients were chest pain, throat pain or discomfort, and dyspnea. Nine patients had a precipitating event leading to SPM. Twelve patients had normal chest X-ray findings but were subsequently diagnosed with SPM on chest computed tomography (CT). Additional procedures including esophagogram (n = 36), bronchoscopy (n = 14) and endoscopy (n = 1) were done but none of patients were found to have organ damage. All patients received oxygen inhalation therapy. Oral intake was restricted in 36 patients and 43 patients received prophylactic antibiotics. The mean time taken for symptomatic improvement was 1.73 ± 0.85 days from diagnosis. The mean hospital stay was 3.93 ± 1.44 days and no patient developed recurrence of SPM during the follow-up period.

CONCLUSIONS

In addition to chest X-ray, chest CT is recommended for accurate diagnosis of SPM. However, further invasive investigations, restriction of oral intake and the use of prophylactic antibiotics have minimal role in the diagnosis and treatment of SPM.

Scary gas: a spectrum of soft tissue gas encountered in the axial body (part II)

Ectopic gas in the mediastinum, subperitoneal abdomen, and superficial soft tissues is concerning and can be seen in the setting of trauma, iatrogenic injuries, infection, and inflammation. It can spread along different dissection pathways and may present remotely from the involved organ as described in part one. Recognition of ectopic gas on imaging and differentiating it from other causes of benign gas is very important as these conditions associated with ectopic gas can lead to rapid patient deterioration and usually require urgent surgery. In part two, the different causes of ectopic and benign gas in the torso are reviewed as well as the imaging features that can help to narrow the differential diagnosis.

Presence of subpleural pulmonary interstitial emphysema as an indication of single or multiple alveolar ruptures on CT in patients with spontaneous pneumomediastinum

Background There are no previous reports regarding the computed tomography (CT) findings of subpleural pulmonary interstitial emphysema (PIE) in patients with spontaneous pneumomediastinum. Purpose To evaluate CT findings of subpleural PIE that may indicate a direct site of terminal alveolar rupture. Material and Methods We retrospectively evaluated chest CT and the medical records of 34 patients with spontaneous pneumomediastinum. Subpleural PIE was defined as the presence of an interstitial air collection in the subpleural portion of the lungs excluding the bronchovascular bundle. Results Subpleural PIE on CT was identified in six of 34 patients (17.6%) with spontaneous pneumomediastinum. In four of these (66.7%), subpleural PIE was present in multiple lobes suggesting multiple simultaneous ruptures of terminal alveoli. The shape of subpleural PIE was elongated linear (4/6), branching and linear (1/6), and elliptical (1/6). Conclusion The presence of subpleural PIE on CT suggests an origin of pneumomediastinal air from alveolar rupture.

Spontaneous Pneumomediastinum as a Potential Predictor of Mortality in Patients with Idiopathic Pulmonary Fibrosis

BACKGROUND

Spontaneous pneumomediastinum (PM) is a rare event in patients with idiopathic pulmonary fibrosis (IPF) with unknown prognostic implications.

OBJECTIVES

To analyze the incidence and prognostic impact of PM in a cohort of patients with IPF.

METHODS

PM diagnosed by computed tomography was identified retrospectively in the clinical and radiological records of 182 patients with IPF who were admitted to our center between August 2006 and July 2013. PM patients were compared to matched IPF patients not affected by PM and analyzed for survival.

RESULTS

PM occurred in 9/182 IPF patients [5%; 6 males; median age: 63 years; median percent predicted of vital capacity (VC%) at baseline: 53%]. The median time between IPF diagnosis and PM occurrence was 3 months (interquartile range: 0-33). The control group included 36 IPF patients (28 males; median age: 69 years; VC% at baseline: 57%). In a multivariate Cox regression analysis, PM was a significant predictor of mortality [hazard ratio (HR): 3.0; p = 0.032]. Considering only patients experiencing PM at the time of IPF diagnosis (n = 4), PM was a strongly significant predictor of mortality in multivariate analysis (HR: 6.4; p = 0.007).

CONCLUSIONS

Spontaneous PM is a rare but serious complication in patients with IPF and may be considered as a potential predictor of mortality.

Clinical experience of spontaneous pneumomediastinum: diagnosis and treatment

BACKGROUND

Spontaneous pneumomediastinum (SPM) is a benign disease with a variety degree of severity but definite treatment modality is not clearly identified with its rarity. The purpose of this study was to review our experience and discuss the management of SPM according to the severity of disease.

METHODS

From March 1996 to December 2012, total 64 patients were enrolled and classified as mild, moderate and severe groups and subsequent clinical courses were analyzed retrospectively.

RESULTS

Fifty-one were males and 13 were females (M:F =3.9:1) with a mean age of 18 years old (range: 10-30 years old). Thirty-six patients were in mild, 22 in moderate and 6 in severe group. Chief complaints were chest pain (50 cases; 78.1%), neck pain (35 cases; 54.7%), dyspnea (18 cases; 28.1%), odynophagia (9 cases; 14.1%) and precipitating factors were coughing in 12 cases, feeding problems in 9 cases, and vomiting in 7 cases; however, 34 patients (53.1%) had no precipitating signs. All patients received oxygen therapy (100%), prophylactic antibiotics in 57 patients (89.1%), and pain medications in 47 patients (73.4%). The mean hospital stay was 4.6 days (range: 1-10 days). There was an increased linear trend according to time to visit (P=0.023) but clinical course demonstrated no significant trend between groups.

CONCLUSIONS

These data demonstrated that there was no difference in symptom, clinical course and SPM was adequately treated with conservative management regardless of the degree of severity of SPM.

Pneumomediastinum: etiology and a guide to diagnosis and treatment

BACKGROUND

Pneumomediastinum may be associated with mediastinal organ injury. The aim of this study was to identify predictive factors of mediastinal organ injury in patients with pneumomediastinum to guide diagnosis and treatment.

METHODS

A retrospective review was conducted including patients aged ≥18 years with Current Procedural Terminology code 518.1 (interstitial emphysema) from 2005-2011.

RESULTS

There were 279 of 343 patients (81%) with and 64 of 343 (19%) without history of trauma. In the trauma population, 13 patients (5%) were found to have mediastinal organ injuries, 10 (4%) had airway injuries, and 3 (1%) had esophageal injuries. In the nontrauma population, 36 patients (56%) had spontaneous pneumomediastinum, esophageal injuries were seen in 17 (27%), pneumothorax in 9 (14%), and airway injuries in 2 (3%). The predictors of esophageal injury were instrumentation (odds ratio [OR], 45.7; P < .0001), pleural effusion (OR, 10.5; P < .0001), and vomiting (OR, 9.3; P < .0001). Previous instrumentation was the most significant predictor of airway injury (OR, 9.05; P < .02).

CONCLUSIONS

Mediastinal organ injury in patients with pneumomediastinum is uncommon. Patients presenting with pneumomediastinum without a history of instrumentation, pleural effusion, or vomiting most commonly do not have mediastinal organ injuries.

Spontaneous pneumomediastinum: analysis of 87 pediatric patients

OBJECTIVES

Early reports on pneumomediastinum studied the adult population, and recent analyses of pneumomediastinum in pediatric patients contain small numbers of patients. We aimed to summarize the experience of a larger number of pediatric patients with spontaneous pneumomediastinum (SPM) in a tertiary children's facility in northern Taiwan.

METHODS

We performed a retrospective chart review of clinical manifestations and outcome of SPM on pediatric patients who were admitted to our hospital during a 10-year period.

RESULTS

Forty-three patients (49.4%) had primary SPM, with a male predominance in adolescents. None of the 16 patients younger than 6 years had primary SPM; 43 of 71 patients older than 6 years had secondary SPM (0% vs 60.6%, P < 0.05). The common causes of secondary SPM were asthmatic exacerbation, pneumonia or lower respiratory tract infections, or choking. Ten patients had normal frontal chest radiograph finding (sensitivity, 89.1%); the lateral neck radiographs clearly demonstrated subcutaneous emphysema in 9 of these 10 patients.

CONCLUSIONS

All patients younger than 6 years with SPM were secondary; therefore, they should be vigilantly examined for predisposing causes. For adolescent patients with SPM with no catastrophic events, asthma with exacerbation should be considered first, and extensive or invasive diagnostic examinations are not needed. Primary SPM usually requires conservative treatment only with no sequel or recurrence. Lateral neck radiograph has a higher sensitivity for the demonstration of subcutaneous emphysema in doubtful cases.

Diagnosis and treatment of patients with spontaneous pneumomediastinum

BACKGROUND

Although many patients complaining of chest pain visit the emergency department, very few are diagnosed with spontaneous pneumomediastinum (SPM). We present the management of 20 patients with SPM.

METHODS

We retrospectively analyzed the clinical features, past history, chest X-rays (CXRs), 64-slice helical computed tomography (CT) images, and clinical course of 20 patients with SPM (19 men and 1 woman) who visited the emergency department of the Tokyo Metropolitan Bokutoh Hospital between 2005 and 2010.

RESULTS

SPM predominantly resulted from physical exertion during such activities as sports and weight lifting (8 patients). The most common complaint was chest pain (15 patients), followed by dysphagia (10 patients), and dyspnea (8 patients). Subcutaneous emphysema was detected in 9 patients. The mean body mass index of the patients was 20.8±1.4kg/m(2). Although CXR findings of pneumomediastinum were absent in 5 patients, CT showed findings of the Macklin effect in all patients-interstitial gas was observed in the perihilar area in all patients and in the peripheral lung area in 9 patients (45%). Ten patients were hospitalized. The others received ambulatory care in the form of analgesics without antibiotics. All patients fully recovered without complications.

CONCLUSIONS

Our results showed that 64-slice helical CT is more reliable than CXRs for diagnosing SPM. Moreover, some patients with SPM can be treated without hospitalization, thus decreasing medical expenses for these patients.