respiratory investigation 52 (2014) 36 –40

Contents lists available at ScienceDirect

Respiratory Investigation journal homepage: www.elsevier.com/locate/resinv

Original article

Diagnosis and treatment of patients with spontaneous pneumomediastinum Masahiko Okadaa,n, Hideo Adachib, Yasuhiro Shibuyac, Susumu Ishikawad, Yuuichi Hamabee a

Department of Emergency Medicine, Tokyo Metropolitan Bokutoh Hospital, 23-15 Kotohbashi4-chome, Sumida-ku, Tokyo 130-8575, Japan b Department of Cardiovascular Surgery, Saitama Medical Center, Jichi Medical University, 1-847 Amanuma, Omiya-ku, Saitama 330-8503, Japan c Department of Respiratory Medicine, Tokyo Metropolitan Bokutoh Hospital, 23-15 Kotohbashi4-chome, Sumida-ku, Tokyo 130-8575, Japan d Department of Cardiothoracic Surgery, Tokyo Metropolitan Bokutoh Hospital, 23-15 Kotohbashi4-chome, Sumida-ku, Tokyo 130-8575, Japan e Tertiary Emergency Medical Center, Tokyo Metropolitan Bokutoh Hospital, 23-15 Kotohbashi4-chome, Sumida-ku, Tokyo 130-8575, Japan

ar t ic l e in f o

abs tra ct

Article history:

Background: Although many patients complaining of chest pain visit the emergency

Received 23 January 2013

department, very few are diagnosed with spontaneous pneumomediastinum (SPM).

Received in revised form

We present the management of 20 patients with SPM.

10 April 2013

Methods: We

Accepted 3 June 2013

X-rays (CXRs), 64-slice helical computed tomography (CT) images, and clinical course of

Available online 5 July 2013

20 patients with SPM (19 men and 1 woman) who visited the emergency department of the

analyzed

the

clinical

features,

past

history,

chest

Tokyo Metropolitan Bokutoh Hospital between 2005 and 2010.

Keywords:

Results: SPM predominantly resulted from physical exertion during such activities as

Pneumomediastinum Computed tomography Macklin effect 64-Slice helical computed tomography

retrospectively

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 20.871.4 kg/m2. 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. & 2013 The Japanese Respiratory Society. Published by Elsevier B.V. All rights reserved.

Abbreviations: BMI,

body mass index; CRP,

C-reactive protein; CT,

computed tomography; CXR,

chest X-ray;

PM, pneumomediastinum; SPM, spontaneous pneumomediastinum n Corresponding author. Tel.: +81 3633 6151; fax: +81 3 3633 7129. E-mail addresses: [email protected] (M. Okada), [email protected] (H. Adachi), [email protected] (Y. Shibuya), [email protected] (S. Ishikawa), [email protected] (Y. Hamabe). 2212-5345/$ - see front matter & 2013 The Japanese Respiratory Society. Published by Elsevier B.V. All rights reserved. http://dx.doi.org/10.1016/j.resinv.2013.06.001

respiratory investigation 52 (2014) 36 –40

1.

Introduction

Pneumomediastinum (PM) is defined as the presence of air within the mediastinum [1]. The definition of spontaneous pneumomediastinum (SPM) is controversial because of variations in the underlying pulmonary pathology in patients with PM. SPM is a rare and predominantly benign finding in younger male patients without a history of an obvious precipitating event [2–4]. The differential diagnosis of PM is important because it can also be caused by trauma, gasproducing organisms, and esophageal rupture, which are all potentially fatal [5] and require surgical intervention and intensive care. Chest X-rays (CXRs) are generally useful for diagnosing PM, although there are cases of false-negative results. For these cases, Kaneki et al. [6] concluded that computed tomography (CT) is more effective than CXRs alone for diagnosing PM because of thin slices obtained in CT. Sixtyfour-slice helical CT reveals minute changes in the organs and peripheral tissues. In this study, we report our experience managing 20 patients with SPM. We focused on the Macklin effect, which is a known CT finding caused by alveolar rupture [7,8], and investigated the frequency and distribution of this finding on chest CT. In addition, we report the results of ambulatory treatment without antibiotics for some patients with SPM in whom PM, which is potentially lethal, was ruled out by clinical and CT findings.

2.

Materials and methods

We retrospectively analyzed the clinical records of 20 patients with SPM (19 men and 1 woman) who presented at the emergency department of the Tokyo Metropolitan Bokutoh Hospital, Japan, between 2005 and 2010. During this period, a total of 279,997 patients presented at the emergency department. This retrospective study was approved for number 5 by the Tokyo Metropolitan Bokutoh Hospital Institutional Review Board on May 1, 2012, and the requirement for individual patient consent was waived. Data collection was performed under strict guidelines to protect patient information. We also performed a retrospective analysis of presenting complaints, precipitating factors, comorbidities, symptoms, signs, clinical courses, treatment regimens, length of hospital stays, and outcomes. All patients underwent CXRs and 64slice helical CT (without contrast enhancement) to decide definitive disposition assessed by an emergency physician. CT images were evaluated for the Macklin effect, which is defined as the accumulation of air through the peribronchial and perivascular sheaths into the surrounding tissue. Patients were classified on the basis of the location of the Macklin effect: perihilar or peripheral lung areas. The exclusion criteria were trauma, gastrointestinal perforation, and pharyngitis, which were assessed on the basis of clinical presentations and CT findings. Patients were also classified on the basis of the type of medical care they received: hospitalization or ambulatory. Categorical variables are expressed as percentages, and continuous variables are expressed as mean7standard error.

37

Categorical variables were compared using a univariate analysis using the t test or Fisher's exact test as indicated. Continuous variables were compared using the Mann–Whitney U test. Pearson's correlation coefficients between clinical parameters were determined. Statistical analyses were performed using the GraphPad Prism 5 software (GraphPad Software, USA). In all analyses, a p value of o0.05 was considered statistically significant.

3.

Results

The average patient age was 22.071.4 years (range, 13–41 years). The annual incidence of SPM in our hospital was approximately 1 per 14,000 patients presenting at the emergency department (annual incidence of approximately 3.3 patients per year). SPM was caused by physical exertion during such activities as sports and weight lifting (8 patients), severe cough (3 patients), karaoke singing (3 patients), and vomiting (2 patients). The cause of SPM was unknown in 4 patients. No patient had a history of inhalation drug abuse (Table 1). The most common presenting complaints were chest pain (15 patients, 75%), dysphagia (10 patients, 50%), and dyspnea (8 patients, 40%) (Table 2). Subcutaneous emphysema was detected in 9 patients (45%). Hamman's sign was audible only in 2 patients (10%). The average body mass index (BMI) was 20.871.4 kg/m2 (Table 3). The average time between the onset of symptoms and consultation was 1.1570.17 days. The mean baseline SpO2 was 96.2%70.9% (within the normal range). The leukocyte count was 11.9770.88  103/μl And Creactive protein (CRP) level was 0.8570.33 mg/dL (Table 4). CXRs and 64-slice helical CT were performed in all 20 patients, and esophagography was required only in 1 patient. Five patients had no CXR findings suggestive of PM. In contrast, the Macklin effect was identified on CT in all patients. Interstitial free air was visible in the perihilar area in all patients (Fig. 1), and in the peripheral lung area in 9 patients (45%) (Fig. 2). CT was more reliable than CXRs in excluding other causes of nonspontaneous PM, such as necrotizing mediastinitis and esophageal rupture. After the diagnosis of SPM was confirmed by clinical and CT findings, a 5-question admission checklist was used to determine whether patients required hospitalization or ambulatory care (Fig. 3). Ten patients with negative responses to all questions received ambulatory care and were administered analgesics without antibiotics. The average follow-up period in ambulatory care was 17.174.9 days. None of these patients experienced complications. The remaining 10

Table 1 – Causes of spontaneous pneumomediastinum. Etiology

n

Physical exertion Cough Karaoke singing Vomiting Unknown

8 3 3 2 4

38

respiratory investigation 52 (2014) 36 –40

diagnosed by CXRs and electrocardiography further underwent

Table 2 – Symptoms of spontaneous pneumomediastinum.

64-slice helical CT. According to the available data, lung blebs and bullae caused by SPM and spontaneous pneumothorax

Symptom

n%

Chest pain Dysphagia Dyspnea Pharyngeal pain Vomiting Neck pain Cough

15.75 10.50 8.40 5.25 2.10 2.10 1.5

frequently occur in thin young men with a BMI of less than 22 kg/m2 [12–14]. The average patient age and BMI in our study were similar to the values in these reports. Our results suggest that bleb and bullae affect the incidence of SPM. All but 1 patient in our study were men, which is in line with the previous reports [1,10,11]. SPM is associated with inhalation drug abuse [15,16], childbirth [17], diabetic ketoacidosis [18], coughing or physical exertion [10], and other activities related to the Valsalva maneuver [9,13]. In this study, physical exertion was the most common cause. The onset of SPM due to karaoke singing seems

Table 3 – Clinical data of the patients.

to be more common in Japanese patients. The history of

Parameter

Value

Number of patients Age (years) Male-to-female ratio Number of smokers Body mass index (kg/m2) Onset to ED consultation (days) Initial SpO2 (%) Leukocyte count (103/μl) CRP (mg/dl) Number of outpatients Hospital stay (days) Number of patients using antibiotics

20 22.071.4 19:1 3 20.871.4 1.1570.17 96.270.9 11.9770.88 0.8570.33 10 7.0071.22 4

Abbreviations: CRP, C-reactive protein; ED, emergency department.

patients were admitted because they had at least 1 positive response, and only 4 of these patients received antibiotics. Three patients were placed on nil per os order. The mean length of hospital stay in these 3 patients was 7.0071.22 days, and they were discharged without complications. SPM did not recur in any of the patients (Fig. 3). The length of hospital stay correlated with baseline SpO2 (r¼ −0.731, p¼ 0.016), body temperature (r¼ −0.689, p¼ 0.031), leukocyte count (r¼ 0.223, p¼ 0.537), and CRP level (r¼ 0.354, p¼ 0.316).

4.

Discussion

Macklin and Macklin [7] argued that air may escape from the terminal alveoli due to increased alveolar pressure and enter the pulmonary interstitial spaces, perivascular sheaths, and the mediastinum, causing PM. CT findings of SPM observed in our study supported this theory, because the Macklin effect was observed in all patients. Newcomb [9] stated that SPM is an uncommon condition presenting in approximately 1 of 30,000 emergency department referrals. Many authors report the incidence of SPM as approximately 2 patients per year [3,9,10,11], whereas an incidence of 3 patients per year has been reported in Japan [6]. However, the incidence of SPM in this study was 3.3 patients per year, which is higher than that in other reports. This discrepancy is probably due to a different study approach, which included examining patients presenting with mild-to-moderate chest pain in our emergency department. In addition, patients with continuous chest pain who could not be differentially

bronchial asthma has been reported as an etiological factor of SPM in upto 50% of the patients [9,10,19]. In our study, only 20% of the patients had present or past history of bronchial asthma. The most common symptom was chest pain (75%) associated with dysphagia, which is in line with other reports. Nine patients had subcutaneous emphysema (45%), and its incidence was lower than that reported in other studies. Hamman's sign [2], a precordial crunching sound, was audible only in 2 patients. The small number of patients with Hamman's sign could be attributed to the auscultation of the patient's chest in the left lateral position, which may have made it difficult to decipher sounds. Blood examinations for inflammatory markers help in the early detection of mediastinitis. However, severe inflammatory reactions, as evident from the increase of CRP levels and leukocyte counts, were absent in our patients. CRP levels and leukocyte counts sometimes do not increase in the early phases of mediastinitis; therefore, mediastinitis should not be ruled out even when these values are low [20]. We believe that these parameters are supplementary diagnostic tools for the detection of SPM. Even though CXRs are useful in the initial diagnosis of SPM, it should not be the only tool because approximately 30% of the patients with SPM cannot be diagnosed using CXRs [6]. In the present study, 25% of the patients had false-negative CXRs, and 64-slice helical CT proved invaluable for improving the detection rates and differential diagnosis of PM. It is important to distinguish between PM and SPM in the emergency department. In the present study, we documented the Macklin effect, suggesting alveolar rupture on 64-slice helical CT, which rules out the diagnosis of nonspontaneous PM [8,21]. We believe that the disparity in the frequency of findings of the Macklin effect between perihilar and peripheral lung areas is due to the tightness and pressure gradient of the surrounding tissue. In our literature review, recommendations for excluding nonspontaneous PM included gastroscopy, bronchoscopy, and esophagography [11]. In our study, only 1 patient underwent esophagography because 64-slice helical CT was particularly effective in investigating the wall of the gastrointestinal tract from the pharynx to the esophagus. CT also enabled the detection of air in the perivascular and peribronchial sheaths, a pathognomonic finding in SPM, which is caused by the rupture of blebs and bullae. Therefore, we conclude that 64-slice helical CT can replace technically demanding procedures, such as esophagography, and

respiratory investigation 52 (2014) 36 –40

39

Table 4 – Hospital-stay length and clinical data correlation. Clinical data

R

P value

Initial SpO2 Initial body temperature WBC count CRP

−0.731 −0.689 0.223 0.354

0.016 0.031 0.537 0.316

Fig. 1 – Computed tomography showing findings of the Macklin effect in the perihilar area. The Macklin effect is evidenced by air lucencies around the bronchi caused by the dissection of the peribronchial tissue due to escape of alveolar air (arrow).

Fig. 3 – Clinical course and trial for disposition of patients with spontaneous pneumomediastinum (SPM). Some authors argued that long-term hospitalization, such as that exceeding 7 days, is not necessary for SPM [22–24]. The mean duration of hospital stay in the present study was 7.0071.22 days, which was similar to that in other studies. Among admitted patients, lower SpO2 and higher body temperature at baseline were correlated with a prolonged hospital stay. According to some reports, patients with SPM should be admitted to the hospital [11,13]; nonetheless, 50% of the patients in our study were treated by ambulatory care. All these 10 patients were followed up and they fully recovered. We believe that hospital admission is critical in those patients with SPM in whom nonspontaneous PM cannot be ruled out and in those in whom SPM is caused by exacerbation of emphysema. SPM may rarely rapidly progress to tension PM, which may be fatal [25]; therefore, patients showing an exacerbation of dyspnea should be carefully monitored. In this study, we observed the Macklin effect, which was identified as the presence of air in the perivascular and peribronchial sheaths arising from the rupture of blebs or bullae of the lungs, in all 20 patients by 64-slice helical CT, and we were

Fig. 2 – Computed tomography showing findings of the Macklin effect in the peripheral lung area. The Macklin effect is evidenced by pulmonary interstitial emphysema around the peripheral vascular area of the lung (arrowhead).

able to rule out lethal PM in these patients. To confirm this, we developed a 5-question checklist for determining whether patients required ambulatory care or hospitalization, and we were able to treat 10 patients on ambulatory basis. Some authors argued that antibiotic therapy is necessary for SPM treatment [13,26]. However, antibiotic therapy has been proved unnecessary

invasive examinations, such as gastroscopy and bronchoscopy, which are performed for the differential diagnosis of PM.

for spontaneous pneumothorax, which is caused by the rupture of blebs or bullae [27,28]. Because the etiology of SPM in ambulatory patients was similar to that in spontaneous

40

respiratory investigation 52 (2014) 36 –40

pneumothorax, antibiotic therapy was considered unnecessary and these patients were treated only with analgesics. All patients receiving ambulatory care recovered without any complications. This is important because eliminating unnecessary admissions and treatment procedures contributes to decreased medical expenses for patients with SPM. Significant limitations of the study are the small sample size and its retrospective nature. Future large-scale and prospective studies can further elucidate the best treatment protocols for SPM.

5.

Conclusions

SPM is a self-limiting disease. Therefore, careful differential diagnosis, using 64-slice helical CT to exclude nonspontaneous PM, is particularly important for the successful management of patients. SPM is usually a benign condition that responds well to conservative treatment. In our study, 10 ambulatory care patients who were treated without antibiotics had a good prognosis. Therefore, our study indicates that some patients with SPM can be treated without hospital admission or use of expensive invasive procedures, thus decreasing medical expenses for these patients.

Conflict of interest None of the authors has any conflict of interest associated with this study.

references

[1] Bodey GP. Medical mediastinal emphysema. Ann Intern Med 1961;54:46–56. [2] Hamman L. Spontaneous mediastinal emphysema. Bull Johns Hopkins Hosp 1939;64:1–21. [3] Munsel WP. Pneumomediastinum. J Am Med Assoc 1967;202:129–33. [4] Yellin A, Gapany-Gapanaticus M, Liebermann Y. Spontaneous pneumomediastinum: is it a rare cause of chest pain? Thorax 1983;38:383–5. [5] Maunder RJ, Pierson DJ, Hudson LD. Subcutaneous and mediastinal emphysema: pathophysiology, diagnosis, and management. Arch Intern Med 1984;144:1447–53. [6] Kaneki T, Kubo K, Kawashima A, et al. Spontaneous pneumomediastinum in 33 patients: yield of chest computed tomography for the diagnosis of the mild type. Respiration 2000;67:408–11. [7] Macklin MT, Macklin CC. Malignant interstitial emphysema of the lungs and mediastinum as an important occult complication in many respiratory diseases and other conditions: an interpretation of the clinical literature in the light of laboratory experiment. Medicine 1944;23:281–358. [8] Sakai M, Murayama S, Gibo M, et al. Frequent cause of the Macklin effect in spontaneous pneumomediastinum: demonstration by multidetector-row computed tomography. J Comput Assist Tomogr 2006;30:92–4.

[9] Newcomb AE, Clarke CP. Spontaneous pneumomediastinum: a benign curiosity or a significant problem? Chest 2005;128:3298–302. [10] Abolnic I, Lossos IS, Breuer R. Spontaneous pneumomediastinum. A report of 25 cases. Chest 1991;100:93–5. [11] Gerazounis M, Athanassiadi K, Kalantzi N, et al. Spontaneous pneumomediastinum: a rare benign entity. J Thorac Cardiovasc Surg 2003;126:774–6. [12] Macklin CC. Transport of air along sheaths of pulmonic blood vessels from alveoli to mediastinum: clinical implications. Arch Intern Med 1939;64:913. [13] Miura H, Taira O, Hiraguri S, et al. Clinical features of medical pneumomediastinum. Ann Thorac Cardiovasc Surg 2003;9:188–91. [14] Amjadi K, Alvarez GG, Vanderhelst E, et al. The prevalence of blebs or bullae among young healthy adults: a thoracoscopic investigation. Chest 2007;132:1140–5. [15] Panacek EA, Singer AJ, Sherman BW, et al. Spontaneous pneumomediastinum: clinical and natural history. Ann Emerg Med 1992;21:1222–7. [16] Koullias GJ, Korkolis DP, Wang XJ, et al. Current assessment and management of spontaneous pneumomediastinum: experience in 24 adult patients. Eur J Cardiothorac Surg 2004;25:852–5. [17] Sutherland FW, Ho SY, Campanella C. Pneumomediastinum during spontaneous vaginal delivery. Ann Thorac Surg 2002;73:314–5. [18] Weathers LS, Brooks WG, DeClue TJ. Spontaneous pneumomediastinum in a patient with ketoacidosis: a potentially hidden complication. South Med J 1995;88:483–4. [19] Chapdelaine J, Beaunoyer M, Daigneault P, et al. Spontaneous pneumomediastinum: are we overinvestigating? J Pediatr Surg 2004;39:681–4. [20] Levin B. The continuous diaphragm sign. A newly-recognized sign of pneumomediastinum. Clin Radiol 1973;24:337–8. [21] Ho AS, Ahmed A, Huang JS, et al. Multidetector computed tomography of spontaneous versus secondary pneumomediastinum in 89 patients: can multidetector computed tomography be used to reliably distinguish between the 2 entities? J Thorac Imaging 2012;27:85–92. [22] Al-Mufarrej F, Badar J, Gharagozloo F, et al. Spontaneous pneumomediastinum: diagnostic and therapeutic interventions. J Cardiothorac Surg 2008;3:59. [23] Koullias GJ, Korkolis DP, Wang XJ, et al. Current assessment and management of spontaneous pneumomediastinum: experience in 24 adult patients. Eur J Cardiothorac Surg 2004;25:852–5. [24] Freixinet J, García F, Rodríguez PM, et al. Spontaneous pneumomediastinum long-term follow-up. Respir Med 2005;99:1160–3. [25] Jougon JB, Ballester M, Delcambre F, et al. Assessment of spontaneous mediastinum experience with 12 patients. Ann Thorac Surg 2003;75:1711–4. [26] Takada K, Matsumoto S, Hiramatsu T, et al. Management of spontaneous pneumomediastinum based on clinical experience of 25 cases. Respir Med 2008;102:1329–34. [27] Olgac G, Aydogmus U, Mulazimoglu L, et al. Antibiotics are not needed during tube thoracostomy for spontaneous pneumothorax: an observational case study. J Cardiothorac Surg 2006;1:43. [28] LeBlanc KA, Tucker WY. Prophylactic antibiotics and closed tube thoracostomy. Surg Gynecol Obstet 1985;160:259.

Diagnosis and treatment of patients with spontaneous pneumomediastinum.

Although many patients complaining of chest pain visit the emergency department, very few are diagnosed with spontaneous pneumomediastinum (SPM). We p...
1000KB Sizes 0 Downloads 0 Views