as Determined by Etiology

Transcription

1 ORIGINAL ARTICLE omparative Study of Mediastinal Emphysema as Determined by Etiology Yoshihiro Kobashi, Niro Okimoto, Toshiharu Matsushima* and Rinzo Soejima** Abstract Introduction Objective To evaluate the difference in the clinical features of mediastinal emphysema as classified into three groups based on etiology; patients in whom it was spontaneous with unknown etiology (A group), those in whom it was secondary to bronchial asthma (B group), and those in whom it was secondary with other respiratory diseases (C group). Patients Forty-three cases (45 episodes) with mediastinal emphysema treated at Kawasaki Medical School Kawasaki Hospital between April 1985 and March 2000 (A roup: 17 cases, B group: 17 cases, C group: 9 cases). Results The average ages ofthea and B groups were of little significance. Most of the patients in the A group were males with a thin body. Three patients in the A group had episodes of pneumothorax or mediastinal emphysema in their past history. Five patients in the A group had Hamman's sign on physical examination. In all of the patients in the C group, mediastinal emphysema was accompanied by subcutaneous emphysema, whereas only eight patients in the A group had subcutaneous emphysema. The prognosis was good for A and B groups because the mediastinal emphysema disappeared within 10 days, but was poor in the C group because its disappearance was very late compared with that in the other two groups and skin incision was required in three patients in the C group due o severe subcutaneous emphysema. Conclusions We suggest that the existance and kind of underlying diseases significantly affect the method of treatment and the prognosis. (Internal Medicine 41 : , 2002) ey words: clinical features, spontaneous, secondary, subcutaneous emphysema, Hamman'ssign, underlying disease Mediastinal emphysema connotes the presence of gas in the mediastinal space. It is most common in newborn infants in whom it has been reported to occur in 1% (1), but it is rare in adults in whom it mainly appears as a complication of thoracic injury, surgical operation, or pulmonary infection (2). It has been regarded as being secondary to any respiratory disease. Spontaneous mediastinal emphysema is a separate entity occurring in previously healthy subjects without respiratory underlying diseases. We have treated 43 cases of mediastinal emphysema during the past 15 years. These cases were largely separated into two groups of spontaneous and secondary mediastinal emphysema due to their etiology, and we have suggested that secondary mediastinal emphysema occurring with reversible bronchial asthma might differ from that with other irreversible respiratory diseases with regard to its clinical course and prognosis. Therefore, we retrospectively evaluated differences in the clinical features and classified mediastinal emphysema into three groups according to etiology; cases in whom it was spontaneous with unknown etiology, those in whom it was secondary to bronchial asthma, and those in whom it was secondary to other respiratory diseases. Patients and Methods The study was carried out at Kawasaki Medical School Kawasaki Hospital in Okayama Prefecture, Japan. Patients were entered into the study if they were older than 15 years of age. A total of 43 cases (45 episodes) with a diagnosis of mediastinal emphysema were identified during the period from April 1985 to March 2000; these were classified into three groups; a spontaneous mediastinal emphysema group consisting of 17 cases (A group), a secondary group composed of patients with bronchial asthma numbering 17 cases, 19 episodes (B group) and a secondary group composed of patients with other respiratory diseases numbering 9 cases (C group). The following data were collected; 1) age and sex, 2) height and weight including the body mass index (BMI), 3) smoking rom the Division of Respiratory Diseases, Department of Medicine, Kawasaki Medical School Kawasaki Hospital, Okayama, *the Division of Respiratory Diseases, Department of Medicine, Kawasaki Medical School, Kurashiki and **Kawasaki Medical Welfare University, Kurashiki Received for publication January 23, 2001 ; Accepted for publication September 20, 2001 eprint requests should be addressed to Dr. Yoshihiro Kobashi, the Division of Respiratory Diseases, Department of Medicine, Kawasaki Medical School Kawasaki Hospital, Nakasange, Okayama Internal Medicine Vol. 41, No. 4 (April 2002) 277

2 Kobashi et al We measured the maximum width of both mediastinal and subcutaneous emphysema on all chest X-ray films separated per 10 mm which were recognized to be emphysema; mean±sd (mm) was recorded at seven points. Figure 1. Points of measurement of air leakage width. habits, 4) past history of pneumothorax or mediastinal emphysema including underlying respiratory disease, 5) kind of evoked episode, 6) clinical symptoms and physical examinations indicating subcutaneous emphysema and Hamman's sign, 7) radiographic findings indicating the size of the mediastinal and subcutaneous emphysema, 8) the number of days it took to recognize disappearance of this leakage, and 9) the treatment methods. Air leakage width in the mediastinum and subcutaneum in cases with mediastinal emphysema was measured at the following seven points on chest X-rays; the upper mediastinum, the circumference of the heart, the base of the heart, the circumference of the descending aorta in the mediastinum and the supraclavicular fossa-the cervix, the lateral supraclavicular fossa, and the axilla in the subcutaneum (Fig. 1). Measurement of air leakage width was performed using chest X-rays in all cases. Namely, on all chest X-ray films separated per 10 mm on which mediastinal and subcutaneous emphysema was recognized, the maximum width of emphysema was measured and means ±SD were recorded at the seven points. All results are presented as means ±SD For data analysis, the x2 test was used to determine the significance of differences in discrete variables among the three groups. The analysis of variance (ANOVA) was used to determine whether the means of continuous variables were significantly different among the three groups. Spearman's rank correlation coefficient was performed to examine the correlation between two variables. Table 1. Background of the Patients Body massindex (BMI): Weight (kghheight (m)} Internal Medicine Vol. 41, No. 4 (April 2002)

3 Results Comparative Study of Mediastinal Emphysema Forty-three cases (45 episodes) with a diagnosis of mediastinal emphysema during the study period of the past 15 years were retrospectively analyzed. These patients were separated into three groups according to background (Table 1). The mean age of 65.4 years in the A group was significantly higher than that in the other two groups. In the A group, male cases were significantly muchyounger (70.6%) than those in the other two groups. As for the body cage, there were many thin and slender menin the A group with a mean body mass index of Smoking was most frequent in the C group with three cases (33.3%). A past history of mediastinal emphysema or pneumothorax was found in four cases in the A group, two in the B group, and one in the C group. Otherwise, the underlying diseases in the C group were pulmonary fibrosis; 4, pulmonary emphysema; 2, lung cancer; 1, pneumonia; 1, and druginduced pneumonitis; 1. Although the cause of the evoked episode was most frequently "unknown"in the A group, it was mostly "cough" in both B and C groups. Table 2 shows the frequency of clinical symptoms, physical examination, and main laboratory findings in the three groups. As for clinical symptoms, while chest pain was significantly frequent in the A group, dyspnea was more frequent in both the B and C groups. Physically, Hamman's sign was recognized in six cases in the A group, three cases in the B group, and one case in the C group. Subcutaneous emphysema was also palpated in 8 cases in theagroup, 13 cases in the B group, and in all 9 cases in the C group. Table 3 shows radiological findings measuring the air leakage width at seven points on chest X-rays. There were no significant differences between the A and B groups at any of the points, but the C group showed the longest width at two points; e.g. the upper mediastinum with mediastinal emphysema and the axilla with subcutaneous emphysema. Disappearance of this leakage took 10 days or less for both the A and B groups, but over 20 days for the C group. Figure 2 shows the relationship between the maximum width of mediastinal emphysema (four points) and the maximum width of subcutaneous emphysema (three points). There were no significant relationships between both types of emphysema in the three groups, and between the maximum width of mediastinal emphysema and that of subcutaneous emphysema. Only Table 2. Clinical Symptoms, Physical Examinations *Hamman's sign: A mediastinal crunch on auscultation heard over the cardiac apex and the left sternal border. Table 3. Radiological Findings InternalMedicine Vol. 41, No. 4 (April 2002) 279

4 Kobashi et al Figure 2. The relationship between the maximum width of mediastinal emphysema (four points) and the maximum width of subcutaneous emphysema (three points). three cases in the C group requiring skin incision showed a longer width of subcutaneous emphysema than other cases in he C group. Figure 3 shows the relationship between the maximumwidth of mediastinal emphysema (four points) and the interval until the disappearance of this leakage. There were no significant relationships between the maximum width of mediastinal emphysema and the interval until the disappearence of this leakage among the three groups. But the three cases in the C group that needed skin incision, required long periods (17-75 days) ntil the disappearance of the leakage. Figure 4 shows the relationship between the maximumwidth of subcutaneous emphysema (three points) and the interval until the disappearance of the leakage. Although there were no significant relationships between the maximumwidth of subcutaneous emphysema and the interval until the disappearence of the leakage among the three groups, the three cases in the C group that required skin incision showed good correlation of the maximumwidth of subcutaneous emphysema with the inerval until the disappearance of the leakage. Table 4 shows the treatment for the three groups. The prognosis was good in both the A and B groups because both mediastinal emphysema and subcutaneous emphysema improved with rest only. However, it was poor in the C group, because a skin incision was necessary due to severe subcutaneous emphysema in three of nine cases. Figure 3. The relationship between the maximumwidth of mediastinal emphysema (four points) and the interval until the disappearance of this leakage. 280 Internal Medicine Vol. 41, No. 4 (April 2002)

5 Comparative Study of Mediastinal Emphysema Figure 4. The relationship between the maximum width of subcutaneous emphysema (three points) and the interval until the disappearance of this leakage. Table 4. Treatment Discussion Mediastinal emphysema had been recognized since at least 1827, when Laennec (3) referred to it as "interlobular emphysema". In 1939, Hammanproposed the term "Hamman' sign" (4) and first recognized it on chest X-rays. Since the emerging mechanism of mediastinal and subcutaneous emphysema was demonstratedby Macklin in 1939 (5), there have been several reports concerning only spontaneous mediastinal emphysema (without pulmonary underlying diseases) (6, 7) and secondary mediastinal emphysema with bronchial asthma (8-10). However, few reports have mentioned the difference in clinical features and none have classified mediastinal emphysema into three groups according to its etiology. Therefore, we evaluated the backgrounds, physical examinations, radiological findings, complications and prognoses of 43 cases, and separated them into three groups based on the kinds of pulmonary underlying diseases. Subsequently, most of the patients in the A group were found to be young males with a thin body cage. Three patients in the A group had episodes of pneumothorax or mediastinal emphysema. Most of the patients in the B group were young, but there wereno significant sex or body cage characteristics. Otherwise, most of the patients in the C group were elderly and threehad a smoking history. Our findings on patients with spontaneousmediastinal emphysema resembled those of Horikoshi et al (1 1), who mentioned that patients with spontaneous mediastinalemphysema were young males with a thin body cage who also experienced spontaneous pneumothorax. Regarding clinical toms, such as chest symptoms, they were usually mild symp- pain, chest oppression, dyspnea and dysphagia,or there were no symptoms. While chest pain was significantly more frequent in the A group, dyspnea was more frequentin the B and C groups. As for physical examinations, althoughhamman' sign was most frequently encountered in the Agroup, wecould not determine the reason. Subcutaneous emphysemawas a complication in all cases in the C group when compared with the air leakage width in the A and B groups. In addition, because the number of days until the disappearanceof leakage was significantly longer in the C group than in the A and B groups in the analysis of chest X-rays, the prognosiswasthe poorest in the C group with secondary mediastinalemphysema with respiratory diseases other than bron- InternalMedicine Vol. 41, No. 4 (April 2002) 281

6 Kobashi et al chial asthma. Although an analysis (12) has been made of the number of days until the disappearance of subcutaneous emphysema which appeared secondary to bronchial asthma, it was indicated that the subcutaneous emphysema disappeared within 14 days in most cases and there were no significant relationships between the number of days until the disappearance of mediastinal emphysema and that of subcutaneous emphysema. The size of the subcutaneous emphysema did not later influence the frequency of subcutaneous emphysema, clinical symptoms, or prognosis. Homma et al (13) stated that the number of days required until the disappearance of emphysema in cases complicated by both mediastinal and subcutaneous emphysema during an attack of bronchial asthma was 8.8 days for mediastinal emphysema and 9.2 days for subcutaneous emphysema. These findings were relatively compatible with our results. Although there have been no reports concerning the prognosis of mediastinal or subcutaneous emphysema secondary to pulmonary diseases except bronchial asthma, we found out that, as treatment in this study, skin incision was only required in three cases with a significantly longer width of subcutaneous emphysema. We could not find any relationship between the width of mediastinal or subcutaneous emphysema and the prognosis in these cases. Regarding the prognosis in these groups, it is suggested that whether the underlying diseases are reversible or irreversible is important for the prognosis, since, in our cases, spontaneous or secondary mediastinal emphysema with bronchial asthma improved naturally or following the remission of asthma attacks, but secondary mediastinal emphysema with irreversible pulmonary diseases, such as pulmonary fibrosis or pulmonary emphysema utilizing mechanical ventilation did not improve and required skin incision in three patients to reduce the positive pressure due to subcutaneous emphysema. There have been few reports (1 1, 14) in which the mortality of mediastinal emphysema cases following pulmonary underlying diseases, such as lung cancer or pulmonary tuberculosis, was high, and improvement in mediastinal emphysema following pulmonary fibrosis or mediastinitis was difficult and required drainage utilizing mediastinoscopy. Therefore, when mediastinal emphysema is recognized by chest X-rays or chest CTs, it is necessary to determine the existence and kind of pulmonary underlying diseases to ensure the correct decision regarding treatment. Although we analyzed 43 cases (45 episode) with spontaneous and secondary mediastinal emphysema treated in our hospital, we found no similar reports comparing the clinical findings of groups with differences in pulmonary underlying diseases in the literature. This study showed a good prognosis for spontaneous mediastinal emphysema cases without underlying disease in young males with thin body cages. We suggest that the existance and kind of underlying diseases significantly affect the prognosis and influence the method of treatment. References 1) Lillard RL, Allen RP. The extrapleural air sign in pneumomediastinu Radiology : , ) Bodey GR Medical mediastinal emphysema. Ann Intern Med 54: 46-3) Laennec RTH. A Treatise on Diseases of the Chest and on Mediate A cultation. Translated by John Forbes. 2nd ed. T&C Underwood, Londo Hosp64: 1, ) Hamman L. Spontaneous mediastinal emphysema. Bull Johns Hopki 5) Macklin CC. Transport of air along sheaths of pulmonic blood vessel from alveoli to mediastinum: Clinical implications. Arch Int Med 64: 9 6) Abolnik I, Lossos IS, Breuer R. Spontaneous pneumomediastinum. A report of 25 cases. Chest 100: 93-95, ) Yellin A, Gapany-Gapanavicius M, Lieberman Y. Spontaneous pneu mediastinum: is it a rare cauce of chest pain?. Thorax 38: , 198 8) Dattwyler RJ, Goldman MA, Bloch KJ. Pneumomediastinum as a co plication Immunolof asthma in teenage and young adult patients. J Allergy Clin 63: , ) Odajima H. Mediastinal and subcutaneous emphysema complicating 10) chial Takeshi asthma. T, Acta Nishima Paediatr S, Kano Jpn S. 23: Air , leak syndrome (ALS) as complic 1 of 1) asthma. Horikoshi Acta H, Paediatr Hanajima Jpn T, 31: Morita , T, et al. Five cases of spontaneou momediastinum without causal disease or apparent precipitating episod 12) Jpn Odajima J Chest H, Dis Iwasaki 55: , E, Ooide 1983 S, (in et al. Japanese, Eighteen Abstract cases ofmediastinal in English). a subcutaneous emphysema complicating bronchial asthma in infants and 13) children. Homma Nippon K, Soma Kyobu K, Tomita Rinsyo T. 37: Mediastinal , and subcutaneous emph sema. 14) ICU Rosenberg and CCU JC, 6: , Bowles AL Nonneoplastic disorders of the mediastin Fishman AP eds, Pulmonary Diseases and Disorders. 2nd ed. McGraw- Hill, New York, 1988: , Internal Medicine Vol. 41 No. 4 (April 2002) 282