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Tracheobronchomegaly: clinical aspects and radiological features
European Journal of Radiology, 10 (1990) 126-129 Elsevier
126
EURRAD
00027
Tracheobronchomegaly : clinical aspects and radiological features E. Meyer’, E. Dinkel’ and A. Nilles2 ‘Abt. Riintgendiagnostikand ‘Abt. Lungenchirurgie, UniversitiitFreiburg, Freiburg, F.R.G. (Received
19 August 1989; accepted 9 November
Key words: Tracheobronchomegaly;
1989)
Bronchus, disease; Mounier-Kuhn
syndrome
Abstract Tracheobronchomegaly is a rare -probably congenital - disorder. Its clinical appearance is non-specific. The diagnosis is made by radiological methods. This paper describes the typical features in early and advanced stages and outlines the diagnostic approach.
Introduction Tracheobronchomegaly is a very rare condition, being defined as a marked dilatation of the trachea and main bronchi. The first description of its pathologic changes is credited to Czylharz [2] in 1897. It was not until 1932 that the first clinical description was published by Mounier-Kuhn [ 151. The clinical presentation is non-specific: there are symptoms of chronic respiratory tract disease, i.e., hoarseness, loud cough with or without sputum production, recurring pneumonia and even spontaneous pneumothoraces. Patients often report an onset of symptoms in childhood. Radiological features are, however, unequivocal, thus leading to the correct diagnosis. Case report A 34-year-old electrical engineer presented at our hospital because of recurrent bronchitis and exertional dyspnea. The patient gave a history of chronic coughing of 15 years duration with the complaint becoming more severe in the year prior to his admission. He reported having ‘double pneumonia’ as a child which had been treated with antibiotics. Physical examination revealed Address for reprints: Dr. Elke Meyer, Radiologische Universitatsklinik, Abt. Rontgendiagnostik, Hugstetter Strasse 55, D-7800 Freiburg, F.R.G. 0720-048X/90/$03.50
0 1990 Elsevier Science Publishers
medium to coarse bubbling rhonchi over both medium lung fields. There was a slightly raised BSR (25/45 mm/h) and a mild leucocytosis (12 500/ml). Chest radiography
There are striated ‘butterfly-shaped’ infiltrates in both lungs (Fig. 1, a and b). There is tracheal dilatation as well as dilatation of both main bronchi. Computed tomography
CT allows two-dimensional quantitative analysis of the dilated trachea and bronchi. The trachea measured 3.4 cm at its greatest diameter, the left main bronchus 2.5 cm and the right main bronchus 2.9 cm (Fig. 2, a and b). The supracarinal level demonstrates the dilatation of both bronchi of the lower lobes and the scarried, striated infiltrates (Fig. 3). Several calcareous masses can be identified within the pulmonary parenchyma (max. diameter 1.2 cm) (Fig. 4). Bronchography
Bronchography demonstrates the dilatation of the trachea and of both main bronchi. The peribronchial infiltrates are also demonstrated. Even in forced expiration the walls of the trachea and main bronchi did not collapse. Note ‘notching’ of the ventral wall of the trachea on the side view (Fig. 5, a and b).
B.V. (Biomedical
Division)
127
Fig. 2. (ab) CT: trachea 3.4 cm, right main bronchus main bronchus 2.5 cm.
Fig. 1. (a,b) Plain and lateral chest X-rays: dilated trachea main bronchi. ‘Butterfly-like’ infiltrates.
and
Discussion According to the literature the width of the normal adult intrathoracic trachea is between 15 and 25 mm in chest radiographs [ 61. More accurate measurements by CT yield to a limit of 22 mm in men and 19 mm in women [ 171. As a rule of thumb, the air column of a
2.9 cm, left
normal trachea in the chest radiograph should be half as broad as the body of a thoracic vertebra. In a study of 50 adults the mean diameters, determined from bronchography, of the right and left main bronchi were 16 mm and 14 mm respectively [ 111. A tracheal system measured above these limits must be considered a tracheobronchomegaly. Other reports use the terms ‘megatrachea’ [4], ‘tracheobronchiectasis’ [lo], ‘tracheal diverticulitis’ [ 31, ‘trachea-bronchopathia malacia’ [ 161 or ‘MounierKuhn syndrome’ [ 11,121 synonymously for tracheo-
128
Fig. 3. Localization
Fig. 4. Calcifications
of infiltrates.
within infiltrates.
bronchomegaly. We agree with Katz [ 1 l] that the term ‘tracheobronchomegaly’ is preferable since “it is simple, anatomically descriptive and avoids confusion with phonetically allied expressions such as tracheomalacia . . .” [ 111. Contrary to tracheomalacia, which is characterized by a softening of the bridges of cartilage, tracheobronchomegaly is characterized by a weakness of the paries membranaceas, enlargement of the bridges of cartilage and a resulting expansion of the intercartilaginous sinuses (Fig. 5b). Pathological studies have demonstrated atrophy of the muscle fibers of the m. transversus trachea and a decrease in the number of the elastic longitudinal fibers [ 1,2,16].
Fig. 5. (a,b) Signs of chronic bronchitis, ‘notching’ of ventral wall of the trachea.
Most authors [ 11-131 believe in the congenital etiology of tracheobronchomegaly. This concept is based on the pathological findings, as described above, on the male predominance and the description of familial cases [lo]. Tracheobronchomegaly is extremely rare as compared with the multitude of other pulmonary diseases. On the other hand, patients with tracheobronchomegaly suffer a striking number of concomitant pulmonary diseases. We feel that these should be considered as consequences of the primary lesion. The following are
129
some pathophysiological considerations relating to tracheobronchomegaly. Dilatation of the trachea leads to changes in the inspiratory and expiratory circulatory dynamics. Normally, the flow of breath is a laminar air flow, with a critical dilatation of the trachea this air flow becomes turbulent which leads to a considerable increase of airway resistance. Thus, to achieve the same air volume, the pressure has to be increased accordingly [ 18,193. In the course of the disease, the paries membranacea, being already weakened, will be exposed to remarkable expansion forces. This may result in a total loss of tonicity. Given this, the paries membranacea will fall into the tracheal lumen on expiration, thus causing complete obstruction. Clinically, this is manifested by asthma-like attacks of suffocation. Cases reported previously have not reported this complication [ $7,141. In our patient this did not occur. Katz [ 1 l] also reported on patients without an expiratory collapse of the tracheal wall. The other striking radiological feature besides the tracheobronchial dilatation is the centrally localized, bilateral infiltrations with included calcareous deposits. Bronchography and computed tomography demonstrate their location at the passage from the normal lobar bronchi to the dilated bronchial system. We feel, that this is due to the failure of expectoration from the dilated bronchi: the coughing thrust ‘fizzles out’ in the enormous width of the tube. Secreta and pus, originating from inflammation, will only be expectorated from the lung periphery into the dilated bronchi. Ciliary transportation alone is not capable of removing mucus produced by the inflammation. Hence, it continues to lie in the passage of the centrally dilated bronchial system. Bronchoscopy demonstrates “eddies and currents due to mixing of air, contrast media and secretions, giving the appearance of a boiling pot” [ 161. Calcifications of these secretions may even lead to the development of broncholiths [ 81. Due to their pathognomonic high Hounsfield unit values they can easily be identified by CT (Fig. 4). Considering the non-specific clinical symptoms, only radiological examination leads to the diagnosis, guided by the plain radiograph of the chest. It demonstrates the dilated central bronchial system. Beyond this, secondary changes such as pneumonia and fibrosis can be identified. Fluoroscopy may demonstrate an expiratory collapse in advanced stages. CT allows two-dimensional measurement of the tracheal dilatation. Parenchymal changes and calcilications can be diagnosed earlier and more accurately than by the plain radiography. An expiratory collapse
of the trachea and the main bronchi can also be identitied by CT [ 9,141, but can normally be easily visualized by fluoroscopy. Discrete changes of the bronchial walls, like small diverticula, are best shown by bronchography. Likewise, functional effects, i.e., dyskinesias of the bronchial system are best demonstrated by this method. There is no primary treatment for tracheobronchomegaly. Thus medical management has to be restricted to the control of the chronic recurrent infections of the respiratory tract. References 1 Brenner F, Kramer St. Uber einen Fall von besonderer Grol3e der Luftrohre. W Klin Wschr 1938; 51: 896-898. 2 Czylharz ERv. Uber ein Pulsionsdivertikel der Trachea mit Bemerkungen iiber das Verhalten der elastischen Fasern an normalen Tracheen und Bronchien. Centralbl Alg Path Anat 1897; 8: 721-728. Drymalski GW, Thompson JR, Sweany HC. Tracheal diverticula; report of a case. AJR 1948; 60: 403-407. Fischer E, Schaub R. Megatrachea. Rofo 1966; 104: 682-686. Frank A, Heckenthaler W. Die Tracheobronchomegalie - ein Symptom gestorter Atemmechanik? Rijfo 1971; 114: 605-616. Fraser RG, Pare JAP. Diagnosis of diseases of the chest, Vol. II. Philadelphia: Saunders, 1970. Herzog H. Expiratorische Stenose der Trachea und der groBen Bronchien, hervorgerufen durch eine erschlafhe Pars membranacea. Dtsch Med. Wochenschr 1959; 39: 1766-1773. 8 Huzly A. Form- und Lageanomalien der Trachea und der Bronchien. In: Schinz HR, et al, eds. Lehrbuch der Riintgendiagnostik Bd.IV/Z hrsg.v. Stuttgart: Thieme, 1973. 9 Imhof H, Lechner G, Rota R., Niederle P, Dinstl K. Computertomographische Beurteilung des Trachealquerschnittes. R&tgen-Bl. 1982; 35: 17-18. 10 Kartagener M, Ulrich K. Uber Tracheobronchiektasie, zugleich Bemerkungen zur Begutachtung der Bronchiektasen. Schweiz Med Wschr 1940; 70: 1266-1270. 11 Katz I, Levine M, Herman P. Tracheobronchiomegaly: The Mounier-Kuhn Syndrome. AJR 1962; 88: 1084-1094. 12 Lange S. Radiologische Diagnostik der Lungenerkrankungen. Stuttgart, New York: Thieme, 1986. 13 Meschan I. Analyse der Rontgenbilder, Bd 2: Atemwege, Herz. Stuttgart: Enke, 1981. 14 Mildenberger P, Schild HH. Tracheobronchomegalie. Radiologe 1988; 28: 236-238. 15 Mounier-Kuhn P. Dilatation de la trachee; constatations radiographiques et bronchoscopiques. Lyon M&d 1932; 150: 106-109. 16 Pohl R. Universelle Erweichungszustande am Tracheobronchialsystem (Trachea-Bronchopathia malacia) Rofo 195 1; 74: 40-43. 17 Vock P, Spiegel Th, Fram EK, Effman EL. CT assessment of the adult intrathoracic cross section of the trachea. J Comp Assist Tomogr 1984; 8: 1076-1082. 18 Weber HH. Radiologische Exploration des Hustenaktes. Teil I. R&if0 1959; 90: 275-290. 19 Weber HH. Radiologische Exploration des Hustenaktes. Teil II. RiSfo 1959; 90: 452-471.
126
EURRAD
00027
Tracheobronchomegaly : clinical aspects and radiological features E. Meyer’, E. Dinkel’ and A. Nilles2 ‘Abt. Riintgendiagnostikand ‘Abt. Lungenchirurgie, UniversitiitFreiburg, Freiburg, F.R.G. (Received
19 August 1989; accepted 9 November
Key words: Tracheobronchomegaly;
1989)
Bronchus, disease; Mounier-Kuhn
syndrome
Abstract Tracheobronchomegaly is a rare -probably congenital - disorder. Its clinical appearance is non-specific. The diagnosis is made by radiological methods. This paper describes the typical features in early and advanced stages and outlines the diagnostic approach.
Introduction Tracheobronchomegaly is a very rare condition, being defined as a marked dilatation of the trachea and main bronchi. The first description of its pathologic changes is credited to Czylharz [2] in 1897. It was not until 1932 that the first clinical description was published by Mounier-Kuhn [ 151. The clinical presentation is non-specific: there are symptoms of chronic respiratory tract disease, i.e., hoarseness, loud cough with or without sputum production, recurring pneumonia and even spontaneous pneumothoraces. Patients often report an onset of symptoms in childhood. Radiological features are, however, unequivocal, thus leading to the correct diagnosis. Case report A 34-year-old electrical engineer presented at our hospital because of recurrent bronchitis and exertional dyspnea. The patient gave a history of chronic coughing of 15 years duration with the complaint becoming more severe in the year prior to his admission. He reported having ‘double pneumonia’ as a child which had been treated with antibiotics. Physical examination revealed Address for reprints: Dr. Elke Meyer, Radiologische Universitatsklinik, Abt. Rontgendiagnostik, Hugstetter Strasse 55, D-7800 Freiburg, F.R.G. 0720-048X/90/$03.50
0 1990 Elsevier Science Publishers
medium to coarse bubbling rhonchi over both medium lung fields. There was a slightly raised BSR (25/45 mm/h) and a mild leucocytosis (12 500/ml). Chest radiography
There are striated ‘butterfly-shaped’ infiltrates in both lungs (Fig. 1, a and b). There is tracheal dilatation as well as dilatation of both main bronchi. Computed tomography
CT allows two-dimensional quantitative analysis of the dilated trachea and bronchi. The trachea measured 3.4 cm at its greatest diameter, the left main bronchus 2.5 cm and the right main bronchus 2.9 cm (Fig. 2, a and b). The supracarinal level demonstrates the dilatation of both bronchi of the lower lobes and the scarried, striated infiltrates (Fig. 3). Several calcareous masses can be identified within the pulmonary parenchyma (max. diameter 1.2 cm) (Fig. 4). Bronchography
Bronchography demonstrates the dilatation of the trachea and of both main bronchi. The peribronchial infiltrates are also demonstrated. Even in forced expiration the walls of the trachea and main bronchi did not collapse. Note ‘notching’ of the ventral wall of the trachea on the side view (Fig. 5, a and b).
B.V. (Biomedical
Division)
127
Fig. 2. (ab) CT: trachea 3.4 cm, right main bronchus main bronchus 2.5 cm.
Fig. 1. (a,b) Plain and lateral chest X-rays: dilated trachea main bronchi. ‘Butterfly-like’ infiltrates.
and
Discussion According to the literature the width of the normal adult intrathoracic trachea is between 15 and 25 mm in chest radiographs [ 61. More accurate measurements by CT yield to a limit of 22 mm in men and 19 mm in women [ 171. As a rule of thumb, the air column of a
2.9 cm, left
normal trachea in the chest radiograph should be half as broad as the body of a thoracic vertebra. In a study of 50 adults the mean diameters, determined from bronchography, of the right and left main bronchi were 16 mm and 14 mm respectively [ 111. A tracheal system measured above these limits must be considered a tracheobronchomegaly. Other reports use the terms ‘megatrachea’ [4], ‘tracheobronchiectasis’ [lo], ‘tracheal diverticulitis’ [ 31, ‘trachea-bronchopathia malacia’ [ 161 or ‘MounierKuhn syndrome’ [ 11,121 synonymously for tracheo-
128
Fig. 3. Localization
Fig. 4. Calcifications
of infiltrates.
within infiltrates.
bronchomegaly. We agree with Katz [ 1 l] that the term ‘tracheobronchomegaly’ is preferable since “it is simple, anatomically descriptive and avoids confusion with phonetically allied expressions such as tracheomalacia . . .” [ 111. Contrary to tracheomalacia, which is characterized by a softening of the bridges of cartilage, tracheobronchomegaly is characterized by a weakness of the paries membranaceas, enlargement of the bridges of cartilage and a resulting expansion of the intercartilaginous sinuses (Fig. 5b). Pathological studies have demonstrated atrophy of the muscle fibers of the m. transversus trachea and a decrease in the number of the elastic longitudinal fibers [ 1,2,16].
Fig. 5. (a,b) Signs of chronic bronchitis, ‘notching’ of ventral wall of the trachea.
Most authors [ 11-131 believe in the congenital etiology of tracheobronchomegaly. This concept is based on the pathological findings, as described above, on the male predominance and the description of familial cases [lo]. Tracheobronchomegaly is extremely rare as compared with the multitude of other pulmonary diseases. On the other hand, patients with tracheobronchomegaly suffer a striking number of concomitant pulmonary diseases. We feel that these should be considered as consequences of the primary lesion. The following are
129
some pathophysiological considerations relating to tracheobronchomegaly. Dilatation of the trachea leads to changes in the inspiratory and expiratory circulatory dynamics. Normally, the flow of breath is a laminar air flow, with a critical dilatation of the trachea this air flow becomes turbulent which leads to a considerable increase of airway resistance. Thus, to achieve the same air volume, the pressure has to be increased accordingly [ 18,193. In the course of the disease, the paries membranacea, being already weakened, will be exposed to remarkable expansion forces. This may result in a total loss of tonicity. Given this, the paries membranacea will fall into the tracheal lumen on expiration, thus causing complete obstruction. Clinically, this is manifested by asthma-like attacks of suffocation. Cases reported previously have not reported this complication [ $7,141. In our patient this did not occur. Katz [ 1 l] also reported on patients without an expiratory collapse of the tracheal wall. The other striking radiological feature besides the tracheobronchial dilatation is the centrally localized, bilateral infiltrations with included calcareous deposits. Bronchography and computed tomography demonstrate their location at the passage from the normal lobar bronchi to the dilated bronchial system. We feel, that this is due to the failure of expectoration from the dilated bronchi: the coughing thrust ‘fizzles out’ in the enormous width of the tube. Secreta and pus, originating from inflammation, will only be expectorated from the lung periphery into the dilated bronchi. Ciliary transportation alone is not capable of removing mucus produced by the inflammation. Hence, it continues to lie in the passage of the centrally dilated bronchial system. Bronchoscopy demonstrates “eddies and currents due to mixing of air, contrast media and secretions, giving the appearance of a boiling pot” [ 161. Calcifications of these secretions may even lead to the development of broncholiths [ 81. Due to their pathognomonic high Hounsfield unit values they can easily be identified by CT (Fig. 4). Considering the non-specific clinical symptoms, only radiological examination leads to the diagnosis, guided by the plain radiograph of the chest. It demonstrates the dilated central bronchial system. Beyond this, secondary changes such as pneumonia and fibrosis can be identified. Fluoroscopy may demonstrate an expiratory collapse in advanced stages. CT allows two-dimensional measurement of the tracheal dilatation. Parenchymal changes and calcilications can be diagnosed earlier and more accurately than by the plain radiography. An expiratory collapse
of the trachea and the main bronchi can also be identitied by CT [ 9,141, but can normally be easily visualized by fluoroscopy. Discrete changes of the bronchial walls, like small diverticula, are best shown by bronchography. Likewise, functional effects, i.e., dyskinesias of the bronchial system are best demonstrated by this method. There is no primary treatment for tracheobronchomegaly. Thus medical management has to be restricted to the control of the chronic recurrent infections of the respiratory tract. References 1 Brenner F, Kramer St. Uber einen Fall von besonderer Grol3e der Luftrohre. W Klin Wschr 1938; 51: 896-898. 2 Czylharz ERv. Uber ein Pulsionsdivertikel der Trachea mit Bemerkungen iiber das Verhalten der elastischen Fasern an normalen Tracheen und Bronchien. Centralbl Alg Path Anat 1897; 8: 721-728. Drymalski GW, Thompson JR, Sweany HC. Tracheal diverticula; report of a case. AJR 1948; 60: 403-407. Fischer E, Schaub R. Megatrachea. Rofo 1966; 104: 682-686. Frank A, Heckenthaler W. Die Tracheobronchomegalie - ein Symptom gestorter Atemmechanik? Rijfo 1971; 114: 605-616. Fraser RG, Pare JAP. Diagnosis of diseases of the chest, Vol. II. Philadelphia: Saunders, 1970. Herzog H. Expiratorische Stenose der Trachea und der groBen Bronchien, hervorgerufen durch eine erschlafhe Pars membranacea. Dtsch Med. Wochenschr 1959; 39: 1766-1773. 8 Huzly A. Form- und Lageanomalien der Trachea und der Bronchien. In: Schinz HR, et al, eds. Lehrbuch der Riintgendiagnostik Bd.IV/Z hrsg.v. Stuttgart: Thieme, 1973. 9 Imhof H, Lechner G, Rota R., Niederle P, Dinstl K. Computertomographische Beurteilung des Trachealquerschnittes. R&tgen-Bl. 1982; 35: 17-18. 10 Kartagener M, Ulrich K. Uber Tracheobronchiektasie, zugleich Bemerkungen zur Begutachtung der Bronchiektasen. Schweiz Med Wschr 1940; 70: 1266-1270. 11 Katz I, Levine M, Herman P. Tracheobronchiomegaly: The Mounier-Kuhn Syndrome. AJR 1962; 88: 1084-1094. 12 Lange S. Radiologische Diagnostik der Lungenerkrankungen. Stuttgart, New York: Thieme, 1986. 13 Meschan I. Analyse der Rontgenbilder, Bd 2: Atemwege, Herz. Stuttgart: Enke, 1981. 14 Mildenberger P, Schild HH. Tracheobronchomegalie. Radiologe 1988; 28: 236-238. 15 Mounier-Kuhn P. Dilatation de la trachee; constatations radiographiques et bronchoscopiques. Lyon M&d 1932; 150: 106-109. 16 Pohl R. Universelle Erweichungszustande am Tracheobronchialsystem (Trachea-Bronchopathia malacia) Rofo 195 1; 74: 40-43. 17 Vock P, Spiegel Th, Fram EK, Effman EL. CT assessment of the adult intrathoracic cross section of the trachea. J Comp Assist Tomogr 1984; 8: 1076-1082. 18 Weber HH. Radiologische Exploration des Hustenaktes. Teil I. R&if0 1959; 90: 275-290. 19 Weber HH. Radiologische Exploration des Hustenaktes. Teil II. RiSfo 1959; 90: 452-471.