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A case of tracheobronchomegaly

Published:January 18, 2017DOI:https://doi.org/10.1016/j.ejim.2017.01.011

      Highlights

      • Tracheobronchomegaly is characterized by dilation of the trachea and main bronchi due to the disruption and loss of elastic components of the airway.
      • There is an association between tracheobronchomegaly and pulmonary fibrosis.
      • Recurrent bronchopulmonary infections, bronchiectasis, and tracheobronchomalacia are its frequent complications.

      Abstract

      Tracheobronchomegaly (Mounier-Kuhn syndrome) is a rare condition characterized by an abnormally enlarged trachea and main bronchi. Herein, we present a case of 79-year-old male with idiopathic pulmonary fibrosis and acute hypoxemic respiratory failure due to multilobar pneumonia. Computed tomography of the chest demonstrated a markedly dilated trachea, with the transverse diameter of 31 mm and the sagittal diameter of 30 mm. The clinical manifestations as well as its diagnosis, classification, and treatment are discussed.

      Keywords

      1. Case presentation

      A 79-year-old male presented to the hospital with worsening dyspnea, fever, and productive cough. His medical problems included a 20-pack-year history of smoking and idiopathic pulmonary fibrosis, which had been deteriorating and was complicated by pulmonary hypertension, chronic hypoxemic respiratory failure, and recurrent bronchopulmonary infections. On examination, the heart rate was 124 beats per minute, the blood pressure 109/72 mmHg, and the respiratory rate 44 breaths per minute. Bibasilar coarse crackles were present, whereas increased tactile fremitus and fine crackles were appreciated over the right middle and lower lung fields. Arterial blood gas, performed while breathing 5 liters of oxygen per minute by nasal cannula, revealed a pH of 7.43, pCO2 of 53 mmHg, pO2 of 30 mmHg, and bicarbonate of 34 mmol/L. A chest radiography showed right middle and lower lobe alveolar infiltration and extensive interstitial markings. Subsequent computed tomography demonstrated multilobar pneumonia superimposed on pulmonary fibrosis. A dilated trachea was noted (Fig. 1A–C ). Broad spectrum antibiotics was administered. Unfortunately, his condition declined rapidly and he died nine hours after admission.
      Fig. 1
      Fig. 1An unenhanced axial computed tomography confirmed the presence of multilobar pneumonia, together with honeycomb cystic changes associated with traction bronchiectasis predominantly in subpleural and basal area. Note the markedly dilated trachea: the transverse diameter was 31 mm (A) and the sagittal diameter, 30 mm (B). An enlarged right main bronchus was marked with an asterisk on the coronal reconstruction (C).

      2. What is the diagnosis?

      Tracheobronchomegaly (TBM; Mounier-Kuhn syndrome) is a rare condition characterized by an abnormally enlarged trachea and main bronchi. Pathologically, disruption and loss of elastic tissue in the tracheal wall are seen. The diagnosis is made when the transverse and/or sagittal diameters of the trachea are respectively more than 21 and 25 mm in females and 25 and 27 mm in males. It is commonly diagnosed after the third decade of life and there is a male-to-female ratio of 4:1 [
      • Payandeh J.
      • McGillivray B.
      • McCauley G.
      • Wilcox P.
      • Swiston J.R.
      • Lehman A.
      A clinical classification scheme for tracheobronchomegaly (Mounier-Kuhn syndrome).
      ,
      • Schmitt P.
      • Dalar L.
      • Jouneau S.
      • Toublanc B.
      • Camuset J.
      • Chatte G.
      • et al.
      Respiratory conditions associated with tracheobronchomegaly (Mounier-Kuhn syndrome): a study of seventeen cases.
      ].
      TBM cases can be categorized according to the etiology into four distinct groups: (1) those with prior tracheal intervention; (2) those whose TBM occurs after recurrent infections or is associated with pulmonary fibrosis; (3) those with signs of extra-pulmonary elastolysis; and (4) those without clear predisposing factors. Diffuse bronchiectasis and tracheobronchomalacia commonly co-occur with TBM. Possibly due to decreased clearance of respiratory secretion, 88% of the cases develop recurrent bronchopulmonary infections. Recurrent infection as well as increased traction on airway wall from advanced pulmonary fibrosis is hypothesized to have caused the tracheal dilation in our patient [
      • Payandeh J.
      • McGillivray B.
      • McCauley G.
      • Wilcox P.
      • Swiston J.R.
      • Lehman A.
      A clinical classification scheme for tracheobronchomegaly (Mounier-Kuhn syndrome).
      ,
      • Schmitt P.
      • Dalar L.
      • Jouneau S.
      • Toublanc B.
      • Camuset J.
      • Chatte G.
      • et al.
      Respiratory conditions associated with tracheobronchomegaly (Mounier-Kuhn syndrome): a study of seventeen cases.
      ].
      There is no specific treatment for TBM. Bronchodilators and corticosteroids are used to control symptoms. Bronchiectasis is managed with chest physiotherapy, influenza and pneumococcal vaccinations, and often with long-term or cycled antibiotics. In advanced disease, tracheal stenting, surgical tracheobronchoplasty, and double lung transplantation have been performed [
      • Schmitt P.
      • Dalar L.
      • Jouneau S.
      • Toublanc B.
      • Camuset J.
      • Chatte G.
      • et al.
      Respiratory conditions associated with tracheobronchomegaly (Mounier-Kuhn syndrome): a study of seventeen cases.
      ].

      Funding

      No funding has been received for preparation of this manuscript.

      Conflict of interest

      The authors do not have any conflicts of interest to disclose.

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