(Chest. 2002;121:644-646.)
© 2002
American College of Chest Physicians
Repeated Infections in a 68-Year-Old Man*
Steven M. Sorenson, MD;
Emelya Moradzadeh, MD and
Rajnikant Bakhda, MD
From the Department of Radiology (Dr. Sorenson), UCLA School of Medicine; and West Los Angeles Veterans Administration Medical Center (Drs. Moradzadeh and Bakhda), Los Angeles, CA.
Correspondence to: Steven M. Sorenson, MD, UCLA School of Medicine, Department of Radiology, 10833 Le Conte Ave, Los Angeles, CA 90095; e-mail: ssorenson{at}usa.net
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Introduction
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A 68-
year-old man presents to the emergency department with increasing
dyspnea. His medical history is significant for a myocardial infarction
7 years prior, with marked coronary artery disease diagnosed at that
time. He has an 80 pack-year history of tobacco use, but quit several
years ago. In addition, he had multiple prior episodes of pneumonia,
some of which required intubation and prolonged hospitalization. On one
occasion, a tracheostomy was placed. Three years prior to presentation,
the patient underwent pulmonary function testing that revealed moderate
reduction in functional residual capacity, with a mild reduction in the
FEV1. Diffusing capacity of the lung for carbon
monoxide was mildly reduced as well. This was interpreted as a
restrictive ventilatory defect, although he carried a clinical
diagnosis of COPD. Twenty years prior to presentation, he had pulmonary
tuberculosis.
The patient describes frequent bouts of severe dyspnea with a
productive cough. Two years prior, a chest radiograph was performed
that revealed pneumonia in the right lower lobe and dilation of the
trachea. CT was ordered and showed marked dilatation of the trachea and
the central bronchi, one of which contained an air-fluid level. The
patient was treated with antibiotics, improved, and was discharged. The
patient now returns to the emergency department with similar
symptoms.
A chest radiograph was performed (Fig 1
, 2
), which showed dilation of the central airways but no focus of
pneumonia. CT performed a few days later again showed marked dilatation
of the trachea and
central
airways (Fig 3
, 4
). The patient was treated with antibiotics and improved.
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What is your diagnosis?
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Diagnosis: Mounier-Kuhn syndrome or tracheobronchomegaly
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Tracheobronchomegaly, or Mounier-Kuhn syndrome, was first
described in 1932.1
Fewer than 100 cases have been
reported in the world literature. The incidence of the disease is
probably higher as the clinical symptoms mimic chronic bronchitis and
bronchiectasis. Many patients carry the clinical diagnosis of COPD, as
in this case.
The disease consists of dilation of the trachea and major bronchi. Most
patients experience repeated respiratory infections, usually with
marked sputum production. As a result, CT scans will often reveal
parenchymal scarring, due to chronic infection. Bronchoscopy on these
patients generally shows dilated central airways with edematous mucosa,
believed to be the inciting factor for inflammation and infection. The
severe inflammation of the tracheobronchial mucociliary system leads to
decreased clearance of mucus. This contributes to the cycle of
infection and continued inflammation, leading to bronchiectasis,
recurrent pneumonia, and the development of emphysema.
Pathologically, there is loss of cartilage and muscle within the
trachea and bronchi, resulting in dilatation. Because of the loss of
inherent tracheal wall support, diverticula develop, commonly
posteriorly.2
The inciting factor, however, is not known.
Some authors have speculated that the disease is congenital in nature
(a dysplasia), sometimes associated with Ehlers-Danlos syndrome in
adults and cutis laxa in children.3
It has also been
associated with double carina, tracheal trifurcation, and a
congenitally short right upper lobe bronchus. Interestingly, there is a
return to normal bronchial size at the fourth or fifth bronchial
generation.4
Others have suggested an acquired origin of
the disease, noting that almost 50% of patients show no symptoms until
the third decade of life.5
This might be in association
with cigarette smoking, although causation has not been studied. A rare
variant of the disease demonstrates an autosomal recessive pattern of
inheritance. The majority of patients are men.
Standard chest radiographs often do not demonstrate the disease to the
full extent seen on CT. In this patient, only the lateral radiograph
showed the true degree of dilatation of the trachea. Anatomic studies
based on radiography and bronchography have determined that the upper
limit of normal for the diameter of the trachea is 3.0 cm, while the
left main bronchus diameter should not exceed 2.3 cm and the diameter
of the right main stem bronchus should not exceed 2.4 cm.6
In the present case, the diameter of the right main bronchus was 4 cm,
while the left was 3 cm. The trachea measured nearly 4 cm in maximal
cross-sectional diameter.
Management of these patients is difficult. The centralized nature of
the disease prevents extensive surgical intervention. Herniation of
mucosa into saccular diverticulations leads to pooling of secretions
and recurrent infections. For this, patients are treated with postural
drainage and antibiotic therapy. Bronchoscopy may be required for
clearance of secretions. In particularly recalcitrant cases,
tracheostomy may be required.
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Footnotes
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This work was performed at the West Los Angeles Veterans Administration
Medical Center.
Received for publication November 10, 2000.
Accepted for publication January 4, 2001.
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References
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-
Mounier-Kuhn, P (1932) Dilatation de la trachee: constatations radiographiques et bronchoscopiques. Lyon Med 150,106-109
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Himalstein, MR, Gallagher, JC (1973) Tracheobronchomegaly. Ann Otol Rhinol Laryngol 82,223-227[ISI][Medline]
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Aaby, GV, Blake, HA (1966) Tracheobronchomegaly. Ann Thorac Surg 2,64-70[Medline]
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Gay, S, Dee, P (1984) Tracheobronchomegaly: the Mounier-Kuhn syndrome. Br J Radiol 57,640-644[ISI][Medline]
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Bateson, EM, Woo-Ming, M (1973) Tracheo-bronchomegaly. Clin Radiol 24,345-358
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Vock, P, Spiegel, T, Fram, EK, et al (1984) CT assessment of the adult intrathoracic cross section of the trachea. J Comput Assist Tomogr 8,1076-1082[Medline]
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Introduction
What is your diagnosis?
