An unusual cause of spontaneous pneumothorax: the Mounier-Kuhn syndrome.

Item Type Article

Authors Kent, B D;Sulaiman, I;Akasheh, N B;Nadarajan, P;Moloney, E;Lane, S J

Citation An unusual cause of spontaneous pneumothorax: the Mounier- Kuhn syndrome. 2011, 104 (5):152-3 Ir Med J

Journal Irish medical journal

Download date 25/09/2021 21:25:14

Link to Item http://hdl.handle.net/10147/136819

Find this and similar works at - http://www.lenus.ie/hse An Unusual Cause of Spontaneous Pneumothorax: The Mounier-Kuhn Syndrome

Abstract:

BD Kent, I Sulaiman, NB Akasheh, P Nadarajan, E Moloney, SJ Lane Department of Respiratory Medicine, Pulmonary and Sleep Disorders Unit, St Vincent’s University Hospital, Dublin 4

Abstract We present the case of a 54-year old woman referred to our service with an unusual presentation of an under-diagnosed condition. A life-long non-smoker, she was referred to respiratory services by our emergency department with a left sided pneumothorax, progressive dyspnoea on exertion, and recurrent chest infections. Subsequent investigation yielded findings consistent with Mounier-Kuhn syndrome (Tracheobronchomegaly), a condition characterised by marked dilatation of the proximal airways, recurrent chest infection, and consequent emphysema and bronchiectasis. Although rarely diagnosed, some degree of Mounier-Kuhn syndrome may occur in up to 1 in 500 adults.

Case Report A 54 year old woman was referred to the respiratory service from the emergency department with acute onset left sided pleuritic chest pain, and associated dyspnoea, wheeze, and productive cough. Over the preceding three years she had noted a progressive decline in her exercise tolerance. She was now breathless on climbing the stairs or following performance of household chores. She had required treatment on five occasions in the previous year due to recurrent chest infections, characterised by acute dyspnoea and purulent sputum production. She was a life-long non-smoker, had no known significant occupational or environmental exposures, and had no significant family history of pulmonary disease. She was on no regular medications.

Figure 1: Admission chest x-ray, demonstrating an apical left-sided pneumothorax and background chronic inflammatory changes. Note the calibre of the proximal airways.

On examination, the patient was tachypnoic (40 breaths/minute), and tachycardic (108 beats/minutes) at rest, but apyrexial and normotensive. She was of short stature, and thin. There were reduced breath sounds over her left apical region, bibasal course crackles, and a mild diffuse expiratory wheeze. Arterial blood gas demonstrated a moderate degree of hypoxia (pO2 9kPa), normal pH and normal pCO2. Investigations for underlying causes of chronic inflammatory disease were non-contributory, including serum immunoglobulins, Alpha-1 Antitrypsin level and genotype, and cystic fibrosis genotyping and sweat test. A chest radiograph (Figure 1) at presentation demonstrated a left apical pneumothorax. However, note the calibre of the proximal airways on the plain film. Subsequent CT Thorax (Figure 2) showed dilatation of the and proximal bronchi, with associated severeparaseptal emphysema, and bronchiectasis. Pulmonary function tests showedmoderately-severe airflow obstruction. These findings are consistent with a diagnosis of Mounier-Kuhn syndrome (Tracheobronchomegaly).

Figure 2: CT of upper thorax, demonstrating marked tracheomegaly and severe paraseptal emphysema.

Discussion Tracheobronchomegaly (TBM) was first reported by Czyhlarz in 1897, but is named after1 Mounier-Kuhn, who described the radiographic and bronchoscopic features of the syndrome in 1932 2 . TBM would appear to be significantly under-diagnosed a review of 500 bronchographies found a 1% prevalence . Its aetiology remains uncertain, although there are occasional reports of a link with connective tissue disease. Histology shows loss of main airway smooth muscle and cartilage, and associated tracheal diverticulosis. Dilatation of the trachea and proximal bronchi causes impaired secretion clearance,3 inefficient cough, persistent airway inflammation, and subsequent distal bronchiectasis and/or emphysema .

The majority of patients present with recurrent chest infections, and copious purulent mucus production, while others

An Unusual Cause of Spontaneous Pneumothorax: The Mounier-Kuhn Syndrome 1 present with wheeze or progressive exertional dyspnoea. Mounier-Kuhn syndrome has been4 described in virtually all age groups, with reported diagnoses in neonates and a 79 year old woman , but generally presents in the third or fourth decade of life. Prognosis is unpredictable some patients may remain relatively asymptomatic, others may progress to respiratory failure. Radiological diagnosis can be established with plain chest radiograph alone. Woodring et al 5 published radiographic measurements of the trachea and proximal bronchi, which can be used to diagnose TBM . CT thorax may be required to confirm airway measurements, and may additionally demonstrate associated pathology such as diverticulae and bronchiectasis.

Bronchoscopy may show dilated proximal airways with associated dynamic collapse, purulent secretions, and tracheal diverticulae. Recent data would suggest that with confocal microscopy may aid diagnosis by permitting real-time analysis of6 the bronchial mucosal microstructure, demonstrating a deficiency of elastin fibres within the bronchial wall . Lung function testing will generally show an obstructive pattern, with increased total lung capacity and residual volume consistent with air-trapping. Asymptomatic patients may require no specific treatment. Otherwise, the mainstay of therapy is the prevention and/or treatment of infectious complications, using methods such as effective clearance of secretions and rotational antibiotics. Tracheal stenting can improve symptoms in patients with recurrent infections, severe dyspnoea, and exercise limitation, but can be associated with significant complications. Tracheobronchoplasty using7 a polypropylene mesh may improve symptoms, quality of life scores, and exercise tolerance in selected patients . has been performed8 in at least two cases of Mounier-Kuhn syndrome, one of who unfortunately died in the post-operative period .

We are aware of only one other case presenting initially with spontaneous pneumothorax; hence the literature provides little guidance regarding ideal management in this situation. However, the clinical setting could be considered analogous to the development of secondary spontaneous pneumothorax in chronic obstructive pulmonary disease, whereby 9 recurrence is common following conservative treatment, and surgical management is frequently necessary . Our patient subsequently required surgical following recurrence of her pneumothorax on two separate occasions.

Correspondence: B Kent Department of Respiratory Medicine, Adelaide& Meath Hospital, Tallaght, Dublin 24 Email: [email protected]

References 1. Mounier-Kuhn P. Dilatation de la trachee: constatations radiographiques et bronchoscopiques. Lyon Med 1932;150:106. 2. Himalstein MR, Gallagher JC. Tracheobronchiomegaly. Ann Otol Rhinol Laryngol. 1973;82:223-7. 3. Schwartz M, Rossoff L. Tracheobronchomegaly. Chest 1994;106:1589-90 4. Falconer M, Collins DR, Feeney J, Torreggiani WC. Mounier-Kuhn syndrome in an older patient. Age Ageing. 2008 Jan;37:115-6 5. Woodring JH, Howard RS 2nd, Rehm SR. Congenital tracheobronchomegaly: a report of 10 cases and review of the literature. J Thorac Imaging 1991 Apr;6:1-10. 6. Thiberville L, Moreno-Swirc S, Vercauteren T, Peltier E, Cavˆ' C, Bourg Heckly G. In Vivo Imaging of the Bronchial Wall Microstructure Using Fibered Confocal Fluorescence Microscopy. Am J Respir Crit Care Med 2007;175:22-31 1991; 6:1-10. 7. Majid A, Guerrero J, Gangadharan S, Feller-Kopman D, Boiselle P, DeCamp M, Ashiku S, Michaud G, Herth F, Ernst A. Tracheobronchoplasty for severe . Chest 2008;134;801-807. 8. Minai O, Mehta AC, Pettersson G, Demet K. Lung transplantation in a patient with Mounier-Kuhn syndrome. J Thorac Cardiovasc Surg. 2006;132:737-8. 9. Tschopp JM, Rami-Porta R, Noppen M, Astoul P. Management of spontaneous pneumothorax: state of the art. Eur Respir J. 2006 Sep;28:637-50.

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