Recurrent lower respiratory tract infections in a 14-year-old boy with tracheobronchomegaly (Mounier-Kuhn syndrome)

Tracheobronchomegaly (Mounier-Kuhn Syndrome) in a 43-Year-Old Male: A Case Report

Mounier-Kuhn syndrome (MKS) or congenital tracheobronchomegaly is a rare disorder characterized by marked dilatation of the trachea and main bronchi, bronchiectasis, and recurrent respiratory tract infections. The etiology of this disorder is uncertain and the clinical presentation is variable. The diagnosis is usually made based on the characteristic computed tomography (CT) scan findings. This report describes a case of a 43-year-old man presenting with persistent cough and recurrent lower respiratory tract infections since childhood associated with copious amounts of purulent sputum, difficulty in breathing, and weight loss. In addition, he reported palpitations, dyspnea, orthopnea, abdominal and lower limb swelling. The chest X-ray showed a dilated trachea (35mm) and bronchi (26mm (right) and 27mm (left)) with cystic bronchiectasis and reticulolinear opacities predominantly involving the middle and lower lung zones. Chest CT scan confirmed the diagnosis of MKS as evidenced by dilated trachea and bronchi complicated by diverticula formation. Electrocardiogram, echocardiography and abdominal ultrasound scan showed features of right-sided heart failure secondary to pulmonary hypertension. MKS, although rare, should be considered as a possible diagnosis in patients presenting with productive chronic cough, recurrent pneumonia, or incomplete response to appropriate antibiotic therapy for pneumonia.

Improving Airways Patency and Ventilation Through Optimal Positive Pressure Identified by Noninvasive Mechanical Ventilation Titration in Mounier-Kuhn Syndrome: Protocol for an Interventional, Open-Label, Single-Arm Clinical Trial

BACKGROUND

Mounier-Kuhn syndrome or congenital tracheobronchomegaly is a rare disease characterized by dilation of the trachea and the main bronchi within the thoracic cavity. The predominant signs and symptoms of the disease include coughing, purulent and abundant expectoration, dyspnea, snoring, wheezing, and recurrent respiratory infection. Symptoms of the disease in some patients are believed to be pathological manifestations arising due to resident tracheobronchomalacia. Although treatment options used for the management of this disease include inhaled bronchodilators, corticosteroids, and hypertonic solution, there is no consensus on the treatment. The use of continuous positive airway pressure (CPAP) has been reported as a potential therapeutic option for tracheobronchomalacia, but no prospective studies have demonstrated its efficacy in this condition.

OBJECTIVE

The purpose of this is to identify the presence of tracheobronchomalacia and an optimal CPAP pressure that reduces the tracheobronchial collapse in patients with Mounier-Kuhn syndrome and to analyze the repercussion in pulmonary ventilation. In parallel, we aim to evaluate the prevalence of obstructive sleep apnea/hypopnea syndrome.

METHODS

This interventional, open-label, single-arm clinical trial will enroll patients who are diagnosed Mounier-Kuhn syndrome. Patient evaluation will be conducted in an outpatient clinic and involve 3 visits. Visit 1 will involve the collection and registration of social demographic, clinical, and functional data. Visit 2 will entail polysomnography, bronchoscopy for the evaluation of tracheobronchomalacia, titration of the optimal pressure that reduces the degree of collapse of the airway, and electrical impedance tomography. In visit 3, patients exhibiting a reduction in collapse areas will be requested to undergo chest computed tomography during inspiration and forced expiration with and without positive pressure (titrated to determine optimal CPAP pressure).

RESULTS

This protocol is a doctorate project. The project was submitted to the institutional review board on January 24, 2017, and approval was granted on February 2, 2017 (Brazilian Research database number CAAE 64001317.4.000.0068). Patient evaluations started in April 2018. Planned recruitment is based on volunteers' availability and clinical stability, and interventions will be conducted at least once a month to finish the project at the end of 2020. A preliminary analysis of each case will be performed after each intervention, but detailed results are expected to be reported in the first quarter of 2021.

CONCLUSIONS

There is no consensus on the best treatment options for managing Mounier-Kuhn syndrome. The use of positive pressure could maintain patency of the collapsed airways, functioning as a "pneumatic stent" to reduce the degree of airflow obstruction. This, in turn, could promote mobilization of thoracic secretion and improve pulmonary ventilation.

TRIAL REGISTRATION

ClinicalTrails.gov NCT03101059; https://clinicaltrials.gov/ct2/show/NCT03101059.

INTERNATIONAL REGISTERED REPORT IDENTIFIER (IRRID)

DERR1-10.2196/14786.

Tracheobronchomegaly associated with laryngo-tracheal amyloidosis: First case report

Tracheobronchomegaly (TBM) is a rare enlargement of the tracheal cartilage, also known as Mounier-Kuhn syndrome (MKS). Here, we describe an unusual case of acquired TBM in an adult, caused by amyloid regeneration and associated tracheal weakening, rather than by MKS. CT scan and fiberscopic examination of a 55-year-old woman suffering from severe dyspnea revealed TBM and subglottic stenosis, which was caused by deposition of amyloid tissue. We performed a tracheostomy and vaporized the subglottic stenosis with a CO2 laser, after which we installed a silicone T-tube. After the first operation, re-stenosis occurred, and the procedure was repeated; stenosis was subsequently cured and the dyspnea disappeared, after which the tracheostomy could be closed. This is the first report of adult TBM associated with amyloid deposition in the subglottis and trachea. This diagnosis is very difficult, as amyloid deposition in the trachea can have various clinical presentations.

A Clinical Classification Scheme for Tracheobronchomegaly (Mounier-Kuhn Syndrome)

INTRODUCTION

Tracheobronchomegaly (Mounier-Kuhn Syndrome) is a rare disease characterized by tracheal enlargement and associated loss of elastic fibers in the trachea and main bronchi.

MATERIALS

MEDLINE, Index Medicus, and other databases were searched with pre-defined criteria to identify cases of tracheobronchomegaly (TBM). Two new cases of TBM were also identified from the Provincial Medical Genetics Program of British Columbia.

RESULTS

We identified 166 publications describing 365 occurrences of TBM. We observed that affected individuals could be grouped into subgroups according to clinical features. Type 1A (105 individuals) consists of infants who developed TBM after having undergone fetoscopic tracheal occlusion, and Type 1B patients (24 individuals) are infants and children who developed TBM after prolonged intubation. Type 2 individuals developed TBM following recurrent pulmonary infections (2A) (14 individuals) or pulmonary fibrosis (2B) (10 individuals). Type 3 represents TBM with evidence of extra-pulmonary elastolysis (18 individuals), and Type 4 denotes the development of TBM with no clear predisposing factors (196 individuals). Both of our patients had TBM and evidence of extra-pulmonary elastolysis. As well, one patient had a mildly dilated aortic root, which is a previously unreported co-occurrence.

CONCLUSION

We introduce a novel classification scheme, which may sort patients into etiologically distinct groups, furthering our understanding of its pathogenesis and potentially, prevention or therapy. We also hypothesize that TBM and generalized elastolysis may have etiological commonalities, suggesting a need for further study.

Mounier-Kuhn syndrome or congenital tracheobronchomegaly: a literature review

Mounier-Kuhn syndrome or congenital tracheobronchomegaly is a chronic airway condition which for currently unknown reasons mostly affects males. It is commonly overlooked on conventional chest X-rays, and is considered to be rare, but the prevalence might be higher as commonly assumed. The hallmark of it is a dilatation of the main airways which frequently, but not always, causes marked, mainly respiratory, symptoms, and patients usually present with varying degrees of recurrent infections, breathlessness, haemoptysis, dyspnoea. Although at least 200 case reports have been published, there have been only a few attempts to review them, and none in the last 20 years. Due to the lack of clinical trials and wide variability of case-report format, a systematic review was deemed not feasible, therefore PubMed and Medline databases were searched using terms "Mounier-Kuhn syndrome", "tracheobronchomegaly", "tracheomegaly", and "bronchomegaly", without any time restrictions, to summarize currently known facts about the syndrome. To the authors' best knowledge, the result is currently the most comprehensive review of previously published literature about the congenital tracheobronchomegaly, and summarizes what's known about symptoms, prevalence, disease associations, and treatment options for this syndrome.

A child with progressive multiple tracheal diverticulae: a variation of the Mounier-Kuhn syndrome

Mounier-Kuhn syndrome is a rare disorder characterized by tracheobronchomegaly. Most commonly presenting in adults, a broad spectrum of clinical abnormalities has been described. We report a young woman followed since 4 years of age for respiratory symptoms who was eventually found to have tracheobronchomegaly and multiple tracheal diverticulae.

Mounier-Kuhn syndrome: a rare cause of severe bronchial dilatation with normal pulmonary function test: a case report

Tracheobronchomegaly (TBM) (Mounier-Kuhn syndrome) is dilatation of the trachea and major bronchi because of atrophy or absence of elastic fibers and smooth muscle cells. We present a case of TBM with normal pulmonary function test (PFT). The patient was a 37-year-old man with increasing productive cough and without fever, wheezes, chest pain, weight loss or any respiratory disease. Chest helical computed tomography (CT) scan showed tracheomegaly with transversal diameters of the trachea of 44mm. CT scan showed collapse of the trachea. Few large diverticular out-pouching and openings in the trachea was seen in bronchoscopy. PFT results were normal. PFT in large airway disorders may be normal while abnormalities may indicate underlying small airway disorder. An underlying small airway disorders is responsible for abnormal reports in PFT of these patients. We may need to re-evaluate the role of PFT within follow-up of patients with large airway disorder.

Renal Transplantation in a Patient Affected by Mounier-Kuhn Syndrome

Tracheobronchomegaly, also called Mounier-Kuhn syndrome, consists in dilatation of the trachea and major bronchi because of atrophy or absence of their elastic fibers and smooth muscle cells. Standard chest radiography often does not permit diagnosis because only lateral imaging, obtained with X-rays or chest CT scan, shows the true degree of tracheal dilatation. Surgery has no role in tracheomegaly, except for the complications of tracheal stenosis or pneumothorax. The present work reports cadaveric renal transplantation in a 43-year-old woman affected by end-stage renal disease and suffering from congenital tracheobronchomegaly diagnosed during the first decade of life. No surgical or anesthetic problems were encountered during the immediate perioperative period. The patient did not require pulmonary physiotherapy. Antibiotic prophylaxis was given for 10 days. No pulmonary infection developed, and the patient was discharged from the hospital asymptomatic with normal renal function at 25 days after the transplant. Four months later, the patient experienced bronchitis with cough and fever. Antibiotic therapy was performed with totally resolution of symptoms. At 8 months of follow-up after kidney transplantation, the patient is asymptomatic with normal renal function.

Tracheomalacia and Tracheobronchomalacia in Children and Adults

Tracheomalacia and tracheobronchomalacia are disorders that are encountered in both pediatric and adult medicine. Despite increasing recognition of these disease processes, there remains some uncertainty regarding their identification, causes, and treatment. This article is intended to be a comprehensive review of both the adult and pediatric forms of the diseases, and includes sections on the historical aspects of the disorders, and their classification, associated conditions, histopathology, and natural history. We also review the various modalities that are used for diagnosis as well as the state of the art of treatment, including airway stent placement and surgical intervention.

Rapidly progressing case of Mounier-Kuhn Syndrome in early childhood

Reports of Mounier-Kuhn Syndrome in childhood are extremely rare, as it usually presents in the third or fourth decades. In the only other report of a case diagnosed in early childhood, the child was well at the time of publication. We report on a 15-month-old boy who presented with his first respiratory illness at age 3 months. His disease course was more severe than previously reported. Diagnosis was characteristically delayed until acute respiratory failure complicated a respiratory tract infection at 13 months, prompting high-resolution computerized tomography (HRCT) of the chest. He gradually deteriorated, eventually requiring ventilatory support; death occurred at age 15 months. This report illustrates the clinical heterogeneity of the syndrome. We review the theories about etiology and the recognized clinical findings in adults. Incidence may be higher than previously estimated, and tracheobronchomegaly (TBM) should be considered as a cause of respiratory failure and recurrent pneumonia in children where other investigations, including chest X-ray (CXR), are normal. A chest HRCT (cHRCT) scan and bronchoscopy are usually diagnostic.