A Curious Confluence: Acquired Tracheal Web in a Child With Mounier–Kuhn Syndrome

A 7-year-old girl presented with complaints of progressive wet cough and dyspnoea for 2 weeks. She had a history of severe pneumonia at 2 years of age, which required intubation and mechanical ventilation for 10 days. After hospital discharge, her growth was normal, and she was well until 5 years of age. Subsequently, she had recurrent episodes of lower respiratory tract infections requiring antibiotics (approximately 1–2 episodes/year). There was no history suggesting aspiration, immunodeficiency symptoms, or noisy breathing. On physical examination, she was tachypneic with grade 1 digital clubbing. There was no pallor or hypoxemia. Chest examination revealed mild retractions and bilateral coarse crepitus. A working diagnosis of chronic suppurative lung disease was made. A Chest x-ray showed multifocal patches of opacities, and consolidations in both lung fields with grossly dilated trachea and proximal bronchi (Figure 1). The hemogram was unremarkable with a normal total leucocyte count (12470/μL). Spirometry showed a restrictive pattern (% of predicted: FVC = 41, FEV1 = 44, FEV1/FVC = 108). The immunoglobulin profile was unremarkable (IgM-170 mg/dL, IgA-216 mg/dL, IgG-1430 mg/dL, IgE-152 IU/mL). Sweat chloride was 28 mEq/L and 2D echocardiography was normal. Flexible fibreoptic bronchoscopy demonstrated a dilated trachea with two tracheal webs. One semilunar web from the left lateral wall of the mid-trachea caused 30% luminal narrowing and a circumferential web immediately distal to that first web caused 75% luminal narrowing (Figure 2). Bronchoalveolar lavage was negative for bacteria, tuberculosis and fungus culture. A Computerised Tomography of the chest confirmed tracheobronchomegaly (Trachea = 1.7 × 1.5 cm, right main bronchus 1 cm and left main bronchus 1.1 cm) with diffuse bronchiectasis suggesting Mounier–Kunh syndrome with tracheal webs at T1 and T2 vertebral levels (Figure 3). She was treated with antibiotics for the acute infection and chest physiotherapy, postural drainage and Azithromycin immunomodulator therapy for bronchiectasis. Tracheal web resection is planned. Mounier-Kuhn syndrome (MK) is a rare condition associated with congenital tracheobronchomegaly due to progressive atrophy of luminal longitudinal and elastic muscle fibres. There is a paucity of data regarding its prevalence, largely due to the underdiagnosis of the condition, with fewer than 400 cases reported till now. There is a strong male predominance with an 8:1 male-to-female ratio, although this case demonstrates that it does occur in females. In a systematic analysis of MKS among 128 patients, the mean age of presentation was 54 years, with the youngest age reported being 20 years. The aetiology of MKS, whether acquired or congenital, is still under debate. MKS has been associated with Ehlers-Danlos, and, Marfan's syndromes, Ankylosing spondylitis, and with cutis laxa [1, 2]. Chest X-rays should raise suspicion of MKS when the tracheal size exceeds the width of the vertebral column [1]. However, CT and bronchoscopy are more accurate for the diagnosis of MKS [1]. Numerous saccular diverticula usually noted in the later stage of diseases are due to flaccidity of the tracheal wall [1]. Treatment relies predominantly on mucolytics, chest physiotherapy, and postural drainage, while surgical stenting and tracheobronchoplasty may be needed in severe cases [3]. A tracheal web (TW), formed by a thin layer of membranous tissue can be congenital or acquired. Congenital TW is very rare, with an incidence of 1 in 10,000 births and they present during early infancy with atypical wheezing or a history of difficult intubation [4]. Nonetheless, the acquired form is predominantly due to traumatic or prolonged endotracheal intubation, and patients present with wheezing, dyspnea, stridor, and recurrent infections. Bronchoscopy remains the investigation of choice for visualising and the excision helps in the permanent remedy of TW [5]. The presence of TW further impaired the clearance of secretions in this case, contributing to airway infection and inflammation. A high index of suspicion should be kept for MKS in chronic suppurative lung disease with dilated proximal and distal airways in X-ray. To our knowledge, this is the first case reporting an acquired tracheal web association in a girl with Mounier-Kuhn syndrome. Kalyana Prabhakaran: conceptualization, validation. Nithish Kumar: writing – original draft. Taruna Yadav: validation, visualization, investigation. Prawin Kumar: writing – review and editing, visualization. Jagdish Prasad Goyal: supervision, validation. Informed consent was given by the parents, who gave permission to publish clinical images. The authors declare no conflicts of interest. Data sharing does not apply to this article as no new data were created or analysed in this study.