Congenital bronchial atresia presenting with chronic cough in a young male

Sir,

A 28-year-old male was presented to the respiratory outpatient department with complaints of cough with mucopurulent expectoration of 02 weeks duration. He denied any history of fever, dyspnoea, or haemoptysis. He also gave a history of having a similar episode about 06 months back which was managed as pneumonia, and he had responded to oral antibiotics prescribed as per standard guidelines. Since his recovery 06 months back, he was never completely asymptomatic but continued to have episodes of cough with sputum which used to relieve with conservative measures like steam inhalation. His cough and sputum had increased in the last 02 weeks which prompted him to seek medical attention. There were no abnormal findings on chest auscultation. His haematological and biochemical laboratory investigations were normal. Sputum analysis was negative for acid fast bacilli, and no microorganism could be isolated on sputum culture. His chest X-ray posteroanterior view demonstrated a homogenous opacity in the right middle zone [Figure 1]. He underwent contrast-enhanced computed tomography (CECT) of the chest which showed a 5.2 cm × 3.0 cm size non-enhancing club-shaped density (10–15 Hu) with smooth rounded margins involving the posterior segment of the right upper lobe and areas of hyperinflation with air trapping distal to the lesion [Figure 2]. We did a fibreoptic bronchoscopy to rule out any endobronchial lesion. No bronchial abnormality could be appreciated within visualised bronchial segments. Bronchoalveolar lavage from the posterior segment of the right upper lobe was negative for malignant cytology or an infective aetiology. The characteristic CECT picture of mucocele with evidence of distal hyperinflation in the present clinical scenario confirmed the diagnosis of congenital bronchial atresia. The patient was managed symptomatically and recommended regular follow-up.

Figure 1.

Chest roentgenogram posteroanterior view demonstrating a homogenous density in right middle zone near hilum

Figure 2.

Non-contrast (a and b) and contrast-enhanced (c) computed tomography of chest showed 5.2 cm × 3.0 cm size non-enhancing club-shaped density (10–15 HU) with smooth rounded margins involving posterior segment of right upper lobe and areas of hyperlucency (red arrows) distal to the lesion. Coronal section in minimum intensity projection (d) demonstrating hyperlucent areas distal to the lesion (red arrow)

Congenital bronchial atresia is an uncommon congenital broncho-pulmonary developmental anomaly of the lung which develops due to focal obliteration of subsegmental, segmental or lobar bronchus.[1] Segmental and subsegmental levels are the more common sites of atresia as compared to the lobar bronchus.[2] The atretic bronchus is not in continuity with the central bronchial tree, and air trapping secondary to collateral ventilation through pores of Kohn and channels of Lambert results in hyperinflation of obstructed lung parenchyma.[1,3] Like our case, bronchial atresia is commonly detected in the second and third decades of life.[4]

The left upper lobe, particularly the apical-posterior segment, is the most affected segment followed by the right upper lobe and middle lobe.[4-6]

Most adult patients are asymptomatic and often diagnosed incidentally.[4] Bronchial segments distal to atretic bronchi branches normally. These normal segments produce secretions that can accumulate and result in distal mucus impaction.[1] Occasionally, the distal area which is filled with mucus and has improper drainage may act as a focus of infection.[1,5] There are few case reports of infection with diverse pathogens like mycobacterium, cytomegalovirus and aspergillosis.[2,7] Probably in our case also patient had recurrent chest infections secondary to mucocele which use to resolve with antibiotic therapy and symptomatic management. There have been instances of bronchial atresia presenting with pneumothorax and calcified mucocele.[8,9]

Chest radiograph shows a branched tubular or oval opacity near the hilum usually accompanied by surrounding hyperinflation.[6,10] Computed tomography of the chest is the preferred investigation of choice as it delineates bronchial abnormality and helps in the differentiation of mucocele from vascular structures or other mass-like lesions.[4,10] The characteristic findings on chest tomography are the presence of mucocele as a branched or round opacity, no visible communication between obstructed and central bronchus and distal hyperinflation.[1,3,4]In our case, we could visualise a non-enhancing club-shaped lesion with surrounding hyperinflation in the right upper lobe which was virtually diagnostic of bronchial atresia.

We proceeded with bronchoscopy to rule out other associated conditions which may have a similar radiological picture. Bronchial stenosis, endobronchial tumours, impacted foreign body, mucus plugging in the lung with underlying cystic lesions and secondary proximal bronchial atresia post-inflammatory diseases like tuberculosis may give a similar radiological picture.[1,3,5] Presence of blind-ending bronchus confirms the diagnosis of bronchial atresia, but similar to this case bronchoscopy can be normal in as many as 50% of cases.[1] In cases of bronchial stenosis, the luminal narrowing can be appreciated on bronchoscopy and CECT chest, while benign endobronchial tumours may have a vague radiological picture but will be clearly visible during bronchoscopy.

In young patients with no life-threatening illness, management should be conservative.[1,6] Symptomatic cases can sometimes warrant surgical management in patients with recurrent respiratory infections, poor pharmacological response and severe haemoptysis.[1,2] Since the patient was not very symptomatic, we counselled him about the condition and have kept him on our regular follow-up.

Congenital bronchial atresia is a rare disease that is often detected incidentally in young adults and a high index of suspicion is required. Typical radiological findings often assisted by bronchoscopy are diagnostic of bronchial atresia when other causes of unilateral hyperlucency have been excluded.

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