Swyer-James-Macleod syndrome as a rare cause of unilateral hyperlucent lung: Three case reports.

RATIONALE: Swyer-James-Macleod syndrome (SJMS) is a rare lung disorder characterized by unilateral hyperlucent lungs which arises as a complication of bronchiolitis obliterans. It is typically diagnosed during childhood, although some patients may only be diagnosed in adulthood, often as an incidental finding, but others due to recurrent chest infections. PATIENT CONCERNS: Three patients were referred to our institution with complaints of dyspnea on exertion, chronic productive cough, and recurrent pulmonary infections. Two of them had a history of lower respiratory tract infections during childhood. DIAGNOSIS: A computed tomography scan was performed and showed unilateral reduced density of the lung and bronchiectasis in the 3 patients. Based on the clinical presentation and radiologic features, the diagnosis of SJMS was established. INTERVENTIONS: Patients started inhaled corticosteroids and long acting beta agonist, vaccines to prevent respiratory infections were administered and airway clearance techniques were taught. OUTCOMES: Two patients became asymptomatic with inhaled therapy and no recurrent chest infections were observed over a 3-year follow-up period, being discharged from our institution to the general practitioner. The 3rd patient had some improvement in the frequency of pulmonary infections and dyspnea, without improvement in respiratory function tests, maintaining vigilance at our center. LESSONS: These cases highlight the importance of being aware of this condition and its frequent association with bronchiectasis, which may adversely affect the prognosis, to manage patients appropriately and prevent recurrent pulmonary infections.

The vanishing lung: an important cause of hyperlucency on chest radiograph.

Giant bullous emphysema is an uncommon condition characterised by large asymmetric bullae with upper lobe predominance. This condition is most frequent in young male smokers. Patients usually present with progressive breathlessness which is secondary to enlargement of the bullae leading to compression of the lung parenchyma. Large asymmetrical bullae may appear as a unilateral hyperlucency on a plain chest radiograph, and may mimic the appearances of pneumothorax. A computed tomography scan is needed to delineate the lung pathology. We describe two cases with this condition that presented acutely and discuss the management of bullous emphysema.

[MacLeod syndrome and pneumothorax: don't be fooled]. / Syndrome de MacLeod et pneumothorax : une source d'erreur diagnostique et thérapeutique.

INTRODUCTION: MacLeod syndrome, also known as Swyer-James syndrome, is a rare syndrome characterized by unilateral lung hyperlucency. It is a form of constrictive bronchiolitis which is caused by repeated acute bronchiolitis and/or pulmonary infections during infancy. CASE REPORT: The patient was a 26-year-old man who had had a first left pneumothorax at the age of 21. He smokes tobacco. When he was 1-year-old he had experienced repeated episodes of acute bronchiolitis. At age 26, he suffered from a second left pneumothorax which was wrongly diagnosed as a recurrent drain-resistant pneumothorax. Misdiagnosed, he underwent a chemical pleurodesis during thoracoscopy. As a hyperlucency remained in the left upper part of the lung on chest X-ray, further investigations were undertaken and a diagnosis of MacLeod syndrome was made. CONCLUSIONS: MacLeod syndrome is rare. It can be associated with pneumothorax which can be a source of misdiagnosis and error in the management of these patients. Therefore, the diagnostic criteria and therapeutic indications are reiterated. The probable mechanism of association between pneumothorax and Macleod syndrome is also discussed.

Unilateral hyperlucent lung in a child caused by a foreign body identified with v/q scintigraphy.

A 5-year-old girl presented with episodes of coughing, inspiratory stridor, and occasionally squeaking breath sounds. There was no history of a foreign body aspiration. Initially, she was diagnosed with allergic asthma. However, signs and symptoms continued despite a trial of inhaled corticosteroids. A chest radiograph showed a hyperlucent right lung, mainly in the upper lobe, with decreased vascular markings compatible with Swyer-James-MacLeod syndrome, or foreign body aspiration. V/Q imaging showed markedly diminished right lung ventilation and perfusion, especially in the upper lobe, with a hot spot in the area of the right bronchus. At bronchoscopy, a pistachio nutshell was removed from the right main bronchus.

Genetic, host, and environmental interactions in a 19 year old with severe chronic obstructive lung disease; observations regarding the pathophysiology of airflow obstruction.

A case of a 19-year-old with severe chronic obstructive pulmonary disease is presented. This case illustrates genetic (severe alpha-1 antitrypsin deficiency) and host factors (such as developmental diaphragmatic hernia and the innate response to injury), and environmental (high oxidative stress and lung injury) interactions that lead to severe chronic obstructive lung disease. The development of chronic lung disease was caused by lung injury under high oxidative and inflammatory conditions in the setting of a diaphragmatic hernia. In the absence of normal alpha-1 antitrypsin levels, a pro-elastolytic environment in the early period of lung growth enhanced the development of severe hyperinflation and precocious airflow obstruction.

[Increased transparency in thin-slice computed tomography of lung parenchyma]. / Vermehrte Transparenz in der Dünnschicht-CT des Lungenparenchyms.

Areas with reduced density are a common finding with thin-slice computed tomography (CT) examinations of lung parenchyma. Diffuse and localized patterns can be differentiated. The most frequent cause for a diffuse decrease in density is pulmonary emphysema which can be classified into centrilobular, panlobular and paraseptal emphysema based on the distinct anatomical features. A mosaic pattern (due to mosaic perfusion or air trapping) is also characterized by a diffuse decrease in density. Focal cystic changes can be differentiated from emphysematous changes and mosaic patterns which do not reveal wall structures. Langerhans cell histiocytosis and lymphangioleiomyomatosis are the most frequent cystic diseases of the lung parenchyma. Based on the geometry and anatomical distribution of the cysts a differentiation is mostly possible. Rare diseases leading to a reduced lung density include the Birt-Hogg-Dubé syndrome, lymphoid interstitial pneumonia as well as congenital diseases or diseases which are acquired during early childhood, such as cystic adenomatoid malformation or Swyer-James syndrome.