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J. bras. pneumol. vol.38 no.4 São Paulo July/Aug. 2012
Unilateral pulmonary agenesis*
Maura Cavada MalconI; Claudio Mattar MalconII; Marina Neves CavadaIII; Paulo Eduardo Macedo CarusoIV; Lara Flório RealV
IPulmonologist. Pelotas City Hall, Pelotas, Brazil
IIPulmonologist. Pelotas, Brazil
IIIMedical Student. Federal University of Pelotas, Pelotas, Brazil
IVMedical Student. Federal University of Pelotas, Pelotas, Brazil
VResident in Gynecology and Obstetrics. Hospital Nossa Senhora da Conceição de Porto Alegre, Porto Alegre, Brazil
Pulmonary agenesis is a rare congenital anomaly. We report the case of an 8-year-old boy with left lung agenesis, without any other congenital malformations. When the patient presented symptoms, including cough, wheezing, and dyspnea, with no clinical improvement after a period of 30 days, imaging studies were conducted and the diagnosis was made.
Keywords: Congenital abnormalities; Respiratory tract diseases; Bronchoscopy.
Pulmonary agenesis is a rare congenital anomaly, consisting of complete absence of the lung parenchyma, bronchi, and pulmonary vessels.(1-4) The cause is unknown. In 50% of cases, especially in cases of right lung agenesis, cardiovascular, musculoskeletal, gastrointestinal, and renal malformations are also present.(3,5-7) The prognosis is better in cases of left lung agenesis and when there are no cardiac malformations.(3) Herein, we report the clinical case of a boy with left lung agenesis, without any other congenital malformations.
An 8-year-old White male patient from the city of Jaguarão, Brazil, sought medical attention. He had been born at term, and there had been no complications during pregnancy. He had a family history of asthma. Since early 2006, when he was 7 years old, the patient had been having attacks of wheezing, having been treated at home by his family. When he sought medical attention in February of 2007, the patient presented with a dry cough that progressed to wheezing and dyspnea for one month. He was hospitalized in his hometown. A chest X-ray performed at admission showed opacity of the left hemithorax, which was treated as bacterial pneumonia (Figure 1). Physical examination by a pulmonologist revealed that the patient was active, acyanotic, and breathing normally; pulmonary auscultation revealed retraction of the left hemithorax, dullness to percussion, and absent breath sounds on the left with wheezing on the right; cardiac auscultation revealed normal, rhythmic heart sounds without heart murmurs. The following tests were requested: chest HRCT; bronchoscopy; Doppler echocardiography; and abdominal ultrasound. Chest HRCT showed left lung agenesis, compensatory hypertrophy of the right lung, and normal right pulmonary circulation with leftward deviation of the mediastinal structures. There were no changes in upper abdominal structures (Figure 2). Abdominal ultrasound and echocardiography showed normal findings. Bronchoscopy revealed a blind-ending left main bronchus. Two months later, the patient returned for a follow-up evaluation. He presented with clinical signs of wheezing and was treated with a β2 agonist, which provided symptom relief. Chest X-ray findings remained consistent with left lung agenesis. Spirometry revealed moderate obstructive lung disease, with no significant variation in flow or volume after bronchodilator use. Pre-bronchodilator values were as follows: FVC = 1.19 L (106% of predicted); FEV1 = 0.60 L/s (56% of predicted); and FEV1/FVC ratio = 0.50 (55% of predicted). Post-bronchodilator values were as follows: FVC = 1.21 L (108% of predicted); FEV1 = 0.61 L/s (57% of predicted); and FEV1/FVC ratio = 0.51 (56% of predicted). Follow-up echocardiography, performed in 2008 and 2009, revealed right ventricular enlargement (right ventricular diameter = 29 mm; reference value = 7-18 mm) with normal pulmonary flow and no communications, shunts, or intracardiac obstructions.
Unilateral pulmonary agenesis is a rare congenital anomaly, which occurs in isolation or in association with other anomalies. Its estimated incidence is 1 per 10,000-15,000 autopsies. Although its etiology remains unknown, its pathogenesis is believed to be related to genetic factors, viral factors, or vitamin A deficits.(3,7) Its pathology has been categorized as per the classification by Schneider & Schwalbe(3,6,8):
agenesis-complete absence of a lung and bronchi, with no blood supply to the affected side
aplasia-presence of a rudimentary bronchus with complete absence of parenchyma
hypoplasia-lobar agenesis and hypoplastic lung
The clinical presentation of the disease varies among patients. In some cases, symptoms manifest at birth as respiratory distress syndrome. In others, patients remain asymptomatic until adulthood, when the defect is incidentally detected during routine examination. Patients with unilateral pulmonary agenesis can have recurrent respiratory infections,(3) as well as cardiovascular, digestive, and musculoskeletal malformations. Chief among cardiovascular malformations are patent ductus arteriosus and patent foramen ovale. Digestive tract anomalies commonly include tracheoesophageal fistula and duodenal atresia. Musculoskeletal malformations include hemivertebrae, absence of ribs, and changes in extremities (absence of the radius). Facial and renal anomalies, such as horseshoe kidney, have also been described.(7)
Imaging studies are essential for the diagnosis of pulmonary agenesis. Chest X-ray and chest CT show hyperinflation of the remaining lung and displacement of the mediastinum toward the affected side.(2) Echocardiography plays a fundamental in ruling out cardiac anomalies. Other ancillary tests, such as bronchoscopy for confirming the diagnosis and magnetic resonance imaging for detecting vascular malformations, might be indicated.(3-5)
In right lung agenesis, the association with cardiovascular anomalies, malrotation of the carina, and rightward deviation of the heart and mediastinum with bronchial distortion and distortion of vascular structures results in a worse prognosis.(3,4) Asymptomatic patients do not require intervention, especially in the absence of associated anomalies. However, pulmonary infection or other lung diseases should be treated early. Pulmonary hypertension is a complication that requires attention, since it is more common in such patients because of a reduction in the pulmonary vascular bed that, if associated with congenital heart disease (left-to-right shunt), can progress to irreversible vascular disease.(4,9) At this writing, right ventricular enlargement, without changes in pulmonary flow, had been detected, and the patient was under annual follow-up with a pediatric cardiologist.
The patient in this report remained asymptomatic for a long period of his life, which is due to his having no other congenital malformations and to his having left lung agenesis, both of which are factors that translate to a better prognosis. The clinical diagnosis was made when the child presented with respiratory infection and wheezing. Chest X-ray and intravenous contrast-enhanced CT of the chest confirmed the diagnosis.
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Correspondence to: Submitted: 15 April 2010. * Study carried out at the private practice of the first author, Pelotas, Brazil.
Rua Félix da Cunha, 916, apto. 1001
CEP 96010-000, Pelotas, RS, Brasil
Tel. 55 53 3222-9875 or 55 53 3222-7338
Accepted, after review: 26 October 2010.
Financial support: None.
Submitted: 15 April 2010.
* Study carried out at the private practice of the first author, Pelotas, Brazil.