ABSTRACT. Congenital abnormalities of the lung are rare and are often misdiagnosed. We report the case of a young girl who was initially diagnosed to have ...
CASE REPORT
Unilateral Pulmonary Agenesis: An Uncommon Cause of Lower Zone Lung Opacity A. Mohan, R. Guleria, R. Sharma and C. Das Department of Medicine, All India Institute of Medical Sciences, New Delhi, India
ABSTRACT Congenital abnormalities of the lung are rare and are often misdiagnosed. We report the case of a young girl who was initially diagnosed to have pleural effusion with collapse. After detailed evaluation including computerised tomographic (CT) scan and fiberoptic bronchoscopy, a final diagnosis of unilateral pulmonary agenesis was made. This condition must be suspected in differential diagnosis in a young person presenting with features of lung collapse. Key words: Pulmonary agenesis, Opaque hemithorax.
[Indian J Chest Dis Allied Sci 2005; 47: 53-56]
INTRODUCTION Congenital malformations of the lung are rare and vary widely in their presentation and severity1. Their management can be a challenge, since they are often misdiagnosed for the more common entities affecting the lung, and a high index of suspicion is required to make an early diagnosis. Many patients with congenital malformations present in adult life when a clinical diagnosis becomes more difficult, consequently these patients are often mismanaged. We report the case of a young girl with unilateral pulmonary agenesis who was initially treated as pleural effusion and collapse.
CASE REPORT A 15-year-old girl presented with complaints of gradually progressive shortness of breath
and right-sided chest discomfort of six months duration. The pain was diffuse, located anteriorly as well as posteriorly and did not increase on deep inspiration or coughing. She did not give any history of orthopnoea, palpitations, cough, expectoration, fever and anorexia or weight loss. She had no past history of pulmonary tuberculosis or rheumatic heart disease. However, there was history of an episode of pneumonia in childhood. She was born of a non-consanguineous marriage. Her perinatal history was uneventful and none of her siblings had similar complaints. She was advised a chest radiograph by her physician and initially diagnosed to have pleural effusion. A pleural aspiration was attempted but no fluid could be drawn. She was treated with analgesics and then referred to this hospital with a diagnosis of loculated pleural effusion/lung collapse.
[Received: July 31, 2003; accepted after revision: December 11, 2003] Correspondence and reprints request: Dr Randeep Guleria, Professor, Department of Medicine, All India Institute of Medical Sciences, Ansari Nagar, New Delhi-110 029; Telex: 91-011-26593676, 26588700; E-mail: .
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On examination, she was an average built female and afebrile. There was no pallor, icterus, cyanosis, clubbing, lymphadenopathy, edema of feet or raised jugular venous pulse. There was decreased movement of the right hemithorax and the trachea and the heart were shifted to the right. The entire right hemithorax, except the supraclavicular and infraclavicular areas was dull to percussion. Breath sounds were absent on the right side. The left side was normal on clinical examination. Cardiovascular, abdominal, musculoskeletal and neurological systems were normal. The chest radiograph showed an opacity in the mid and lower zones of the right lung (Figure 1). The trachea and the heart were shifted towards the right. The computed tomogram revealed complete absence of lung tissue on the right side with gross ipsilateral mediastinal shift (Figures 2 and 3). The right main bronchus was of a smaller caliber than the left and ended abruptly just distal to the tracheal bifurcation. The upper part of the left lung was seen herniating to the opposite side due to compensatory hypertrophy. The right
Figure 2. Contrast enhanced computed tomogram of the chest showing a small right main bronchus (arrow). The mediastinum is grossly shifted towards the right side.
Figure 3. Contrast enhanced computed tomogram of the chest showing herniation of the left lung to the right side. The pulmonary vascular markings are visualised within. The right lung is absent.
pulmonary artery was also much smaller as compared to the left side. The overall radiological picture was compatible with a right-sided pulmonary agenesis.
Figure 1. Chest radiograph showing opacity in the right lower zone with ipsilateral shift of the heart and oesophagus. The right hemithorax is shrunken causing ipsilateral scoliosis.
Fiberoptic bronchoscopy showed a small right main bronchus approximately 2 cm long ending abruptly as a rudimentary bud. Subsequently, an abdominal ultrasound and an echocardiography of the heart were performed, both of which were normal. She was diagnosed
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as a case of right-sided pulmonary agenesis. In view of her relatively mild symptoms and absence of associated congenital anomalies, symptomatic treatment was given. The patient was discharged after explaining the nature of the illness to her as well her parents. She has been on regular follow up for two years. Her radiological picture has not changed and she has remained asymptomatic.
DISCUSSION Pulmonary agenesis is a rare malformation that may be seen in isolation or may be associated with other anomalies such as esophageal atresia, tracheo-esophageal fistula, cardiac malformation, horse-shoe kidney and anal atresia. Abnormal development of the aortic arches during embryogenesis, especially involving the first and the second branchial arches are the most common overt malformations and may be the possible cause of these associated anomalies2. Parental consanguinity through an autosomal recessive mode of inheritance, may be a predisposing factor3. The incidence of this condition, though not precisely known, ranges between 0.0034 and 0.0097 percent.3 Pulmonary agenesis is classified morphologically by the extent to which bronchopulmonary tissue is absent. Spencer divided pulmonary agenesis into: (1) bilateral complete agenesis, (2) unilateral agenesis with (a) complete absence of bronchi, (b) rudimentary bronchus present but no pulmonary tissue, or (c) poorly developed main bronchus with poorly organised parenchyma, and (3) lobar agenesis 4 . However, a more useful clinical classification would be to use angiographic data to divide the patients into two groups : one in which there is complete absence of lung parenchyma and the ipsilateral pulmonary artery; and the other where hypoplastic pulmonary tissue is present. The latter group may be further divided into two subgroups : one where the affected lung receives its blood supply from the ipsilateral pulmonary artery; and the other in which it is supplied by the systemic circulation3. This may have important
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therapeutic implications because in the absence of a systemic blood supply, if the ipsilateral pulmonary artery is also absent, there will be no lung tissue on that side and hence surgery should never be considered. In contrast, pneumonectomy or lobectomy may be required in the second subgroup when the systemic blood flow causes congestive heart failure or recurrent respiratory infections. Almost 70% of cases affect the left side and males predominate over females 1. Associated malformations are present in 50% of the cases and are a major cause of morbidity and mortality. Most patients suffer from recurrent chest infections in childhood, and about half of the affected individuals die within the first five years of life itself. However, as in the present case, many persons remain asymptomatic till adulthood and may even survive up to old age. In contrast, bilateral pulmonary agenesis is obviously incompatible with life. Clinically, this condition is almost indistinguishable from a pulmonary collapse of the involved side. This was the initial diagnosis considered in the case reported. However, in the presence of an opaque hemithorax with ipsilateral cardiomediastinal shift and an intact diaphragm on the radiograph, pulmonary agenesis should always be considered. Other differential diagnoses include diaphragmatic hernia, adenomatoid cystic malformations and sequestrations. Bronchography has now become obsolete with the advent of the CT scan, which provides an accurate picture of the lung parenchyma, bronchial tree and the pulmonary vasculature and is now regarded as the optimal non-invasive diagnostic modality if the chest radiography is not definitive5. Bronchoscopy allows direct visualisation of the bronchial tree, including the absent or rudimentary bronchus. The best method for precise diagnosis of pulmonary agenesis is pulmonary angiography, which confirms the absence of the ipsilateral pulmonary vessel 6 . Furthermore, cardiac catheterisation is a useful procedure for the diagnosis and elucidation of anatomic abnormalities and identification of associated cardiac defects.
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Asymptomatic cases need no intervention. However, chest infections should be treated promptly and aggressively. Patients having a rudimentary bud may require surgical resection if medical management fails to control the infection. Associated congenital anomalies should be corrected wherever feasible. The present case report highlights the fact that in younger age, clinical features suggestive of collapse may be due to uncommon conditions like pulmonary agenesis .
REFERENCES 1. Gilbert EF, Opitz JM. The pathology of some malformations and hereditary disease of the respiratory tract. Birth Defects 1976; 12: 239-70. 2. Cunningham ML, Mann N. Pulmonary
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agenesis: A predictor of ipsilateral malformations. Am J Med Genet 1997; 70: 391-98. 3. Mardini MK, Nyhan WL. Agenesis of the lung: Report of four patients with unusual anomalies. Chest 1985; 87: 522-27. 4. Gould SJ, Hasleton PS. Congenital abnormalities. In: Hasleton PS, ed Spencer’s Pathology of the Lung; 5th ed. New York: McGraw-Hill; 1996: 57-114. 5. Schwartz MZ, Ramachandran P. Congenital malformations of the lung and mediastinum: A quarter century of experience from a single institution. J Pediatr Surg 1997; 32: 44-47. 6. Guven S, Koyuturk Y, Cerrah Celayir A, Karadeniz L, Celikoglu S. An unusual cause of respiratory distress: Unilateral pulmonary agenesis. Arch Dis Child 2001; 84: F197.
