Dextrocardia

(CHEST 2000; 118:1202-1204)

A 5-month-old girl was referred to our hospital due to a bout of sneezing, mucoid discharge, and progressive dyspnea for 2 days. The infant was born at 38 weeks by vaginal delivery at a weight of 3,110 g. No respiratory disorders were reported during the neonatal period. During her first 5 months of life, the patient was fed by bottle, had proper weight gain, and remained asymptomatic. There was no family history of congenital defect or consanguinity.

A physical examination revealed a well-nourished girl. She presented subcostal and intercostal retractions with no cyanosis. Breath sounds were diminished on the right side, and cardiac sounds were displaced to that side with no murmur. Vital signs were normal, including oxygen saturation levels. The results of serum chemistry tests and CBC count also were normal.

A posteroanterior chest radiograph showed total opacity of the right hemithorax with a shift of the mediastinum to the right, dextroposition, and no bronchial or pulmonary vascular markings. On the lateral radiograph there appeared to be herniation of the left lung through the anterior mediastinum (Fig 1).

[Figure 1 ILLUSTRATION OMITTED]

On the days following presentation, treatment with bronchodilators, oxygen, and physiotherapy improved the patient's condition, and she was discharged when she became asymptomatic.

What is the diagnosis?

Diagnosis: Unilateral pulmonary agenesis

Pulmonary agenesis is a rare developmental defect in which there is a complete absence of the lung and bronchus and no vascular supply.[1] The condition has been categorized according to the Schneider and Schwalbe classification. They recognized the following three degrees of the anomaly: (1) agenesis, in which the three structures are absent; (2) aplasia, in which there is no lung and pulmonary artery but there is a rudimentary bronchus coming off the trachea; and (3) hypoplasia, in which there is both hypoplastic lung parenchyma and a rudimentray bronchus.[2,3] In accordance with this system, we classified our case as right agenesis. Whereas bilateral pulmonary agenesis is incompatible with extra-uterine life, morbidity and mortality in unilateral agenesis are directly related to other associated malformations. These are present in about 50% of cases and may affect the skeletal, GI, genitourinary, and cardiovascular systems.[4] Association with cardiac abnormalities involves a worse prognosis. Dextrocardia has been described, as well as septal defects, tetralogy of Fallot, and transposition of the great arteries.[4-6]

The etiology remains unknown. The coexistence of multiple malformations suggests a teratogenic origin, but mechanical and genetic reasons also have been considered.[1,2,5] Both sexes appear to be almost equally affected.[2]

Right-sided agenesis has a poor prognosis due to malrotation of the carina and the greater shift of the heart and mediastinum, leading to more significant distortion of the bronchial and vascular structures.[1,2,4-6]

The clinical onset is variable. In some cases, symptoms appear soon after delivery, whereas in other cases the patient remains asymptomatic until adulthood, when the defect is detected during a routine examination.[1,4] Cyanosis, tachypnea, cough, noisy respiration, wheezing, stridor, and respiratory distress may be the initial symptoms. Those patients with isolated pulmonary agenesis are frequently recognized due to recurrent respiratory infections.[1]

The chest radiograph usually suggests the diagnosis, but it should be confirmed by MRI because this technique shows not only the pulmonary agenesis but also any associated anomalies. An echocardiographic study is mandatory in order to rule out cardiac anomalies. A helical chest CT scan with tridimensional reconstruction may be helpful as well. In some cases, complementary examinations such as bronchography, bronchoscopy, and cardiac catheterization may be indicated.

A color Doppler echocardiogram performed on our patient showed dextrocardia and situs solitus with an otherwise normal heart. MRI confirmed the absence of right lung parenchyma, bronchi, and vessels and also confirmed the dextrocardia (Fig 2).

[Figure 2 ILLUSTRATION OMITTED]

REFERENCES

[1] Safa Kaya I, Dilmen U. Agenesis of the lung. Eur Respir J 1989; 2:690-692

[2] Mardine MK, Nyhan WL. Agenesis of the lung: report of four patients with unusual anomalies. Chest 1985; 87:522-527

[3] Campanella C, Odell JA. Unilateral pulnonary agenesis: a report of 4 cases. S Afr Med J 1987; 71:785-787

[4] Argent AC, Cremin BJ. Computed tomography in agenesis of the lung in infants. Br J Radiol 1992; 65:221-224

[5] Wu CT, Chen MR, Shih SL, et al. Case report: Agenesis of the right lung diagnosed by three-dimensional reconstruction of helical chest CT. Br J Radiol 1996; 69:1052-1054

[6] Capuani A, Del Torso S, Lincoln JC. Right lung agenesis: a case report. G Ital Cardiol 1982; 12:381-383

(*) From the Pediatrics Department, Fundacion Jimenez Diaz, Universidad Autonoma de Madrid, Madrid, Spain. Manuscript received September 2, 1999; revision accepted November 5, 1999.

Correspondence to: Mercedes Bernacer Borja, MD, Pediatrics Department, Fundacion Jimenez Diaz, Avda Reyes Catolicos no 2, 28040 Madrid, Spain; e-mail: rpediatria@fjd.es

COPYRIGHT 2000 American College of Chest Physicians
COPYRIGHT 2001 Gale Group