Perinatal/Neonatal Case Presentation Primary Unilateral : Neonate through Early Childhood F Case Report, Radiographic Diagnosis and Review of the Literature

Matthew E. Abrams, MD (Figure 1) and a retrosternal opacity on lateral view (Figure 2). Veda L. Ackerman, MD Serial radiographs failed to show improvement in the appearance William A. Engle, MD of the right hemithorax. However, the patient’s respiratory status normalized. Computed topography (CT) scan of the chest (Figure 3) at the infant’s referring hospital was interpreted as complete collapse of the right upper lobe versus a right upper lobe Unilateral pulmonary hypoplasia is a rare cause of respiratory distress in the chest mass. The infant was transferred to our institution at 9 days neonate. It is usually secondary to other causes such as diaphragmatic of life for further evaluation. At this time, the infant was symptom hernia. We present a case of a newborn with primary hypoplasia of the right free without , cyanosis, or cough. The infant otherwise upper lobe who was later found to also have . We appeared normal without any dysmorphic features. Review of the describe the clinical course through early childhood. chest radiograph series and chest CT scan confirmed the diagnosis Journal of Perinatology (2004) 24, 667–670. doi:10.1038/sj.jp.7211156 of unilateral right upper lobe pulmonary hypoplasia without any evidence for a chest mass. A magnetic resonance image (MRI) of the chest (Figure 4) was consistent with hypoplasia of the right upper lobe. An assessment of pulmonary venous drainage was not possible secondary to technical problems. There was no evidence of CASE PRESENTATION tracheobronchial abnormalities other than mild shift of the A 2900-g 36-week appropriate-for-gestational age infant male was mediastinum and to the right. There was no evidence for born by cesarean section for maternal vaginal bleeding and an accessory diaphragm or for a mass. Echocardiogram showed placenta previa. His mother was a 25-year-old gravida-2, para-2 normal cardiac with a right pulmonary artery that was white female whose pregnancy was uncomplicated. There was no approximately 2/3 the diameter of the left pulmonary artery. Two reported medication use during the pregnancy. Apgar scores were 7 normal left pulmonary and at least one normal right and 9 at 1 and 5 minutes, respectively. Supplemental oxygen was pulmonary appeared to drain normally into the left . given shortly after birth because of an oxygen saturation of 87% The infant was hospitalized overnight and remained in room air and tachypnea. The initial arterial blood gas on asymptomatic. He was subsequently discharged to home at 11 days 1 l per minute of oxygen by nasal canula was pH ¼ 7.35, of life. At 1 month of life, he remained asymptomatic. A PCO2 ¼ 43 mmHg, PO2 ¼ 123 mmHg, Base excess ¼À1.9 mEq/l. On physical examination, the baby was intermittently tachypneic with respirations as high as 90 breaths per minute and decreased right-sided chest wall movement. A sepsis evaluation was initiated and the infant was started on intravenous antibiotics. The patient clinically improved and was weaned to room air within 12 hours. The complete blood count was within normal limits and a blood culture was subsequently negative after 72 hours, at which time antibiotics were discontinued. Initial chest radiographs (CXR) showed haziness of the right hemithorax on anteroposterior view

Departments of (M.E.A., W.A.E.), Indiana University, Riley Hospital for Children, Indianapolis, IN, USA; and Department of Pediatric (V.L.A.), Indiana University, Riley Hospital for Children, Indianapolis, IN, USA. Figure 1. Chest radiograph shows diffuse haziness of the right Address correspondence and reprint requests to: William A. Engle, MD, James Whitcomb Riley hemithorax (arrow), slight deviation of the trachea and heart to the Hospital for Children, 699 West Drive, RR208, Indianapolis, IN 46202, USA. right, and poor differentiation of the right heart border.

Journal of Perinatology 2004; 24:667–670 r 2004 Nature Publishing Group All rights reserved. 0743-8346/04 $30 www.nature.com/jp 667 Abrams et al. Case Report of a Newborn with Pulmonary Hypoplasia

Figure 4. MRI of the chest shows the smaller right with otherwise normal lung architecture and a homogeneous density filling the area of the upper right lobe (arrow) consistent with the thymus and fibrous tissue filling the upper lobe defect.

ventilation–perfusion scan of the chest showed no ventilation or perfusion defects but did show a small but normally shaped right lung. Infant pulmonary function tests (PFTs) at that time were within normal limits. At 3 months of age, he developed intermittent wheezing. Repeat infant PFTs were consistent with moderate lower airway obstruction. He was started on aerosolized bronchodilators. At 4 months of age, he developed wheezing unresponsive to aerosolized Figure 2. Lateral chest radiograph shows a large thymus and well- bronchodilators. Flexible showed moderate-to-severe demarcated retrosternal opacity (arrows). and a small indentation in the right posterior– lateral wall of the upper trachea. An upper gastrointestinal series did not show a tracheoesophageal fistula. Rigid bronchoscopy and esophagoscopy at 6 months of age again showed no tracheoesophageal fistula but evidence of severe tracheobronchomalacia. There was severe dynamic obstruction of the right upper and middle bronchi, as well as the left mainstem . Also, at this time, a CXR revealed elevation of the right hemidiaphragm. Surgical exploration showed no evidence for a hernia of Morgani or a chest mass but there was significant eventration of the right hemidiaphragm. At 5 years of age, growth and development are progressing well while being maintained on inhaled b-2 agonists and inhaled steroids. Pulmonary function tests continue to show moderate-to- severe obstructive disease, which is only mildly responsive to bronchodilators. A repeat echocardiogram showed normal left pulmonary venous drainage and at least one normal right pulmonary vein draining into the left atrium. Chromosomes were not evaluated.

DISCUSSION Figure 3. CT scan of the chest shows a homogeneous density in the anterior mediastinum and right upper chest (arrows). The trachea and Pulmonary hypoplasia includes a spectrum of problems which bronchial tree appears normal. includes hypoplasia, aplasia, or agenesis of selected or all lung

668 Journal of Perinatology 2004; 24:667–670 Case Report of a Newborn with Pulmonary Hypoplasia Abrams et al.

segments. The lesions may be lobar, unilateral, or bilateral. Some hypoplasia. The radiographic stripe is due to the difference in degree of the pulmonary hypoplasia spectrum is reported to be densities between the fatty and areolar tissues located anterior and found in 7 to 26% of all neonatal autopsies.1–6 However, most the normally aerated lung lobe positioned posteriorly. cases of pulmonary hypoplasia are secondary to conditions that Differentiation between isolated lobar pulmonary hypoplasia and limit fetal lung growth.7 Primary pulmonary hypoplasia is rare. It pulmonary hypoplasia secondary to an accessory diaphragm is may be caused by an embryologic defect of the lung or vascular difficult on plain radiographs. Chest CT or MRI may be needed to tissues or an in utero vascular accident. better delineate the defect. Nowotny et al.10 recommended Cases of primary pulmonary hypoplasia have been described in pulmonary function tests for infants with pulmonary hypoplasia. If the literature with varying degrees of severity ranging from bilateral PFTs reveal airflow obstruction and elevated resistance, then hypoplasia of the to simple hypoplasia of an isolated lobe. flexible bronchoscopy is recommended. In our case, the initial Cases of isolated lobar defects with or without tracheobronchial PFTs were normal. This may reflect the inaccuracy of the test or abnormalities, has only been rarely reported.8–13 the possibility that the airway obstruction actually worsened during With unilateral lobar pulmonary hypoplasia, gross pathology of the first months of life, which is frequently the clinical course for the affected lobes shows a decrease in size and weight and, and tracheomalacia. Wu et al.16 described a case of histologically, a decrease in the number of alveoli. The alveoli are unilateral lung hypoplasia diagnosed by three-dimensional often immature but otherwise demonstrate no distinct reconstruction of helical chest CT. Argent and Cremin17 used abnormalities. The number of bronchioles and arterioles is also contrast-medium-enhanced CT to elucidate the anatomy of two diminished.14 patients with right lung agenesis. Becmeur et al.13 were only able Clinically, infants with unilateral lobar pulmonary hypoplasia to diagnose an accessory diaphragm with the use of an MRI scan. may have variable presentations depending on the extent of lung It was not clear on CT scan whether the finding represented an involvement and comorbidities. Some infants present with severe accessory diaphragm or a band of atelectasis. respiratory distress in the first few hours of life whereas some may A number of associated anomalies have been described in be completely asymptomatic. Some patients may present months to patients with pulmonary hypoplasia, but none has been specifically years later with repeated pulmonary and wheezing.15 associated with patients with lobar hypoplasia. Nakamura et al.18 The differential diagnosis of respiratory distress in the newborn in a large series of autopsy cases revealed five statistically associated with marked opacification of one side of the on significant risk factors associated with pulmonary hypoplasia: (1) radiograph includes atelectasis, congenital ; (2) renal anomalies; (3) diaphragmatic hernia; (4) (CDH), congenital cystic adenomatoid malformation (CCAM), skeletal anomalies; (5) and polyhydramnios. , chylothorax, pulmonary hypoplasia, Similar findings were found by Wigglesworth and Desai1 in a study bronchogenic cyst, and a chest tumor (e.g., neuroblastoma, of 20 infants with pulmonary hypoplasia. A number of studies have , fibrosarcoma). In a right-sided CDH, there may be described associated anomalies including heart defects, skeletal and opacification of the right hemithorax if the liver is occupying that vertebral anomalies, abdominal defects, facial abnormalities, space. A left-sided CDH will have air-filled loops of bowel in the kidney defects, as well as numerous lung and tracheo-bronchial chest except possibly in a chest radiograph taken shortly after birth tree defects.6,8,19–24 There have been a number of case reports of or following bowel decompression. CCAM will usually appear as a pulmonary hypoplasia and tracheoesophageal fistula and a cystic mass rather than a homogenous opacification. A chylothorax number of reports of an association of tracheal stenosis with that presents in the first few days of life may be due to a congenital .8,19,21,22,24–27 Similar to patients with more malformation of the lymphatic system or traumatic injury of the severe degrees of pulmonary hypoplasia, neonates with isolated thoracic duct at delivery. Obstruction of the bronchus with lobar hypoplasia may demonstrate other congenital malformations. resultant opacification of the hemithorax may occur with a The natural history in the case reported illustrates the bronchogenic cyst or a vascular sling. Neonatal chest tumors are importance of close follow-up for neonates with unilateral lobar very rare and may present as a focal abnormality on CXR. pulmonary hypoplasia. Although mildly symptomatic or Diagnosis of unilateral lobar pulmonary hypoplasia requires a asymptomatic during the newborn period, they may develop high index of clinical suspicion and experience with reading obstructive pulmonary disease associated with neonatal and infant radiographs. The radiographic findings will tracheobronchomalacia and reactive airway disease. It could be vary depending on the extent of lung involvement. In right-sided argued that all neonates with pulmonary hypoplasia should have lobar pulmonary hypoplasia due to an accessory diaphragm, the pulmonary function testing. If PFTs are abnormal or there are heart and the trachea are displaced toward the right and the right clinical signs of airway disease, flexible bronchoscopy should be heart border or superior mediastinum is obscured.14 A large apical performed to assess for tracheobronchial abnormalities. All infants cap or a poorly defined retrosternal stripe or density may be present with suspected pulmonary hypoplasia should have an on lateral view of the chest and is characteristic for lobar echocardiogram to assess for congenital cardiac defects as well as

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to assess pulmonary venous drainage. Chromosomes should be 14. Swischuk L. . Imaging of the Newborn, Infant, and sent if there are multiple anomalies. The long-term prognosis is Young Child. 4th ed. Philadelphia, PA: Lippincott Williams & Wilkins; 1997. directly related to the degree of pulmonary hypoplasia and presence p. 56–62. of comorbidities. 15. Thomas RJ, Lathif HC, Sen S, Zachariah N, Chako J. Varied presentations of unilateral lung hypoplasia and agensis: a report of four cases. Pediatr Surg Int 1998;14:94–5. References 16. Wu C, Chen M, Shih S, Huang F, Hou S. Case report: agenesis of the right 1. Wigglesworth J, Desai R. Is fetal respiratory function a major determinant of lung diagnoses by three-dimensional reconstruction of helical chest CT. Br J perinatal survival? Lancet 1982;i:264–7. Radiol 1996;69:1052–4. 2. Ashkenazi S, Perlman M. Pulmonary hypoplasia: lung weight and radial 17. Argent A, Cremin B. Computed tomography in agenesis of the lung in alveolar count as criteria of diagnosis. Arch Dis Child 1979;54:614–8. infants. Br J Radiol 1992;65:221–4. 3. Hussein A, Hessel R. Neonatal pulmonary hypoplasia: an autopsy study of 18. Nakamura Y, Harada K, Yamamoto I, et al. Human pulmonary hypoplasia: 25 cases. Pediatr Pathol 1993;13:475–84. statistical, morphological, morphometric, and biochemical study. Arch 4. Moessinger A, Santiago A, Paneth N, Rey H, Blanc W, Driscoll J. Time trends Pathol Lab Med 1992;116:635–42. in necroscopy prevalence and birth prevalence of lung hypoplasia. Pediatr 19. Felson B. Pulmonary agenesis and related anomalies. Semin Roentgenol Perinat Epidemiol 1989;3:421–31. 1972;7:17–30. 5. Knox W, Barson A. Pulmonary hypoplasia in a regional perinatal unit. 20. Hoffman M, Superina R, Wesson DE. Unilateral pulmonary agenesis with Early Hum Dev 1986;114:33–42. and distal trachoesophageal fistula: report of two cases. 6. Page D, Stocker J. Anomalies associated with pulmonary hypoplasia. Am J Pediatr Surg 1989;24:1084–5. Rev Respir Dis 1982;125:216–21. 21. Knowles S, Thomas R, Lundenbaum R, Keeling J, Winter R. Pulmonary 7. Porter H. Pulmonary hypoplasia. Arch Dis Child Fetal Neonatal Ed agenesis as part of the VACTERL sequence. Arch Dis Child 1988;63:723–6. 1999;81:81F–3F. 22. Osbourne J, Masel J, McCredie J. Spectrum of skeletal anomalies associated 8. Benson J, Olsen M, Fletcher B. A spectrum of bronchopulmonary anomalies with pulmonary agenesis: possible neural crest injuries. Pediatr Radiol associated with tracheoesophageal malformations. Pediatr Radiol 1989;19:425–32. 1985;15:377–80. 23. Renert W, Berdon W, Baker D, Rose J. Obstructive urologic malformations of F 9. Sbokos C, McMillan I. Agenesis of the lung. Br J Dis chest 1977;71:183–97. the and infant relation to neonatal pneumomediastinum and 10. Nowotny T, Ahrens B, Bittigau K, et al. Right-sided pulmonary aplasia: penumothorax. Radiology 1972;105:97–105. longitudinal lung function studies in two cases and comparison to results 24. Steadland K, Langham M, Greene M, Bagwell C, Kays D, Talbert J. from healthy term neonates. Pediatr Pulmonol 1998;26:138–44. Unilateral pulmonary agenesis, esophageal atresia, and distal tracheoeso- 11. Schwartz M, Ramachandran P. Congenital malformations of the lung and phageal fistula. Ann Thorac Surg 1995;59:511–3. mediastinum F a quarter century of experience from a single institution. 25. Brenner V. Unilateral pulmonary hypoplasia/agenesis in the neonate: a case J Pediatr Surg 1997;32:44–7. report. Neonat Netw 1987;12:49–57. 12. Cremin B, Bass E. Retrosternal density: a sign of pulmonary hypoplasia. 26. Booth J, Berry C. Unilateral pulmonary agenesis. Arch Dis Child Pediat Radiol 1975;3:145–7. 1967;42:361–74. 13. Becmeur F, Horta P, Donato L, Savage P. Accessory diaphragm F review of 27. Sherer D, Davis J, Woods JR Jr. Pulmonary hypoplasia: a review. Obstet 31 cases in the literature. Eur J Pediatr Surg 1995;5:43–7. Gynecol Surv 1990;45:792–803.

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