Recurrent Respiratory Tract Infections and Dysphagia in a Child with an Aortic Vascular Ring.

ABSTRACT: Recurrent respiratory tract infections and dysphagia after the first years of life are rarely caused by vascular rings, and only a high index of clinical suspicion helps to avoid diagnostic delay and inappropriate treatment. Diagnostic workup in a 2-year-old girl with acute foreign body impaction into the esophagus and frequent respiratory tract infections revealed right descending aortic arch with ligamentum arteriosum as the cause of extrinsic esophagealtracheal compression. Dividing the ligament gave release to the encircled esophagus and trachea. Relief of symptoms was achieved immediately after surgery.

Vascular rings caused by anomalies of the aortic arch and its branches generally present with respiratory distress, dyspnea, stridor, and swallowing difficulties shortly after birth. Less commonly, vascular rings have been proved to be the cause of recurrent respiratory tract difficulties and dysphagia later in life, without symptoms in early infancy. Diagnosis becomes more difficult and may be delayed for years in infants with less specific symptoms. We describe a 2-year-old girl in whom diagnostic workup of a foreign body impaction in the esophagus and recurrent respiratory tract infections revealed tracheal compression and impression of the esophagus due to a right aortic arch and ligamentum arteriosum.

CASE REPORT

A 2-year-old girl was admitted to the hospital because of an acute episode of foreign body impaction in the esophagus. After having ingested a large bit of sausage, she had excess drooling, vomiting, and dysphagia, as well as respiratory difficulties (choking, coughing, wheezing). A detailed medical history revealed frequent respiratory tract infections since the age of 1 year, but she had never had stridor or respiratory distress. With the introduction of solid food, she increasingly developed swallowing difficulties (esophageal vomiting, regurgitation, dysphagia, failure to thrive). During the 3 months before admission, she had had two episodes of pneumonia with atelectasis of the middle lobe, for which she was treated with antibiotics, bronchodilators, and physiotherapy.

At the time of admission, the girl was in good general condition and showed stable respiratory status. A barium study of the esophagus showed a complete stop at the site of the physiologic second constant bronchoaortic constriction. Esophagoscopy, done with general anesthesia, confirmed the impacted large bit of sausage that had led to complete occlusion of the esophageal lumen. The foreign body was removed in pieces, and this maneuver freed the passage for the scope into the stomach. There were no signs of a mucosal lesion, granulation tissue, or stenosis at the site of impaction.

After recovery, further evaluation was done because of the conspicuous medical history. Barium esophagogram revealed a deep persistent impression on the posterior aspect of the esophagus and gave reason to presume an aortic arch anomaly (Fig 1). Magnetic resonance imaging (MRI) confirmed our suspicion but did not help to distinguish the exact configuration of the anomaly. Therefore, we did an angiography in a two-dimensional imaging modality, which showed a right descending aorta with a ligamentum arteriosum and mirror branching (Fig 2). Bronchoscopy showed anterior-lateral compression from the right side in the distal part of the trachea.

The patient was operated on through a left-sided thoracotomy. After careful dissection of the aortic arch and its branches, the ligamentum arteriosum could be easily divided (Figs 3 and 4). This gave release to the encircled esophagus and trachea. Postoperative recovery was uneventful, and during a follow-up period of 5 years, the girl has had no further episodes of dysphagia or foreign body impaction. Respiratory tract infections have since decreased in number and severity, and repeated esophagography showed the release of the previously shown posterior dentation.

DISCUSSION

Recurrent upper airway symptoms and dysphagia are common in infancy and childhood, and the workup must include a wide range of differential diagnostic possibilities. (1,2) Extrinsic compression of the airway and esophagus caused by a vascular ring is an uncommon cause of respiratory tract disorders in children, and clinical presentation will depend on the severity of narrowing. (1,2) Severe obstruction leads to respiratory distress and stridor shortly after birth, whereas less serious lumen compromise can be manifested months or years later with rather unspecific clinical signs and symptoms (eg, wheezing, intermittent stridor, recurrent pneumonia, respiratory difficulties associated with feeding, dysphagia, failure to thrive). Some patients with a vascular ring could be asymptomatic their entire life and have the malformation discovered incidentally. It might take years before the association between vascular rings and recurrent respiratory tract infections is recognized. Therefore, a high index of clinical s uspicion is required to avoid missed diagnosis and therapeutic delay. (3-5)

Aortic arch anomalies are the result of abnormal embryologic development with patency of a vascular segment that should have normally regressed. (5) Many pathoanatomic variations must be considered during evaluation. (5,6) Right aortic arch with left-sided ligamentum arteriosum was thoroughly studied in the 1930s by Fray (7) and in the 1940s by Neuhauser (8) and thus has been termed "Neuhauser's anomaly." (5,7-9) Characteristic features consist of the ascending aorta lying in normal position, with the horizontal part of the aortic arch running to the right of the trachea and esophagus (Fig 3). The descending aorta might turn variably either to the right or to the left side. The ligamentum arteriosum extends from the left pulmonary artery to the aorta at the isthmus and encircles and compresses the esophagus and trachea (Figs 3 and 4). Variations occur with respect to the course of the arch and branching pattern (eg, mirror branching, aberrant left subclavian artery, isolated left subclavian artery). In the ty pe with mirror branching, the first branch of the arch is the left innominate artery, which is followed by the right carotid and the right subclavian artery (Fig 2). Right aortic arch could be associated with left aortic dilatation in retroesophageal position, the ligamentum arteriosum entering this diverticulum (Kommerel). Presence of a diverticulum may result in additional compression of the esophagus. (5,7-9) Neuhauser's anomaly can be confused with the picture of a double aortic arch, an anomalous left innominate subclavian artery, or a pulmonary artery sling.

Various diagnostic techniques can be used to confirm and identify tracheoesophageal compression by anomalies of the aortic arch. Initial evaluation of suspected aortic arch anomalies includes chest radiogram and barium esophagogram, followed by MRI and computed tomography (CT), bronchoscopy, and angiography. (5,10-12) The radiographic findings can be subtle and rather similar in all cases of vascular ring. The major part of the aorta and aortic arch is on the right side of the midline. Special attention should be paid to the radiologic outlines of the trachea with a possible narrowing from the right on the lower part of the trachea. Many authors, however, consider the chest x-ray film to be of limited value. In larger series of chest radiographs in infents with vascular rings, only 20% of cases showed remarkable narrowing of the trachea. (13)

Barium esophagography is the most reliable diagnostic step. The vascular ring produces a deep persistent indentation of the posterior esophagus. This filling defect is caused by the ligamentum arteriosum. Bilateral persistent impression is usually present with a double aortic arch. (5,6,10-12)

In infants with suspected extrinsic tracheoesophageal compression, bronchoscopy is generally necessary to confirm the location and severity of the obstruction. One must recognize that vascular rings are often associated with tracheal anomalies (eg, lack of the membranous part of the wall, tracheomalacia, dyskinesia). In Neuhauser's anomaly, endoscopy reveals a defect on the right anterior side of the trachea at the level of the aortic arch. Bronchoscopy can also be used to evaluate the repair site after surgical correction.

Echocardiography can be useful as a screening method for demonstrating aortic anomalies in infants but is more valuable in ruling out associated cardiac malformations, which are found in up to 63% of cases (eg, tetralogy of Fallot, ventricular septal defect, coarctation of the aorta) (5,10,11)

Biplane angiography will be reserved for difficult cases and can clearly exhibit the course of the aorta with the arch on the right side and the thoracic aorta descending on the right. In the mirror type, there is reversal of the aortic arch branches so that the left-sided innominate artery arises as the first branch and divides into a left subclavian and left common carotid. No visualization of the ductus arteriosus is obtained, since this structure is closed. (5,11,12)

Increasing evidence indicates that CT or MRI may replace other modalities as the procedure of choice for definitive evaluation of vascular rings. Magnetic resonance imaging provides accurate information in evaluating external vascular airway compression, demonstrating the level, severity, and exact cause of the compression. Magnetic resonance imaging also provides additional anatomic details of nonvascular structures and their relationship to the vascular anatomy. In particular, coronal and sagittal images can be helpful in confusing cases. Spiral CT with angiographic reconstruction might be just as effective in these patients. Sedation or anesthesia is often required for performing MRI in infants and young children. (14-17)

The severity of the symptoms warrants surgical exploration for release of the vascular ring. Surgical exploration with division of the ligamentum arteriosum is done to free the vascular structures, resulting in complete relief of stridor and dysphagia. In the case of Kommerell diverticulum, the diverticulum must be excised completely, otherwise esophageal compression will persist to some degree. (5,6) Relief of symptoms is achieved immediately after surgery in 43%. Functional troubles disappear and respiratory function becomes normal in 90% of children during postoperative follow-up. (4,6,8) The trachea that has been compressed over a long period does not always immediately return to normal size and function, but it usually will with time.

CONCLUSION

Prolonged or recurrent respiratory complaints or dysphagia in early infancy or childhood should alert the pediatrician to the possibility of a vascular ring. The absence of symptoms early in life does not rule out the possibility of a vascular ring. Diagnosis of a vascular ring can be established with certainty by chest radiography and barium esophagography, with additional imaging techniques (CT, MRI, or angiography) when needed.

From the Division or Pediatric surgery, University of Vienna, and the Department of Pediatrics, Donauspital-SMZO, Vienna.

Reprint requests to wolfgang Pumberger, MD, University of Vienna, Division of Pediatric Surgery, Waehringer Guertel 18-20, A-1090 Vienna/Wien, Austria.

References

(1.) Myers NA: Esophageal disorders associated with emesis in infants and children. Semin Pediatr Surg 1995; 4:166-175

(2.) Bentz BG, Dunham ME: Extrinsic tracheobronchial compression. Curr Opin Otolaryngol Head Neck Surg 1998; 6:368-372

(3.) Van Aalderen WMC, Hoekstra MO, Hess J, et al: Respiratory infections and vascular rings. Acta Paediatr Scand 1990; 79:477-480

(4.) Bakker DAH, Berger RMF, Witsenburg M, et al: Vascular rings: a rare cause of common respiratory symptoms. Acta Paediatr 1999; 88:947-952

(5.) Langlois J, Binet JP, De Brux JL, et al: Aortic arch anomalies. Current Topics in General Thoracic Surgery: Pediatric Thoracic Surgery. Fallis JC, Filler RM, Lemoine C (eds). New York, Elsevier Science Publishing Co Inc, 1st Ed, 1991, pp 172-191

(6.) Backer CL, Iblawi MN, Idriss FS, et al: Vascular anomalies causing tracheoesophageal compression: review of experience in children. J Thorac Cardiovasc Surg 1989; 97:725-731

(7.) Fray WW: Right aortic arch. Radiology 1936; 26:27-36

(8.) Neuhauser EBD: Tracheo-esophageal constriction produced by right aortic arch and left ligamentum arteriosum. Radiology 1949; 62:493-499

(9.) Knight L, Edwards JE: Right aortic arch: types and associated cardiac anomalies. Circulation 1974; 50:1047-1051

(10.) Lowe GM, Donaldson JS, Backer CL: Vascular rings: 10-year review of imaging. Radiographics 1991; 11:637-646

(11.) Van Son JAM, Julsrud PR, Hagler DJ, et al: Imaging strategies for vascular rings. Ann Thorac Surg 1994; 57:604-610

(12.) Neuhauser EBD: The roentgen diagnosis of double aortic arch and other anomalies of the great vessels. Am J Roentgenol 1946; 56:1-12

(13.) Pickardt PJ, Siegel MJ, Gutierrez FR: Vascular rings in symptomatic children: frequency of chest radiographic findings. Radiology 1997; 203:423-426

(14.) Azarow KS, Pearl RH, Hoffman MA, et al: Vascular ring: does magnetic resonance imaging replace angiography? Ann Thorac Surg 1992; 53:882-885

(15.) Beekman RP, Hazekamp MG, Sobotka MA, et al: A new diagnostic approach to vascular rings and pulmonary slings: the role of MRI. Magn Reson Imaging 1998; 16:137-145

(16.) Rimell FL, Shapiro AM, Meza MP, et al: Magnetic resonance imaging of the pediatric airway. Arch Otolaryngol Head Neck Surg 1997; 123:999-1003

(17.) Hopkins KL, Patrick LE, Simoneaux SF, et al: Pediatric great vessel anomalies: initial clinical experience with spiral CT angiography. Raidology 1996; 200:811-815

RELATED ARTICLE: KEY POINTS

* Frequent respiratory tract infections and dysphagia in early childhood may be caused by vascular rings.

* Clinical presentation of vascular rings depends on severity of narrowing.

* Diagnostic workup requires a clear concept, including all modern imaging modalities (radiography, computed tomography, and magnetic resonance imaging).

* A high index of suspicion helps to avoid missed diagnosis and therapeutic delay.