IMAGES IN THORAX

Tracheal bronchus in a 6-month-old infant identified by CT with three-dimensional airway reconstruction

W A Gower¹, S A McGrath-Morrow¹, K D MacDonald¹, E K Fishman²

¹ Eudowood Division of Pediatric Respiratory Sciences, Johns Hopkins Medical Institutions, Baltimore, Maryland, USA
² Russell H Morgan Department of Radiology, Johns Hopkins Medical Institutions, Baltimore, Maryland, USA

Correspondence to:
Dr Sharon McGrath-Morrow, Eudowood Division of Pediatric Respiratory Sciences, Johns Hopkins Hospital, 200 North Wolfe Street, Third Floor, Baltimore, Maryland 21287, USA; smorrow{at}jhmi.edu

A 6 month old infant presented with a history of cough and noisy breathing since 5 weeks of age. He had been evaluated many times in a local emergency department for episodes of cough, wheeze and retractions. His parents reported that his symptoms seemed to be worse when he was supine and did not respond well to steroids or bronchodilators. He had been feeding and growing normally.

On examination he was slightly tachypnoeic with mild subcostal retractions and coarse upper airway sounds. He was admitted for observation and underwent CT scanning of the chest and neck with intravenous contrast followed by three-dimensional reconstruction and virtual bronchoscopy. This revealed a right sided tracheal bronchus arising 1.2 cm above the carina, comparable in size to the right mainstem bronchus (figs 1 and 2).

View larger version (110K): in this window | in a new window | PowerPoint for Teaching   Figure 1 Three-dimensional reconstruction of airway and lungs from neck and thoracic CT scan showing right sided tracheal bronchus arising 1.2 cm above the carina.

 

View larger version (132K): in this window | in a new window | PowerPoint for Teaching   Figure 2 Detail from box in fig 1 showing a closer view of the tracheal bronchus (TB) and carina (C).

 

Scanning was performed on a 64-slice multidetector CT scanner (Siemens Sensation 64) using low dose paediatric protocols for minimum patient dose. Specific scan parameters included CARE Dose software (Siemens) with kV 120 and mAs 60. Slice thickness was 0.75 mm from 0.6 mm detectors and scan reconstruction was at 0.5 mm intervals. The effective radiation dose to a patient of this size can be as high as 4.6 mSv using these parameters. The risks and costs of such a study must be weighed against those of bronchoscopy under sedation, the usual means of making the diagnosis.

An incidence of up to 2% has been reported for tracheal bronchus.¹ The term "pig bronchus" or "bronchus suis" is used when the entire right upper lobe bronchus stems from the trachea. Congenital tracheobronchial abnormalities may be asymptomatic and discovered as incidental findings or may present with stridor, recurrent pneumonia or atelectasis.² Expectant management is preferred and surgical resection is typically reserved for patients with severe or persistent symptoms.

The patient was discharged from hospital with medical treatment for gastro-oesophageal reflux. His symptoms resolved over the course of 2 months.

ACKNOWLEDGMENTS

TOP ACKNOWLEDGMENTS REFERENCES

The authors thank Dr Mahadevappa Mahesh for his assistance with radiation dose calculation.

FOOTNOTES

Competing interests: None.

REFERENCES

TOP ACKNOWLEDGMENTS REFERENCES

1. Ghaye B, Szapiro D, Fanchamps JM, et al. Congenital bronchial abnormalities revisited. Radiographics 2001; 21: 105–19.[Abstract/Free Full Text]
2. Sanchez I, Navarro H, Mendez M, et al. Clinical characteristics of children with tracheobronchial anomalies. Pediatr Pulmonol 2003; 35: 288–91.[CrossRef][Medline]

CiteULike    Complore    Connotea    Del.icio.us    Digg    Reddit    Technorati    What's this?