Indian J Pediatr (2010) 77:1037–1038 DOI 10.1007/s12098-010-0162-6
PEDIATRIC RADIOLOGY
Tracheal Bronchus (Pig Bronchus) Y. C. Manjunatha & Arun Kumar Gupta
Received: 17 June 2010 / Accepted: 17 June 2010 / Published online: 26 August 2010 # Dr. K C Chaudhuri Foundation 2010
A five-months-old baby boy presented with acute onset of fever, cough, difficulty in breathing and stridor. On examination baby was febrile and tachypnic. Mother gave history of recurrent respiratory tract infections since birth. Routine hematological investigations showed leucocytosis.
Imaging Findings
Fig. 1 a Chest radiograph frontal view showing airspace opacities in the right upper lobe and the abnormal bronchus seen arising from the trachea few centimeters above the carina and supplying upper lobe on right side (arrow), b Axial CT image of lung window showing consolidation with air bronchogram in the right upper lobe with an abnormal bronchus (arrow) directly arising from the trachea (arrow) suggestive of tracheal bronchus (pig bronchus). Coronal minimum intensity projection image c and CT virtual bronchoscopy image d better delineates the tracheal bronchus. Note the tracheal bronchus is arising 2 cm above the carina Y. C. Manjunatha : A. K. Gupta (*) Department of Radiodiagnosis, AIIMS, New Delhi, India e-mail:
[email protected]
Discussion The tracheal bronchus is defined as a bronchial anomaly originating from the trachea or either main bronchus and directed to the upper lobe territory. These are classified [1, 2] either as displaced bronchus (when one branch of upper lobe bronchus is missing) or supernumerary bronchus (when normal branching of upper lobe is present) (Fig. 1). Any bronchus originating from the trachea between 2 cm to 6 cm from the carina and supplying the entire right upper lobe is called “true tracheal bronchus” or “bronchus sui” (or “pig bronchus” because that is the normal morphology in pigs). The incidence of true tracheal bronchus is 0.2%. Majority of these cases are asymptomatic but may present with recurrent local infections, persistent cough, stridor, acute respiratory distress, and hemoptysis. The tracheal bronchus may be associated with other anomalies which include azygos lobe, partial anomalous pulmonary venous return and displaced segmental arteries. Chest radiograph is the initial radiological investigation and it may show bronchus directly arising from the trachea, as was seen in our case. CT is imaging modality of choice as it depicts the exact tracheal and bronchial anatomy. Computed tomography virtual bronchoscopy (CTVB) is a technique in which simulated endobronchial views are generated from volumetric CT data and are helpful in the detection of endobronchial lesions, evaluation of focal stenosis, and their longitudinal extent [1]. It is important to identify the tracheal bronchus in patients undergoing cardiac surgery with one lung ventilation since serious hypoxia and atelectasis may occur if not diagnosed preoperatively [3]. In case of recurrent pneumonia complicated by bronchiectasis surgical resection of the anomalous lobe or segment is the treatment of choice [4]. Teaching Point Tracheal bronchus is an important rare congenital abnormality of airway. In addition to the conventional axial CT scan images, multiplanar reconstruction images, volume
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rendering images, minimum intensity projection images and virtual bronchoscopy images depicts exact anatomy of airway which helps in the diagnosis and management of the tracheal bronchus and its complications. References 1. Ghaye B, Szapiro D, Fanchamps JM, Dondelinger RF. Congenital bronchial abnormalities revisited. Radiographics. 2001;21(1):105–19.
Indian J Pediatr (2010) 77:1037–1038 2. Foster-Carter AF. Broncho-pulmonary abnormalities. Br J Tuberc. 1946;40:111–24. 3. Iwamoto T, Takasugi Y, Hiramatsu K, Koga Y, Konishi T, Kozuka K, et al. Three-dimensional CT image analysis of a tracheal bronchus in a patient undergoing cardiac surgery with one-lung ventilation. J Anesth. 2009;23(2):260–5. 4. Doolittle AM, Mair EA. Tracheal bronchus: classification, endoscopic analysis, and airway management. Otolaryngol Head Neck Surg. 2002;126:240–3.
