2 Discussion
CBBF is a rare disease with congenital abnormal connection between the hepatic duct and trachea or bronchus. The age of onset and severity of symptoms depend on the diameter of the fistula. Therefore, the symptoms appear at any age from newborn to adults[9,10,29]. Typical clinical feature of CBBF is bilious sputum or bile-stained sputum in tracheal intubation. Patients usually have chronic wet coughing, recurrent wheezing, shortness of breath and growth retardation[12]. CBBF has usually been misdiagnosed as an esophagotracheal fistula, gastroesophageal reflux, aspiration pneumonia, tracheoesophageal fistula or high intestinal obstruction[30,31].
In 1952, Neuhauser et al[29] reported the first case of CBBF. Up to now, 27 cases have been enrolled in English and Chinese (Table 1). Among them, fourteen (51.8%) cases were diagnosed in the neonatal period, nine (33.3%) were diagnosed in infancy, four (14.8%) were diagnosed in puberty or adulthood. The common manifestations were biliary sputum (24/27, 88.9%), recurrent pneumonia (9/27, 33.3%) and bilious vomiting (7/27, 22.2%). CBBF was more common in female (19/27, 70.3%). The abnormal fistula originates different location around the carina: right main bronchus (21/27, 77.8%), left main bronchus (3/27, 11.1%), right intermediate bronchus (2/27, 7.4%), and bilateral main bronchus (1/27, 3.7%).
The mechanism of CBBF formation is not clearly clarified. However, there are two possible speculated mechanisms. One is considered as the duplication of the upper gastrointestinal tract, which growing between the laryngotrachea and hepatic diverticulum; the other is believed to be the fusion between abnormal bronchial buds and abnormal bile ducts[20,26]. The pathological results in our case consistent with the latter pathogenesis.
The detection of bilirubin crystallization in sputum or/and BALF plays crucial role in CBBF diagnosis[4,5,11-14,29,31]. Furthermore, abnormal fistula was easily found via bronchoscopy. In this case, the bilirubin detection was positive in the BALF and the location of the fistula connection was confirmed via bronchoscopy and fistula angiography, which provided more comprehensive information and was verified intraoperatively.
Chest CT and airway reconstruction, MRI or isotope examination can find an abnormal fistula from the trachea, through the diaphragm, into the abdominal cavity, and liver lobes communicate with each other[15]. Intraoperative management of fistula could base on preoperative isotope examination[32]. Liu AH et al[31] indicated gas accumulation in the lumen of the right hepatic duct and the gallbladder lumen by hepatobiliary B-ultrasound, which provided clues for clinical diagnosis of BBF.
Patients with CBBF are ineffective to routine treatment and require operation to remove the fistula. If the bile drainage is normal, only thoracic fistula resection can be performed[33,34]; there also has reports of resection of thoracic and abdominal fistulas [13]. Fistula-jejunostomy Roux-en-Y anastomosis, hilar-jejunostomy, or Cholecystojejunostomy can be performed to fully drain bile so as to avoid fistula recurrence for cases with biliary malformation, such as absence of common bile duct, abnormal bile-intestinal drainage[14].
As surgery has higher cost and more damage, interventional therapy is alternative for CBBF patients without severe biliary malformation. The bronchial occlusion with biological glue has achieved good results in the treatment of adult respiratory diseases[35,36]. Tissue glue occlusion via bronchoscopy also have been used in the treatment of adult secondary bronchobiliary fistulas[36-38]. Chen X et al[7] successfully cured the pediatric patient with congenital brachobiliary fistula for the first time via bronchoscopy. The interventional treatment via bronchoscopy in patients with bronchobiliary fistula requires respiratory intervention doctors to achieve further breakthroughs in future.
Combined this case and literature review, twenty-three (85.2%) patients recovered after operation, four (14.8%) patients died from severe comorbidities (biliary dysplasia (n=1), biliary atresia(n=1), congenital diaphragmatic hernia(n=1), esophageal atresia and/or tracheoesophageal fistula (n=1)). Two cases had complications (pneumothorax (n=1), septicemia(n=1)). one case with no surgery. CBBF patients with delayed or no operation, severe biliary malformation, or severe postoperative complications have poor prognosis[17,23,24,28].