Hepatic cyst infection complicated by a hepatobronchial fistula diagnosed with unique features

A hepatobronchial fistula (HBF) is a rare condition, defined as an abnormal connection of the respiratory system with the liver parenchyma. Although imaging may be helpful for diagnosis, fistulae are often difficult to identify. An 81-year-old woman presented with mild fever and right upper quadrant abdominal pain. Computed tomography (CT) showed bilateral pneumonia and hepatic cyst infection with air-fluid levels. After mechanical ventilation, abdominal CT showed increased air in the hepatic cyst. The drainage bag for the hepatic cyst infection was also inflated by positive pressure ventilation, suggesting a possible HBF. The ventilator was adjusted to minimize pressure on the fistula and prevent retrograde infection. The fistula eventually closed spontaneously. Appropriate antibiotic treatment and continuous drainage resulted in improvement of the hepatic cyst infection; however, the patient died due to respiratory complications. HBF should be suspected when positive pressure ventilation results in increased air at the hepatic infection site.