Fluoroscopic characteristics of tracheal collapse and cervical lung herniation in dogs: 222 cases (2012-2015)

This retrospective study included 222 dogs suspected to have tracheal collapse (TC) and examined between 1 January 2012 and 31 December 2015. Fluoroscopic and radiographic images and medical records were evaluated to investigate the fluoroscopic characteristics of TC and cervical lung herniation (CLH), and to determine their relationships to various influencing. Grade of TC, existence of tracheal kinking, location of CLH (right or left side), and grade of CLH were evaluated fluoroscopically. One hundred ninety-nine dogs (89.6%) were diagnosed with TC. Presence of TC was not associated with the patients' cough history; however, CLH was positively correlated with cough history (odds ratio [OR], 2.896; 95% confidence interval [CI], 1.556 to 5.390) and was affected by tracheal kinking (OR, 3.841; 95% CI, 1.884 to 7.831). Chronic cough was not related with CLH. Since TC can be observed in patients without a history of cough, presence of TC should be ruled out by using physical examination and diagnostic imaging. Although CLH is associated with a history of cough, it is a common appearance in dogs, and transient coughing can elicit CLH in patients without a history of cough.