Lung ultrasonography findings in dogs with various underlying causes of cough

To characterize lung ultrasonography (LUS) findings in dogs with a primary clinical complaint of cough.

100 client-owned coughing dogs.

A standardized LUS examination was performed for all dogs to quantify the number of B lines and identify subpleural abnormalities at 4 sites on each hemithorax. The final clinical diagnosis (reference standard) was determined by medical record review, and sensitivity and specificity of LUS for the diagnosis of selected causes of cough was determined.

Common underlying causes of cough included dynamic airway collapse (n = 37), cardiogenic pulmonary edema (CPE; 12), and bronchitis (10). Compared with dogs with other causes of cough, dogs with bacterial pneumonia (n = 7) were more likely to have subpleural shred signs, whereas dogs with pulmonary neoplasia (4) were more likely to have subpleural nodule signs. Dogs with CPE had higher total B-line scores and higher numbers of LUS sites strongly positive for B lines (> 3 B lines/site) than other dogs. The LUS criteria of total B-line score ≥ 10 and presence of ≥ 2 sites strongly positive for B lines were each 92% sensitive and 94% specific for CPE diagnosis. Notably, 18% (16/88) of dogs with noncardiac causes of cough had been treated previously with diuretics because of prior CPE misdiagnosis.

LUS profiles in dogs with cough differed by the underlying cause. In dogs with a clinical history of cough, this imaging modality could be diagnostically useful, particularly to help exclude the possibility of underlying CPE.