Lung ultrasonography findings in dogs with various underlying causes of cough

Abstract

OBJECTIVE To characterize lung ultrasonography (LUS) findings in dogs with a primary clinical complaint of cough. ANIMALS 100 client-owned coughing dogs. PROCEDURES 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. RESULTS 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. CONCLUSIONS AND CLINICAL RELEVANCE 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.

Usefulness of Chest Ultrasonography in Predicting Diagnosis in Non-emergency Small Animal Patients With Lung Parenchymal and Pleural Disease

“…The diagnostic value of ultrasound-guided fineneedle aspiration/biopsy of consolidated pulmonary lesions or thoracocentesis for effusion drainage has been reported in earlier studies and case reports (1,16,18,19). A recent study focusing on coughing dogs reported that subpleural shred signs and nodule signs were more often present in dogs with bacterial pneumonia and pulmonary neoplasia, respectively (15). These findings imply that the utility of chest ultrasonography in small animal patients warrants further attention and investigations.…”

“…Comet-tail artifacts, shown in 88% of cases, was the most prevalent finding among all sonographic abnormalities in the present study. The application of using the severity of comet-tail artifacts, so-called B line on the point-of-care lung ultrasound, to help determine the presence of cardiogenic pulmonary edema in dogs and cats has been evaluated in recent years (11)(12)(13)15). The generation of comet-tail artifacts is caused by the impedance gradient between fluid/tissue and surrounding air; thus, any alveolar or interstitial pulmonary pathology can result in this type of artifacts (14).…”

“…In this study, convex probes were primarily used, and sector and linear probes were occasionally used, depending on the operator's preference, equipment availability, and body size of the animals. Various types of ultrasound probes were used in previous studies in dogs and cats, including sector (7-7.5 MHz) (1,16,17), convex (4-10 MHz) (7, 13), linear (2.4-15 MHz) (9)(10)(11)16), and curvilinear (5-8 MHz) (8,(12)(13)(14)(15) probes. The advantage of using a linear probe is the increase in the resolution of near-field structures, which caused impaired penetration of lesions at deeper location in a consolidated lung or within a large effusion (4,23).…”

“…For dogs and cats with respiratory distress, point-of-care lung ultrasound is a clinically useful and easily available tool for the purpose of initial assessment in emergency room and intensive care unit (5)(6)(7). The presence/absence and characteristics of comet-tail artifacts (also known as lung rockets, ring-down artifacts, or B line) on lung ultrasound have currently been evaluated for diagnostic performance in canine and feline patients with various emergency conditions, including lung contusion, pneumothorax, cardiogenic pulmonary edema, and alveolar-interstitial syndrome (8)(9)(10)(11)(12)(13)(14)(15).…”

“…Other sonographic features that have also been described as abnormal findings of thoracic ultrasound in dogs and cats include the presence of pleural effusion, subpleural nodule, pulmonary mass, consolidation, atelectasis, and ruptured diaphragm (1,13,(15)(16)(17). The diagnostic value of ultrasound-guided fineneedle aspiration/biopsy of consolidated pulmonary lesions or thoracocentesis for effusion drainage has been reported in earlier studies and case reports (1,16,18,19).…”