RESUMEN
Thoracic radiography and abdominal ultrasonography are part of standard diagnostic investigations in cases of canine immune-mediated polyarthritis (IMPA). However, the clinical importance of thoracic and abdominal imaging towards the management of canine IMPA currently remains unknown. The primary aim of this study was to describe the findings documented on thoracic radiography and abdominal ultrasonography in dogs diagnosed with IMPA, and to evaluate the diagnostic utility of thoracic radiography and abdominal ultrasonography in the initial approach and management of these cases. Seventy-seven dogs diagnosed with IMPA who underwent thoracic radiography and abdominal ultrasonography at a single referral hospital between 2008 and 2022 were included. The diagnostic imaging studies of these 77 dogs were reviewed by one blinded board-certified diagnostic imaging specialist for quality assurance. The medical records, including the diagnostic imaging reports of these dogs, were then reviewed by three blinded board-certified internal medicine specialists. Using a modified version of a previous question and scoring system, the three internal medicine specialists then generated an answer for the overall diagnostic utility and a diagnostic utility score for thoracic radiography and abdominal ultrasonography for each case. The abnormal findings identified in radiography and ultrasonography were described. In the cases where the findings were considered significant enough to immediately affect the case management, the results of the further investigations that were subsequently performed were also described. No abnormalities were detected in thoracic radiography for 30 cases, and none were detected in abdominal ultrasound for 6. The majority of the internists considered thoracic radiography to be not useful in the overall case management at the time of IMPA diagnosis in 70 cases, and considered abdominal ultrasonography to be not useful in the overall case management in 57 cases. The majority of the internists agreed on the utility of thoracic radiography in 95% of the cases, and in 61% of the cases for abdominal ultrasonography. The most common finding in the thoracic radiography was a mild bronchial pulmonary pattern, and the most common in the abdominal ultrasonography was mild lymphadenomegaly. Therefore, although thoracic radiography and abdominal ultrasonography identified numerous abnormal findings in this population of dogs, in the majority of the cases, the findings were deemed not useful towards the overall case management at the time of the initial diagnosis of IMPA. Thus, the use of thoracic radiography and abdominal ultrasonography should be taken into careful consideration when considering initial diagnostic investigations for canine IMPA.
RESUMEN
The most common bacterial isolates in dogs with pyothorax include mixed anaerobes, Enterobacteriaceae (especially Escherichia coli), Pasteurella spp., Streptococcus spp., and Staphylococcus spp. A fluoroquinolone with amoxicillin (±clavulanate) or a fluoroquinolone with clindamycin are the most commonly recommended empirical antimicrobials whilst pending bacterial culture of the pleural effusion. The aim of this study is to review and compare the pleural effusion culture and antimicrobial susceptibility results to the PROTECT ME poster and other published antimicrobial use guidelines. The medical records of 53 dogs diagnosed with pyothorax between 2014 and 2020 at two veterinary referral centres were reviewed. Information, including culture and susceptibility results, was assessed. Antimicrobial susceptibility panels varied; susceptibility to a particular antibiotic was calculated as a percentage of isolates tested against the same antibiotic. A total of 30 of 53 dogs (57.7%) had a positive pleural fluid culture. The most common isolates were Pasteurella species (23.3%), Escherichia coli (23.3%), and mixed anaerobes (20%). From the aerobic isolates, 73-83% were susceptible to a fluoroquinolone, 14/19 (74%) to amoxicillin, and 20/22 (91%) to potentiated amoxicillin. Resistance to clindamycin was documented in 9/13 (69%) aerobic isolates, with all Gram-negative bacteria (9/9) being resistant. The combination of potentiated amoxicillin with marbofloxacin would have been appropriate in most of the dogs (75-92.9%). This study shows a high rate of resistance to clindamycin, which is not a suitable option for monotherapy and may be less effective in combination therapy compared to potentiated amoxicillin.
