for evaluation of a 2-month history of a cough, lethargy, and progressive inappetence. The cough was occasionally productive and occurred multiple times a day. Results of routine CBC and blood chemistry tests performed by the referring veterinarian were unremark-able, and thoracic radiographs revealed right cranial lung lobe consolidation and hilar lymphadenopathy. The dog was treated with amoxicillin (25 mg/kg PO q8h), without improvement. The dog also had a history of urinary tract infections that had been treated intermittently with enrofloxacin. One year before presentation , the dog had been acquired from a rescue organization, which, in turn, had acquired the dog from a pet store in northern California. Other pets in the current household were 29 parakeets. On examination, the dog was alert, hyperthermic (103.2uF [39.6uC]), panting, and had a body condition score of 8 of 9. Abnormalities of cardiac rate or rhythm were not detected. Thoracic auscultation revealed harsh lung sounds bilaterally. Thoracic radiographs revealed right cranial lung lobe consolidation, with interstitial to alveolar infiltrates in the right middle lung lobe. A lobular soft-tissue opacity was noted dorsal to the carina on the right lateral projection that was thought to represent hilar lymphadenopathy or a juxtahilar mass. An abdominal ultrasound examination disclosed no abnormalities. Serology for Coccidioides antibodies was negative. Cytologic analysis of fine needle aspirates from the consolidated lung tissue revealed mild inflammation that consisted of activated macrophages, nondegenerate neutrophils, and small mature lymphocytes. Several small clusters of cuboidal epithelial cells were observed, with high nuclear : cytoplasmic ratios and variably distinct borders, some of which were suggestive of an adenocarcinoma. A small amount of pink, fibrillar material was noted, consistent with collagen. There was also a small amount of mucinous material, mineralized debris, and cholesterol crystals suggestive of necrosis. The owner declined further diagnostic testing. Treatment with clavulanic-acid amoxicillin a (25 mg/ kg PO q12h), enrofloxacin b (3.4 mg/kg PO q12h), and piroxicam c (0.25 mg/kg PO q24h) for 4 weeks resulted in improvement in the dog's appetite and cough, but, on discontinuation of this therapy, the inappetence, cough, and lethargy returned. Physical examination 7 weeks after initial presentation disclosed mild weight loss (body weight, 36.2 kg). Thoracic radiographs showed extension of the right cranial lung lobe consolidation and persistent hilar lymphadenopathy. The previous treatment was reinstituted, and the dog's condition again improved. Eight months after initial examination, thoracic radiographs were unchanged. Urine culture for aerobic bacteria revealed Escherichia coli that was resistant to enrofloxacin and clavulanic acid-amoxicillin. Antimi-crobial therapy was changed to chloramphenicol d (38 mg/kg PO q8h), which was discontinued after 2 weeks because the dog was vomiting. Because the coughing worsened, the o...
