Lynelle R. Johnson - Canine and Feline Respiratory Medicine

Table 2.5 Lower respiratory tract flora found in healthy dogs and cats.

Table 2.6 Characteristics of pleural fluid.

Initial analysis on pleural fluid should always include a packed cell volume (PCV), cell count, protein or specific gravity, and cytology. Smears can also be prepared for Gram staining to aid in decisions regarding empiric antibiotic therapy while awaiting culture results. Additional diagnostic tests for systemic disease such as a CBC, chemistry panel, urinalysis, or echocardiogram can be chosen after the character of the pleural fluid is determined ( Table 2.6). Additional tests to perform on pleural fluid include bacterial culture and susceptibility testing (aerobic and anaerobic cultures), protein electrophoresis, or a cholesterol/triglyceride ratio for the diagnosis of chylothorax.

When an exudative pleural effusion is obtained (protein > 3 g/dl and cells > 5000/μl), samples of pleural fluid should be cultured for both aerobes and anaerobes. In a retrospective study of pyothorax (Walker et al. 2000), bacteria were isolated from 45 of 47 cats (96%) and were visible on cytology in 41 of 45 samples (91%). Obligate anaerobes were present in 40 of 45 samples (89%), and a mixture of obligate anaerobes and facultative organisms was found in 20 of 45 (44%) of culture‐positive cats. An average of 2.1 species of obligate anaerobic bacteria and 1.2 species of aerobic bacteria were isolated in cats. In dogs, bacteria were isolated from 47 of 51 samples (92%) and were visible on cytology in 32 of 47 samples (68%). Bacteria included obligate anaerobes in 17 of 47 positive samples (36%), and mixed obligate anaerobes and facultative organisms in 17 of 47 samples (36%). An average of 2.4 species of obligate anaerobic bacteria and 1.6 species of aerobic bacteria were isolated in dogs. In dogs, enteric organisms were the most common aerobic bacteria isolated, while in cats, Pasteurella species were isolated most commonly. Similar anaerobes were isolated from cats and dogs, with Peptostreptococcus , Bacteroides , and Fusobacterium isolated most commonly. Mycoplasma has been proposed to play a role in pleural infection in cats, although this is poorly characterized.

1 Barton‐Lamb, A.L., Martin‐Flores, M., Scrivani, P.V. et al. (2013). Evaluation of maxillary arterial blood flow in anesthetized cats with the mouth closed and open. Vet. J. 196 (3): 325–331.

2 De Lorenzi, D., Bonfanti, U., Masserdotti, C. et al. (2006). Diagnosis of canine nasal aspergillosis by cytological examination: a comparison of four different collection techniques. J. Small Anim. Pract. 47: 316–319.

3 Dye, J.A., McKiernan, B.C., Rozanski, E.A. et al. (1996). Bronchopulmonary disease in the cat: historical, physical, radiographic, clinicopathologic, and pulmonary functional evaluation of 24 affected and 15 healthy cats. J. Vet. Intern. Med. 10: 385–400.

4 Farrell, K.S., Epstein, S., and Hopper, K. (2019). Evaluation of pulse oximetry as a surrogate for PaO2 in awake dogs breathing room air and anesthetized dogs on mechanical ventilation. J. Vet. Emerg. Crit. Care. doi: 10.1111/vec.12898.

5 Foster, S.F., Martin, P., Braddock, J.A., and Malik, R. (2004). A retrospective analysis of feline bronchoalveolar lavage cytology and microbiology. J. Feline Med. Surg. 6: 189–198.

6 Hawkins, E.C. and Berry, C.R. (1999). Use of a modified stomach tube for bronchoalveolar lavage in dogs. J. Am. Vet. Med. Assoc. 215: 1635–1629.

7 Hawkins, E.C., Stoskopf, S.K., Levy, J. et al. (1994). Cytologic characterization of bronchoalveolar lavage fluid collected through an endotracheal tube in cats. Am. J. Vet. Res. 55: 795–802.

8 Johnson, L.R. (2016). Laryngeal structure and function in dogs with cough. J. Am. Vet. Med. Assoc. 249 (2): 195–201.

9 Johnson, L.R., Queen, E.V., Vernau, W. et al. (2013). Microbiologic and cytologic assessment of bronchoalveolar lavage fluid in dogs with lower respiratory tract infection. J. Vet. Intern. Med. 27 (2): 259–267.

10 Kol, A. and Borjesson, D.L. (2010). Application of thrombelastography/thromboelastometry to veterinary medicine. Vet. Clin. Pathol. 39 (4): 405–416.

11 Lisciandro, G.R., Fulton, R.M., Fosgate, G.T., and Mann, K.A. (2017). Frequency and number of B‐lines using a regionally based lung ultrasound examination in cats with radiographically normal lungs compared to cats with left‐sided congestive heart failure. J. Vet. Emerg. Crit. Care 27 (5): 499–505.

12 Malik, R., Wigney, D.I., Muir, D.B., and Love, D.N. (1997). Asymptomatic carriage of Cryptococcus neoformans in the nasal cavity of dogs and cats. J. Med. Vet. Mycol. 35: 27–31.

13 McKiernan, B.C., Smith, A.R., and Kissil, M. (1982). Bacterial isolates from the lower trachea of clinically healthy dogs. J. Am. Anim. Hosp. Assoc. 20: 139–142.

14 Miller, C.J., McKiernan, B.C., Pace, J., and Fettman, M.J. (2002). The effects of doxapram hydrochloride (dopram‐V) on laryngeal function in healthy dogs. J. Vet. Intern. Med. 16: 524–528.

15 Mount, M.E., Kim, B.U., and Kass, P.H. (2003). Use of a test for proteins induced by vitamin K absence or antagonism in diagnosis of anticoagulant poisoning in dogs: 325 cases (1987–1997). J. Am. Vet. Med. Assoc. 222: 194–198.

16 Oliveira, C.R., Ranallo, F.N., Pijanowski, G.J. et al. (2011). The VetMousetrap: a device for computed tomographic imaging of the thorax of awake cats. Vet. Radiol. Ultrasound 52 (1): 41–52.

17 Peeters, D.E., McKiernan, B.C., Weisiger, R.M. et al. (2000). Quantitative bacterial cultures and cytological examination of bronchoalveolar lavage specimens in dogs. J. Vet. Intern. Med. 14: 534–541.

18 Pollard, R.E., Johnson, L.R., and Marks, S.L. (2018). The prevalence of dynamic pharyngeal collapse is high in brachycephalic dogs undergoing videofluoroscopy. Vet. Radiol. Ultrasound 59 (5): 529–534.

19 Pomrantz, J.S., Johnson, L.R., Nelson, R.W., and Wisner, E.R. (2007). Comparison of serologic evaluation via agar gel immunodiffusion and fungal culture of tissue for diagnosis of nasal aspergillosis in dogs. J. Am. Vet. Med. Assoc. 230: 1319–1323.

20 Walker, A.L., Jang, S.S., and Hirsh, D.W. (2000). Bacteria associated with pyothorax of dogs and cats: 98 cases (1989–1998). J. Am. Vet. Med. Assoc. 216: 359–363.