Risk factors, prognostic indicators, and outcome of pyothorax in cats: 80 cases (1986-1999).
OBJECTIVE
To identify risk factors associated with development of pyothorax in cats, assess survival rates for cats that are treated, determine prognostic indicators, and determine recurrence rates.


METHODS
Retrospective study.


METHODS
80 cats with pyothorax and 212 control cats.


METHODS
History; month of evaluation; physical examination findings; results of hematologic, serum biochemical, and retrovirus testing; radiographic findings; outcome; recurrence rate; and necropsy findings were recorded. For control cats, age, sex, breed, indoor versus outdoor status, vaccination history, and single- versus multi-cat household status were recorded.


RESULTS
Cats from multi-cat households were 3.8 times as likely (95% confidence interval, 1.9 to 8.2) to develop pyothorax, compared with cats from single-cat households. Indoor or outdoor status was not a risk factor. Cats with pyothorax were significantly younger (mean, 3.83 +/- 3.43 years) than controls (mean, 5.62 +/- 5.27 years). Nonsurvivors had significantly lower heart rates than survivors. Hypersalivation was significantly more common in nonsurvivors (11/39; 26.8%) than survivors (1/39; 3%). Overall, 48.8% (39/80) of cats survived. When cats that were euthanatized without treatment were excluded from analyses, the survival rate was 66.1% (39/59). Pyothorax recurred in 1 of 17 cats for which follow-up information was obtained.


CONCLUSIONS
Cats with pyothorax that received treatment had a fair to good prognosis, with low recurrence rates in survivors. Hypersalivation and low heart rate were associated with worse clinical outcome. Cats with pyothorax were likely to come from multi-cat households.
D000367:Age Factors; D000818:Animals; D000900:Anti-Bacterial Agents / Q000627:therapeutic use*; D002371:Cat Diseases / Q000382:microbiology / Q000401:mortality / Q000628:therapy*; D002415:Cats; D004322:Drainage / Q000662:veterinary; D016724:Empyema, Pleural / Q000382:microbiology / Q000401:mortality / Q000628:therapy / Q000662:veterinary*; D005260:Female; D006339:Heart Rate; D008297:Male; D011379:Prognosis; D012008:Recurrence; D012189:Retrospective Studies; D012307:Risk Factors; D012798:Sialorrhea / Q000150:complications / Q000662:veterinary; D016019:Survival Analysis; D016896:Treatment Outcome
D000900:Anti-Bacterial Agents