Diagnosis and management of overt and covert pleuropneumonia (Proceedings)
Nov 01, 2009
CVC IN SAN DIEGO PROCEEDINGS
This case represents what clinical impression indicates is the most common form of pleuropneumonia seen in equine practice. These cases present with fever of unknown origin (FUO) with few if any signs referable to the respiratory system. Several texts and the literature were reviewed and this form of pleuropneumonia is rarely discussed. In general, the more severe form of pleuropneumonia with extensive purulence and exudation, lung infarction, etc is the focus of most literature discussion.
Case ISignalment and history
A 10-year-old Hanovarian mare presented with a 3 week history of sporadic malaise. It was noted that the depression would invariably occur late in the afternoon. Most often, the following morning, the horse appeared bright, alert and responsive. This did not occur daily, but the owner felt it had occurred at least every other day. The horse was in light use, and continued to jump 1 meter fences. She was transported from Ohio to California 40 days prior to presentation. Other than the chief complaint the horse had shown no other clinical signs.
Treatment and outcome
It has been the author's experience, that a thoracic ultrasound is warranted whenever a horse presents with persistent continuous or intermittent pyrexia and few if any other clinical signs. This can be performed with a 5 megaHz linear ultrasound probe. Clearly thoracic ultrasonographic evaluation is more warranted if there is a purulent nasal discharge or cough, or other more "text book described" clinical signs of pleuropneumonia. Many of the mild or occult cases have small amounts of purulent pleural fluid that has increased echodensity and opacities in the fluid. However, the volume can be small and have a very elevated white blood cell count (Figure 4). A personal review of 48 cases where imaging has been captured indicates that shipping, parturition, or exercise, were evident in many horses before pyrexia developed. In many cases, no specific historical incident was identified.
As is common, in the author's experience with these cases, antimicrobial therapy did not seem to resolve the pyrexia in the short term. There is a tendency to declining temperature and less depression, but less often resolution during the antimicrobial regimen. There seem to be no advantage of applying antibiotics until the pyrexia is completely resolved. That does not seem to be fruitful, reduce the duration of the disease, nor necessary in these cases.
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