Pleuritis secondary to pneumonia or lung abscessation in 90 horses.

Of 122 horses with pleural effusion, 90 (73.8%) had pleuritis secondary to pneumonia or lung abscessation. Fifty-one horses died or were euthanatized. The highest prevalence was in Thoroughbred and Standardbred racehorses. Eleven (12.2%) horses were postsurgical patients and 22 (24.4%) horses had been transported over 500 miles. There was no relationship between final outcome and the age, sex, breed, hematologic values, or laboratory findings pertaining to pleural fluid except for the bacterial isolation of Escherichia coli from the pleural fluid, as this was more frequently associated with death. Follow-up on 38 of the 39 horses that survived showed that 18 (46.2%) recovered and were able to return to performance equal to that prior to their illness. Ten (25.6%) were returned for breeding or pleasure use, with no attempt made to return them to racing. Follow-up was not available for 5 horses, 4 horses had just recently been discharged from the hospital, and 2 horses are racing poorer than prior to their illness.

Endoscopic findings in the upper respiratory tract of 479 horses.

A flexible fiberoptic endoscope was used to examine the upper respiratory tract of 479 horses and 41 (8.6%) had abnormalities. Pharyngeal lymphoid hyperplasia (PLH) was found in 141 horses (29.5%). Statistical analysis showed a relationship between the age of the horse and the prevalence of PLH. Sixteen (3.3%), 10 (2.1%), and 6 (1.3%), of the horses had laryngeal hemiplegia, epiglottic entrapment, and dorsal displacement of the soft palate, respectively. There was no association between the age of the horse and the prevalence of any of these abnormalities; nor was there a positive correlation between the prevalence of exercise-induced pulmonary hemorrhage and PLH or laryngeal hemiplegia.

Exercise-induced pulmonary hemorrhage in Thoroughbreds after racing and breezing.

Thoroughbred horses (n = 191) were examined with a flexible fiberoptic endoscope within 2 hours of racing on a dirt track; 147 (75.4%) had evidence of exercise-induced pulmonary hemorrhage (EIPH), and 13 (9.0%) had blood at the nostrils. Of 107 Thoroughbreds examined within the same period after breezing, 41 (38.3%) had evidence of EIPH. One horse (2.4%) of this group had blood at the nostrils. Statistical analysis of frequency data showed that a relationship existed between EIPH and the horse's age or distance raced or breezed. Relationship did not exist between EIPH and sex or finishing position. Thoroughbreds were also examined endoscopically after steeplechase, flat turf, and timber races; 67.7% (21/31), 14.3% (2/14), and 66.6% (2/3) of the horses in such races were EIPH-positive, respectively; and 14.3% (3/21), 0% (0/2), and 100% (2/2) of these EIPH-positive horses had blood at the nostrils. Of 32 breezing Thoroughbreds in a 3rd survey, 21 (65.5%) were EIPH-positive. None bled from the nostrils. Endoscopic findings of EIPH are repeatable in the horses, indicating that bleeding is not a random event.

Brain abscess in three horses.

Three horses with brain abscesses had different clinical manifestations: 1 had a protracted clinical course whereas 2 had a short clinical course. Clinical signs in 2 horses (1 acute case, 1 chronic case) included unilateral loss of vision, head tilt, circling, abnormal mental status, and ataxia. The 3rd horse had bilateral loss of vision, altered mental status, and apparent deafness. Results of cerebrospinal fluid analysis were inconsistent. The horse with the protracted clinical course had paradoxic central vestibular disease.

Percutaneous lung biopsy in the horse.

Percutaneous lung biopsies with a cutting needle (Vim Tru Cut) were obtained from 20 horses. The procedure was performed in standing horses under a local anesthesia without sedation. All lung tissue specimens were suitable for histologic examinations and contained both pulmonary parenchyma and large airways. The only complication was hemoptysis in 2 (10%) horses which required no therapy. All horses were subsequently killed, and no gross abnormalities were present at the biopsy site.