Intestinal myxosarcoma in a thoroughbred mare.

A large fibrotic mass originating from the cecal base was discovered upon surgical exploration of the abdomen in a Thoroughbred mare with a history of chronic colic and weight loss. The mass protruded intraluminally resulting in partial obstruction. Surgical excision was not feasible due to the location of the mass and the inability to exteriorize it adequately from the abdominal cavity. The mass was fibrous with a shiny, gelatinous material present throughout the neoplasm. Histologically, large confluent spaces filled with mucopolysaccharides were identified by staining with Alcian blue. The diagnosis of myxosarcoma was based upon finding of atypical fibroblastic cells, mucinous stroma, local invasiveness, and metastasis to the regional lymph nodes. Myxomatous tumors have not previously been documented to occur in the equine intestinal tract.

Long-term jugular vein catheterization in horses.

The use of soft catheter materials in large-bore veins has allowed safe long-term venous access in human patients. Similar principles were applied to groups of horses; the jugular vein was catheterized for 14 days (group 1) and for 30 days (group 2). Three catheter materials were compared, and the clinical and histologic findings indicated that the least reaction was associated with silastic, followed by polyurethane; polytetraflouroethylene caused marked reaction. Our results suggest that by using catheters made of materials (especially silastic) that are less stiff or rigid, the duration of catheterization can be increased to 14 days or longer with minimal complications.

The management of open joint injuries.

The prognosis for returning horses with open joint injuries to athletic function is most closely related to the duration of the injury prior to treatment. Prompt diagnosis and appropriate therapy should yield a favorable result. Delayed diagnosis or inappropriate therapy that allow the wound to progress to an infected state makes the likelihood of return to athletic function poor. Refractory joint infection can occur despite early diagnosis and prompt appropriate therapy. The development of these infections is undoubtedly increased by tissue loss and gross contamination. Appropriate antibiotics given long term probably play the most significant role in resolving joint sepsis. When the refractory nature of the infection is accompanied by cartilage loss and bone proliferation, aggressive treatment by open drainage, synovectomy, and arthrodesis of the joint should be considered.

Management of traumatic tendon lacerations.

This article deals with the diagnosis and treatment of tendon lacerations. Tendon healing, with its implications relative to treatment, is discussed. The various pros and cons of suturing severed tendons are addressed as well as methods of immobilizing the injured limb. The need for prompt diagnosis and aggressive treatment of tendon sheath injuries is also discussed.

Keratoconjunctivitis sicca associated with fracture of the stylohyoid bone in a horse.

Keratoconjunctivitis sicca developed in a mare with fracture of the stylohyoid bone. Treatment was directed at preserving the health of the globe while local inflammation at the fracture site was resolved.

Congenital inguinal hernias associated with a rent in the common vaginal tunic in five foals.

Five foals were admitted because of colic that developed within 24 hours after birth. Physical examination revealed swelling from the inguinal region to the cranial aspect of the prepuce. Through the skin overlying the swelling, distended loops of bowel could be palpated. The hernias could be reduced with the foals restrained in dorsal recumbency. Surgical exploration showed the swelling to be an inguinal hernia with small bowel herniation through a rent in the common vaginal tunic. Concurrent rupture of the vaginal tunic should be suspected when a congenital inguinal hernia is associated with colic, swelling that extends to the prepuce, or intestine that is easily palpated within the hernial swelling. Repeated manual reduction in these cases would be of little benefit and surgical intervention would be recommended.

Projectile dart foreign body in a horse.

A 3-year-old Welsh pony mare was referred for evaluation of right hind limb lameness. The lameness developed 4 months after the pony had been captured by use of a projectile dart syringe to administer a tranquilizer. The lameness was attributable to a projectile dart foreign body. The dart was removed after induction of local anesthesia, and the lameness improved. The use of projected syringes has inherent risk, and clients should be advised before they are used.

Propagation of a dorsal cortical fracture of the third metacarpal bone in two horses.

Seemingly, propagation of a dorsal cortical fracture in the third metacarpal bone developed after continued race performance in 2 horses. Historically, both horses had intermittent lameness that had responded to nonsteroidal anti-inflammatory drugs and brief rest periods. However, lameness in both horses had increased in severity. Radiography revealed a dorsal cortical fracture of the third metacarpal bone, with propagation of the fracture plane proximally. Fractures were incomplete and healed with stall rest in both horses.

Consolidating pneumonia and pneumothorax in a horse.

A 3-year-old Thoroughbred mare with signs of acute abdominal pain and chronic pneumonia was found to have pneumothorax. A single application of suction was successful in resolving the pneumothorax. The underlying pneumonia was treated with long-term antibiotic administration selected on the basis of results of bacteriologic culture and antimicrobial susceptibility testing of a transtracheal aspirate. The pneumonia resolved, and the mare returned to competition as a show hunter.

Tracheal reconstruction in a foal.

A 6-month-old Standardbred foal was admitted for repair of an acquired tracheal deformity. At 2 months of age, 4 midcervical tracheal rings had been transected and, as a result, that portion of the trachea would collapse when the foal became excited or was exercising. At surgery, partial chondrotomies allowed remodeling of the deformed rings, which were then anchored to 2 partially encircling, polypropylene prostheses. After surgical repair, the horse raced successfully.

Effect of endotoxin administration on body fluid compartments in the horse.

Plasma volume, extracellular fluid volume (ECFV), and total body water (TBW) were measured before and after endotoxin (Escherichia coli) administration in 6 conscious adult horses. Evan's blue dye, sodium thiocyanate, and antipyrine were the test substances used to estimate plasma volume, ECFV, and TBW, respectively. Pharmacokinetic analysis of plasma concentration vs time was used to determine changes in body fluid compartments. The pathophysiologic effects of endotoxin were monitored by clinical evaluation, blood chemical changes, and blood gas determinations. All horses became dyspneic within 15 minutes of endotoxin administration and clinical signs of colic were evident 30 to 45 minutes after endotoxin administration. After endotoxin administration, serum glucose and creatinine concentrations were significantly (P less than 0.05) elevated, and all horses became hypoxic and developed marked metabolic acidosis, and plasma volume decreased approximately 15% (P less than 0.05). A significant change in ECFV or TBW during the 300-minute experimental period was not observed.

Apical fractures of the proximal sesamoid bones in 109 Standardbred horses.

One-hundred and nine apical fractures of the proximal sesamoid bones were diagnosed in Standardbred racehorses at the Ohio State University Veterinary Hospital during a 5-year period ending December 1978. Lateral sesamoids of the hindlimbs accounted for 61 of the 109 fractures, which was a significantly (P less than 0.05) greater proportion than that for fractures in all other sesamoid bones. Two- and three-year-old horses accounted for 73 of the 109 apical sesamoid fractures. The remaining 36 apical sesamoid fractures were in horses 4 to 9 years old. The apical fragment was removed in 80 of the horses. Thirty-six (45%) of these had raced prior to surgery, and 40 (50%) of them raced after surgery. Surgical treatment did not significantly change the earnings, starts, or order of finish score of the horse, when average before-injury performance values were compared with average after-surgery performance values. Sixty-four percent of horses that raced before injury raced afer surgery. horses that raced before injury had significantly better (P less than 0.05) performance after surgery than those not raced prior to injury. Sixty percent of horses undergoing surgery within 30 days of injury returned to race performance, and these horses had significantly (P less than 0.05) better performance after surgery than those operated on more than 30 days after injury. Thirty-six percent of horses with suspensory desmitis raced after surgery, and their race performance was poor. Twenty-nine horses with apical fractures were treated nonsurgically. Twenty-one (69%) had raced before injury, and 10 (37%) raced after injury. The performance of the 10 was significantly poorer (P less than 0.05) when their preinjury performance was compared to their after-injury performance. There was bias in selecting patients for nonsurgical treatment.