Retrospective study of palmar/plantar annular ligament injury in 71 horses: 2001-2006

REASON FOR PERFORMING STUDY: Constriction of the digital flexor tendon sheath (DFTS) and its contents by the palmar/plantar annular ligament (PAL) is well recognised. However, primary injury of the PAL has not been well documented. OBJECTIVES: To describe the clinical features of PAL injury, determine its prevalence with or without subcutaneous fibrosis and/or concurrent injury within the DFTS, and assess response to treatment. METHODS: Horses were selected for inclusion based upon clinical features consistent with PAL injury and the presence of a thickened PAL (> or =2 mm) verified ultrasonographically. A retrospective analysis of case records from 3 clinics was performed. Details of breed, age and use, and results of clinical and ultrasonographic assessments and response to treatment were recorded. Horses were treated conservatively or surgically by desmotomy of the PAL, with or without tenoscopic evaluation of the DFTS. A telephone questionnaire was performed to assess response to treatment. RESULTS: Seventy-one horses were included in the study and middle aged or older general purpose riding horses predominated. PAL desmopathy occurred more frequently in hind- than in forelimbs. The method of treatment, thickness of the PAL or presence of subcutaneous fibrosis did not significantly affect prognosis; however, <50% of horses were able to return to athletic function. There was a trend for horses with PAL desmopathy alone to have the best outcome. Bilateral thickening of the PAL or concurrent fore- and hindlimb injuries had a negative effect on prognosis, as did the simultaneous presence of subcutaneous fibrosis and lesions within the DFTS. CONCLUSIONS AND CLINICAL RELEVANCE: PAL injury is characterised by a convex contour of the palmar/plantar aspect of the fetlock, associated with thickening of the ligament with or without subcutaneous fibrosis. Bilateral PAL thickening is common in older horses, ponies and cobs; however, bilateral PAL enlargement is often present with only unilateral lameness. Treatment methods used in this study did not appear to influence outcome significantly.     

Clostridial myonecrosis in horses (37 cases 1985-2000)

REASONS FOR PERFORMING STUDY: Previous reports of clostridial myonecrosis have either focused on individual case reports or have been small retrospective studies reporting very high mortality rates. OBJECTIVES: The objective of this study was to describe the outcome of cases of clostridial myonecrosis submitted to 2 referral equine hospitals in the United States over a 15 year period. METHODS: A retrospective study of case material selected on the basis of positive Clostridium spp. culture or the identification of Clostridium spp. by specific fluorescent antibody testing from soft tissue wounds was performed at Cornell and Wisconsin. RESULTS: 37 cases of clostridial myonecrosis were documented. Twenty-seven horses survived, 8 were subjected to euthanasia and 2 died during treatment for an overall survival rate of 73%. Twenty-five cases (68%) were associated with Clostridium perfringens alone, 6 cases (16%) with Cl. septicum alone, 4 cases with mixed clostridial infections (11%), 1 case with Cl. sporogenes and 1 with an unspeciated Clostridium spp. The highest survival rate of 81% was documented for those cases from which Cl. perfringens alone was isolated. The most common antecedent condition prior to referral was colic. The myonecrotic lesion occurred within 6-72 h of a soft tissue injection in 34 cases but was associated with a wound or laceration in the remaining 3 cases. Of the 34 cases associated with recent injections, 24 were associated with i.m. injections in the cervical region, 4 in the semimembranosus/semitendinosus region, 3 in the gluteal region, 2 with perivascular leakage of drugs administered into the jugular vein and 1 case developed simultaneously in the gluteal and neck region following injections at both sites. CONCLUSIONS: Clostridial myonecrosis can occur following the i.m. or inadvertent perivascular administration of a wide variety of commonly administered drugs. It is most common in the neck musculature. Aggressive treatment can be associated with survival rates of up to 81% for cases due to Cl. perfringens alone. Survival rates for other Clostridial spp. tend to be lower. POTENTIAL RELEVANCE: A combination of high dose i.v. antibiotic therapy and surgical fenestration/debridement is the best approach to cases of clostridial myonecrosis. With rapid diagnosis and therapeutic intervention, horses may have up to an 81% chance of survival.     

Underlying cause, pathophysiologic abnormalities, and response to treatment in cats with septic peritonitis: 51 cases (1990-2001)

OBJECTIVE: To determine the underlying cause, pathophysiologic abnormalities, and response to treatment in cats with septic peritonitis and identify differences between cats that survived following treatment and cats that did not survive despite treatment. DESIGN: Retrospective study. ANIMALS: 51 cats with septic peritonitis. PROCEDURE: Medical records were reviewed for clinical findings; results of clinicopathologic testing, microbial culture, and radiography; diagnosis; treatment; and outcome. RESULTS: Signs of pain during palpation of the abdomen were reported for only 29 of 47 (62%) cats. Eight (16%) cats had relative bradycardia (heart rate < 140 beats/min). The most commonly isolated organisms included Escherichia coli, Enterococcus spp, and Clostridium spp. The most common cause of peritonitis was gastrointestinal tract leakage (24 cats). No definitive source could be identified in 7 cats. Treatment, including exploratory surgery, was pursued in 23 cats, of which 16 (70%) survived and were discharged. There were no significant differences between survivors and nonsurvivors in regard to heart rate, age, rectal temperature, serum lactate concentration, WBC count, PCV, blood glucose concentration, or serum albumin concentration. CONCLUSIONS AND CLINICAL RELEVANCE: Results suggest that clinicopathologic abnormalities and outcome in cats with septic peritonitis are similar to those reported for dogs. However, certain features may be unique, including an absence of signs of pain during abdominal palpation, relative bradycardia, and apparent spontaneous peritonitis in some cats.     

Congestive heart failure in horses: 14 cases (1984-2001)

OBJECTIVE: To identify clinical signs, underlying cardiac conditions, echocardiographic findings, and prognosis for horses with congestive heart failure. DESIGN: Retrospective study. ANIMALS: 14 horses. PROCEDURE: Signalment; history; clinical signs; clinicopathologic, echocardiographic, and radiographic findings; treatment; and outcome were determined by reviewing medical records. RESULTS: All 14 horses were examined because of a heart murmur; tachycardia was identified in all 14. Twelve horses had echocardiographic evidence of enlargement of 1 or more chambers of the heart. Other common clinical findings included jugular distention or pulsation, crackles, cough, tachypnea, and ventral edema. Nine horses had signs consistent with heart failure for > 6 days. Underlying causes for heart failure included congenital defects, traumatic vascular rupture, pericarditis, pulmonary hypertension secondary to heaves, and valvular dysplasia. Seven horses were euthanatized after diagnosis of heart failure; 5 were discharged but were euthanatized or died of complications of heart disease within 1 year after discharge. The remaining 2 horses were discharged but lost to follow-up. CONCLUSIONS AND CLINICAL RELEVANCE: Results suggest that congestive heart failure is rare in horses. A loud heart murmur accompanied by either jugular distention or pulsation, tachycardia, respiratory abnormalities (crackles, cough, tachypnea), and ventral edema were the most common clinical signs. Echocardiography was useful in determining the underlying cause in affected horses. The long-term prognosis for horses with congestive heart failure was grave.     

Medical and surgical treatment of pyothorax in dogs: 26 cases (1991-2001)

OBJECTIVE: To compare outcomes of dogs with pyothorax treated medically versus surgically and to identify prognostic indicators for dogs with pyothorax. DESIGN: Retrospective study. ANIMALS: 26 dogs. PROCEDURE: Medical records were reviewed to obtain information regarding signalment, results of physical and laboratory evaluations at the time of initial examination, results of bacterial culture of pleural fluid, radiographic abnormalities, treatment (surgical vs medical), complications, whether the disease recurred, disease-free interval, survival time, and cause of death. RESULTS: Calculated proportions of dogs free from disease 1 year after treatment were 25 and 78%, respectively, for dogs treated medically and surgically. Treatment was 5.4 times as likely to fail in dogs treated medically as in dogs treated surgically. Two regression models relating treatment group (medical vs surgical) to disease-free interval were found to be significant. The first contained terms for medical treatment and isolation of Actinomyces spp from pleural fluid; the second contained terms for medical treatment and radiographic detection of mediastinal or pulmonary lesions at the time of initial examination. CONCLUSIONS AND CLINICAL RELEVANCE: Results suggest that surgical treatment is associated with a better outcome than medical treatment in dogs with pyothorax. In addition, surgery should be considered if radiographic evidence of mediastinal or pulmonary lesions is detected or if Actinomyces spp is isolated from the pleural fluid.     

Rabies in horses: 21 cases (1970-1990).

The records of 21 horses with rabies were reviewed. Results of fluorescent antibody testing for rabies antigen in brain tissue were positive in each case. According to the histories, 5 of the horses had been vaccinated for rabies between 4 to 24 months prior to the onset of the clinical signs. Bite wounds were not observed on any of the horses, and exposure to a suspected rabid animal was witnessed in only 5 cases. Clinical signs of disease at the time of initial examination included ataxia and paresis of the hindquarters (9/21, 43%), lameness (5/21, 24%), recumbency (3/21, 14%), pharyngeal paralysis (2/21, 10%), and colic (2/21, 10%). The major clinical signs observed over the course of hospitalization included recumbency (21/21; 100%), hyperesthesia (17/21; 81%), loss of tail and anal sphincter tone (12/21; 57%), fever (11/21; 52%), and ataxia and paresis of the hindquarters (11/21; 52%). Mean survival time after the onset of clinical signs was 4.47 days (range, 1 to 7 days). Supportive treatment, given to 9 horses, had no effect on survival time and did not correlate with the detection of negri bodies at necropsy. Cerebrospinal fluid (CSF) was obtained from 6 horses and was determined to be abnormal in 5. The most common abnormality was a slightly high total cell count (5/6), with a predominance of lymphocytes (4/6). The CSF total protein concentration was high in only 2 horses. At necropsy, there was gross evidence of diffuse brain edema, meningeal congestion, and focal areas of hemorrhage in 5 horses (24%).(ABSTRACT TRUNCATED AT 250 WORDS)     

Ultrasonography of the medial palmar intercarpal ligament in the Thoroughbred: technique and normal appearance

REASONS FOR PERFORMING STUDY: Tearing of the medial palmar intercarpal ligament (MPICL) has been recognised as a cause of lameness in the Thoroughbred, but diagnosis is difficult due to the nonspecific clinical signs, and can be achieved only by performing arthroscopy on the mid carpal joint (MCJ). It would be beneficial to be able to image the MPICL using ultrasonography to determine whether pathology is present in the ligament in order to aid diagnosis and prognosis. OBJECTIVES: To determine whether the MPICL could be imaged using ultrasound from the dorsal aspect of the MCJ, and to describe the technique and normal ultrasonographic appearance of the ligament. METHODS: A pilot study was performed using 2 cadaver carpi. Each carpus in turn had the MPICL imaged simultaneously using arthroscopy and ultrasound, with a metallic probe positioned on the dorsal aspect of the ligament to highlight the position of the MPICL. Six further pairs of carpi had the MPICL imaged ultrasonographically followed by dissection of the carpus to evaluate the ligament and relate its anatomy to the ultrasound images. Finally, 15 Thoroughbreds with no history of lameness isolated to the carpus had their MPICLs assessed and measured ultrasonographically. RESULTS: The MPICL could be imaged via the dorsal aspect of the MCJ using standard ultrasound equipment. The body and division into medial and lateral branches could be seen as a distinct, moderately dense granular echogenic structure in the palmar aspect of the joint, with clearly defined margins. CONCLUSIONS: The normal MPICL can be imaged reliably using ultrasound in the Thoroughbred from the dorsal aspect of the MCJ. There is a wide range in the normal width of the lateral aspect of the MPICL, but there is good symmetry between contralateral limbs. POTENTIAL RELEVANCE: This report of the normal ultrasonographic appearance of the ligament will be beneficial in acting as a reference for the detection of pathology using ultrasound.     

Retrospective evaluation of surgical versus conservative treatment of keratomas in 41 lame horses (1995-2001)

A keratoma is a rather uncommon disorder of the equine hoof that can lead to lameness. Few quantitative data exist about the prognosis of different treatment regimens. The outcome of 41 cases that were presented to the Department of Equine Sciences in the period 1995-2001 and that were treated according to different regimens was retrospectively evaluated. All horses showed lameness that could be attributed to the keratoma: 23 (56%) were treated surgically using a standardized procedure, while the other 18 (44%) were treated conservatively. Results were based upon 35 horses; 6 were lost to follow-up. Range of recovery time for the surgically treated patients, was 2-12 months and for the conservatively treated group 2 weeks to 6 months. Of the surgically treated patients 83% (n =23) returned to the same or higher performance level as before the onset of the lameness, as opposed to 42% (n = 12) of the conservatively treated horses (p<0.05). The average hospitalization period was significanty longer for the surgically treated patients (35 vs. 5 days, p<0.05). It is concluded that surgical excision of the keratoma is the preferred treatment for horses suffering from lameness caused by a keratoma, because the better outcome outweighs the longer hospitalization and the longer overall recovery time.     

Fistulous withers in horses: 24 cases (1984-1990).

Between Jan 1, 1984 and Aug 1, 1990, 27 horses were admitted to the veterinary medical center for evaluation of fistulous withers. Nine (37.5%) of 24 horses tested for antibody to Brucella abortus were seropositive. Horses that tested seropositive were significantly (P = 0.046) more likely to have been pastured with cattle that were seropositive for B abortus, and were significantly (P = 0.010) more likely to have had radiographic evidence of vertebral osteomyelitis than were horses that tested seronegative. Five horses that were seropositive for B abortus were administered strain 19 brucella vaccine sc (n = 1) or iv (n = 4). The horse treated by sc injection of vaccine improved during hospitalization, but was lost to follow-up evaluation. Three (75%) of 4 horses treated by iv injection died, but 1 horse recovered within 4 weeks of treatment.     

Gastric ulceration in horses: 91 cases (1987-1990).

Gastroendoscopy was performed on 111 horses (1 to 22 years old) that had signs of abdominal discomfort of variable duration and severity. At least 1 episode of colic had been observed within 48 hours of examination in 31 horses. Recurrent episodes of colic were observed in 28 horses within 2 to 10 days of examination, 31 horses within 11 to 30 days, 12 horses within 31 to 60 days, and in 9 horses at more than 60 days after the initial examination. Gastric ulceration was found in 91 of 111 horses examined. Other abnormalities involving the gastrointestinal tract or other abdominal viscera were not found on examination in 57 of 91 horses with gastric ulcers. The most frequent concurrent abnormalities found in the remaining 34 horses with gastric ulcers were impaction of the large colon (n = 6), colonic tympany (n = 6), peritonitis (n = 6), gastric impaction (n = 4), ileocecal intussusception (n = 3), small-colon impaction (n = 4), and proximal enteritis (n = 2). Thirteen horses with gastric ulceration underwent abdominal surgery, and in 5 horses, lesions were not found at surgery. Gastric ulceration was determined to be the primary cause of colic in 31 horses on the basis of the lack of other abnormalities, clinical response to treatment with histamine type-2 receptor (H2) antagonists, and confirmation of improvement or resolution of gastric ulceration via endoscopy. Gastric ulceration was the suspected cause of colic in 26 other horses on the basis of the lack of other abnormalities, severity of lesions, and clinical response to treatment with H2 antagonists.(ABSTRACT TRUNCATED AT 250 WORDS)     

Prepurchase evaluation of horses: 134 cases (1988-1990).

To quantify some components of prepurchase evaluations in horses, records from 134 evaluations performed during a 2-year period were reviewed and the outcome was determined via telephone follow-up interview. Sixty-two percent of the prepurchase evaluations had been performed at the clinic and 38% had been performed in the field by the ambulatory service. All evaluations included physical and lameness examinations, whereas radiography (49%), endoscopy (15%), nerve blocking (5%), transrectal palpation (3%), hematologic analysis (2%), electrocardiography (2%), drug testing for analgesic agents (2%), and ultrasonography of the flexor tendons (1%) were not always performed. Fifty-nine percent of horses evaluated at the clinic were radiographed, compared with 33% of horses evaluated in the field (P less than 0.05). Thirty-seven percent of horses evaluated were judged serviceable for their intended use. Thirty-five percent of horses evaluated at the clinic were assessed to be serviceable, compared with 41% of those evaluated in the field (P less than 0.05). Horses used for pleasure riding (48%) tended to be considered serviceable more often than horses used for more athletic endeavors (3-day eventing, 33%; hunter/jumper, 24%; show, 31%; dressage, 30%). The most common basis for finding a horse unserviceable was lameness (88%).(ABSTRACT TRUNCATED AT 250 WORDS)     

Desmitis of the straight sesamoidean ligament in horses: 9 cases (1995-1997)

OBJECTIVE: To determine clinical signs, diagnostic findings, and outcome for horses with desmitis of the straight sesamoidean ligament (SSL) near its insertion on the middle phalanx. DESIGN: Retrospective study. ANIMALS: 9 horses. PROCEDURE: Medical records were reviewed, and information on signalment, history, clinical signs, diagnostic findings, and treatment was obtained. Follow-up information was obtained through telephone conversations with owners. RESULTS: In all horses, the diagnosis was made by use of high-resolution ultrasonography. Seven horses had moderate lameness on initial examination; lameness was exacerbated in 6 horses following flexion of the distal limb joints. The cause of lameness could not be determined on the basis of clinical signs, and diagnostic local anesthesia was necessary to localize the source of lameness to the distal portion of the limb. Five horses had forelimb involvement (1 bilateral), and 4 had hind limb involvement (1 bilateral). Treatment consisted primarily of a 6-month rest and rehabilitation program. Six of the 9 horses were able to return to their intended use. CONCLUSIONS AND CLINICAL RELEVANCE: Results suggest that injury to the SSL proximal to its insertion on the middle phalanx should be considered as a possible cause of lameness in horses, particularly performance horses, with lameness localized to the distal portion of the forelimb or hind limb that do not have any radiographic abnormalities. High-resolution ultrasonography was necessary to make the diagnosis. Horses with an acute injury appeared to have a reasonable chance of responding to treatment and returning to their intended use.     

Fractures of the palmar aspect of the carpal bones in horses: 10 cases (1984-2000)

OBJECTIVE: To determine clinical and radiographic findings, treatment, and outcome of horses with fractures of the palmar aspect of the radial carpal bone, with or without concurrent fractures of the palmar surfaces of the other carpal bones. DESIGN: Retrospective study. ANIMALS: 10 horses. PROCEDURE: Medical records were reviewed to obtain information on history, signalment, clinical and radiographic findings, treatment, and outcome. Follow-up information was gathered from owners and referring veterinarians. RESULTS: 7 horses became lame after recovery from general anesthesia for treatment of an unrelated problem. The remaining 3 horses developed a fore-limb lameness after falling (1 horse) or being turned out in a pasture (2 horses). Fractures involved the palmar surface of the radial carpal bone in all 10 horses; in addition, the ulnar carpal bone was affected in 2 horses, the intermediate carpal bone in 2 horses, and the distal aspect of the radius in 4 horses. None of the 4 horses treated nonsurgically returned to work, and 3 were euthanatized because of recalcitrant lameness. In the other 6 horses, fragments were removed surgically. Two were euthanatized because of continued lameness, 1 was euthanatized for other reasons, 2 were sound enough for light work, and 1 returned to athletic work. CONCLUSIONS AND CLINICAL RELEVANCE: Results suggest that fractures of the palmar aspect of the carpal bones are uncommon in horses. The prognosis appears to be poor for affected horses but may be better for horses that undergo arthroscopic removal of intra-articular fragments.     

Ultrasonographic findings in horses with right dorsal colitis: five cases (2000-2001)

OBJECTIVE: To determine whether ultrasonography would be useful in the diagnosis of right dorsal colitis in horses. DESIGN: Retrospective study. ANIMALS: 5 horses with right dorsal colitis and 15 healthy adult horses. PROCEDURE: Mural thickness and appearance of the right dorsal colon were determined from ultrasonographic images obtained at right intercostal spaces 10, 11, 12, 13, and 14. RESULTS: The right dorsal colon could be imaged most consistently at the right 11th, 12th, and 13th intercostal spaces, below the margin of the lung and axial to the liver. Mural thickness measured from ultrasonographic images was significantly greater in horses with right dorsal colitis than in healthy horses. The right dorsal colon in affected horses had a prominent hypoechoic layer associated with submucosal edema and inflammatory infiltrates. Successful treatment of 1 horse with right dorsal colitis was associated with a decrease in mural thickness coincident with an increase in serum albumin and total protein concentrations and weight gain. A decrease in mural thickness was also observed in a second horse treated for right dorsal colitis that was not associated with healing of the right dorsal colon or an increase in serum albumin concentration but rather thinning of a segment of the right dorsal colon that eventually ruptured. CONCLUSIONS AND CLINICAL RELEVANCE: Results suggest that ultrasonographic measurement of mural thickness and evaluation of the appearance of the right dorsal colon may be useful in the diagnosis of right dorsal colitis in horses.     

Prevalence and risk factors associated with outcome of surgical removal of pedunculated lipomas in horses: 102 cases (1987-2002)

OBJECTIVE: To determine the prevalence of pedunculated lipomas and identify risk factors affecting postoperative complications and survival in horses at a veterinary teaching hospital undergoing surgery for colic caused by pedunculated lipomas. DESIGN: Retrospective study. ANIMALS: 102 horses with a diagnosis of pedunculated lipoma. PROCEDURE: Age, breed, weight, and sex of horses with pedunculated lipomas were compared with the total equine hospital population and the population of horses admitted for abdominal surgery during the same period. Follow-up information was obtained by reevaluation or contact with owners via telephone or written request. RESULTS: Prevalence of pedunculated lipomas as a reason for abdominal surgery in horses, compared with the population of horses with and without lipomas admitted for abdominal surgery, was 10%. Castrated male Saddlebred and Arabian horses > 14 years old were identified as being at risk for developing pedunculated lipomas. Postoperative complications were detected in 72% of horses with pedunculated lipomas. Variables associated with low survival rates included surgery before 1992, heart rate > 80 beats/min, abnormal color of abdominal fluid, pale mucous membranes, surgery requiring intestinal resection, and inability to attain a mean arterial pressure > or = 100 mm Hg. Horses undergoing surgery from 1992 to 1996, weighing < 409 kg (900 lb), or requiring jejunojejunal anastomosis had a high survival rate. CONCLUSIONS AND CLINICAL RELEVANCE: Although many of the variables reflected the health of the horse at the time of surgery, results may help veterinarians recognize risk factors associated with development of pedunculated lipomas and better predict the outcome of horses undergoing surgery for colic caused by pedunculated lipomas.     

Stress reactions and stress fractures of the proximal palmar aspect of the third metacarpal bone in horses: 58 cases (1980-1990).

The case records, radiographs, and nuclear bone scans of 58 horses with stress reactions or stress fractures of the proximal palmar aspect of the third metacarpal bone (MC3) were reviewed. There were 47 Standardbreds, 4 Quarter Horses, 3 Thoroughbreds, 2 Arabians, 1 Oldenburg, and 1 Pony of America. Fifty-six of the horses were racehorses or performance horses. The mean and median ages of affected horses were 4 and 3 years, respectively. Lameness ranged from mild to severe. Physical findings were usually subtle and included signs of pain on deep palpation of the proximal palmar aspect of MC3 and slight effusion of the middle carpal joint in some cases. Lameness was commonly improved by high palmar and palmar metacarpal nerve blocks or anesthesia of the middle carpal joint. Fifty-three horses had higher than normal radiopharmaceutical uptake in the proximal palmar aspect of MC3 in the left or right limb. The other 5 horses had higher than normal radiopharmaceutical uptake bilaterally. Fifty-six of the 63 limbs with abnormal bone scans also had abnormal radiographs. Treatment consisted of a variable period of rest (1 to 6 months). Healing was best assessed by follow-up bone scans. Of the 45 horses for which follow-up information was adequate, 29 (64%) returned to their previous level of performance.     

Risk factors for reduced postoperative fecal output in horses: 37 cases (1997-1998)

OBJECTIVE: To determine prevalence and risk factors for development of ileus of the large intestine after surgery in horses, identified by reduced postoperative fecal output (RPFO). DESIGN: Retrospective study. ANIMALS: 37 horses that developed RPFO after undergoing general anesthesia for reasons unrelated to the gastrointestinal tract. PROCEDURE: Fecal output was obtained from medical records as number of defecations per 24-hour period after surgery; RPFO was defined as < or = 3 defecations per 24-hour period after surgery. The reference population included 48 horses that defecated > or = 4 times during the same period. Demographic, clinical, and surgical variables were evaluated for their association with development of RPFO by use of logistic regression analysis. RESULTS: Ten (12%) horses, all of which had RPFO, developed signs of colic after surgery. Horses > or = 5 years old that underwent orthopedic procedures of > 60 minutes' duration and that did not receive phenylbutazone after surgery were at significant risk for developing RPFO. CONCLUSIONS AND CLINICAL RELEVANCE: Results suggest that after surgery unrelated to the gastrointestinal tract in horses, there is an intermediate clinical phase characterized by reduced fecal output preceding overt signs of colic. Recognition of RPFO may reduce morbidity and mortality of such horses.     

West Nile virus encephalomyelitis in horses: 46 cases (2001)

OBJECTIVE: To determine signalment, clinical findings, results of diagnostic testing, outcome, and postmortem findings in horses with West Nile virus (WNV) encephalomyelitis. DESIGN: Retrospective study. ANIMALS: 46 horses with WNV encephalomyelitis. PROCEDURE: Clinical data were extracted from medical records of affected horses. RESULTS: On the basis of clinical signs and results of serologic testing, WNV encephalomyelitis was diagnosed in 46 of 56 horses with CNS signs. Significantly more males than females were affected. Increased rectal temperature, weakness or ataxia, and muscle fasciculations were the most common clinical signs. Paresis was more common than ataxia, although both could be asymmetrical and multifocal. Supportive treatment included anti-inflammatory medications, fluids, antimicrobials, and slinging of recumbent horses. Results of the IgM capture ELISA and the plaque reduction neutralization test provided a diagnosis in 43 horses, and only results of the plaque reduction neutralization test were positive in 3 horses. Mortality rate was 30%, and 71% of recumbent horses were euthanatized. One horse that had received 2 vaccinations for WNV developed the disease and was euthanatized. Follow-up communications with 19 owners revealed that most horses had residual deficits at 1 month after release from the hospital; abnormalities were resolved in all but 2 horses by 12 months after release. CONCLUSIONS AND CLINICAL RELEVANCE: Our findings were similar to those of previous WNV outbreaks in horses but provided additional clinical details from monitored hospitalized horses. Diagnostic testing is essential to diagnosis, treatment is supportive, and recovery rate of discharged ambulatory horses is < 100%.