Admission clinicopathological data, length of stay, cost and mortality in an equine neonatal intensive care unit.

Veterinary internists need to prognosticate patients quickly and accurately in a neonatal intensive care unit (NICU). This may depend on laboratory data collected on admission, the cost of hospitalisation, length of stay (LOS) and mortality rate experienced in the NICU. Therefore, we conducted a retrospective study of 62 equine neonates admitted to a NICU of a private equine referral hospital to determine the prognostic value of venous clinicopathological data collected on admission before therapy, the cost of hospitalisation, LOS and mortality rate. The WBC count, total CO2 (TCO2) and alkaline phosphatase (ALP) were significantly higher (P < or = 0.05) and anion gap lower in survivors compared with nonsurvivors. A logistic regression model that included WBC count, hematocrit, albumin/globulin ratio, ALP, TCO2, potassium, sodium and lactate, was able to correctly predict mortality in 84% of cases. Only anion gap proved to be an independent predictor of neonatal mortality in this study. In the study population, the overall mortality rate was 34% with greatest mortality rates reported in the first 48 hours and again on day 6 of hospitalisation. Amongst the various clinical diagnoses, mortality was highest in foals after forced extraction during correction of dystocia. Median cost per day was higher for nonsurvivors while total cost was higher in survivors.

Gastroduodenal ulceration in foals.

Gastroduodenal ulceration is becoming recognised as an important disease in foals during the first few months of life. Aetiopathogenesis is presumed to be similar to peptic disease in humans associated with back diffusion of hydrogen ions into the mucosa. Many factors have been incriminated as predisposing foals to ulceration but few have been proven. To date, use of non-steroidal anti-inflammatory agents has been the only documented cause of gastroduodenal ulceration in foals. The clustering of affected foals on certain farms suggests an infectious aetiology but attempts to identify a causative organism have been unsuccessful. Four clinical syndromes defined for foals with gastroduodenal ulceration include: silent ulcers, which occur most often in the non-glandular stomach along the margo plicatus and are identified as incidental findings at necropsy; active ulcers which are often manifested by abdominal pain, excessive salivation and bruxism; perforating ulcers which usually result in a severe, diffuse peritonitis; and pyloric or duodenal obstruction from a healing ulcer. General approaches to therapy of a foal with active ulceration consist of reduction of gastric acidity and enhancement of mucosal protection. Antacids and type 2 histamine receptor antagonists are used most often to neutralise or decrease acid secretion, respectively. Sucralfate, a locally active sulphated sucrose preparation, is commonly used as a cytoprotective agent. The efficacy and safety of many products used have not been evaluated adequately in foals. Perforating ulcers are usually associated with death or humane destruction of the foal because of fulminating peritonitis. Surgical intervention and bypass procedures are indicated in foals that develop pyloric or duodenal obstructions from healing ulcers.

Acute renal failure in six horses resulting from haemodynamic causes.

Six horses had been admitted to the hospital because of illness other than renal failure; diarrhoea, myositis, abdominal pain and/or suspected bacterial sepsis. Hypotension and disseminated intravascular coagulopathy were frequent findings in the horses. Abnormally high serum creatinine concentration and urine specific gravity of less than 1.022 were found in the horses with acute renal failure. Hyponatraemia and hypochloraemia were the most common abnormal electrolyte findings. Pronounced hyperkalaemia was not found. Variable degrees of tubular necrosis were seen in three of the four horses that had kidney sections submitted for microscopic examination. Renal cortical necrosis occurred in one horse. Intravenous fluid and electrolyte replacement was the most important therapy in those cases that were non-oliguric. Furosemide, mannitol and dopamine were used in horses with oliguria. The prognosis was generally good if the predisposing cause could be corrected and the acute renal failure was not oliguric.

Cranial thoracic masses in the horse: a sequel to pleuropneumonia.

The formation of cranial thoracic masses (CTM) as a sequel to infectious pleuropneumonia is described. Using ultrasound, masses were diagnosed subjectively as abscesses or loculations. Eight of 99 cases with pleuropneumonia had CTM. Clinical signs associated with the presence of a CTM included increased heart rate, jugular distention, forelimb 'pointing' and caudal displacement of the heart. Techniques used for diagnostic ultrasonographic examination of the cranial thorax are described. Five of the eight horses with CTM responded to conservative medical management; the other three required percutaneous drainage of the mass to relieve worsening signs of cardiac decompensation. Improvements in cardiovascular parameters were evident within 12 h of drainage. The indications for and limitations of invasive drainage of cranial thoracic masses are discussed.

Antidotal effect of vitamin K1 against warfarin-induced anticoagulation in horses.

Warfarin-induced anticoagulation and reversal of the induced anticoagulation by vitamin K1 were evaluated in 4 mature horses. Each horse was given warfarin IV until the prothrombin (PT) time was prolonged by approximately 1.5 times the predosing base-line value. In experiment 1, we evaluated the time required for PT to return to the predosing value (PT reversal time) after warfarin administration was discontinued. Between each experiment, a 1-week rest period was allowed. In experiment 2, two doses of vitamin K1 (100 mg/dose) were administered IM 6 hours apart, and the PT was monitored hourly for 24 hours. In experiments 3 and 4, the horses were dosed with warfarin as in experiment 1, and the PT reversal time was evaluated after administration of 300- and 500-mg doses of vitamin K1 IM, respectively. In experiment 5, one horse was eliminated from the study, 1 horse was given 300 mg of vitamin K1 IV, and 2 horses were given 300 mg of vitamin K1 subcutaneously (SC); the reversal times were evaluated in the 3 horses given vitamin K1. Therapeutic response time was designated as the time required for the mean PT time of treated horses to reach the midpoint between the longest mean PT time achieved during anticoagulation and the mean base-line PT time. The therapeutic response time, without supportive therapy, after discontinuation of warfarin administration was 30 hours, and there was a PT reversal time of approximately 5 days from the last dose of warfarin. The 100-mg dose of vitamin K1 shortened the therapeutic response time to 12 hours and the PT reversal time to 24 hours.(ABSTRACT TRUNCATED AT 250 WORDS)

Experimental induction of Proteus mirabilis cystitis in the pony and evaluation of therapy with trimethoprim-sulfadiazine.

Proteus mirabilis cystitis was induced in 9 ponies by chemically eroding the bladder mucosa before the organism was inoculated. Comparisons were made in the treatment of P mirabilis cystitis between ponies treated daily for 13 days with a trimethoprim-sulfadiazine (TMP-SDZ) paste and both positive and negative controls. Urine cultures from ponies treated with TMP-SDZ became negative for P mirabilis between days 3 and 9 after the start of the treatment, whereas positive controls remained infected until day 13. Urine cultures from all ponies were negative for P mirabilis on day 28. Urine concentrations of TMP and SDZ were relatively high after day 1 of therapy.

Diarrhea associated with enterotoxigenic Bacteroides fragilis in foals.

Enterotoxigenic Bacteroides fragilis (ETBF) was isolated from the feces of 10 of 40 Thoroughbred foals with naturally acquired diarrhea. Of the 10 foals positive for ETBF, 6 were less than or equal to 7 days old. Fecal specimens from 4 of the 10 foals also were positive for rotavirus, and one fecal specimen was positive for Salmonella enteritidis. Clinical or hematologic differences were not evident between foals infected with ETBF only and those infected with ETBF and another recognized enteric pathogen. Only 1 of 10 foals infected with ETBF died. Of 25 adult rabbits with ligated ceca, 23 developed mucoid, often hemorrhagic, diarrhea after inoculation of 5 X 10(9) viable ETBF cells into the ileum. Nine of 13 (69%) rabbits inoculated with 1 of 3 isolates of ETBF died, but none of 12 inoculated with 1 of 6 other isolates of ETBF died. Enteric disease did not develop in 15 rabbits inoculated with nonenterotoxigenic B fragilis.

Activated coagulation test in normal and heparinized ponies and horses.

Activated coagulation test (ACT) was performed in 37 adult ponies and 31 adult horses. The mean ACT time of all ponies and horses was 2 minutes 38 seconds, with a standard deviation (SD) of 29 seconds. The ACT was compared with the Lee-White clotting test in heparinized ponies. The correlation of ACT with the Lee-White test was 0.95. Anticoagulation heparinized ponies during prolonged cardiopulmonary bypass was successfully monitored with the ACT. The ACT is simple and reproducible, has a definite end point, and would seem to be an ideal screening test for hemorrhagic diathesis in equine animals.

Activated coagulation time (ACT) of whole blood in normal dogs.

The activated coagulation time (ACT) test is technically simple, inexpensive, and commercially available and provides a rapid, accurate assessment of canine whole blood clotting time. The medium ACT for 72 normal dogs ranging in age from 6 monhts to 11 years was 75 seconds, with a range of from less than 60 seconds to 125 seconds and a mean of 77.5 seconds. Significant difference in the ACT due to sex or age of the animals tested was not found.

Serum concentrations of trimethoprim and sulfadiazine following oral paste administration to the horse.

Two fasted and 2 fed horses were dosed orally with a combined trimethoprim and sulfadiazine paste formulation at a dose of 35 mg (1:5 combined active ingredients)/kg. Serum concentrations of each drug were determined periodically for 3 consecutive days for the 4 horses. The extent and rate of absorption for trimethoprim were variable, but peak serum concentrations occurred generally within 3 hours; sulfadiazine absorption was slower, reaching peak concentrations by 6 hours. Fasting did not have a consistent effect on the serum concentration profiles for either drug. Both drugs achieved serum concentrations that equaled or exceeded the minimum inhibitory concentrations necessary to inhibit the growth of certain pathogens common to the horse. Thus, the paste formulation provides an effective means of dose administration of horses.

Neomycin toxicosis in calves.

Calves (n = 4) were given neomycin (2.25 or 4.5 mg/kg) twice daily IM and were compared with 2 calves given penicillin IM. The 2 hallmarks of aminoglycoside toxicosis, nephrotoxicosis and ototoxicosis, were seen with both dosages of parenterally administered neomycin. Nephrotoxicosis was confirmed by abnormal findings in urinalysis (granular casts, proteinuria, low specific gravity), renal biopsy results (tubular degeneration and necrosis), and increased 24-hour amounts of urinary enzymes (alanine aminopeptidase and gamma-glutamyltranspeptidase). Azotemia, decreased creatinine clearance, polyuria, and polydipsia also were documented in calves given neomycin. Clinically, deafness was suspected in 2 calves and was documented by electrical auditory-evoked response tests. Abnormalities in partial thromboplastin times and renal residues of neomycin were seen in all 4 calves that were given neomycin, but not in calves that were given penicillin.

Prognosis for return to racing after recovery from infectious pleuropneumonia in thoroughbred racehorses: 70 cases (1984-1989).

OBJECTIVE: To determine the percentage of Thoroughbred racehorses that would be capable of racing performance after recovery from infectious pleuropneumonia. DESIGN: Retrospective case series. ANIMALS: 70 Thoroughbred horses that had recovered from pleuropneumonia. Only horses < or = 5 years old and horses > 5 years old known to be in race training at the time of illness were included in the study. RESULTS: Forty-three of the 70 (61%) horses raced after recovery, and 24 of the 43 (56%) won at least 1 race. Horses that required placement of an indwelling thoracic drain apparently did not have a worse prognosis than did horses that did not require placement of a drain. The prognosis for racing for horses that developed pleuropneumonia-associated complications (pulmonary abscess, cranial thoracic mass, bronchopleural fistula) was worse than the prognosis for horses that did not develop these complications. Duration of hospitalization was not considered indicative of outcome. CLINICAL IMPLICATIONS: In Thoroughbreds, the prognosis for return to racing after recovery from uncomplicated pleuropneumonia appears to be good.

Correction of bilateral ureteral defects in a foal.

Bilateral ureteral defects were diagnosed as the cause of depression and azotemia in an 8-day-old Thoroughbred filly. The azotemia resulted from accumulation of urine in the retroperitoneal area. A ventral midline laparotomy was performed, and defects found in both the left and right ureter were repaired. Uroperitoneum and abdominal distention, presumably from urine leakage at the left ureteral surgery site, were detected on the fourth postoperative day and necessitated abdominal drainage. Thirty-six hours later, the leakage stopped spontaneously, and the foal recovered normally. This report should help to differentiate ureteral defects in foals from the more common syndrome of ruptured bladder.

Renal dysfunction associated with infection of Leptospira interrogans in a horse.

Renal failure associated with infection of Leptospira interrogans was detected in a horse. Fever, leukocytosis, pyuria, isosthenuria, and azotemia were suggestive of an inflammatory urinary tract disease. Despite persistent pyuria, no bacteria were found during routine microscopic examinations or bacteriologic culturing of urine. A fluorescent antibody examination of the urine was positive for L interrogans. Serologic testing during a 6-month period, supported an acute infection with L interrogans serovar pomona. Treatment with intravenously administered fluids and antimicrobials resulted in clinical recovery. Leptospira interrogans serovar pomona has been reported as causing fever, uveitis, or abortion in horses.

Warfarin anticoagulation in the horse.

The hematologic and clinical effects of anticoagulation with warfarin were documented in 4 horses. All of the animals had thrombophlebitis (external jugular vein). Measures of coagulation were monitored, with a prothrombin time of 1.5 to 2.5 x base-line value being used as the effective range of anticoagulation. Recanalization was achieved in 2 of 4 cases. Hemorrhage, both subcutaneous and through a surgical incision, was a complication. Vitamin K1, an antidote to warfarin toxicosis, was administered intravenously to reverse anticoagulation and to control hemorrhage.

Percutaneous nephrostomy in short-term management of ureterolithiasis and renal dysfunction in a filly.

Percutaneous nephrostomy was used to provide urine output in a 3-year-old Thoroughbred filly with azotemia and obstructive ureterolithiasis. Previous left ureteral surgery had failed to provide clinical improvement, and the filly became more azotemic. Nephrostomy was performed in the standing patient, with ultrasonographic guidance and local anesthesia. Continuing IV fluid therapy and diuresis through the nephrostomy tube resulted in a decrease in clinical signs of azotemia. However, the filly developed a cecal impaction, which ruptured during surgery because of colic, and was euthanatized.

Effect of hydroxyethyl starch infusion on colloid oncotic pressure in hypoproteinemic horses.

OBJECTIVE: To determine the effect of hydroxyethyl starch (HES) on colloid oncotic pressure (pi) during fluid resuscitation of hypoproteinemic horses and to evaluate the clinical usefulness of direct and indirect methods for determination of pi before and after infusion of a synthetic colloid. DESIGN: Prospective clinical study. ANIMALS: 11 hypoproteinemic horses. PROCEDURE: Horses received IV infusions of 8 to 10 ml of a 6% solution of HES/kg (3.6 to 4.5 ml/lb) of body weight during fluid resuscitation. Blood samples were obtained for determination of plasma measured colloid oncotic pressure (pi meas) and plasma total protein and albumin (A) concentrations. Plasma globulin concentration (G) was calculated as the difference between plasma total protein and albumin concentrations. Calculated values for colloid oncotic pressure (piA + G) were determined by use of a predictive nomogram previously developed for horses. RESULTS: There was no significant difference between the means of pi meas and piA + G at the beginning of HES infusion. After HES infusion, the mean of pi meas was increased significantly from baseline for 6 hours. Mean plasma total protein and albumin concentrations and piA + G were decreased significantly from baseline for 24 hours. Differences between mean pi meas and piA + G after HES infusion were significant for 24 hours. CONCLUSIONS AND CLINICAL RELEVANCE: There was good agreement between plasma pi meas and piA + G in blood samples obtained from hypoproteinemic horses immediately before infusion of HES. Use of a predictive nomogram did not, however, account for the oncotic effect of HES. Results of comparison of pi meas to piA + G after HES infusion suggest that a significant oncotic effect was maintained for 24 hours in the study horses.

Brainstem auditory evoked response in the diagnosis of inner ear injury in the horse.

Brainstem auditory evoked response (BAER) testing was done to evaluate inner ear/VIIIth cranial nerve (CN8) function in the horse. The BAER test consisted of stimulating the auditory system with clicks and recording far-field responses of the brainstem auditory components via cutaneous electrodes and a signal averaging system. The normal response was shown to be a series of waves occurring within the first 10 msec after the stimulus click. Functional loss of the auditory receptor organ (cochlea) or CN8 results in loss of the entire response on the side of the injury. Because of the anatomic relationships of the peripheral auditory and vestibular systems, trauma to one will injure the other. Therefore, auditory testing (BAER tests) may be used to advantage in the diagnosis of peripheral vestibular disease. The BAER test was used in a horse that had signs suggestive of vestibular dysfunction or a brain lesion. The test helped to demonstrate a unilateral inner ear/CN8 lesion and to discount the probability of a more central lesion.