Objective—To determine the effects of long-term oral administration of levothyroxine sodium (L-T4) on glucose dynamics in adult euthyroid horses.
Animals—6 healthy adult mares.
Procedures—Horses received L-T4 (48 mg/d) orally for 48 weeks. Frequently sampled IV glucose tolerance test procedures were performed on 3 occasions (24-hour intervals) before and at 16, 32, and 48 weeks during the treatment period. Data were assessed via minimal model analysis. The repeatability of measurements was evaluated.
Results—During treatment, body weight decreased significantly from the pretreatment value; mean ± SD weight was 49 ± 14 kg, 43 ± 7 kg, and 25 ± 18 kg less than the pretreatment value at weeks 16, 32, and 48, respectively. Compared with pretreatment findings, 1.8-, 2.4-, and 1.9-fold increases in mean insulin sensitivity (SI) were detected at weeks 16, 32, and 48, respectively; SI was negatively correlated with body weight (r = −0.42; P < 0.001). During treatment, glucose effectiveness increased and the acute insulin response to glucose decreased. Overall mean within-horse coefficients of variation were 5% and 29% for plasma glucose and serum insulin concentrations, respectively, and 33%, 26%, and 23% for SI, glucose effectiveness, and the acute insulin response to glucose, respectively.
Conclusions and Clinical Relevance—Long-term administration of L-T4 was associated with weight loss and increased SI in adult euthyroid horses, although other factors may have confounded results. Levothyroxine sodium may be useful for the treatment of obesity and insulin resistance in horses, but further studies are required.
Objective—To evaluate the safety, with respect to
the development of gastric ulcers and erosions, of
concurrent administration of meloxicam and dexamethasone
for 3 days to healthy dogs.
Animals—20 conditioned purpose-bred research
Procedure—Seven days prior to treatment, dogs
were anesthetized for endoscopic evaluation of the
upper portion of the gastrointestinal tract (ie, the gastric
and duodenal mucosa). Five regions of the gastroduodenal
area were scored by 2 investigators.
Dogs were randomly assigned to 1 of 4 treatment
groups as follows: saline-saline, dexamethasonesaline,
saline-meloxicam, and dexamethasone-meloxicam
groups. On days 1, 2, and 3, dogs received either
dexamethasone or saline (0.9% NaCl) solution injections
SC twice daily. On days 2, 3, and 4, dogs
received either meloxicam or saline solution injections
SC once daily. On day 2, dogs were anesthetized
for a sham surgery (ie, electrostimulation).
On day 5, the gastroduodenal area of each dog was
reevaluated by use of endoscopic evaluation and histologic
examination of biopsy specimens.
Results—The total endoscopic score of the dexamethasone-
meloxicam group was significantly greater
than the scores of the other groups. The dexamethasone-
saline group had a mean cumulative score that
was significantly greater than the saline-meloxicam or
saline-saline groups. Endoscopic scores of the salinemeloxicam
group were not significantly different from
scores of the saline-saline group. No significant differences
in histologic findings were found between
Conclusions and Clinical Relevance—In healthy
dogs, meloxicam appears to be safe with regard to
adverse effects on the gastrointestinal tract.
Concurrent administration of dexamethasone and
meloxicam is more likely to cause gastric erosions
than meloxicam administration alone. (Am J Vet Res 2003;63:1369–1375)
Objective—To ascertain whether laminitis can be induced via administration of oligofructose (OF) at doses of 5.0 and 7.5 g/kg in horses and to assess glucose and insulin dynamics before and after treatment.
Animals—19 adult horses.
Procedures—Horses were fed OF (1.0 g/kg) mixed with oats for 6 days. Oligofructose at doses of 5.0 and 7.5 g/kg was then mixed with 4 L of water and administered (0 hours) to 8 (group A) and 4 (group B) horses, respectively, via nasogastric intubation; 8 horses received water alone. One horse in group A that did not develop laminitis was subsequently treated again and included in group B. Before and at intervals after treatment, resting plasma glucose and serum insulin concentrations were measured and frequently sampled IV glucose tolerance tests were performed. Area under the glucose curve (AUCg) and area under the insulin curve (AUCi) were calculated, and minimal model analyses were performed.
Results—3 of 8 horses in group A and all 4 horses in group B developed laminitis. Significant treatment-time effects were detected for resting plasma glucose concentrations and AUCg. Among horses in group A, mean AUCg values at 24 and 48 hours were 34% and 32% higher, respectively, than the mean value at 24 hours. Treatment groups did not differ significantly with respect to resting serum insulin concentration, AUCi, or minimal model analysis results.
Conclusions and Clinical Relevance—In horses, laminitis can be induced and glucose dynamics altered via nasogastric administration of 5.0 g of OF/kg. An alteration in insulin dynamics was not detected following treatment with OF.
CASE DESCRIPTION 5 dogs between 9 and 11 years of age were evaluated for treatment of primary (n = 2) or metastatic (3) hepatic neoplasia.
CLINICAL FINDINGS Patients were evaluated on an elective (n = 3) or emergency (2) basis. Two dogs with primary hepatic neoplasia were evaluated because of lethargy and inappetence. One dog was referred after an enlarged anal sac was detected via palpation per rectum during a routine physical examination. Two dogs were evaluated on an emergency basis because of lethargy and weakness, and hemoabdomen in the absence of a history of trauma was detected. All 5 dogs underwent thoracic radiography and abdominal ultrasonography, with CT performed in both dogs with primary hepatic neoplasia. All dogs had preoperative evidence of abdominal neoplasia, and none had evidence of thoracic metastasis.
TREATMENT AND OUTCOME All dogs underwent ventral midline laparotomy and had diffuse hepatic neoplasia that precluded complete resection. Locoregional treatment with MWA was applied to hepatic lesions (0.5 to 2.5 cm diameter) without procedural complications. Histopathologic diagnoses were biliary adenocarcinoma (n = 1), hemangiosarcoma (2), hepatocellular carcinoma (1), and apocrine gland adenocarcinoma (1).
CLINICAL RELEVANCE MWA is being increasingly used as an adjunct in the surgical treatment of human patients with primary and metastatic liver disease. Results of the present small case series suggested that MWA is feasible and potentially effective as an adjunctive treatment for appropriately selected dogs with nonresectable hepatic tumors. Further investigation is indicated.
CASE DESCRIPTION A 17-month-old neutered female Labrador Retriever with a 3- to 4-month history of abdominal distention was referred for evaluation and treatment.
CLINICAL FINDINGS Evaluation of a peritoneal fluid specimen collected by the referring veterinarian indicated a pure transudate. At admission, transabdominal ultrasonography revealed microhepatica, dilation of the intrahepatic and mesenteric vasculature, peritoneal effusion, and multiple aberrant blood vessels. A large, high-flow hepatic arteriovenous malformation (HAVM) with secondary portal hypertension, peritoneal effusion, multiple acquired portosystemic shunts, and microhepatica was evident on CT angiography.
TREATMENT AND OUTCOME Transfemoral hepatic arteriography and staged coil and glue (n-butyl cyanoacrylate) embolization of the complex arteriovenous malformation nidus and central main left hepatic artery resulted in ablation of the lesion, restoration of arterial blood flow to the contralateral hepatic lobes, and resolution of the peritoneal effusion. The dog remained without clinical signs of hepatic disease until it was euthanized 5 months after treatment for an unrelated condition.
CLINICAL RELEVANCE Successful endovascular management of a HAVM was accomplished by means of coil and glue embolization in the patient of this report. Dogs with comparable HAVMs may benefit from similar minimally invasive treatment.
A 2-year-old 5.1-kg (11.2-lb) castrated male Siberian cat was examined because of a history of an abnormal right pelvic limb gait and a 4- to 5-month history of progressive constipation. Radiographs obtained by the referring veterinarian showed an osteoproductive and osteolytic bony lesion that involved the right ischium and filled the obturator foramen.
A hard mass was palpable in the right inguinal area, and rectal examination revealed a smooth bony mass on the ventral aspect of the right pelvic floor with marked reduction in the pelvic canal space. A 3.9 X 3 X 4.6-cm, mineralized mass bridging the right obturator foramen was present on CT images. The ventral component of the mass was slightly larger than its dorsal component, and lysis of the right pubic bone was present. There was no obvious soft tissue involvement.
TREATMENT AND OUTCOME
A limb salvage procedure involving internal hemipelvectomy with ipsilateral ischiectomy, contralateral partial ischiectomy, ipsilateral partial acetabulectomy, and femoral head and neck excision was performed. Histologic examination revealed that the mass was an osteochondroma. The cat recovered well and had good functional limb use immediately after surgery. The cat was still alive 1 year after surgery with good limb use.
Internal hemipelvectomy involving ischiectomy, partial acetabulectomy, and femoral head and neck excision can result in a good functional outcome in cats if the procedure is planned appropriately with a full understanding of the regional anatomy and adherence to surgical oncologic principles. (J Am Vet Med Assoc 2021;258:401–405)
OBJECTIVE To determine the prevalence and clinical characteristics of incidental adrenal gland masses identified in dogs undergoing abdominal CT.
DESIGN Retrospective case series.
ANIMALS 270 client-owned dogs.
PROCEDURES Medical records of dogs that underwent abdominal CT from June 2013 through June 2014 were reviewed. Patients were excluded if they had undergone CT because of a history or clinical signs of an adrenal gland mass or disease. Information collected included history, signalment, initial complaint, serum alkaline phosphatase activity, urine specific gravity, and whether abdominal ultrasonography was performed. Imaging reports generated by the board-certified radiologist who evaluated the CT images were reviewed.
RESULTS Incidental adrenal gland masses were detected in 25 of the 270 (9.3%) dogs. Dogs with incidental adrenal gland masses were significantly older (median, 12.0 years; range, 8.0 to 15.0 years) than dogs without (8.2 years; range, 0.1 to 13.1 years). Dogs examined for neoplasia were significantly more likely to have an incidental adrenal gland mass (22/138 [15.9%]) than were dogs examined for any other reason (3/132 [2.3%]), but these dogs were also significantly older. No other risk factors were identified. Histologic examination was performed in only 3 of the 25 dogs with incidental adrenal gland masses; 2 had cortical adenomas and 1 had a pheochromocytoma and cortical adenoma.
CONCLUSIONS AND CLINICAL RELEVANCE Results suggested that a clinically important percentage of dogs undergoing abdominal CT will have incidental adrenal gland masses, with incidental masses more likely in older than in younger dogs.
Case Description—A 7-year-old spayed female Labrador Retriever was evaluated because of pericardial effusion.
Clinical Findings—The dog had a history of decreased appetite and exercise intolerance of 3 days' duration. Thoracic radiography performed by the referring veterinarian revealed a large cardiac silhouette. Heart sounds were muffled. Echocardiographic findings were indicative of severe pericardial effusion with cardiac tamponade; no pleural effusion was identified. Pericardiocentesis yielded a considerable amount of chylous fluid. A diagnosis of chylopericardium in the absence of pleural effusion was made.
Treatment and Outcome—Conservative management was not effective, and subtotal pericardectomy and thoracic duct ligation were recommended. Surgery was postponed by the owners for 25 days, at which time the dog had both chylopericardium and chylothorax. The dog underwent subtotal pericardectomy and thoracic duct ligation; to delineate the thoracic duct, intraoperative lymphangiography was performed by injection of a radiopaque contrast agent directly into a mesenteric lymph node and subsequent injection of methylene blue solution into another mesenteric lymph node. Surgical treatment resulted in complete resolution of the clinical signs and pleural effusion.
Clinical Relevance—To the authors' knowledge, this is the first report of the development of chylopericardium prior to development of chylothorax in a dog. Treatment with thoracic duct ligation and pericardectomy resulted in complete resolution of the effusion and clinical signs.
Objective—To evaluate the effects of endotoxin administered IV on glucose and insulin dynamics in horses.
Animals—16 healthy adult mares.
Procedures—Each week of a 2-week randomized crossover study, each horse received an IV injection (duration, 30 minutes) of Escherichia coli O55:B5 lipopolysaccharide (LPS) in 60 mL of sterile saline (0.9% NaCl) solution (20 ng/kg) or sterile saline solution alone (control treatment). Frequently sampled IV glucose tolerance test procedures were performed at 24 hours before (baseline) and 24 and 48 hours after injection; glucose and insulin dynamics were assessed via minimal model analysis.
Results—13 of 16 horses had a clinical response to LPS, which was characterized by mild colic and leukopenia. Before treatment, mean ± SD insulin sensitivity was 2.9 ± 1.9 × 10−4 L·min−1·mU−1; this significantly decreased to 0.9 ± 0.9 × 10−4 L·min−1·mU−1 24 hours after treatment (69% reduction) and was 1.5 ± 0.9 × 10−4 L·min−1·mU−1 48 hours after treatment. At baseline, mean ± SD acute insulin response to glucose was 520 ± 196 mU·min·L−1; this significantly increased to 938 ± 620 mU·min·L−1 (80% increase) and 755 ± 400 mU·min·L−1 (45% increase) at 24 and 48 hours after LPS treatment, respectively.
Conclusions and Clinical Relevance—Compared with baseline values, insulin sensitivity was decreased for 24 hours after IV injection of LPS, and affected horses had a compensatory pancreatic response. These disturbances in glucose and insulin dynamics may contribute to development of laminitis in horses.
Objective—To assess survival time in dogs that underwent treatment for stage III osteosarcoma and evaluate factors affecting survival.
Design—Retrospective case series.
Animals—90 dogs with stage III osteosarcoma.
Procedures—Records in the osteosarcoma database at the Animal Cancer Center at Colorado State University from 1985 to 2004 were searched for dogs with metastatic disease at the time of evaluation. Dogs were included in the study if they had metastasis to any site and if treatment was initiated. A Kaplan-Meier survival analysis was performed, and the influences of age, sex, breed, primary tumor site, metastatic sites, and treatment on outcome were analyzed via log-rank analysis.
Results—Median survival time was 76 days, with a range of 0 to 1,583 days. No significant differences in survival times on the basis of age, sex, breed, or primary site were observed. Breeds and primary tumor sites were typical of those usually associated with osteosarcoma in dogs. Dogs treated palliatively with radiation therapy and chemotherapy had a significantly longer survival time (130 days) than dogs in all other treatment groups. Dogs treated with surgery alone had a significantly shorter survival time (3 days) than dogs treated with surgery and chemotherapy (78 days). Dogs with bone metastases had a longer survival time than dogs with soft tissue metastases.
Conclusions and Clinical Relevance—Treatment of dogs with stage III osteosarcoma can result in various survival times. Dogs with metastasis to bone and dogs that were treated palliatively with radiation and chemotherapy had the longest survival times.