Nontraumatic rupture of an adrenal gland tumor causing intra-abdominal or retroperitoneal hemorrhage in four dogs.

Diagnosis and surgical management of intra-abdominal or retroperitoneal hemorrhage in 4 dogs with rupture of an adrenal gland tumor were determined. All 4 dogs were lethargic and weak with pale mucous membranes on initial examination. Three dogs did not have any history of clinical signs of hyperadrenocorticism or pheochromocytoma prior to examination. In 3 of the dogs, a mass in the area of the adrenal gland was identified with ultrasonography prior to surgery. All dogs developed ventricular premature contractions before or during anesthesia. Three dogs survived adrenalectomy; 1 dog was euthanatized during surgery because of an inability to achieve adequate hemostasis. The remaining 3 dogs all survived more than 5 months after surgery; 1 was euthanatized 9 months after surgery because of rupture of a hepatic mass. On the basis of these results, we suggest that hemodynamic stabilization followed by adrenalectomy is the treatment of choice for dogs with nontraumatic rupture of an adrenal gland tumor and resulting life-threatening hemorrhage.

Comparison of pharmacokinetics of fentanyl after intravenous and transdermal administration in cats.

OBJECTIVE: To compare pharmacokinetic and pharmacodynamic characteristics of fentanyl citrate after IV or transdermal administration in cats. ANIMALS: 6 healthy adult cats with a mean weight of 3.78 kg. PROCEDURE: Each cat was given fentanyl IV (25 mg/cat; mean +/- SD dosage, 7.19 +/- 1.17 mg/kg of body weight) and via a transdermal patch (25 microg of fentanyl/h). Plasma concentrations of fentanyl were measured by use of radioimmunoassay. Pharmacokinetic analyses of plasma drug concentrations were conducted, using an automated curve-stripping process followed by nonlinear, least-squares regression. Transdermal delivery of drug was calculated by use of IV pharmacokinetic data. RESULTS: Plasma concentrations of fentanyl given IV decreased rapidly (mean elimination half-life, 2.35 +/- 0.57 hours). Mean +/- SEM calculated rate of transdermal delivery of fentanyl was 8.48 +/- 1.7 mg/h (< 36% of the theoretical 25 mg/h). Median steady-state concentration of fentanyl 12 to 100 hours after application of the transdermal patch was 1.58 ng/ml. Plasma concentrations of fentanyl < 1.0 ng/ml were detected in 4 of 6 cats 12 hours after patch application, 5 of 6 cats 18 and 24 hours after application, and 6 of 6 cats 36 hours after application. CONCLUSIONS AND CLINICAL RELEVANCE: In cats, transdermal administration provides sustained plasma concentrations of fentanyl citrate throughout a 5-day period. Variation of plasma drug concentrations with transdermal absorption for each cat was pronounced. Transdermal administration of fentanyl has potential for use in cats for long-term control of pain after surgery or chronic pain associated with cancer.

Tracheal rupture in cats: 16 cases (1983-1998).

OBJECTIVE: To determine causes of tracheal rupture in cats and the mechanism of injury. DESIGN: A retrospective study was conducted to identify cats with tracheal rupture. A second study was conducted to establish mechanism of injury, and a third study was conducted to determine volume of air needed to obtain an airtight seal when inflating the cuff of an endotracheal tube in a cat. ANIMALS: 16 cats with clinical signs of tracheal rupture, 10 cat cadavers, and 20 clinically normal cats that were undergoing anesthesia. PROCEDURES: Details were extracted from medical records of 16 cats with tracheal rupture (9 treated surgically and 7 treated conservatively). For the cadaver study, the trachea of each cat cadaver was intubated and observed during overinflation of the endotracheal tube cuff. For clinically normal cats, volume of air needed to obtain an airtight seal for the endotracheal tube was recorded. RESULTS: Most ruptures were associated with cats anesthetized for dental procedures. Clinical signs associated with tracheal rupture included subcutaneous emphysema, coughing, gagging, dyspnea, anorexia, and fever. Tracheoscopy was the method of choice for documenting tracheal rupture. Surgical and conservative management were successfully used, unless the injury extended to the carina. In the cadaver study, overinflation of the endotracheal tube cuff with > 6 ml of air resulted in tracheal rupture in 7 of 10 cadavers. For clinically normal cats, the volume of air (mean +/- SD) needed to obtain an airtight seal was 1.6 +/- 0.7 ml. CLINICAL IMPLICATIONS: Overinflation of an endotracheal tube cuff may result in tracheal rupture in cats.

Abnormalities of the thoracic bellows: stress fractures of the ribs and hiatal hernia.

The thoracic bellows mechanism consists of the rib cage and the diaphragm. The purpose of this study was to determine if nontraumatically acquired lesions of the bellows were secondary to underlying disease. Abnormalities of the bellows, specifically stress fractures of the ribs and hiatal hernia, were found in 21 dogs and cats with underlying cardiopulmonary disease, neuromuscular disease, or metabolic disease. A case-control study of Bulldogs demonstrated that hiatal hernia was associated with the more severe manifestations of brachycephalic syndrome. Stress fractures occurred mostly in females and in cats, and involved multiple ribs. Fractures were usually related to severe respiratory effort, but also occurred in association with metabolic disease. Hiatal hernia was also associated with severe respiratory effort, but may be exacerbated if a neuromuscular disorder affecting the diaphragm is present. Abnormalities of the thoracic bellows, such as rib stress fractures and hiatal hernia, may be signs of underlying disease, rather than being primary causes of disease.

Comparison of transdermal fentanyl and intramuscular oxymorphone on post-operative behaviour after ovariohysterectomy in dogs.

The effects of transdermal fentanyl and i.m. oxymorphone on behavioural and physiological responses, after ovariohysterectomy in dogs, were investigated. The study involved three groups of 10 dogs: fentanyl/surgery (FS), oxymorphone/surgery (OS), fentanyl/control (FC). A transdermal fentanyl delivery system (50 microg hour(-1)) (FS and FC) was applied 20 hours before surgery, or i.m. oxymorphone (OS) was administered. After ovariohysterectomy (FS and OS) or anaesthesia alone (FC), dogs were continuously videotaped for 24 hours and a standardised hourly interaction with a handler performed. The videotapes were analysed, and interactive and non-interactive behaviours evaluated. In addition, pain and sedation scores, pulse and respiratory rates, rectal temperature, arterial blood pressure, plasma cortisol and plasma fentanyl concentrations were measured. This study showed that transdermal fentanyl and i.m. oxymorphone (0.05 mg kg(-1)) produced comparable analgesic effects over a 24 hour recording period. I.m. oxymorphone produced significantly more sedation and lower rectal temperatures than transdermal fentanyl. There were no significant differences between groups in respiratory and heart rates, and arterial blood pressures.

Use of colostomy to manage rectal disease in dogs.

OBJECTIVE: The purpose of this study was to develop a diverting colostomy technique for use in dogs. STUDY DESIGN: Clinical case series. ANIMALS: Five client-owned dogs presented for diseases requiring diverting colostomy during treatment. METHODS: Diverting colostomy was performed in five dogs. A ventral approach was used in the first dog and the colon was exteriorized adjacent to the linea alba. The technique used in the next four dogs involved creation of a left flank rod-supported loop colostomy in which the colon was exteriorized through a muscle-separating flank approach to the abdomen. RESULTS: Peritoneal leakage of fecal material resulted in the perioperative death of the first dog. The flank colostomies were maintained for times ranging form 3.5 weeks to 7 months. No major complications were observed, but skin excoriation occurred occasionally around the stoma sites in all dogs. CONCLUSION: Diverting colostomy is a technique that is suitable for use in treatment of dogs with obstruction or leakage involving the distal colon or rectum.

Management of osteoarthritis in cats.

OA is a disease of the geriatric cat. Clinical signs include weight loss, anorexia, depression, urinating outside the litter box, poor grooming, and lameness. Radiographs, synovial fluid analysis, and synovial biopsy are used to distinguish this disease from the various forms of inflammatory arthritis that affect the cat. Management consists mainly of environmental manipulation. Aspirin, butorphanol, corticosteroids, and nutritional supplements are used for chronic treatment of painful OA in cats.

Vestibulovaginal stenosis in dogs: 18 cases (1987-1995).

OBJECTIVE: To evaluate vestibulovaginal stenosis in dogs. DESIGN: Retrospective study. ANIMALS: 18 dogs with vestibulovaginal stenosis diagnosed between January 1987 and June 1995. PROCEDURE: Signalment, results of physical examination, and diagnostic testing, treatment, and outcome were analyzed. RESULTS: Mean age at initial examination was 4.6 years. Problems reported by the owners included signs of chronic urinary tract infection (6 dogs), urinary incontinence (4), failure to mate (4), signs of chronic vaginitis (2), and inappropriate urination (1). One dog did not have evidence of a clinical problem. Vestibulovaginal stenosis was detected by means of digital vaginal examination (18/18 dogs), vaginoscopy (17/17 dogs), and positive-contrast vaginography (9/10 dogs). Bacteria were isolated from the urine of 11 of 15 dogs. Twelve of 18 dogs were treated. Manual dilation (4 dogs) and T-shaped vaginoplasty (4) were less successful than vaginectomy (2) or resection of the stenotic area (3). Four of 6 dogs with signs of recurrent urinary tract infection underwent surgical correction, and none of these dogs subsequently had urinary tract infection. Three of 4 dogs with urinary incontinence responded to medical or surgical treatment for sphincter incompetence or for ectopic ureters. CLINICAL IMPLICATIONS: Surgical correction of vestibulovaginal stenosis is indicated in dogs that have mating difficulties or signs of recurrent urinary tract infection or chronic vaginitis, but stenosis is probably an incidental finding in most dogs with urinary incontinence. Vaginectomy and vaginal resection and anastomosis are the preferred surgical options.

Effect of ovariohysterectomy on maintenance energy requirement in cats.

OBJECTIVE: To determine whether maintenance energy requirement (MER) to maintain stable body weight (BW) is substantially lower for spayed female cats than for sexually intact female cats and to assess whether an equation commonly used to estimate MER would accurately predict caloric need in spayed cats. DESIGN: Prospective study. ANIMALS: 10 spayed and 5 sham-operated young adult female cats. PROCEDURE: During an acclimatization period, initial daily food allowance was determined by estimating MER as 1.4 x (30 x BW + 70), then adjusted weekly to maintain BW within 200 g of baseline. Ovariohysterectomy (OHE) or sham laparotomy was performed at week 7, and the study was continued for 15 additional weeks (period 1). To correct for a presumptive effect of continued musculoskeletal growth that resulted in some cats becoming unacceptably thin during period 1, the study was repeated over an additional 10 weeks (period 2), using a new estimate of MER calculated from BW measured after reestablishing normal body condition. RESULTS: Substantial restriction in food allowance was necessary to prevent BW gain in the OHE group during both periods. Caloric intake of spayed cats in dietary balance was significantly lower than that of control cats at the end of each study period. Sexually intact cats appeared to self-regulate food intake, whereas spayed cats tended to eat all food available to them. Significant differences were not detected between OHE and control groups in observations of physical activity before or after surgery. The equation used to predict caloric needs overestimated the apparent MER for spayed and sexually intact cats. CLINICAL IMPLICATIONS: Ad libitum feeding of spayed cats may be inadvisable, and careful monitoring of food allowance, relative to body condition, is suggested to prevent excessive weight gain.

Disposition of transdermally administered fentanyl in dogs.

OBJECTIVE: To evaluate the disposition of fentanyl after i.v. and transdermal administrations. The hypothesis was that transdermal administration of fentanyl would result in a measurable plasma opioid concentration. DESIGN: Each dog received 2 treatments in a randomized, crossover design. ANIMALS: 6 clinically normal Beagles. PROCEDURE: 2 treatments consisting of i.v. fentanyl (50 micrograms/kg of body weight) and transdermal fentanyl (50 micrograms/h) administrations. Plasma fentanyl concentrations were measured at fixed times, and pharmacokinetic values were calculated. RESULTS: Intravenous pharmacokinetics of fentanyl was similar to those previously described in dogs and provided the distribution and clearance data necessary to calculate the rate of absorption of the transdermally administered opioid. The transdermal fentanyl patch produced average steady-state concentrations of 1.6 ng/ml. The actual rate of delivery of transdermal fentanyl was 35.7 (range, 13.7 to 49.8) micrograms/h, which represented 71.48% (range, 27.45 to 99.56%) of the theoretical rate of delivery. The mean elimination half-life of fentanyl after patch removal was 1.39 hours. CONCLUSIONS: Transdermally administered fentanyl resulted in fairly constant plasma concentrations, in the range generally considered to be analgesic, from 24 to 72 hours after application of the patch. The rate of drug delivery was less than expected, and there was substantial individual variation. CLINICAL RELEVANCE: Transdermally administered fentanyl has the potential to be a clinically useful analgesic regimen in dogs, and further evaluation of its analgesic actions and potential side effects warranted

Nonendoscopic antegrade percutaneous gastrostomy: the effect of preplacement gastric insufflation on tube position and intra-abdominal anatomy.

Nonendoscopic tube gastrostomy was performed on 47 anesthetized dogs using the technique of Fulton and Dennis with or without gastric insufflation prior to tube placement. Immediately after tube placement, dogs were euthanized and postmortem examinations performed. When gastric insufflation was not performed (group I), gastrostomy tubes penetrated the visceral surface of the stomach in 25% of dogs. The deep leaf of the omentum was interposed between stomach and body wall in the majority of these dogs, exposing other intra-abdominal organs to potential injury. Additionally, displacement and tethering of the spleen cranial to the gastrostomy site were observed in 33% of dogs in group I. Similar results were obtained when preplacement gastric insufflation was performed after the orogastric tube was inserted sufficiently far to displace the stomach laterally against the body wall (group II). In contrast, consistent positioning of gastrostomy tubes through the parietal surface of the stomach was achieved when the stomach was insufflated prior to lateralizing the left abdominal wall with the gastric end of the orogastric tube (group III). It was concluded that the blind percutaneous gastrostomy technique is made safer by insufflating the stomach immediately prior to pushing the gastric wall laterally into contact with the parietal peritoneum.

Splenic infarction in 16 dogs: a retrospective study.

Sixteen dogs with splenic infarction due to causes other than splenic torsion were identified. Dogs with splenic infarction often had multiple concurrent diseases, and surgical management of splenic infarction was associated with high mortality. Splenic infarction occurred in dogs with hypercoagulable conditions associated with liver disease, renal disease, and hyperadrenocorticism, or as a consequence of uniform splenomegaly, neoplasia, or thrombosis associated with cardiovascular disease. Clinical signs and common laboratory findings generally reflected the underlying disease process. A variety of splenic abnormalities were detected by abdominal ultrasound in 15 dogs, with the ventral extremity of the spleen being most often abnormal. Four dogs were euthanized or died because of the presence of severe systemic disease, whereas 12 dogs underwent laparotomy. Complete splenectomy was performed in 9 dogs and partial splenectomy was performed in 2 dogs. Seven dogs died in the immediate postoperative period, 3 required chronic veterinary care, and 2 had uncomplicated long-term recoveries. Splenic infaraction should be regarded as a sign of altered blood flow and coagulation, rather than as a primary disease, and surgical management should be reserved for patients with life-threatening complications such as hemoabdomen or sepsis.

Pharmacological management of pain and infection in the surgical oncology patient.

Surgical oncology patients are often high-risk patients that require careful perioperative management for a successful outcome. Prophylactic antibiotics are needed to prevent infection in tissues compromised by disease, radiation, or chemotherapy. Pain control is needed to prevent the stress response to surgery from worsening the outcome and to aid in the maintenance of patient comfort.

Sclerosing encapsulating peritonitis in four dogs and a cat.

Sclerosing encapsulating peritonitis (SEP) was diagnosed in four dogs and one cat. Clinical signs included vomiting, abdominal pain, palpable abdominal mass, and ascites. The abdominal fluid was red-tinged and contained large numbers of red blood cells, macrophages, mixed inflammatory cells, reactive mesothelial cells, and fibroblasts. At surgery, the typical appearance was of multiple surfaces covered with granulation tissue or fibrous tissue or both. Multiple adhesions were often present. Causes of SEP included steatitis, fiberglass ingestion, and bacterial infection. Treatment included administration of antibiotic, corticosteroid, and diuretic medications. The major long-term management problems were chronic weight loss, ascites, and progression of concurrent disease.

ATP-MgCl2 increases cisplatin toxicity in the dog and rat.

The purpose of this study was to examine if ATP-MgCl2, an agent that protects against acute cisplatin toxicity in vitro, protected against cisplatin toxicity in vivo. Baseline renal function measurements were obtained on dogs (n = 12) and rats (n = 20) on day -1. Dogs were given 90 mg m-2 cisplatin (n = 5), 90 mg m-2 cisplatin and 50 mumol kg-1 ATP-MgCl2 (n = 5), or 90 mg m-2 cisplatin and 150 mumol kg-1 ATP-MgCl2 (n = 2), in a slow bolus i.v. injection on day 0. Rats were given 4 mg kg-1 cisplatin i.p. (n = 6) and 25 mumol kg ATP-MgCl2 (n = 8) i.v. or 4 mg kg-1 cisplatin i.p. and 25 mumol kg-1 ATP-MgCl2 (n = 6) i.v. on day 0. Renal function was assessed on a routine basis for 14 days. All dogs had significantly decreased creatinine clearance following cisplatin administration. There were no significant differences in renal function tests between groups of dogs. One dog given 50 mumol kg-1 ATP-MgCl2 and both dogs given 150 mumol kg-1 ATP-MgCl2 in addition to cisplatin developed acute anuric renal failure and were euthanatized prior to completion of the study. Rats given 4 mg kg-1 cisplatin and 25 mumol kg-1 ATP-MgCl2 had significantly increased blood urea nitrogen and serum creatinine after drug administration, compared to rats given cisplatin alone. The results indicated that ATP-MgCl2 worsened in vivo cisplatin renal toxicity in the dog and rat.

Unusual prostatic mass in a dog.

Marginal surgical resection and castration were successfully used to treat a dog with a large benign mass involving only the left lobe of the prostate. Pathologic findings were compatible with unusual nodular hyperplasia or adenoma, with smooth muscle proliferation. Although the definitive diagnosis remains controversial, the mass was termed nodular hyperplasia because of histologic and clinical similarities to the disease in human beings.

Effect of time of cisplatin administration on its toxicity and pharmacokinetics in dogs.

Cisplatin (90 mg/m2) was administered in a 5-minute bolus IV infusion to dogs at 8 AM (n = 6) or 4 PM (n = 6). Blood and urine samples were collected over a 4-hour period for statistical moment pharmacokinetic analysis. Mean urinary excretion rate of total platinum was increased, whereas mean plasma residence time of ultrafilterable platinum was decreased, in the group treated at 4 PM (PM group), compared with those treated at 8 AM (AM group). Over a 2-week postinfusion-monitoring period, both groups of dogs developed decreases in creatinine clearance, urine/serum osmolality ratio (UOsm/SOsm), specific gravity, and increase in BUN, serum creatinine concentration, urine gamma-glutamyltranspeptidase/urine creatinine ratio (UGGT/UCr), fractional excretion of magnesium, and fractional excretion of phosphate. Urine specific gravity and UOsm/SOsm were significantly decreased, whereas UGGT/UCr and BUN were significantly increased in the AM group, compared with the PM group. The time of administration had a significant effect on the pharmacokinetics of cisplatin, which resulted in significant differences in cisplatin-induced renal toxicosis.