Dana L. Clarke

Use of intravenous lipid emulsion to treat ivermectin toxicosis in a Border Collie.

CASE DESCRIPTION A 2-year-old spayed female Border Collie was treated with IV lipid emulsion (ILE) after ingesting 6 mg/kg (2.73 mg/lb) of an equine ivermectin anthelmintic paste 8 hours prior to examination. CLINICAL FINDINGS On initial examination, the dog had stable cardiovascular signs but had diffuse muscle tremors and was hyperthermic. Neurologic evaluation revealed that the dog was ataxic and had mydriasis with bilaterally absent menace responses and pupillary light reflexes. The remaining physical examination findings were unremarkable. Results of CBC, serum biochemical analysis, venous blood gas analysis, and measurement of plasma lactate concentration were also within reference limits. TREATMENT AND OUTCOME The dog was treated with ILE in addition to supportive care with IV fluid therapy and cardiovascular, respiratory, and neurologic monitoring. The use of ILE treatment was initiated in this patient on the basis of previous clinical and experimental evidence supporting its use for toxicosis resulting from lipid-soluble agents. An initial bolus of 1.5 mL/kg (0.68 mL/lb) of a 20% sterile lipid solution was administered IV over 10 minutes, followed by a constant rate infusion of 0.25 mL/kg/min (0.11 mL/lb/min) over 60 minutes that was administered twice to treat clinical signs of ivermectin toxicosis. The dog was discharged from the hospital 48 hours after admission and was clinically normal within 4 days after ivermectin ingestion. Further diagnostic evaluation subsequently revealed that this dog was unaffected by the multidrug resistance gene (MDR-1) deletion, known as the ATP-binding cassette polymorphism. CLINICAL RELEVANCE Ivermectin toxicosis in veterinary patients can result in death without aggressive treatment, and severe toxicosis often requires mechanical ventilation and intensive supportive care. This is particularly true in dogs affected by the ATP-binding cassette polymorphism. Novel ILE treatment has been shown to be effective in human patients with lipid-soluble drug toxicoses, although the exact mechanism is unknown. In the patient in the present report, ILE was used successfully to treat ivermectin toxicosis, and results of serial measurement of serum ivermectin concentration supported the proposed lipid sink mechanism of action.

Spontaneous hemoperitoneum in cats: 65 cases (1994–2006)

OBJECTIVE To describe the clinical signs, physical examination findings, clinical laboratory abnormalities, etiology, and outcome in cats with spontaneous hemoperitoneum. DESIGN Retrospective case series. ANIMALS 65 client-owned cats with spontaneous hemoperitoneum. PROCEDURES Medical records of cats with spontaneous hemoperitoneum at 7 large referral clinics were reviewed. Cats were included if a definitive diagnosis of spontaneous hemoperitoneum could be obtained from review of the medical records. RESULTS 65 cats met inclusion criteria. The most common historical findings were lethargy, anorexia, and vomiting. Common findings on physical examination included inadequate hydration status and hypothermia. The most common clinicopathologic abnormalities were high serum AST activity, anemia, prolonged prothrombin time, and prolonged partial thromboplastin time. Forty-six percent (30/65) of cats had abdominal neoplasia, and 54% (35/65) had nonneoplastic conditions. Hemangiosarcoma was the most often diagnosed neoplasm (18/30; 60%), and the spleen was the most common location for neoplasia (11/30; 37%). Eight cats survived to be discharged from the hospital. Cats with neoplasia were significantly older and had significantly lower PCVs than cats with non-neoplastic disease. CONCLUSIONS AND CLINICAL RELEVANCE Spontaneous hemoperitoneum in cats often results in debilitating clinical consequences. In contrast to dogs with hemoperitoneum, the cause of hemoperitoneum in cats is approximately evenly distributed between neoplastic and nonneoplastic diseases. Although only a few cats were treated in this study, the prognosis appears poor.

Outcomes of ureteral surgery and ureteral stenting in cats: 117 cases (2006–2014)

OBJECTIVE To evaluate and compare outcomes in cats following ureteral surgery or ureteral stent placement. DESIGN Retrospective case series. ANIMALS 117 cats. PROCEDURES Data regarding signalment, history, concurrent disease, clinical signs, clinicopathologic tests, surgical procedures, and perioperative complications (including death) were recorded. Follow-up data, including presence of signs of chronic lower urinary tract disease, chronic urinary tract infection, reobstruction, and death, if applicable, were obtained by records review or telephone contact with owners. Variables of interest were compared statistically between cats treated with and without stent placement. Kaplan-Meier analysis and Cox regression were performed to assess differences in survival time between cats with and without ureteral stents. RESULTS Perioperative complications referable to the urinary tract were identified in 6 of 43 (14%) cats that had ≥ 1 ureteral stent placed and 2 of 74 (3%) cats that underwent ureteral surgery without stenting. Perioperative mortality rates were similar between cats with (4/43 [9%]) and without (6/74 [8%]) stents. After surgery, signs of chronic lower urinary tract disease and chronic urinary tract infection were significantly more common among cats with than cats without stents. Nineteen of 87 (22%) cats with follow-up information available had recurrent obstruction; incidence of reobstruction did not differ between cats with and without stents. Median survival time did not differ between the 2 groups. CONCLUSIONS AND CLINICAL RELEVANCE The potential for signs of chronic lower urinary tract disease and chronic infection, particularly among cats that receive ureteral stents, warrants appropriate client counseling. Judicious long-term follow-up for detection of reobstruction is recommended.

End-to-end ureteral anastomosis and double-pigtail ureteral stent placement for treatment of iatrogenic ureteral trauma in two dogs.

CASE DESCRIPTION A 6-month-old spayed female Soft-Coated Wheaten Terrier and 8-month-old spayed female Shih Tzu were referred because of complications related to inadvertent ureteral ligation and transection during recent ovariohysterectomy. CLINICAL FINDINGS The Soft-Coated Wheaten Terrier had a 2-day history of stranguria and polyuria that began after ovariohysterectomy. Initial examination findings were unremarkable with the exception of high rectal temperature. The Shih Tzu had a 10-day history of pyrexia, vomiting, diarrhea, and stranguria that began after ovariohysterectomy. On examination, the dog had signs of depression; clinicopathologic tests revealed hypoalbuminemia, neutrophilia, lymphocytosis, and monocytosis. Abdominal ultrasonography was performed for both dogs, revealing severe unilateral pyelectasia and hydroureter (proximal portion). TREATMENT AND OUTCOME Both dogs underwent exploratory celiotomy; ureteral ligation and transection was confirmed. Ventral cystotomy was performed to allow retrograde placement of a double-pigtail ureteral stent into the affected ureter and renal pelvis. End-to-end ureteral anastomosis was performed over the stent with the aid of an operating microscope. Stent position was confirmed via fluoroscopy, and incisions were closed routinely. Dogs continued to have intermittent signs of stranguria until stent removal via cystoscopy 6 or 7 weeks after surgery. Ultrasonographic examination of the urogenital tract was performed 2 or 4 months after surgery, revealing resolution of pyelectasia and hydroureter. CLINICAL RELEVANCE The surgical technique used provided a viable option for preserving renal function in dogs with focal, iatrogenic ureteral trauma. Use of a ureteral stent facilitated ureteral anastomosis and minimized postoperative complications.

Anesthesia Case of the Month

A 5-year-old 49.7-kg (109.3-lb) castrated male Boxer was referred to the surgical oncology service of the Matthew J. Ryan Veterinary Hospital at the University of Pennsylvania for further evaluation and treatment of a right-sided pulmonary mass discovered by the referring veterinarian on thoracic radiographs. The dog had a 3-month history of a nonproductive cough that had been treated with prednisone at an initial dosage of 1 mg/kg/d (0.45 mg/lb/d), PO, with the dosage having been gradually tapered over the previous month. There were no abnormal findings during a complete preanesthetic evaluation at the time of admission, including a physical examination with cardiopulmonary auscultation, and results of a CBC and serum biochemical analyses were within reference limits. The patient was premedicated with butorphanol (0.2 mg/kg [0.09 mg/lb], IM), and general anesthesia was induced with propofol (3 mg/kg [1.36 mg/ lb] to effect, IV). An endotracheal tube was placed and anesthesia was maintained with isoflurane in oxygen. The patient underwent CT for further evaluation of the pulmonary mass, which was noted to occupy the perihilar region of the right cranial lung lobe, with involvement of the right caudal lung lobe. Multiple CT-guided tissue fine-needle aspirates of the mass were obtained for cytologic evaluation. The patient recovered from the procedure without apparent complications. Results of cytologic examination of the fine-needle aspirates were suggestive of a diagnosis of pulmonary carcinoma. Therefore, the patient was scheduled for elective right cranial, middle, and caudal lung lobectomies via right lateral thoracotomy. On the day of surgery, the dog was panting and appeared anxious, with a heart rate of 104 beats/min and a rectal temperature of 38.5°C (101.3°F). After the dog was premedicated with oxymorphone (0.2 mg/ kg, IM), the right cephalic vein was catheterized with an 18-gauge, 1.16-in over-the-needle polyurethane catheter.a A balanced electrolyte solutionb was administered IV throughout at a rate of 5 mL/kg/h (2.3 mL/lb/h). Supplemental oxygen was provided via face mask for 5 minutes prior to induction of general anesthesia with propofol (2 mg/kg [0.9 mg/lb], IV) and midazolam (0.2 mg/kg, IV). The patient was then orotracheally intubated with an 11-mm-internal-diameter cuffed Murphy endotracheal tube and connected

Radiographic distribution of ureteral stones in 78 cats

OBJECTIVE To document the distribution of ureteral stones in cats. STUDY DESIGN Retrospective case series. ANIMALS Seventy-eight cats. METHODS Abdominal radiographs with ureteral stones were reviewed. The location of stones was categorized as proximal ureter (PU), midureter (MU), or ureterovesicular junction (UVJ). The number, size, and location of stones were recorded by using the kidneys and vertebral bodies as landmarks. Stone location in cats with 1 versus multiple stones was assessed. Descriptive statistics were used to describe the incidence of ureteral stone location. RESULTS Among cats with a single stone (44%, 34/78), 44% (15/34) had a stone in the PU, 41% (14/34) had a stone in the MU, and 15% (5/34) had a stone at the UVJ. When multiple stones were present, 61% (27/44) of cats had at least 1 stone located in the PU, 70% (31/44) had at least 1 stone located in the MU, and 34% (15/44) had at least 1 stone located at the UVJ. The L4 vertebral body most commonly marked stone location in cats with 1 stone and the most distal stone in cats with multiple stones. Stones located at the UVJ site were more common in male (37%) than in female (12%) cats (P = 0.004). Larger stone size was associated with a more proximal location (P = 0.04). CONCLUSION Ureteral stones were more commonly located in the PU and the MU than in the UVJ. UVJ stones were more common in male than in female cats, and larger stones had a more proximal location. CLINICAL SIGNIFICANCE This study enhances our understanding of feline ureteral stone location and identifies a correlation between stone location and stone size.