Immune-mediated polyarthritis and anterior uveitis secondary to zonisamide administration in a dog with refractory epilepsy.

The objective of this article is to describe a case of suspected zonisamide-induced immune-mediated polyarthritis (IMPA) and anterior uveitis in a dog. A 7-year-old male neutered Siberian Husky with a history of refractory idiopathic epilepsy was presented for cluster seizures. Following the addition of zonisamide to the antiepileptic regime, the dog developed new IMPA and anterior uveitis. Within a few weeks of discontinuation of the zonisamide, the dog's IMPA and anterior uveitis resolved. These immune-mediated conditions were thus presumed to be an idiosyncratic reaction to zonisamide. To our knowledge, this is the first report of IMPA and anterior uveitis in dogs associated with zonisamide administration at its recommended dose.

5-Hydroxytryptophan toxicity successfully treated by haemodialysis in a dog.

OBJECTIVE: To describe a case of 5-hydroxytryptophan (5-HTP) toxicity successfully treated with haemodialysis in a dog. CASE SUMMARY: A 3-year-old, male neutered Labrador Retriever, weighing 28.2 kg, presented to the emergency department approximately 4-5 h after ingesting a human supplement containing 200 mg of 5-HTP. The amount of 5-HTP ingested was estimated between 980 and 1988 mg (35-71 mg/kg). At presentation, the dog demonstrated progressive neurologic abnormalities consistent with serotonin syndrome, including altered mentation and ataxia. Due to the magnitude of the ingested dose and progression of clinical signs, extracorporeal blood purification with intermittent haemodialysis was chosen to expedite clearance of 5-HTP. High-efficiency haemodialysis was initiated, and the dog showed continued clinical improvement throughout the 5-h treatment. Clinical signs resolved completely within 12 h. Sequential blood and urine samples were obtained to document levels of both 5-HTP and serotonin. The dog was discharged 24 h after presentation with complete resolution of clinical signs. NEW OR UNIQUE INFORMATION: This is the first report documenting the serial changes in 5-HTP concentrations during treatment with haemodialysis.

Successful treatment of 5-fluorouracil toxicosis with hemodialysis.

OBJECTIVE: To describe the successful treatment of lethal dose 5-fluorouracil (5-FU) toxicosis using hemodialysis. CASE SUMMARY: A 4-month-old intact female Golden Retriever was presented to the emergency department after ingesting 20 g of 5% 5-FU cream. The puppy developed refractory seizures and became comatose with uncontrolled tonic-clonic convulsions. Because of the low molecular weight and minimal protein binding of 5-FU, a single hemodialysis treatment was employed for detoxification. The puppy improved clinically posttreatment and was successfully discharged 3 days after admission. Postingestion leukopenia and neutropenia occurred but were responsive to treatment with filgrastim. The puppy is neurologically normal and has no lasting effects 1 year postingestion. NEW OR UNIQUE INFORMATION PROVIDED: To the authors' knowledge, this is the first reported case in veterinary medicine of a potentially fatal 5-FU ingestion that has been treated with intermittent hemodialysis.

Acute kidney injury from presumptive intramural ureteral hemorrhage secondary to diphacinone rodenticide exposure in a dog.

OBJECTIVE: To describe the clinical features and outcome of a dog with anticoagulant rodenticide (diphacinone) exposure, which was subsequently diagnosed with a coagulopathy characterized by hemoperitoneum, and presumptive ureteral wall hemorrhage contributing to acute kidney injury (AKI). CASE SUMMARY: A 4-year-old, female neutered Australian Cattle Dog was evaluated for an acute onset of lethargy, decreased appetite, and a mild right thoracic limb lameness. Radiographs and point of care ultrasound demonstrated retroperitoneal and peritoneal effusion. Diagnostic abdominocentesis confirmed hemorrhagic effusion. Complete blood count, biochemistry, and coagulation profile showed a regenerative anemia (PCV 32%), thrombocytopenia (platelets 96 × 109 /L [96 × 103 /µl]), azotemia (BUN 38.9 mmol/L [109 mg/dl], creatinine 512.8 µmol/L [5.8 mg/dl]), and coagulopathy (prothrombin time >100 s, activated partial thromboplastin time >42.3 s). The client reported access to anticoagulant rodenticide up to 72 hours prior to presentation. Ultrasonographic examination revealed bilateral pyelectasia and hydroureter with thickened distal ureteral walls at the level of the ureteral-vesicular junctions. The ultrasonographic conclusion was presumptive intramural ureteral hemorrhage resulting in ureteral obstruction. The patient was diagnosed with AKI with likely prerenal, renal, and postrenal components. Treatment included vitamin K and frozen plasma transfusion. The patient recovered fully and was discharged 3 days after presentation. Two days after discharge, the patient had improvement in azotemia (BUN 10.7 mmol/L [30 mg/dl], creatinine 176.6 µmol/L [2.0 mg/dl]). Gas chromatography-mass spectrometry confirmed presence of diphacinone in the blood. Repeat ultrasound and biochemistry 60 and 210 days, respectively, after discharge showed resolution of ureteral wall thickening, hydroureter, pyelectasia, and recovery of kidney parameters. NEW OR UNIQUE INFORMATION: Although nephropathies secondary to anticoagulant therapy have been described in people, the authors believe this is the first report of diphacinone anticoagulant rodenticide exposure contributing to an AKI secondary to obstruction from ureteral wall hemorrhage in the veterinary literature.

Pharmacokinetics and efficacy of trazodone following rectal administration of a single dose to healthy dogs.

OBJECTIVE: To determine the pharmacokinetics and efficacy of trazodone following rectal administration of a single dose to healthy dogs. ANIMALS: 6 healthy adult dogs. PROCEDURES: Each dog received a single dose of trazodone (approx 8 mg/kg) per rectum. Trazodone tablets were crushed into a powder, mixed with 5 mL of tap water, and injected into the rectum via a red rubber catheter. Sedation scores were assigned, and blood samples were collected for determination of plasma trazodone concentration at predetermined times before and after drug administration. Pharmacokinetic parameters were estimated by noncompartmental analysis. RESULTS: Plasma trazodone concentration remained below the detection limit for 1 dog even though it became moderately sedate. Median (interquartile [25th to 75th percentile] range [IQR]) maximum plasma trazodone concentration and volume of distribution and clearance corrected for bioavailability were 1.00 µg/mL (0.66 to 1.40 µg/mL), 10.3 L/kg (7.37 to 14.4 L/kg), and 639 mL/kg/h (594 to 719 mL/kg/h), respectively. Median time to maximum plasma trazodone concentration and elimination half-life were 15 minutes (range, 15 to 30 minutes) and 12 hours (IQR, 7.99 to 12.7 hours), respectively. All dogs became mildly or moderately sedate, and the extent of sedation was maximal at a median of 30 minutes (IQR, 30 to 60 minutes) after trazodone administration. No adverse effects were observed. CONCLUSIONS AND CLINICAL RELEVANCE: Rectal administration of trazodone may be a viable option for sedation and treatment of anxiety in dogs for which administration of sedatives and anxiolytics by other routes is contraindicated. Further research is necessary to better elucidate the pharmacokinetics and efficacy of trazodone following rectal administration and determine optimal dosing.

Suspected Acute Respiratory Distress Syndrome Associated With the Use of Intravenous Lipid Emulsion Therapy in a Dog: A Case Report.

A 12-year-old male neutered Bichon Frise presented to the Emergency Department for stupor and bradycardia after ingestion of chocolate covered 450 mg (90 mg/kg) tetrahydrocannabinol. The patient was hospitalized for supportive care, IV fluid therapy and monitoring in the intensive care unit. During hospitalization the patient became comatose and bradypneic. Treatment with intravenous lipid emulsion (ILE) therapy was instituted to accelerate toxin elimination, reduce the risk of complications related to progressive obtundation and shorten hospitalization time. Five hours after infusion, the patient developed severe respiratory distress and was ultimately euthanized. Post-mortem histologic evaluation of lung revealed severe pulmonary edema consistent with acute respiratory distress syndrome. There are infrequent reports of adverse effects associated with ILE therapy for toxicosis in veterinary medicine despite reports of complications such as acute respiratory distress syndrome in human literature. The purpose of this report is to describe the potential for a severe adverse event after treatment of a toxicosis with ILE therapy.

Electrolyte, acid-base, and hemoglobin oxygen affinity alterations following irradiation and storage of canine packed red blood cells.

BACKGROUND: Irradiation of RBC before transfusion is required to prevent transfusion-associated graft-versus-host disease for human patients undergoing hematopoietic stem cell transplantation. Additional applications for irradiated blood may exist in oncologic surgery. The effect of irradiation on canine packed RBC (pRBC) is unknown. OBJECTIVES: The aim of this study was to explore and characterize the in vitro electrolyte, acid-base, and oxygen-carrying capacity changes to pRBC immediately following irradiation and during storage. METHODS: Ten units of pRBC were irradiated using a linear accelerator. Concentration of potassium and glucose, percentage of free hemoglobin (fHb), hemoglobin oxygen saturation (sO2 ), total oxygen content, partial pressure of oxygen (pO2 ), the pO2 at which 50% of hemoglobin is saturated (p50), lactate, pH, and methemoglobin were measured before and following irradiation, and at 7 and 17 days post irradiation. RESULTS: In both irradiated and nonirradiated units, a significant decrease in pH and glucose, and a significant increase in lactate and potassium were noted. The pO2 , fHb, and the p50 value in both groups increased over the first 7 days. Immediately following irradiation, the pH was significantly lower, and the potassium, lactate, and fHb were significantly higher in irradiated units compared with controls. Small but significant differences were noted between irradiation status in pH, fHb, sO2 , total oxygen content, and p50 value at 7 days post irradiation. CONCLUSIONS: This hypothesis-generating study found irradiation and storage significantly altered in vitro properties of pRBC. The magnitude of these differences was small and the clinical impact of irradiation on pRBC may be negligible.