Incidence of meniscal injury in cats with cranial cruciate ligament ruptures.

This retrospective study evaluated the incidence of meniscal injury in cats with cranial cruciate ligament (CCL) ruptures. Medical records for cats diagnosed with CCL ruptures treated by a lateral fabellotibial suture (LFS) were reviewed for signalment, history, physical examination and surgical findings. Ninety-five cats (98 stifles) met the inclusion criteria. The incidence of meniscal injuries in feline CCL deficient stifles was 67%. Isolated medial meniscal injuries were found in 55 stifles (56%), isolated lateral meniscal injuries were found in 5 stifles (5%), and lateral and medial meniscal injuries were found in 6 stifles (6%). There was no correlation between the presence of a meniscal injury and age, breed, sex, weight, duration of lameness, presence of concurrent medial patellar luxation, degree of degenerative joint disease, or presenting side of lameness. Given the high rate of meniscal pathology in cats with CCL ruptures, exploratory surgery for meniscal assessment and concurrent stifle stabilization should be considered in feline patients.

Pharmacokinetics of butorphanol in cats after intramuscular and buccal transmucosal administration.

OBJECTIVE: To determine the pharmacokinetics of butorphanol in cats following IM and buccal transmucosal (BTM) administration, to determine the relative bioavailability of butorphanol following BTM administration, and to extrapolate a plasma concentration associated with antinociception on the basis of existing data from pharmacologic studies of butorphanol in cats. ANIMALS: 6 healthy adult cats. PROCEDURES: Following IM or BTM butorphanol tartrate (0.4 mg/kg) administration to cats in a 2-way crossover trial, plasma samples were obtained from blood collected via a central venous catheter during a 9-hour period. Plasma butorphanol concentrations were determined by high-performance liquid chromatography. RESULTS: Data from 1 cat contained outliers and were excluded from pharmacokinetic analysis. Mean+/-SD terminal half-life of butorphanol for the remaining 5 cats was 6.3+/-2.8 hours and 5.2+/-1.7 hours for IM and BTM administration, respectively. Peak plasma butorphanol concentrations were 132.0 and 34.4 ng/mL for IM and BTM administration, respectively. Time to maximal plasma concentration was 0.35 and 1.1 hours for IM and BTM administration, respectively. Extent of butorphanol absorption was 37.16% following BTM application. On the basis of data from extant pharmacologic studies of butorphanol in cats, mean+/-SD duration of antinociception was 155+/-130 minutes. The estimated plasma concentration corresponding to this time point was 45 ng/mL. CONCLUSIONS AND CLINICAL RELEVANCE: In cats, IM butorphanol administration at 0.4 mg/kg maintained a plasma concentration of >45 ng/mL for 2.7+/-2.2 hours, whereas BTM administration at the same dose was not effective at maintaining plasma concentrations at >45 ng/mL.

Lobar holoprosencephaly in a Miniature Schnauzer with hypodipsic hypernatremia.

A 9-month-old male Miniature Schnauzer was examined because of a lifelong history of behavioral abnormalities, including hypodipsia. Diagnostic evaluation revealed marked hypernatremia and a single forebrain ventricle. The behavioral abnormalities did not resolve with correction of the hypernatremia, and the dog was euthanatized. At necropsy, midline forebrain structures were absent or reduced in size, and normally paired forebrain structures were incompletely separated. Findings were diagnostic for holoprosencephaly, a potentially genetic disorder and the likely cause of the hypodipsia. Similar evaluation of affected Miniature Schnauzer dogs may reveal whether holoprosencephaly routinely underlies the thirst deficiency that may be seen in dogs of this breed.

Plasma fentanyl concentrations in awake cats and cats undergoing anesthesia and ovariohysterectomy using transdermal administration.

OBJECTIVE: To measure the plasma fentanyl concentrations achieved over time with transdermal fentanyl patches in awake cats and cats undergoing anesthesia and ovariohysterectomy. STUDY DESIGN: Randomized prospective experimental study. ANIMALS: Twenty-four purpose-bred cats. METHODS: Cats were randomly assigned to three groups for Part I of a larger concurrent study. Group P received only a 25 micro g hour-1 transdermal fentanyl patch. Group P/A received the patch and anesthesia. Group A received only anesthesia. After a minimum 1-week washout period, the cats were randomly reassigned to two groups for Part II of the larger study. Group P/A/O received the patch, anesthesia and ovariohysterectomy. Group A/O received anesthesia and ovariohysterectomy. Patches were left in place for 72 hours and plasma samples were obtained for fentanyl analysis while the patches were in place, and for 8 hours after patch removal for cats in Group P, P/A, and P/A/O. RESULTS: The 25 micro g hour-1 transdermal fentanyl patches were well tolerated by the cats in this study (mean body weight of 3.0 kg) and no overt adverse effects were noted. Mean plasma fentanyl concentrations over time, mean plasma fentanyl concentrations at specific times (8, 25, 49, and 73 hours after patch placement), time to first detectable plasma fentanyl concentration, time to reach maximum plasma fentanyl concentration, maximum plasma fentanyl concentration, mean plasma fentanyl concentration from 8 to 73 hours, elimination half-life, and total area under concentration (AUC) were not statistically different among the groups. CONCLUSIONS: Halothane anesthesia and anesthesia/ovariohysterectomy did not significantly alter the plasma fentanyl concentrations achieved or pharmacokinetic parameters measured, when compared with awake cats. There was a high degree of individual variability observed both within and between groups of cats in parameters measured. CLINICAL SIGNIFICANCE: The high degree of variability observed suggests that careful observation of cats with fentanyl patches in place is required to assess efficacy and any potential adverse effects. Anesthesia and anesthesia/ovariohysterectomy do not appear to alter plasma fentanyl concentrations achieved by placement of a 25 micro g hour-1 transdermal fentanyl patch when compared to cats not undergoing these procedures.

Clinical use of low-profile cystostomy tubes in four dogs and a cat.

Traditional cystostomy tubes (used for temporary or permanent diversion of urine in dogs and cats) are long (> or = 22 cm) and cumbersome to stabilize, requiring sutures or bandages to hold the tube against the body. Use of a low-profile gastrostomy port system as a low-profile cystostomy tube (LPCT) in 4 dogs and a cat was investigated; owner satisfaction with the device was assessed. Technical difficulty associated with placement and management of LPCTs was similar to that for traditional cystostomy tubes; with LPCTs, activity and mobility of pets was not compromised, and bandaging was not required. Complications included lower urinary tract infection, mild peristomal leakage of urine and leakage from components of the system, and subcutaneous peristomal infection. Four of 5 owners considered the tube to be easy to use; all owners said they would be comfortable repeating their decision to use the LPCT in their pet.