A prospective evaluation of CT in acutely paraparetic chondrodystrophic dogs.

The clinical usefulness of computed tomography (CT) as a sole diagnostic modality in identifying disc lesion(s) in chondrodystrophic breeds presenting with acute signs of intervertebral disc disease (IVDD) is incompletely characterized. CT was used prospectively to determine the validity of this tool. Neurologic examinations and CT scans were performed on all dogs at presentation. Surgical decompression was based on those findings. Clinical follow-up examinations were performed on days 1 and 14 postsurgically. CT detected a lesion consistent with clinical findings in 63 of 69 cases (91%). All 63 dogs with Hansen type I IVDD lesions were identified on CT alone. The surgeon and radiologist agreed on lesion level in 72 of 78 lesions (92%) and lateralization in 71 of 78 lesions (91%). Improvement in neurologic grade was documented in 60 of 69 dogs (87%) by 14 days. CT imaging can be used as a single imaging modality in chondrodystrophic dogs presenting with acute paresis. CT used in this manner is a reliable and noninvasive tool for detecting spinal compression secondary to IVDD in chondrodystrophic dogs.

Pharmacokinetics of levetiracetam after oral and intravenous administration of a single dose to clinically normal cats.

OBJECTIVE: To determine whether therapeutic concentrations of levetiracetam can be achieved in cats and to establish reasonable i.v. and oral dosing intervals that would not be associated with adverse effects in cats. ANIMALS: 10 healthy purpose-bred cats. PROCEDURES: In a randomized crossover study, levetiracetam (20 mg/kg) was administered orally and i.v. to each cat. Blood samples were collected 0, 10, 20, and 40 minutes and 1, 1.5, 2, 3, 4, 6, 9, 12, and 24 hours after administration. Plasma levetiracetam concentrations were determined via high-performance liquid chromatography. RESULTS: Mean ± SD peak concentration was 25.54 ± 7.97 µg/mL. The mean y-intercept for i.v. administration was 37.52 ± 6.79 µg/mL. Half-life (harmonic mean ± pseudo-SD) was 2.95 ± 0.95 hours and 2.86 ± 0.65 hours for oral and i.v. administration, respectively. Mean volume of distribution at steady state was 0.52 ± 0.09 L/kg, and mean clearance was 2.0 ± 0.60 mL/kg/min. Mean oral bioavailability was 102 ± 39%. Plasma drug concentrations were maintained in the therapeutic range reported for humans (5 to 45 µg/mL) for at least 9 hours after administration in 7 of 10 cats. Only mild, transient hypersalivation was evident in some cats after oral administration. CONCLUSIONS AND CLINICAL RELEVANCE: Levetiracetam (20 mg/kg) administered orally or i.v. to cats every 8 hours should achieve and maintain concentrations within the therapeutic range for humans. Levetiracetam administration has favorable pharmacokinetics for clinical use, was apparently tolerated well, and may be a reasonable alternative antiepileptic drug in cats.

Survival of a suspected case of central nervous system cuterebrosis in a dog: clinical and magnetic resonance imaging findings.

A 3-year-old, spayed female rat terrier was evaluated for acute onset of stupor, disorientation, and tetraparesis. Clinical signs progressed over 3 weeks to eventual right-sided hemiparesis and circling to the left. A Cuterebra spp. larva was discovered in the vomitus of the dog 2 weeks after the onset of clinical signs. Cerebrospinal fluid analysis showed chronic inflammation, and magnetic resonance imaging supported a diagnosis of a parasitic tract through the left cerebral hemisphere. Medical management included a tapering anti-inflammatory dose of prednisone. Clinical signs improved slowly over time. This is the first description of a presumptive antemortem diagnosis of canine cuterebrosis in the central nervous system.

Canine hypophysectomy using a ventral paramedian approach.

OBJECTIVE: To evaluate the degree of pituitary exposure, completeness of hypophysectomy, and perioperative morbidity associated with an alternative paramedian surgical approach and excisional technique for the canine pituitary gland. STUDY DESIGN: Experimental imaging, surgical, and endocrinologic study. ANIMAL POPULATION: Nine healthy, purpose-bred Beagle dogs. METHODS: Surgical landmarks for the pituitary were determined by computed tomography (CT), and then using a ventral paramedian approach medial to the rami of the mandible, the pituitary was exposed and removed en bloc by manipulation and ultrasonic aspiration. Efficacy of the procedure was evaluated using endocrinologic and pathologic observation. RESULTS: CT images allowed the precise location of surgical landmarks for hypophysectomy. Statistically significant decreases in secretion of all measured pituitary hormones except adrenocorticotropic hormone (ACTH) occurred after hypophysectomy. Despite the absence of gross evidence of residual pituitary tissue, immunohistochemical staining revealed residual pituitary cells in the sella turcica of most dogs. CONCLUSION: CT imaging and a paramedian approach facilitated surgical access to the pituitary gland by a transoral technique; however, use of an ultrasonic aspirator removed all visible pituitary glands but left cellular remnants capable of ACTH secretion in the sella turcica. CLINICAL RELEVANCE: Although this technique did not result in complete hypophysectomy, clinical use in dogs with pituitary-dependent hyperadrenocorticism is warranted because the goal is not complete hypophysectomy but removal of a pituitary tumor.

Surgery alone or in combination with radiation therapy for treatment of intracranial meningiomas in dogs: 31 cases (1989-2002).

OBJECTIVE: To compare, for dogs with intracranial meningiomas, survival times for dogs treated with surgical resection followed by radiation therapy with survival times for dogs treated with surgery alone. DESIGN: Retrospective study. ANIMALS: 31 dogs with intracranial meningiomas. PROCEDURE: Medical records of dogs with histologic confirmation of an intracranial meningioma were reviewed. For each dog, signalment, clinical signs, tumor location, treatment protocol, and survival time were obtained from the medical record and through follow-up telephone interviews. RESULTS: Dogs that underwent tumor resection alone and survived > 1 week after surgery had a median survival time of 7 months (range, 0.5 to 22 months). Dogs that underwent tumor resection followed by radiation therapy had a median survival time of 16.5 months (range, 3 to 58 months). CONCLUSIONS AND CLINICAL RELEVANCE: Results suggest that in dogs with intracranial meningiomas, use of radiation therapy as a supplement to tumor resection can significantly extend life expectancy.