Presumed pituitary apoplexy in 26 dogs: Clinical findings, treatments, and outcomes.

BACKGROUND: Pituitary apoplexy refers to hemorrhage or infarction within the pituitary gland resulting in acute neurological abnormalities. This condition is poorly described in dogs. OBJECTIVES: To document presenting complaints, examination findings, endocrinopathies, magnetic resonance imaging (MRI), treatments, and outcomes of dogs with pituitary apoplexy. ANIMALS: Twenty-six client-owned dogs with acute onset of neurological dysfunction. METHODS: Retrospective case series. Dogs were diagnosed with pituitary apoplexy if MRI or histopathology documented an intrasellar or suprasellar mass with evidence of hemorrhage or infarction in conjunction with acute neurological dysfunction. Clinical information was obtained from medical records and imaging reports. RESULTS: Common presenting complaints included altered mentation (16/26, 62%) and gastrointestinal dysfunction (14/26, 54%). Gait or posture changes (22/26, 85%), mentation changes (18/26, 69%), cranial neuropathies (17/26, 65%), cervical or head hyperpathia (12/26, 46%), and hyperthermia (8/26, 31%) were the most frequent exam findings. Ten dogs (38%) lacked evidence of an endocrinopathy before presentation. Common MRI findings included T1-weighted hypo- to isointensity of the hemorrhagic lesion (21/25, 84%), peripheral enhancement of the pituitary mass lesion (15/25, 60%), brain herniation (14/25, 56%), and obstructive hydrocephalus (13/25, 52%). Fifteen dogs (58%) survived to hospital discharge. Seven of these dogs received medical management alone (median survival 143 days; range, 7-641 days) and 8 received medications and radiation therapy (median survival 973 days; range, 41-1719 days). CONCLUSIONS AND CLINICAL IMPORTANCE: Dogs with pituitary apoplexy present with a variety of acute signs of neurological disease and inconsistent endocrine dysfunction. Dogs that survive to discharge can have a favorable outcome.

Novel subcutaneous cytarabine infusion with the Omnipod system in dogs with meningoencephalomyelitis of unknown etiology.

OBJECTIVE: To investigate the feasibility and pharmacokinetics of cytarabine delivery as a subcutaneous continuous-rate infusion with the Omnipod system. ANIMALS: 6 client-owned dogs diagnosed with meningoencephalomyelitis of unknown etiology were enrolled through the North Carolina State University Veterinary Hospital. PROCEDURES: Cytarabine was delivered at a rate of 50 mg/m2/hour as an SC continuous-rate infusion over 8 hours using the Omnipod system. Plasma samples were collected at 0, 4, 6, 8, 10, 12, and 14 hours after initiation of the infusion. Plasma cytarabine concentrations were measured by high-pressure liquid chromatography. A nonlinear mixed-effects approach generated population pharmacokinetic parameter estimates. RESULTS: The mean peak plasma concentration (Cmax) was 7,510 ng/mL (range, 5,040 to 9,690 ng/mL; SD, 1,912.41 ng/mL), average time to Cmax was 7 hours (range, 4 to 8 hours; SD, 1.67 hours), terminal half-life was 1.13 hours (SD, 0.29 hour), and the mean area under the curve was 52,996.82 hours X µg/mL (range, 35,963.67 to 71,848.37 hours X µg/mL; SD, 12,960.90 hours X µg/mL). Cmax concentrations for all dogs were more than 1,000 ng/mL (1.0 µg/mL) at the 4-, 6-, 8-, and 10-hour time points. CLINICAL RELEVANCE: An SC continuous-rate infusion of cytarabine via the Omnipod system is feasible in dogs and was able to achieve a steady-state concentration of more than 1 µg/mL 4 to 10 hours postinitiation of cytarabine and a Cmax of 7,510 ng/mL (range, 5,040 to 9,690 ng/mL; SD, 1,912.41 ng/mL). These are comparable to values reported previously with IV continuous-rate infusion administration in healthy research Beagles and dogs with meningoencephalomyelitis of unknown etiology.

Subaxial cervical articular process subluxation and dislocation: Cervical locked facet injuries in dogs.

OBJECTIVE: To describe neurologic signs, diagnostic imaging findings, potential treatments, and outcomes in dogs with subaxial cervical articular process subluxation and dislocation, or a "locked facet." STUDY DESIGN: Retrospective case series. ANIMALS: Ten client-owned dogs. METHODS: Dogs with a diagnosis of cervical locked facets were identified through medical records and imaging reports searches. Data on presenting signs, diagnostic findings, treatment, and outcome were recorded. RESULTS: All cases were small or toy-breed dogs with preceding trauma. Four dogs were tetraplegic with intact pain perception, five were nonambulatory tetraparetic, and one was ambulatory tetraparetic, with half of the tetraparetic dogs having worse motor function in the thoracic limbs. The only sites affected were C5/6 (n = 6) and C6/7 (n = 4). All dogs had unilateral dorsal displacement of the cranial articular process of the caudal vertebra relative to the caudal articular process of the cranial vertebra at the luxation site. Five dogs were treated surgically, three by external coaptation, one by restriction, and one was euthanized the day after diagnosis. All dogs with outcome data (n = 8) became ambulatory. Nonambulatory dogs returned to ambulation in a median of 4 weeks (IQR 1-12; range 1-28). CONCLUSION: In these dogs, locked facet injuries affected the caudal cervical vertebrae in small breeds and could be identified on imaging through the presence of dorsal displacement of a cranial articular process. Our small cohort had a functional recovery regardless of treatment. CLINICAL SIGNIICANCE: Locked facet injuries should be a differential for small or toy-breed dogs with a cervical myelopathy secondary to trauma.

Outcomes and prognostic indicators in 59 paraplegic medium to large breed dogs with extensive epidural hemorrhage secondary to thoracolumbar disc extrusion.

OBJECTIVE: To evaluate outcomes and prognostic factors after decompressive hemilaminectomy in paraplegic medium to large breed dogs with extensive epidural hemorrhage (DEEH) and thoracolumbar intervertebral disc extrusion (TL-IVDE). STUDY DESIGN: Retrospective, cohort, descriptive study. ANIMALS: Fifty-nine client-owned dogs. METHODS: Medical records and advanced imaging were reviewed for paraplegic dogs with DEEH. Ambulatory status 6 months after surgery and postoperative complications were recorded. Multiple logistic regression models were constructed to explore prognostic factors. RESULTS: Records of 22 dogs with and 37 dogs without pelvic limb pain perception at presentation were included. Median age of dogs was 5 years (interquartile range, 4-7), and mean weight was 26.9 kg (SD, ±9.71). Labradors and Labrador mixes were most common (17/59 [28.8%]). Recovery of ambulation occurred in 17 of 22 (77.3%) dogs with and in 14 of 37 (37.8%) dogs without pain perception prior to surgery. Progressive myelomalacia was recorded in three of 59 (5.1%) dogs, one with pain perception and two without pain perception at presentation. Postoperative complications (14/59 [23.7%]) were common. Factors independently associated with outcome included clinical severity (odds ratio [OR] 0.179, P = .005), number of vertebrae with signal interruption in half Fourier single-shot turbo spin-echo sequences (HASTEi; OR, 0.738; P = .035), and ratio of vertebral sites decompressed to HASTEi (OR, 53.79; P = .03). CONCLUSION: Paraplegic medium to large breed dogs with DEEH have a less favorable outcome after surgical decompression than paraplegic dogs with TL-IVDE. CLINICAL SIGNIFICANCE: Dogs with DEEH can have severe postoperative complications. Loss of pain perception and increased HASTEi are associated with a poor outcome, while more extensive decompression improves outcome.