IMAGING DIAGNOSIS-CONCENTRIC PERIRADICULAR LIPOMA CAUSING LUMBAR NERVE ROOT COMPRESSION IN A DOG.

An 11-year-old, male neutered Jack Russell Terrier was presented with a nerve root signature of the right pelvic limb. Magnetic resonance imaging revealed a well demarcated, ovoid, extramedullary mass at the level of the L7 vertebral body. This showed, compared to normal spinal cord, hyperintense signal on T1- and T2-weighted images, which was suppressed on gradient echo short tau inversion recovery (GE-STIR) images. Additionally, the mass was characterized by a fat density on computed tomography images. Histopathology of the surgically excised mass was consistent with concentric periradicular lipoma, which has not been described in domestic animals yet.

Unusual perianesthetic malignant hyperthermia in a dog.

CASE DESCRIPTION: A 7-month-old male Siberian Husky affected by lower motor neuron tetraparesis was anesthetized for electrodiagnostic testing and collection of muscle and nerve biopsy specimens. CLINICAL FINDINGS: Preanesthetic physical examination revealed a high rectal temperature, and serum biochemical analysis revealed high muscle and liver enzyme activities. The dog was anesthetized twice. The dog was anesthetized with isoflurane and developed moderate hypercarbia and mild hyperthermia. Injectable anesthetic agents were used to anesthetize the dog the second time, during which the dog developed severe malignant hyperthermia. A genetic test performed after anesthesia did not reveal a mutation of the RYR1 gene, the gene that mediates calcium-release channels in skeletal muscle. On the basis of clinical features, and because other neuromuscular disorders were ruled out, a genetic channelopathy involving the skeletal muscle ion channels was suspected. TREATMENT AND OUTCOME: The dog was disconnected from the breathing system, and active cooling of the body was performed with ice packs applied to the body surface and alcohol applied to the foot pads. Cold crystalloid solutions were administered i.v.. Intermittent positive-pressure ventilation with 100% oxygen was performed to decrease end-tidal partial pressure of carbon dioxide. Because dantrolene was not available, acepromazine was administered to facilitate a decrease in body temperature. The dog recovered from malignant hyperthermia and was discharged to the owner after 13 days of hospitalization. CLINICAL RELEVANCE: Dogs affected by genetic muscle disorders should be considered at risk for perianesthetic malignant hyperthermia, even in the absence of an RYR1 gene mutation.

Continuous electroencephalographic monitoring of status epilepticus in dogs and cats: 10 patients (2004-2005).

OBJECTIVE: To describe the use of continuous electroencephalographic (EEG) monitoring for management of status epilepticus (SE) in dogs and cats. DESIGN: Retrospective study. SETTING: University teaching hospital. ANIMALS: Ten patients (7 dogs, 3 cats) with SE of differing etiology (idiopathic epilepsy, n=3; toxicity, n=4; meningoencephalitis, n=2; undefined, n=1). INTERVENTIONS: The EEG was recorded continuously from 5 stainless-steel needle electrodes inserted SC. Animals were treated with diazepam and phenobarbital followed by either propofol (n=3) or pentobarbital (n=7) as a continuous rate of infusion. MEASUREMENTS AND MAIN RESULTS: Clinical seizures stopped after induction of anesthesia in each animal. The EEG, however, still showed distinct epileptiform patterns (spikes, polyspikes) in all animals. Paroxysms were suppressed by increasing the infusion rate of either pentobarbital or propofol. A burst-suppression pattern was achieved in 5 animals. EEG epileptiform activity reappeared in 4 animals when attempting to taper the dose after >6 hours of anesthesia. This was interpreted as ongoing EEG seizure activity and an increased risk for clinical seizures, and the anesthetic dosage was adjusted accordingly. CONCLUSION: Continuous EEG monitoring appears to be a useful tool for therapeutic monitoring of SE in dogs and cats. It allows the detection of EEG seizures without the appearance of clinical seizures. Further investigations with blinded investigators and homogeneous animal groups to define therapeutic endpoints are warranted.