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Abstract

CASE DESCRIPTION A 2-year-old neutered male domestic shorthair cat was evaluated for sudden onset of cluster seizures.

CLINICAL FINDINGS At an emergency clinic, the cat had hyperimmunoglobulinemia and thrombocytopenia. On referral, treatment with levetiracetam, zonisamide, and phenobarbital initially provided good control of cluster seizure activity (attributable to epilepsy of unknow origin). Two weeks later, assessments revealed that serum phenobarbital concentration was within the ideal range but serum zonisamide concentration exceeded the recommended therapeutic range. The dosage of zonisamide was therefore decreased. Four days after dosage reduction, the cat developed generalized lymphadenopathy. Cytologic analysis of lymph node aspirate samples revealed a heterogeneous population of well-differentiated lymphocytes, interpreted as marked reactivity. Although neoplasia could not be ruled out, hypersensitivity to phenobarbital was suspected, and this treatment was discontinued.

TREATMENT AND OUTCOME Despite cessation of phenobarbital administration, generalized peripheral lymphadenopathy progressed and hyperglobulinemia and cytopenias developed. These abnormalities resolved after discontinuation of zonisamide administration. The cat remained seizure free with no recurrence of the aforementioned concerns after reinstitution of phenobarbital treatment.

CLINICAL RELEVANCE To the authors' knowledge, this is the first reported case of zonisamide-related lymphadenopathy, hyperglobulinemia, and cytopenias in a cat. Anticonvulsant hypersensitivity syndrome is well documented in human medicine, but little information has been published in the veterinary medical literature. Although the effects of anticonvulsant hypersensitivity syndrome in this cat were serious, these effects were reversible with treatment discontinuation.

Abstract

Objective—To determine prevalence of adverse effects associated with epidural administration of morphine with or without bupivacaine in dogs and cats undergoing surgery and evaluate effects of epidural administration of morphine on postoperative pain severity.

Design—Retrospective study.

Animals—242 dogs and 23 cats.

Procedure—Morphine with or without bupivacaine was administered prior to surgery with a Tuohy needle, spinal needle, or epidural catheter. In 18 dogs that underwent surgery twice, results of preemptive epidural administration of morphine with or without bupivacaine were compared with results of systemic administration of oxymorphone and ketoprofen.

Results—The delivered fraction of isoflurane was significantly lower in animals given morphine and bupivacaine than in animals given morphine alone. Analgesia was of significantly longer duration in dogs given morphine and bupivacaine than in dogs given morphine alone. During anesthesia, mild respiratory and cardiovascular depression was reported. Seven dogs and 2 cats had urine retention, and 2 dogs developed pruritus. Six dogs vomited when a second dose of morphine was given epidurally the day after surgery. Eight of 72 dogs had delayed hair growth. In 18 dogs that underwent surgery twice, the delivered fraction of isoflurane was significantly lower and the duration of analgesia was significantly longer when morphine with or without bupivacaine was given epidurally than when oxymorphone and ketoprofen were given.

Conclusions and Clinical Relevance—Results suggest that preemptive epidural administration of morphine with or without bupivacaine is a safe and effective method of inducing long-lasting analgesia in dogs and cats and is superior to standard management of postoperative pain with repeated injection of oxymorphone and ketoprofen. (J Am Vet Med Assoc 2002;221:666–672)