Peer-reviewed veterinary case report
Suspected Phenobarbital-Induced Pseudolymphoma in a Dog.
- Journal:
- Journal of veterinary internal medicine
- Year:
- 2017
- Authors:
- Lampe, R et al.
- Affiliation:
- Canada West Veterinary Specialists · Canada
Plain-English summary
A 2.5-year-old male neutered Shepherd mix was brought to the vet after showing signs of being very tired, having a dazed look, and running a fever for three days. While in the hospital, the dog developed swollen lymph nodes and continued to have a fever. He was being treated for epilepsy with two medications, phenobarbital and levetiracetam, both of which were at normal levels in his blood. Tests showed that his liver and spleen were enlarged, and the lymph nodes were reacting to inflammation rather than cancer. After stopping phenobarbital and switching to a different medication, the dog's fever went away within a day, and he recovered fully within a week. This case shows that phenobarbital can cause serious but reversible side effects that might look like cancer in dogs.
Abstract
Pseudolymphoma is a drug reaction to anti-epileptics that is well recognized in humans; it has been reported in one cat but not dogs. In this report, lymphoma-like clinical signs are suspected to be secondary to phenobarbital administration in a dog. A 2.5-year-old male, neutered Shepherd mix presented for a 3-day history of progressive ataxia, dazed mentation, pyrexia, and lethargy. While hospitalized, the dog developed generalized lymphadenopathy and sustained pyrexia. The dog was receiving levetiracetam and phenobarbital for epilepsy, and serum concentrations of both were within standard therapeutic ranges. Abdominal ultrasound revealed hepatomegaly, splenomegaly, and generalized lymphadenopathy. Cytology of the peripheral lymph nodes was consistent with reactive lymph nodes, and aspirates of the liver and spleen revealed histiocytic-neutrophilic inflammation. Phenobarbital was discontinued and replaced with zonisamide. Within 24 hours, the dog was normothermic, and other clinical signs resolved within a week. This case highlights a potentially serious yet reversible adverse reaction to phenobarbital in a dog. This idiosyncratic reaction could be mistaken for neoplasia and is an important differential for lymphoma-like signs in any dog administered phenobarbital.
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Search related cases →Original publication: https://pubmed.ncbi.nlm.nih.gov/28865097/