Abstract
The clinical, laboratory, and pathologic features of a syndrome in dogs characterized by intermittent pain, fever, neutrophilia, and necrotizing arteritis are described to alert others involved in toxicity testing to the existence of this disorder. It is considered that this idiopathic syndrome is a latent condition, the expression of which can be precipitated in predisposed dogs by experimental treatment, and thus, its occurrence could complicate interpretation of toxicity studies. We have observed the disorder in 14 beagle dogs. The syndrome is rare and most cases for study were supplied by the breeder. Typical clinical signs observed included evidence of pain when the mouth was opened, grunting when lifted, and standing with an arched back and lowered head. Appetite was usually reduced. Body temperature was elevated (e.g., 104–106°F). There was progressive, bilateral atrophy of temporal and cervical musculature. Such signs have been observed to persist unremittingly or, more commonly, with periods of expression and remission. Neutrophilic leukocytosis and thrombocytosis were present. Hemoglobin and hematocrit were usually slightly decreased. Serum total protein was usually normal but albumin was reduced and alpha-2 globulins were markedly increased. Rheumatoid factor was elevated in several dogs. Arteritis was observed histologically and was characterized by necrosis, intimal proliferation, neutrophil and mononuclear cell infiltration in the media and periarterial tissues, and hemorrhage. Amyloidosis was observed in several dogs. The cause of this disorder is unknown. Knowledge of the distinct features of this syndrome should obviate complication of interpretation of results in toxicity studies and hopefully will lead to studies of this syndrome to provide an understanding of its etiopathogenesis.