Veterinary Medicine - November 2007 - (Page 732)

Immune-mediated neutropenia O P E E R - R E V I E W E D Azathioprine and chlorambucil Azathioprine at 2 mg/kg daily for one week and then at 1 mg/kg every other day may be instituted at the beginning of prednisone therapy in dogs to allow more rapid tapering of prednisone, thus minimizing prednisone-related adverse effects. Azathioprine can also be added to therapy for dogs that are not responding to prednisone alone. A CBC and hepatic serum chemistry profile should be performed one week after initiating azathioprine therapy and then monthly while the dog receives azathioprine to monitor for adverse effects. If additional immune suppression is needed in cats, chlorambucil can be given. Lithium carbonate Lithium carbonate (10 mg/kg orally b.i.d.) is used in dogs for chemotherapy-associated neutropenia14 and may play a role in treating immune-mediated neutropenia. It causes a nonspecific stimulation of neutrophil production.31 Therapy in people In people, use of recombinant granulocyte-colony stimulating factor has revolutionized therapy.32 Corticosteroids are typically contraindicated because of their affects on immunity, growth, and normal adrenal gland function in children affected with immune-mediated neutropenia. Short courses of corticosteroids, intermittent antibiotics, and intravenous IgG are core to therapy in children until disease remission occurs spontaneously. Administering human recombinant granulocyte-colony stimulating factor in dogs can lead to neutropenia because dogs may develop antibodies to it. These antibodies may then cross-react with endogenous canine granulocyte-colony stimulating factor, impairing neutrophil production in the bone marrow. Antibodies tend to develop within three weeks of initiating therapy.33 Canine recombinant granulocyte-colony stimulating factor is not commercially available, and given the induction of antineutrophil antibodies, it is contraindicated.34 PROGNOSIS The prognosis for remission is good, with 100% of dogs achieving normal neutrophil counts after 1 to 18 days of prednisone therapy in one retrospective study.6 In the published case reports, loss of remission once medication was discontinued was frequently, but not always, reversed with re-institution of therapy.2,11 CONCLUSION Although not commonly recognized, immune-mediated neutropenia should be a differential diagnosis in neutropenic patients that after a diagnostic work-up have no other apparent reason for their neutropenia. These patients tend to be younger and have fairly profound neutropenias 732 November 2007 VETERINARY MEDICINE http://www.shopadvanstar.com/benchmarks2007 http://www.shopadvanstar.com/benchmarks2007

Table of Contents Feed for the Digital Edition of Veterinary Medicine - November 2007

Veterinary Medicine - November 2007 Contents Leading Off The Veterinary Medicine Interview: Dr. Lila Miller Clinical Exposures Idea Exchange A Challenging Case: Uveitis and Secondary Glaucoma in a Cat Is it Immune-Mediated Neutropenia? Pimobendan Treatment in Dogs with Congestive Heart Failure CE Form Product Preview Advertiser Index Marketplace/Classifieds Mind Over Miller Special Supplement by Lilly: Flea Bite Facts Q&A

Veterinary Medicine - November 2007

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