Veterinary Medicine - August 2007 - (Page 530)

Immune-mediated thrombocytopenia O P E E R - R E V I E W E D 1).1,2,6,7 Mucous membranes may be pale if concurrent anemia is present. Gastrointestinal (GI) hemorrhage can manifest as hematemesis, melena, or hematochezia.1,6,7 Hyphema and retinal hemorrhages may be present, possibly causing blindness.1,2,7 Hematuria may result from hemorrhage into the urinary tract. Often, dogs with immunemediated thrombocytopenia are otherwise clinically stable.1 Life-threatening hemorrhage can develop when bleeding occurs into the central nervous system, GI tract, or pulmonary parenchyma.2,13-15 Because of the potential for bleeding in any dog with immune-mediated thrombocytopenia, consider each case a serious and potentially life-threatening disorder, regardless of the signs on presentation. Severe GI hemorrhage is the predominant cause of death in dogs with acute immune-mediated thrombocytopenia.1 1. Petechial hemorrhages on the mucous membranes of a dog with immune-mediated thrombocytopenia. History and physical examination Evaluation of patients with immunemediated thrombocytopenia begins with a thorough history to identify suspected underlying causes such as medications or recent vaccinations (e.g. given within the previous month).8 Identify and discontinue the administration of medications that decrease platelet function (e.g. as- mal.8 Signs of other concurrent illness may be identified in the history or during the physical examination. Determine the location, duration, and severity of bleeding episodes. Also obtain a history regarding previous blood transfusions. Perform a complete physical examination, including an ophthalmic examination. Note any evidence of abnormal hemostasis. A rectal examina- splenic enlargement on physical examination increases the likelihood of a concurrent disorder.1,2 Initial sample collection At presentation, stabilize the patient, if necessary, and then initiate diagnostic testing. But before initiating therapy, collect and save EDTA, sodium citrated, and serum samples.6 Use these samples to perform a CBC with blood smear evaluation, a serum chemistry profile, a coagulation profile, heartworm antigen testing, and a crossmatch, if appropriate, as well as to measure antibody titers for infectious diseases. Collection by atraumatic venipuncture is necessary to avoid activating tissue factor within the needle. Process the samples within a few hours of collection to minimize platelet clumping. If severe thrombocytopenia is suspected, it is vital that the patient be handled as carefully as possible to avoid iatrogenic hemorrhage. When you collect samples, atraumatic venipuncture is necessary to avoid activating tissue factor within the needle. pirin). Ask about travel to areas endemic for diseases such as ehrlichiosis and dirofilariasis, and, in endemic areas, inquire about the use of flea, tick, and heartworm preventives and the prior presence of ticks on the anition may be required to obtain feces to evaluate for melena. Mild fever is present in some dogs with immunemediated thrombocytopenia. 1,13 Splenomegaly may be present,2,13 and some authors suggest that finding Evaluating the CBC and blood smear Confirm thrombocytopenia with a CBC that includes an automatic platelet 530 August 2007 VETERINARY MEDICINE

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

Contents A Veterinary Medicine Interview Veterinary Voices Idea Exchange Diagnosis and Treatment of Solar Dermatitis in Dogs Diagnostic Imaging for Linear Foreign Bodies in Cats Overcoming the Diagnostic and Therapeutic Challenges of Canine Immune-Mediated Thrombocytopenia Ophthalmic drugs: What’s new? CE Form Product Preview Advertiser Index Marketplace/Classifieds Mind Over Miller

Veterinary Medicine - August 2007

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