Page 1369 - Small Animal Internal Medicine, 6th Edition

CHAPTER 82 Anemia 1341

BOX 82.1 BOX 82.2
VetBooks.ir Clinical Manifestations of Anemia in Cats and Dogs Drugs and Toxins That Can Cause Anemia in Cats and
Dogs
History
• Breed (e.g., congenital enzymopathies, babesiosis in Acetaminophen
Pitbulls) Antiarrhythmics
• Family history Anticonvulsants
• Exercise intolerance, syncopal episodes Antiinflammatories (nonsteroidal)
• Pallor, jaundice Barbiturates
• Localized or generalized bleeding Benzocaine
• FeLV or FIV infection Chemotherapeutic agents
• Vector-borne diseases (e.g., ehrlichiosis, anaplasmosis, Chloramphenicol
babesiosis) Cimetidine
• Malnutrition, malabsorption Gold salts
• Chronic inflammation, cancer Griseofulvin
• Travel history Levamisole
Methimazole
Physical Examination
Methionine
• Pallor, jaundice, petechiae, ecchymoses Methylene blue
• Lymphadenopathy Metronidazole
• Hepatomegaly, splenomegaly Penicillins and cephalosporins
• Tachycardia, heart murmur, cardiomegaly, left Phenothiazines
ventricular hypertrophy Propylthiouracil
• Occult blood in the stool Propylene glycol
• Hematuria, bilirubinuria Sulfa derivatives
Vitamin K
FeLV, Feline leukemia virus; FIV, feline immunodeficiency virus. Zinc

• Has the owner noticed any ticks on the dog? Ehrlichiosis that is, not every patient with pale mucous membranes is
can cause bone marrow hypoplasia; babesiosis can cause anemic. The simplest approach is to evaluate the HCT and
hemolysis. capillary refill time (CRT). Dogs and cats with cardiovascu-
• Has the dog been in a fight with a Pitbull? Babesia gibsoni lar disease and hypoperfusion usually have normal HCT
infection causes signs similar to those of immune- values and additional clinical signs, whereas symptomatic
mediated hemolytic anemia, and it is transmitted by anemic dogs have low HCT; in addition, anemic dogs and
Pitbull bites. cats almost always have hyperkinetic pulses. Dogs and cats
• Has the pet been vaccinated recently? Modified live vac- with congestive heart failure can occasionally have dilutional
cines can cause bleeding as a result of platelet dysfunction anemia caused by intravascular fluid retention. The CRT
or thrombocytopenia, or they may be associated with may be difficult to evaluate in anemic patients because of the
immune-mediated hemolysis. absence of contrast due to the pallor.
• Has the dog received any shots for mismating recently or The clinician should also look for petechiae, ecchymoses,
has urinary incontinence? Estrogen derivatives can cause and evidence of deep bleeding in dogs and cats with pallor.
bone marrow aplasia or hypoplasia. These findings are suggestive of a platelet or clotting factor
deficiency (as seen in animals with Evans syndrome, dis-
In addition to these questions, a detailed travel and phar- seminated intravascular coagulation [DIC], or acute leuke-
macologic history should be obtained. Certain infectious mias; see Chapter 87), resulting in blood loss anemia.
diseases associated with anemia used to have a geographic Jaundice is common in dogs but rare in cats with hemolytic
distribution (e.g., babesiosis in the southeastern part of the anemia; in these patients, the color of the gums is white on
United States); however, global warming and worldwide yellow, as opposed to white on pink, because the HCT is low.
travel have extended the range of most of these infectious In our clinic, most dogs with jaundice have hemolysis,
agents. In addition, dogs frequently travel throughout the whereas most cats with jaundice have liver disease.
United States; thus the geographic disease distribution is Particular attention should be paid to the lymphoreticu-
becoming less common. Some drugs and toxins that have lar organs, such as the lymph nodes and spleen, because
been associated with anemia in cats and dogs are listed in several disorders associated with anemia may also result
Box 82.2; however, as a general rule, any drug can cause any in lymphadenopathy, hepatosplenomegaly, or both (Table
cytopenias in a given patient (i.e., idiosyncratic reaction). 82.1). Abdominal radiographs in a dog with intravascular
When evaluating a patient with pallor, first one must hemolysis may reveal metallic foreign bodies in the stomach,
determine whether it is caused by hypoperfusion or anemia; a potential source of zinc that frequently results in intra- and