Page 1406 - Small Animal Internal Medicine, 6th Edition

1378 PART XIII Hematology

BOX 85.4 BOX 85.5
VetBooks.ir Causes of Basophilia in Cats and Dogs Causes of Monocytosis in Cats and Dogs

Disorders Associated With Immunoglobulin E Production
and Binding Inflammation
• Infectious disorders
• Heartworm disease (D, C) • Bacteria
• Inhalant dermatitis (D, C) • Pyometra (D, C)
• Abscesses (D, C)
Inflammatory Diseases • Peritonitis (D, C)
• Gastrointestinal tract disease (D, C) • Pyothorax (D, C)
• Respiratory tract disease (D, C) • Osteomyelitis (D, C)
• Prostatitis (D)
Neoplasms • Higher bacteria
• Mast cell tumors (D, C) • Nocardia (D, C)
• Lymphomatoid granulomatosis (D, C) • Actinomyces (D, C)
• Basophilic leukemia (D) • Mycobacteria (D, C)
• Intracellular parasites
Associated With Hyperlipoproteinemia • Mycoplasma (D, C)
• Hypothyroidism (D?) • Fungi
• Blastomyces (D, C)
Note: Entries in boldface are common causes; entries in italics are • Histoplasma (D, C)
relatively common causes; entries in regular typeface are • Cryptococcus (D, C)
uncommon causes. • Coccidioides (D)
C, Cat; D, dog; ?, poorly documented. • Parasites
• Heartworms (D, C?)
• Immune-mediated disorders
• Hemolytic anemia (D, C)
• Dermatitis (D, C)
Box 85.5. The monocytosis in dogs is typically more pro- • Polyarthritis (D, C)
nounced than that in cats; monocytosis is extremely rare in Trauma With Severe Crushing Injuries (D, C)
Greyhounds. Hemorrhage Into Tissues or Body Cavities (D, C)
Monocytosis is part of a stress leukogram in dogs. It can
result from a variety of bacterial, fungal, and protozoal dis- Stress- or Corticosteroid-Induced Disorders (D)
eases. In the Midwest, systemic fungal disorders (e.g., histo- • Neoplasia
plasmosis and blastomycosis) are relatively common causes. • Associated with tumor necrosis (D, C)
Because monocytes are precursors of tissue macrophages, • Lymphoma (D, C)
granulomatous and pyogranulomatous reactions commonly • Myelodysplastic disorders (D, C)
result in monocytosis (see Box 85.5). In addition, immune- • Leukemias
mediated injury resulting in cell destruction (e.g., immune • Myelomonocytic leukemia (D, C)
hemolysis, polyarthritis) and certain neoplasms (e.g., lym- • Monocytic leukemia (D, C)
• Myelogenous leukemia (D, C)
phomas) may cause monocytosis. Some neoplasms secrete
CSFs for monocytes and can result in marked monocytosis Note: Entries in boldface are common causes; entries in italics are
(>5000/µL or 5 × 10 /L). Although rare, monocytic leukemia relatively common causes; entries in regular typeface are
9
can occur. uncommon causes.
The nature of the clinical evaluation in patients with C, Cat; D, dog; ?, poorly documented.
monocytosis is similar to that used with neutrophilia: it
should concentrate on identifying infectious foci. If an
immune-mediated disorder is suspected, arthrocentesis to
obtain fluid for analysis or other immune tests (see Chapters count in a sick dog or cat is 1000 to 1500/µL. Lymphopenia
69 and 71) should be performed. Treatment should be aimed is also commonly identified in dogs and cats with chronic
at the primary disorder. loss of lymph, such as those with chylothorax or intestinal
lymphangiectasia (Box 85.6).
LYMPHOPENIA In general, cats and dogs with lymphopenia have obvious
Lymphopenia is defined as an absolute decrease in the lym- clinical abnormalities. As a general rule, it should be ignored
phocyte count. It constitutes one of the most common hema- (i.e., a diagnosis should not be pursued) in sick cats and dogs
tologic abnormalities in hospitalized or sick dogs and cats, and in those receiving corticosteroids or chemotherapy. The
in which it is attributed to the effects of endogenous lymphocyte count should be reevaluated after the clinical
corticosteroids (stress leukogram). The typical lymphocyte abnormalities have resolved or steroid therapy has been