Page 1405 - Small Animal Internal Medicine, 6th Edition

CHAPTER 85 Leukopenia and Leukocytosis 1377

EOSINOPHILIA increases in the eosinophil count (>15,000/µL, or 15 × 10 /L).
9
Eosinophilia is defined as an absolute increase in the circu- In dogs, eosinophilia is frequently seen in roundworm and
VetBooks.ir lating eosinophil numbers. It is relatively common in small hookworm infestations or with dirofilariasis or dipetalone-
miasis. Three other relatively common causes of eosinophilia
animals and can have a variety of causes (Box 85.3). Because
eosinophilia is common in dogs and cats with endoparasites
or ectoparasites, no animal should undergo a thorough eval- in cats include eosinophilic granuloma complex, bronchial
asthma, and eosinophilic gastroenteritis. A clinical entity
uation for eosinophilia before parasitic causes have been resembling feline hypereosinophilic syndrome has been
ruled out. In cats, flea infestation usually results in marked reported in Rottweilers (Sykes et al., 2001); in addition,
lesions compatible with oral eosinophilic granulomas have
been reported in Siberian Huskies. Eosinophilia can also
BOX 85.3 occur in dogs and cats with mast cell tumors, but it is rare.
In cats, eosinophilia may occur in association with lym-
Causes of Eosinophilia in Cats and Dogs phoma (i.e., tumor-associated eosinophilia).
Clinical signs in dogs and cats with eosinophilia are
Parasitic Disorders related to the primary disorder rather than to the hemato-
• Ancylostomiasis (D) logic abnormality. Because eosinophilia is so commonly
• Dirofilariasis (D, C) found in animals with parasitic diseases, clinical evaluation
• Dipetalonemiasis (D) of these animals should mainly be aimed at excluding these
• Ctenocephalides (D, C) disorders. Once this has been done, other causes of eosino-
• Filaroidiasis (C) philia should be pursued (see Box 85.3) by using the appro-
• Aelurostrongylosis (C) priate diagnostic procedure (e.g., tracheal wash or pulmonary
• Ascariasis (D, C)
• Paragonimiasis (D, C) fine-needle aspiration for pulmonary infiltrates with eosino-
phils, endoscopic biopsy for eosinophilic gastroenteritis).
Hypersensitivity Disorders Treatment is usually aimed at the primary disorder.
• Atopy (D, C) A syndrome with high eosinophil counts in peripheral
• Flea allergy dermatitis (D, C) blood and tissue infiltration with eosinophils has been well
• Food allergy (D, C) documented in cats, Rottweilers, and occasionally other dog
breeds. This syndrome is termed hypereosinophilic syndrome
Eosinophilic Infiltrative Disorders
and is usually indistinguishable from eosinophilic leukemia.
• Eosinophilic granuloma complex (C) These patients have primarily gastrointestinal tract signs,
• Feline bronchial asthma (C) although multisystemic signs are also common. In cats,
• Pulmonary infiltrates with eosinophils (D) treatment with immunosuppressive doses of corticosteroids,
• Eosinophilic gastroenteritis/colitis (D, C) 6-thioguanine, cytosine arabinoside, cyclophosphamide,
• Hypereosinophilic syndrome (D, C)
and other anticancer agents (see Chapter 76) has been unre-
Infectious Diseases warding, and most affected patients die within weeks of diag-
• Upper respiratory tract viral disorders (C?) nosis. Clinical response to some of these drugs has been
• Feline panleukopenia (C?) documented in Rottweilers.
• Feline infectious peritonitis (C?)
• Toxoplasmosis (C) BASOPHILIA
• Suppurative processes (D, C) Basophilia is defined as an absolute increase in the basophil
numbers and is commonly associated with eosinophilia.
Neoplasia Because basophils are similar to tissue mast cells, their
• Mast cell tumors (D, C) numbers increase in disorders characterized by excessive
• Lymphomas (D, C)
• Myeloproliferative disorders (C) immunoglobulin E production and binding and in a variety
• Solid tumors (D, C) of nonspecific inflammatory disorders. Causes of basophilia
are listed in Box 85.4.
Miscellaneous
• Soft tissue trauma (D?, C?) MONOCYTOSIS
• Feline urologic syndrome (C?) Monocytosis refers to an absolute increase in monocyte
• Cardiomyopathy (D?, C?) numbers. It can occur in response to inflammatory, neoplas-
• Renal failure (D?, C?) tic, or degenerative stimuli. In some patients with acute leu-
• Hyperthyroidism (C?) kemia, the WBC dot plots reveal a large monocyte cloud of
• Estrus (D?) abnormal configuration, even though the total monocyte
numbers may be normal (see Fig. 80.4). Although monocy-
Note: Entries in boldface are common causes; entries in italics are
relatively common causes; entries in regular typeface are tosis has traditionally been observed primarily in chronic
uncommon causes. inflammatory processes, it is also common in acute disor-
C, Cat; D, dog; ?, poorly documented. ders. Causes of monocytosis in cats and dogs are listed in