Page 128 - Withrow and MacEwen's Small Animal Clinical Oncology, 6th Edition

CHAPTER 5 Paraneoplastic Syndromes 107

Fever

VetBooks.ir Paraneoplastic fever can result as part of an innate immune
response against tumor antigens or areas of tumor necrosis. Fever
is mediated primarily by TNF-α, IL-1, and IL-6 on the hypo-
thalamus. These cytokines activate the arachidonic acid cascade,
producing prostaglandin E , which acts on the thermoregulatory
2
center of the hypothalamus. 233 The exact incidence of paraneo-
plastic fever is unknown, but in retrospective studies of fever of
unknown origin, fewer than 10% of dogs were ultimately diag-
nosed with cancer. 234–236 Hematopoietic cancers were identified
most frequently.
When an animal with cancer presents with fever, it is important
to rule out concurrent infection. Tumors can become secondarily
infected, especially if they are ulcerated or have large areas of necro-
sis. Gastrointestinal tumors can perforate the GI tract, resulting in
septic peritonitis Sepsis secondary to myelophthisic leukopenia can
also occur. Infections also can develop as a complication of cancer
treatment: postoperative healing complications, severe neutrope-
nia secondary to chemotherapy and sepsis, vomiting secondary to
chemotherapy and subsequent aspiration pneumonia. A diagnosis
of paraneoplastic fever is often made by ruling out other causes for
fever. Paraneoplastic fever is most effectively treated by eliminating
the inciting cancer. When this is not possible, if the fever is affect-
ing quality of life then symptomatic treatment with and NSAID or
antiinflammatory dose of steroids should be considered.

References

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• Fig. 5.3 Hypertrophic osteopathy (HO), seen radiographically in the distal principles & practice of oncology, ed 8, Philadelphia, 1997, Lippin-
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new bone formation radiating 90 degrees from the long axis of the radius, 2. Freeman LM: Cachexia and sarcopenia: emerging syndromes of
ulna, and metacarpal bones. importance in dogs and cats, J Vet Intern Med 26:3–17, 2012.
3. Loviano A, Meguid RA, Meguid MM: Supportive care and quality
The pathogenesis of HO is not well understood. The classic of life: nutrition support. In DeVita VT, Hellman S, Rosenberg
pathophysiologic changes are increased peripheral blood flow, pro- SA, editors: Cancer: principles & practice of oncology, ed 8, Philadel-
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formation. 214 A neural reflex that originates in the thorax and is car- tion, cachexia and sarcopenia: the skeleton in the closet 40 years
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regression of HO has been reported in dogs after undergoing vagot- 5. Dewys WD, Begg C, Lavin PT, et al.: Prognostic effect of weight
omy. 221,227 More recently, humoral mechanisms have been hypoth- loss prior to chemotherapy in cancer patients. Eastern cooperative
esized. People with lung cancer and HO have higher levels of serum oncology group, Am J Med 69:491–497, 1980.
growth hormone, growth hormone–releasing hormone, vascular 6. Michel KE, Sorenmo K, Shofer FS: Evaluation of body condition
endothelial growth factor (VEGF), and platelet-derived growth fac- and weight loss in dogs presented to a veterinary oncology service,
tor (PDGF). 228 Elevated levels of these and other hormones might J Vet Intern Med 18:692–695, 2004.
result from tissue hypoxia, along with decreased pulmonary clear- 7. Baez JL, Michel KE, Sorenmo K, et al.: A prospective investigation
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changes in body condition in feline cancer patients, J Feline Med
that circulating megakaryocytes and platelet clumps that normally Surg 9:411–417, 2007.
become trapped in pulmonary capillary beds can bypass these capil- 8. Fox LE, Rosenthal RC, Twedt DC, et al.: Plasma histamine and
laries, again due to pathologic shunting, and they subsequently can gastrin concentrations in 17 dogs with mast cell tumors, J Vet Intern
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Whenever possible, the treatment for HO is removal of the 9. Ishiguro T, Kadosawa T, Takagi S, et al.: Relationship of disease
underlying cancer. However, dogs more commonly present with progression and plasma histamine concentrations in 11 dogs with
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