Page 1217 - Veterinary Immunology, 10th Edition

seizures; and behavioral changes. The typical disease course
VetBooks.ir consists of severe episodes with symptom-free remissions. The less

common chronic form may develop following relapses of acute
disease or inadequate treatment. Additional neurological signs

consistent with lesions in the brain and spinal cord such as paresis
or ataxia may develop. These dogs may have concurrent immune-
mediated polyarthritis. The prognosis in young dogs is fair to good
since aggressive antiinflammatory and immunosuppressive

therapy using prednisolone or prednisone leads to rapid clinical
improvement. Once the disease is in remission, the steroid dose
should be gradually reduced to the minimum necessary to prevent
relapses. Treatment may be stopped 6 months after clinical status,

cerebrospinal fluid (CSF), and blood return to normal. It may not be
possible to discontinue treatment completely in chronic cases,
although azathioprine is effective in such cases. Large dogs, such as
Boxers, Weimaraners, and Bernese Mountain Dogs, are commonly

affected, although the disease has also been reported in Beagles.
Dogs under 2 years of age are most commonly affected.
This disease is characterized by increased IgA production, an
acute-phase response, and the development of a necrotizing

vasculitis. Several cytokines play a role in this process. IL-6 and
vascular endothelial growth factor (VEGF) are significantly
increased in cerebrospinal fluid. The changes in IL-6 levels may
promote Th17 cell differentiation. The CSF in acute cases of SRMA

contains high IgA and CXCL8 levels and mature neutrophils.
Serum IgA, C-reactive protein and α -macroglobulin are also
2
elevated. T cell production of IL-2 and IFN-γ is depressed, whereas

Th2 production of IL-4 is enhanced and probably accounts for the
increased IgA production. About 30% of these dogs have a positive
lupus erythematosus (LE) cell test but no detectable antinuclear

antibodies (Chapter 38). In chronic cases, the CSF contains
predominantly mononuclear cells. On necropsy, the spinal
meningeal arteries show fibrinoid degeneration, intimal or medial
necrosis, and hyalinization, and are infiltrated with lymphocytes,
plasma cells, macrophages, and a few neutrophils. Complete

obliteration of the blood vessel lumina may occur, whereas rupture
and thrombosis of inflamed vessels may lead to hemorrhage,
compression, and infarction.

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