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Inflammation of the meninges may lead to abnormalities of the cranial nerves , a group of nerves arising from the brain stem that supply the head and neck area and which control, among other functions, eye movement, facial muscles, and hearing.   Visual symptoms and hearing loss may persist after an episode of meningitis.  Inflammation of the brain ( encephalitis ) or its blood vessels ( cerebral vasculitis ), as well as the formation of blood clots in the veins ( cerebral venous thrombosis ), may all lead to weakness, loss of sensation, or abnormal movement or function of the part of the body supplied by the affected area of the brain.  
The exact etiopathogenesis of SRMA is unknown ( Tipold 2000 ). Activated T cells have been demonstrated in dogs with SRMA, indicating potential contact with an antigenic stimulus; however, no bacterial or viral agents have been identified to date ( Tipold and others 1996 ). A Th2-mediated immune response is most likely, based on the presence of high CD4:CD8a ratios and a high proportion of B cells in peripheral blood and CSF. A Th2-mediated immune response is further supported by the expression of low levels of Th1-response-related cytokines (IL-2, IFN-γ) and upregulation of Th2 cytokines (IL-4) in blood and CSF in dogs with the acute form of SRMA ( Schwartz and others in press ). This Th2-mediated immune response leads to an upregulation of the humoral immune response and excessive IgA production ( Schwartz and others 2008b ).