Cat Diseases; Nervous System Diseases/veterinary; Animals; Cat Diseases/diagnosis; Cat Diseases/etiology; Cat Diseases/surgery; Cat Diseases/therapy; Cats; Coronaviridae Infections/diagnosis; Coronaviridae Infections/etiology; Coronaviridae Infections/therapy; Coronaviridae Infections/veterinary; Diabetic Neuropathies/diagnosis; Diabetic Neuropathies/etiology; Diabetic Neuropathies/therapy; Diabetic Neuropathies/veterinary; Meningeal Neoplasms/diagnosis; Meningeal Neoplasms/etiology; Meningeal Neoplasms/surgery; Meningeal Neoplasms/veterinary; Meningioma/diagnosis; Meningioma/etiology; Meningioma/surgery; Meningioma/veterinary; Peritonitis/diagnosis; Peritonitis/etiology; Peritonitis/therapy; Peritonitis/veterinary