Feline Granulomatous Meningoencephalitis Study Guide

Overview and Clinical Importance

Granulomatous meningoencephalitis (GME) is an idiopathic, non-infectious inflammatory disease of the central nervous system (CNS) that primarily affects dogs but can rarely occur in cats. In cats, this condition is more commonly referred to as Feline Meningoencephalomyelitis of Unknown Origin (FMUO) or simply Meningoencephalitis of Unknown Origin (MUO). The disease is characterized by granulomatous inflammation with perivascular cuffing of mononuclear cells within the CNS white matter.

While infectious causes of meningoencephalitis (such as FIP, toxoplasmosis, and cryptococcosis) are far more common in cats, understanding FMUO is crucial for the NAVLE because it represents an important diagnosis of exclusion that requires systematic rule-out of infectious etiologies and responds to immunosuppressive therapy.

Etiology and Pathogenesis

Unknown Etiology

The exact cause of GME/FMUO remains unknown. The condition is classified as idiopathic and non-infectious. Several hypotheses have been proposed: