<unk>  is a recurrent or chronic inflammation of the protective membranes covering the brain and spinal cord, known collectively as the meninges. Since<unk>  is a recurrent, benign (non-cancerous), aseptic meningitis, it is also referred to as benign recurrent lymphocytic meningitis. It was named for Pierre<unk> , the French neurologist who first described it in 1944. Although chronic meningitis has been defined as "irritation and inflammation of the meninges persisting for more than 4 weeks being associated with pleocytosis in the cerebrospinal fluid", cerebrospinal fluid abnormalities may not be detectable for the entire time. Diagnosis can be elusive, as Helbok et al. note: "in reality, many more weeks, even months pass by until the diagnosis is established. In many cases the signs and symptoms of chronic meningitis not only persist for periods longer than 4 weeks, they even progress with continuing deterioration, i. e. headache, neck stiffness and even low grade fever. Impairment of consciousness, epileptic seizures, neurological signs and symptoms may evolve over time."
Mollaret's meningitis
Rasmussen's encephalitis
La Crosse encephalitis
Fungal meningitis
Brain fever
Japanese encephalitis
Eastern equine encephalitis
Sappinia amoebic encephalitis