The meninges (singular meninx) is the system of membranes which envelop the central nervous system. The meninges consist  of three layers: the dura mater, the arachnoid mater, and the pia mater. The primary function of the meninges and of the cerebrospinal fluid is to protect the central nervous system.<unk>  is the inflammation of these protective membranes.<unk>  may have been described in the Middle Ages, but it was first accurately identified by the Swiss Vieusseux (a scientific-literary association) during an outbreak in Geneva, Switzerland in 1805. In 1661, Thomas Willis first described the inflammation of meninges and an epidemic of<unk> . In the 17th century, Robert Whytt provided a detailed explanation of tuberculous<unk>  and its stages. This was further elaborated by John Cheyne in the same century. Meningococcal<unk>  was than described by Gaspard Vieusseux, Andre Matthey in Geneva and Elisa North in Massachussetes.<unk>  may develop in response to a number of causes, including infectious agents (bacteria, viruses, fungi, or other organisms) or non-infectious causes, such as systemic illnesses that may involve CNS (e.g. neoplasms or connective tissue diseases, such as sarcoidosis, systemic lupus erythematosus (SLE), and wegener's) or certain drugs (e.g. nonsteroidal antiinflammatory drugs, intravenous immunoglobulin, intrathecal agents, and trimethoprim-sulfamethoxazole). While some forms of<unk>  are mild and resolve spontaneously (e.g. viral<unk> ,<unk>  is a potentially serious condition owing to the proximity of the inflammation to the brain and spinal cord. The potential for serious neurologic damage or even death necessitates prompt medical attention and evaluation. The common presenting features of<unk>  are, fever, neck stiffness and headache. Other symptoms include, photophobia (inability to tolerate bright light), phonophobia (inability to tolerate loud noises), irritability, altered mental status (in small children), and seizure. Physical examination of<unk>  may vary in adults and infants. In adults, physical examination findings may include bradycardia, disorientation, papilledema, neck stiffness, positive brudzinski's and kernig's sign. However, petechial rash, bulging fontanelle, neck stiffness, jaundice, and convulsions are physical examination findings in infants. Diagnosis is based on clinical findings and CSF analysis. Treatment options are based on etiology and varies from supportive care and observing the patient (viral<unk>  to antibiotic therapy for bacterial<unk>  or chemotherapy and/or irradiation for neoplastic<unk> .
Meningitis
Cerebritis
Encephalitis
Meningoencephalitis
Meninges
Meningism
Neoplastic meningitis
Lymphocytic choriomeningitis