A condition characterized by neck stiffness, headache, and other symptoms suggestive of meningeal irritation, but without actual inflammation of the meninges (MENINGITIS). Spinal fluid pressure may be elevated but spinal fluid is normal. (DeJong, The Neurologic Examination, 4th ed, p673)

Viral infections of the leptomeninges and subarachnoid space. TOGAVIRIDAE INFECTIONS; FLAVIVIRIDAE INFECTIONS; RUBELLA; BUNYAVIRIDAE INFECTIONS; ORBIVIRUS infections; PICORNAVIRIDAE INFECTIONS; ORTHOMYXOVIRIDAE INFECTIONS; RHABDOVIRIDAE INFECTIONS; ARENAVIRIDAE INFECTIONS; HERPESVIRIDAE INFECTIONS; ADENOVIRIDAE INFECTIONS; JC VIRUS infections; and RETROVIRIDAE INFECTIONS may cause this form of meningitis. Clinical manifestations include fever, headache, neck pain, vomiting, PHOTOPHOBIA, and signs of meningeal irritation. (From Joynt, Clinical Neurology, 1996, Ch26, pp1-3)