an acute infectious disease of children and young adults, caused by Neisseria meningitidis and characterized by fever, headache, photophobia, vomiting, nuchal rigidity, seizures, coma, and a purpuric eruption. Even in the absence of meningitis, meningococcemia can induce toxic phenomena such as vasculitis, disseminated intravascular coagulation, shock, and Waterhouse-Friderichsen syndrome due to adrenal hemorrhage; late complications include paralysis, mental retardation, and gangrene of the extremities. SYN: cerebrospinal fever, epidemic cerebrospinal meningitis.