äge v. krooniline ajukestade põletik, ajukestapõletik, ajukelmepõletik, inflammation of the membranes that cover the brain and spinal cord, inflammation of the meninges and especially of the pia mater and the arachnoid; specifically: a disease marked by inflammation of the meninges that is either a relatively mild illness caused by a virus (such as various Coxsackieviruses) or a more severe usually life-threatening illness caused by a bacterium (especially the meningococcus, Neisseria meningitides, or the serotype designated B of Haemophilus influenzae)