it is an inflammation of the protective layer over the brain
and spinal cord. it can cause deafness,
epilepsy, hydrocephalus, cognitive deficits and it can also be fatal. some of the symptoms are a headache, stiff neck, high fever and altered mental status.
i see that you've put lamictal as your question. it has been recently found out that lamictal can have menegitis as a side effect but it is only in very rare cases.