<prompt> The most common organism amongst the following that causes acute meningitis in an AIDS patients is?Streptococcus pneumoniaeSteptococcus agalactiaeCryptococcus neoformansListeria monocytogenes  <response>: Ans. is c i.e., Cryptococcus neoformans Neurological manifestations . Frequent oppounistic diseases of CNS are ? - Toxoplasmosis most common cause of CNS infection in AIDS patients - Cryptococcosis - Primary CNS lymphoma - Progressive multifocal leukoencephalopathy. . AIDS dementia complex HIV encephalopathy is a result of direct effects of HIV on CNS not an oppounistic disease. It is subcoical dementia. . Most common cause of seizures -- Toxoplasma . Most common cause of meningitis -- Cryptococcus . M.C. cause of focal neurological deficit -- Toxoplasma 