An aneurysm is a protrusion of the wall of an artery or vein due to its thinning and loss of elasticity. This pathology in most cases is congenital. Most often, aneurysm is diagnosed in the vessels of the brain, which makes the disease potentially dangerous.
According to the etiology, inflammation of the soft and arachnoid membranes of the brain (leptomeninges) - meningitis - can be bacterial, viral, parasitic or fungal. Or it could be non-infectious or reactive meningitis.