Leptomeningitis is an inflammation of the meninges, which often occurs as a complication of an infection, such as influenza or tuberculosis. The most severe form of leptomeningitis is tuberculous meningitis. Susceptibility to infection is associated with acquired immunity. The modes of transmission are airborne and intrauterine. Other risk factors include hereditary predisposition. There are also known population groups in large cities and during epidemics that have an increased risk of developing tuberculous leptomeningitis.