brain, spinal cord, and nerve disorders
Acute Bacterial Meningitis
Introduction
Acute bacterial meningitis is rapidly developing inflammation of the layers of tissue that cover the brain and spinal cord (meninges) and of the fluid-filled space between the meninges (subarachnoid space) when it is caused by bacteria. Older children and adults develop a stiff neck that makes lowering the chin to the chest difficult or impossible, usually with a fever and headache. Infants may not develop a stiff neck but may seem generally unwell and have a high or low body temperature, feed poorly, or be irritable or drowsy. Bacterial meningitis is a medical emergency and is treated as soon as possible, before the diagnosis is confirmed. To diagnose meningitis, doctors do a spinal tap (lumbar puncture) as soon as possible. Antibiotics are usually effective if given promptly, anddexamethasone(a corticosteroid) is often given to reduce swelling in the brain. Vaccines can prevent some types of bacterial meningitis. (See also Introduction to Meningitis .) The brain and spinal cord are covered by three layers of tissue called meninges. The subarachnoid space is located between the middle layer and the inner layer of the meninges, which cover the brain and spinal cord. This space contains the cerebrospinal fluid, which flows through the meninges, fills the spaces within the brain, and helps cushion the brain and spinal cord. Within the skull, the brain is covered by three layers of tissue called the meninges. 