Chapter 7 - Brain infections

Abstract

Brain infections can be caused by viruses, bacteria, fungi, or parasites and may be serious or life-threatening. Encephalitis is brain inflammation, usually caused by an arbovirus transmitted by a mosquito bite. A brain abscess is a collection of pus-filled swelling in the brain, usually after bacteria or fungi enter following an infection or severe head injury. Helminthic brain infections are caused by parasitic worms and are most common in developing countries. Rabies is a type of viral encephalitis, usually transmitted by animal bites. With acute encephalitis, inflammation and edema develop in infected areas of the brain or spinal cord. Encephalitis is suspected because of unexplainable alterations of mental status. The condition affects 10–15 people per 100,000 people, globally, every year. It is fatal in up to 40% of people who develop it. Vaccination against measles, mumps, chickenpox, and rubella has reduced the occurrence of encephalitis. The various brain infections generally have a fairly good prognosis with treatment, though without treatment or with treatment that is given too late, the outlook is poor, with many cases being fatal.