automatism A behavior that is performed without conscious knowledge and that does not appear to be under conscious control. This curious type of behavior occurs in a number of neurological and psychiatric disorders. The neurologic disorders associated with automatism include narcolepsy and some forms of epilepsy. The psychiatric conditions associated with automatism include schizophrenia and…
automated external defibrillator A device that automatically analyzes the heart rhythm and that— if it detects a problem that may respond to an electrical shock—delivers a shock to restore a normal heart rhythm. Thanks to their small size and ease of use, AEDs have been installed in many settings (such as schools and airports), and…
autologous In blood transfusion and transplantation, a situation in which the donor and recipient are the same person. Patients scheduled for nonemergency surgery may be autologous donors by donating blood for themselves that will be stored until the surgery. An autologous graft is a graft (such as a graft of skin) that is provided for…
autoimmunity The state of being attacked by one’s own immune system. Patients whose misdirected immune systems attack their own body tissues are said to have autoimmunity. See also antinuclear antibody; autoimmune disorder.
autoimmune thyroiditis See Hashimoto disease.
autoimmune hemolytic anemia A condition in which the immune system destroys red blood cells, resulting in fewer of these oxygen-transporting cells. See also hemolytic anemia.
autoimmune disorder A condition characterized by autoimmunity in which a misdirected immune system acts against the tissues of one’s own body. Autoimmune disorders typically feature inflammation of various tissues of the body and are associated with antinuclear antibodies (ANAs) in the blood. Examples of autoimmune disorders include systemic lupus erythematosus, Sjogren’s syndrome, rheumatoid arthritis, polymyositis,…
autograft Tissue transplanted from one part of the body to another in the same individual. Also known as an autotransplant.
autogenous Self-produced.
autoclave A chamber for sterilizing with steam under pressure. The original autoclave was essentially a pressure cooker in which steam tightened the lid.
autoantibody An antibody that is directed against the patient’s own body. Autoantibodies play a causative role in a number of diseases, such as rheumatoid arthritis, systemic lupus erythematosus, and Hashimoto disease. See also autoimmune disorder.
autistic disorder Autism, particularly the most serious form of autism.