Dictionary

lactase deficiency See deficiency, lactase.

lactation The process of milk production. Human milk is secreted by the mammary glands, which are located within the fatty tissue of the breast. The hormone oxytocin is produced in response to the birth of a new baby, and it both stimulates uterine contractions and begins the lactation process. For the first few hours of…

lactic acid A simple sugar that is the byproduct of glucose metabolism. Most lactic acid is produced by the red blood cells and by muscle cells when oxygen levels are low. When lactic acid accumulates rapidly in the muscle cells during or just after exercise, cramping can result. When lactic acid builds up faster than…

Krabbe disease A progressive degenerative disorder of the nervous system that involves the destruction of myelin, a fatty material that surrounds and insulates nerves. Most patients have the infantile form of Krabbe disease. During the first few months of life, they seem normal, but before 6 months of age, the signs of extreme irritability, spasticity,…

Krukenberg tumor A tumor of the ovary that is caused by the spread of metastatic cancer of the gastrointestinal tract, characteristically from the stomach.

KUB Abbreviation for kidney, ureter, and bladder.

KUB film An abdominal X-ray that shows the kidney, ureter, and bladder.

kuru A slowly progressive fatal disease of the brain that is due to an infectious agent transmitted among people in Papua New Guinea by ritual cannibalism. Kuru is an infectious form of subacute spongiform encephalopathy and is caused by a tiny infectious particle called a prion. It appears to be similar to bovine spongiform encephalopathy…

Kussmaul breathing Air hunger, or the rapid, deep, and labored breathing characteristic of patients with acidosis (excess acidity of tissues). For example, Kussmaul breathing is seen with the acidosis of diabetes mellitus that is seriously out of control. Treatment is directed toward controlling the underlying disease.

kwashiorkor A childhood disease that is caused by protein deprivation. Early signs include apathy, drowsiness, and irritability. More advanced signs are poor growth, lack of stamina, loss of muscle mass, swelling, abnormal hair (sparse, thin, often streaky red or gray hair in dark-skinned children), and abnormal skin that darkens in irritated but not sun-exposed areas….

kyphoplasty A somewhat incorrect name for the vertebroplasty procedure. Kyphoplasty literally means “to repair the bending of the spine to curve outward from the body.” Kyphosis can result when a vertebra (or several vertebrae) suffers a compression fracture from osteoporosis. Vertebroplasty is the procedure that can re-establish the height of a compressed vertebra. Sometimes, but…

kyphoscoliosis A combination of outward curvature (kyphosis) and lateral curvature (scoliosis) of the spine. Kyphoscoliosis can be due to musculoskeletal disease or to unknown causes. Treatment includes physical therapy and wearing a back brace, and in some cases surgery. Surgery for kyphoscoliosis may involve inserting a metal rod in the spine and restructuring some bones,…