Health A-Z


Clinical Definition The natural and physical process of delivering a baby from the uterus, followed by the placenta, is known as labor. It involves contractions of the uterus and effacement and dilation of the cervix, which allows for passage through the birth canal. Labor is triggered by the pituitary gland hormone oxytocin, which starts uterine

Lactose intolerance

Clinical Definition Lactose intolerance is the inability to digest lactose, a milk sugar, usually due to an intestinal deficiency of the enzyme lactase. In Our Own Words When people suffer with the digestive condition lactose intolerance, they are—to varying degrees—unable to digest lactose, which is a form of sugar found in dairy products and many


Clinical Definition Laparoscopy is a surgical procedure performed with a laparoscope, a thin viewing tube that is inserted in the body through a small incision. It is considered less invasive than open surgery, which requires a much larger incision. In Our Own Words Laparoscopy is a minimally invasive surgical procedure in which a thin viewing

Lead Poisoning

Clinical Definition Lead poisoning is a condition usually occurring as a result of ingesting lead-based paint. It is especially dangerous for young children and babies, as it can damage children’s developing nervous system, and other organs, triggering behavioral problems, learning issues and other problems. Symptoms may also include hyperactivity, headaches, vomiting and fatigue. A blood

Legionnaires’ Disease

Clinical Definition Legionnaires’ disease is an infection caused by the bacteria Legionella, found naturally in the environment and typically in warm water. The disease is transmitted via inhalation of droplets of water contaminated with the bacteria and typically can lead to pneumonia. It can be treated with antibiotics. In Our Own Words Legionnaires’ disease is an infection caused


Clinical Definition Leukemia, from the Greek words for white (leukos) and blood (haima), is a disease that affects both children and adults. Also called a blood cancer, leukemia is a malignant disease of the blood and bone marrow (which produces all types of blood cells). Leukemia begins in immature cells of bone marrow and most


Clinical Definition Lice are blood-sucking parasites, known as Pediculus humanus capitis if on the head; Pthirus pubic if in the pubic area; andPediculus humanus corporis if elsewhere on the body. Infestations are typically the result of close person-to-person contact. Incapable of flying or hopping, the parasitic insects must crawl instead. Treatments with prescription or over-the-counter remedies can quell infestations. In


Clinical Definition A lipoma is a benign encapsulated neoplasm, which usually has a soft, rubbery consistency. It is composed of mature adipocytes. Lipomas are usually located in the subcutaneous layer of the skin. They are usually painless and most often do not require treatment. In Our Own Words A lipoma is a non-cancerous, abnormal mass


Clinical Definition A lipoprotein is a particle composed of lipid and protein molecules, bound together, that transports cholesterol in the blood. Low-density lipoproteins (LDL) make up the majority of the cholesterol in the body; high levels increase the risk of coronary artery disease and stroke. High-density lipoproteins (HDL) absorb cholesterol and transport it to the

Liver spots

Clinical Definition Liver spots, or solar lentigines, are often called age spots. These flat, pigmented spots are prevalent on the face, hands, arms, back and feet of fair-skinned people. The etiology is years of sun exposure. Treatments include cryotherapy, laser therapy, chemical peels, and retinoids. In Our Own Words Liver spots, also called age spots, are

Lou Gehrig’s Disease

Clinical Definition Lou Gehrig’s disease, or amyotrophic lateral sclerosis (ALS), is a progressive neuromuscular disease marked by degeneration of the motor nerve cells in the brain and spinal cord. Named after the famed baseball player who retired from the sport in 1939 due to ALS, it involves the wasting away of muscles, including those that

Low Blood Pressure

Clinical Definition Low blood pressure, or hypotension, occurs when the pressure of the blood in your arteries is much lower than normal, leading to an inadequate blood supply for the heart, brain and other body parts. Normally, a healthy blood pressure goal is less than 120/80; low pressure is typically below 90/60. Causes of severe

Low Libido

Clinical Definition Low libido, or low sexual drive, is the lack of sexual drive and diminished sexual desires, which may occur for many emotional, physical or psychosocial reasons. This common sexual dysfunction is considered a desire disorder and may be caused by a decrease in the production of estrogen (in women) and testerone (in men).

Lung Cancer

Clinical Definition Lung cancer is an uncontrolled, abnormal growth of cells that invades and destroys healthy pulmonary tissue. Symptoms can be due to the effects of the tumor in the lungs, metastases to distant sites or the activity of the cancer cells themselves. Smoking causes the vast majority of lung cancers. Treatments include chemotherapy, surgery,


Clinical Definition Systemic lupus erythematosus (SLE) is the most common form of lupus, a serious autoimmune disease that may affect the skin, heart, joints, lungs and brain. The immune system produces antibodies to the body’s own cells, which triggers widespread inflammation and tissue damage. Anyone can be affected, but this disease often strikes women of

Lyme Disease

Clinical Definition Lyme disease is a vector-driven infectious disease caused by the Borrelia burgdorferi bacterium from the bite of a tick. The majority of cases present with acute signs and symptoms as the body mounts an immune response, including the hallmarkerythema migrans rash (it looks like a target) which occurs within one month of the bite. Bacteria spread


Clinical Definition Lymphoma is a cancer of the lymph system that occurs when white blood cells, known as lymphocytes, become abnormal. In Our Own Words Lymphoma is the most common type of blood cancer. However, there are many different types of lymphoma and they fall into two main categories: Hodgkin lymphoma or non-Hodgkin lymphoma (NHL).

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