Legionnaires’ disease A disease that is caused by bacteria found in plumbing, shower heads, and water-storage tanks. The disease was first identified at the 1976 American Legion convention, and subsequent outbreaks have occurred. The bacterium that causes it, now known as Legionella, thrives in the mist of condensers, air conditioners, and evaporative cooling towers, and…
Leigh’s disease A rare, inherited disorder characterized by degeneration of the central nervous system. Leigh’s disease can be caused by mutations in mitochondrial DNA or by deficiencies of an enzyme called pyruvate dehydrogenase. Symptoms usually begin between the ages of 3 months and 2 years and progress rapidly. Early symptoms may include poor sucking ability…
leiomyosarcoma A malignant tumor that originates in smooth muscle, the major structural component of most hollow internal organs and the walls of blood vessels. Leiomyosarcoma can occur almost anywhere in the body but is most frequently found in the uterus and gastrointestinal tract. Complete surgical excision, if possible, is the treatment of choice.
Leishmania A group of parasites that cause several human diseases. See also leishmaniasis.
leishmaniasis A parasitic disease that is spread by the bite of sand flies infected with the protozoa Leishmania. There are several forms of leishmaniasis, the most common being cutaneous and visceral leishmaniasis (known as kala-azar). The cutaneous form of the disease causes skin sores and is usually named for a geographic place (for example, Jericho…
laryngeal papillomatosis The presence of numerous warty growths on the vocal cords caused by human papillomavirus (HPV), which is contracted at birth via the vaginal canal of a mother with genital warts. Laryngeal papillomatosis is most common in young children under age 3 but may occur at any age. Recurrences of laryngeal papillomatosis are, unfortunately,…
laryngectomee A person who has had his or her larynx (voice box) removed. See also laryngectomy.
laryngectomy Surgery to remove part or all of the larynx. The surgeon performs a tracheostomy, creating an opening in the front of the neck (stoma). Air enters and leaves the trachea and lungs through the stoma. A tracheostomy tube keeps the new airway open.
laryngectomy, partial A laryngectomy that preserves the voice. The surgeon removes only part of the larynx (voice box)—just one vocal cord, just part of a vocal cord, or just the epiglottis—and the opening in the front of the neck (stoma) is temporary. After a brief recovery period, the tracheostomy tube is removed, and the stoma…
laryngectomy, total A laryngectomy in which the whole larynx (voice box) is removed, and the opening in the front of the neck (stoma) is permanent. The patient breathes through the stoma and must learn to talk in a new way.
laryngitis An inflammation of the larynx. Inflammation of the larynx is most often caused by viral infections. In these cases, other symptoms, such as sore throat, cough, difficulty swallowing, and fever, generally occur. The voice changes may persist after the fever and other symptoms of acute infection have resolved. Laryngitis can also occur as a…
laryngitis, reflux Inflammation of the larynx (voice box) caused by stomach acid backing up into the esophagus. Reflux laryngitis is associated with chronic hoarseness and symptoms of esophageal irritation such as heartburn, chest pain, asthma, or the feeling of a foreign body in the throat (the globus phenomenon). This can lead to chronic throat clearing,…