Dictionary

NHL Non-Hodgkin’s lymphoma. See lymphoma, non-Hodgkin’s.

niacin deficiency See pellagra.

nicotine An alkaloid (a nitrogen-containing chemical) made by the tobacco plant or produced synthetically. Nicotine has powerful pharmacologic effects (including increased heart rate, heart stroke volume, and oxygen consumption by the heart muscle), as well as powerful psychodynamic effects (such as euphoria, increased alertness, and a sense of relaxation). Nicotine is also powerfully addictive.

nictitate To wink. For example, nictitating spasm is spasm of the eyelid with continuous winking.

nidus In medicine, any structure that resembles a nest in appearance or function. From the Latin for “nest.” A nidus is a breeding place where bacteria, parasites, and other agents of a disease lodge and develop. For example, a nidus of infection is a focus of infection. A nidus is also the nucleus or origin…

Niemann-Pick disease A group of inherited biochemical disorders in which lipid (fat) accumulates in the spleen, liver, lungs, bone marrow, and the brain. Symptoms may include lack of muscle coordination, brain degeneration, learning problems, loss of muscle tone, increased sensitivity to touch, spasticity, feeding and swallowing difficulties, slurred speech, and an enlarged liver and spleen….

night blindness See nyctanopia.

night eating syndrome An eating disorder estimated to affect between 1 percent and 2 percent of adults in which at least 50 percent of the daily food intake is consumed after dinner. Abbreviated NES. The causes of NES have not been understood, but an impaired circadian rhythm of food intake is believed to play a…

night sweats Severe hot flashes that occur at night and result in a drenching sweat. Night sweats can have many different causes, including medications, infections, and cancers.

NIH National Institutes of Health.

Nipah virus A member of the paramyxovirus family isolated from samples from an outbreak of encephalitis and respiratory illness among adult men in Malaysia and Singapore in 1999 that causes a sometimes fatal form of viral encephalitis. The humans were infected by close contact with infected pigs. Symptoms include high fever and aches, coma, and…

nipple The pigmented projection on the surface of the chest in the male and the breast in the female. In the mature female, ducts that conduct milk from the mammary glands to the surface of the breast exit through the nipple. The surrounding flat area of pigmentation is the areola.