Diseases & conditions A-Z List
Diseases & Conditions A-Z List - «N»:
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Niacin
Niacin is a type of B vitamin. It is water-soluble, which means it is not stored in the body. Water-soluble vitamins dissolve in water. Leftover amounts of the vitamin leave the body through the urine. That means you need a continuous supply of such vitamins in your diet.
Function
Niacin assists in...
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Nicotine addiction and withdrawal
Tobacco and nicotine have a potential for addiction that is similar to alcohol, cocaine, and morphine.
Nicotine withdrawal creates anxiety, irritability, headache, hunger, and a craving for cigarettes or other sources of nicotine. These symptoms occur when a nicotine-dependent person suddenly stops ...
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Nicotine poisoning
Nicotine is a bitter-tasting compound that naturally occurs in large amounts in the leaves of tobacco plants.
Nicotine poisoning results from too much nicotine. Acute nicotine poisoning usually occurs in young children who accidentally chew on nicotine gum or patches.
This is for information only an...
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Nicotine replacement therapy
Nicotine replacement therapy involves the use of products that provide low doses of nicotine but do not contain the toxins found in smoke. The goal of therapy is to relieve cravings for nicotine and ease the symptoms when someone stops using cigarettes and smokeless tobacco.
In general, nicotine rep...
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NICU consultants and support staff
AUDIOLOGIST
An audiologist is trained to test a baby's hearing and provide follow-up care to those with hearing problems. Most newborns have their hearing tested before leaving the hospital. Your health care providers will determine which hearing test is best. Hearing tests may be also be done after...
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Niemann-Pick disease
Niemann-Pick disease refers to a group of diseases passed down through families (inherited) in which fatty substances called lipids collect in the cells of the spleen, liver, and brain.
There are four most commonly recognized forms of the disease: Types A, B, C, and D. Types A and B are also called ...
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Night terror
Night terrors are a sleep disorder in which a person quickly awakens from sleep in a terrified state.
Causes
Night terrors (sleep terrors) occur during deep sleep, usually during the first third of the night. The cause is unknown but night terrors may be triggered by fever, lack of sleep, or period...
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Nightmares
A nightmare is a dream that occurs during sleep that brings out strong feelings of fear, terror, distress, or anxiety. Nightmares usually happen in the second part of the night and wake up the sleeper, who is able to remember the content of the dream.
See also:
Generalized anxiety disorder
Night...
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Nikolsky’s sign
Nikolsky's sign is a skin finding in which the top layers of the skin slip away from the lower layers when slightly rubbed.
Considerations
Nikolsky's sign is either positive or negative. A positive result may be present in several different medical conditions. People with a positive sign have loose...
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Nipple problems
Nipple problems can include tenderness, skin changes, changes in shape, or discharge from the nipple portion of the breast.
This article is about nipple problems or changes in women who are not breast-feeding or who have not just had a baby (postpartum).
Causes
Nipple tenderness or skin changes may...
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Nitroblue tetrazolium test
The nitroblue tetrazolium test looks to see if certain immune system cells can change a colorless chemical called nitroblue tetrazolium (NBT) into a deep blue color.
How the Test is Performed
Blood is typically drawn from a vein, usually from the inside of the elbow or the back of the hand. The sit...
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Nocardia infection
Nocardia infection is a rare disorder affecting the lungs, brain, or skin. It occurs mainly in people with weakened immune systems.
Causes
Nocardia infection is a bacterial infection that usually starts in the lungs. It then tends to spread to other organ systems -- most often the brain and the ski...
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Nodules
Nodules are solid, raised bumps in or under the skin that are wider than 10 millimeters....
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Noma
Noma is a type of gangrene that destroys mucous membranes of the mouth and other tissues. It occurs in malnourished children in areas of poor cleanliness.
Causes
The exact cause is unknown, but may be due to bacteria called fusospirochetal organisms.
This disorder most often occurs in young, severe...
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Non-Hodgkin's lymphoma
Non-Hodgkin's lymphoma is cancer of the lymphoid tissue, which includes the lymph nodes, spleen, and other organs of the immune system.
Causes
White blood cells called lymphocytes are found in lymph tissues. Most lymphomas start in a type of white blood cells called B lymphocytes, or B cells.
For m...