Health Library

A nabothian cyst is a mucus-filled lump on the surface of the cervix.

Nail abnormalities are problems with the color, shape, texture, or thickness of the fingernails or toenails.

This poisoning is from swallowing or breathing in (inhaling) nail polish. This is for information only and not for use in the treatment or management of an actual poison exposure. If you have an exposure, you should call your local emergency number (such as 911) or the National Poison Control ...

Naphthalene is a white solid substance with a strong smell. Poisoning from naphthalene destroys or changes red blood cells so they cannot carry oxygen. This is for information only and not for use in the treatment or management of an actual poison exposure. If you have an exposure, you should call ...

Naproxen sodium is a non-steroidal anti-inflammatory drug (NSAID) used to relieve mild to moderate aches and pains. Naproxen sodium overdose occurs when someone accidentally or intentionally takes more than the normal or recommended amount of this medication. This is for information only and not ...

Narcissistic personality disorder is a condition in which people have an inflated sense of self-importance and an extreme preoccupation with themselves.

Narcolepsy is a sleep disorder that causes excessive sleepiness and frequent daytime sleep attacks.

Nasal congestion refers to a stuffy nose.

CPAP stands for “continuous positive airway pressure.” CPAP is a treatment that delivers slightly pressurized air during the breathing cycle. This keeps the windpipe open during sleep and prevents the episodes of blocked breathing in persons with and other respiratory problems. It ...

Nasal discharge is any mucous-like material that comes out of the nose.

Nasal flaring is the enlargement of the opening of the nostrils during breathing. It is often a sign that increased effort is needed to breathe.

A nasal mucosal biopsy is the removal of a small piece of tissue from the lining of the nose so that it can be checked for disease.

Nasal polyps are sac-like growths of inflamed tissue lining the nose (nasal ) or sinuses. See also:

Nasopharyngeal culture is a sample of secretions from the uppermost part of the throat, behind the nose, to detect organisms that can cause disease.

Natal teeth are teeth that are already present at the time of birth. They are different from neonatal teeth, which grow in during the first 30 days after birth.

A natural short sleeper is someone who sleeps a lot less in a 24-hour period than is expected for people of the same age, without being abnormally sleepy.

Nausea is the sensation of having an urge to vomit. Vomiting is forcing the contents of the stomach up through the esophagus and out of the mouth.

“Near drowning” means a person almost died from not being able to breathe (suffocating) under water. If a person has been rescued from a near-drowning situation, quick first aid and medical attention are very important.

Nearsightedness is when light entering the eye is focused incorrectly, making distant objects appear blurred. Nearsightedness is a type of refractive error of the eye. If you are nearsighted, you have trouble seeing things that are far away.

A neck lump is any lump, bump, or swelling in the neck.

A neck is an imaging test to look at cervical vertebrae, the seven bones in the neck area.

Necrosis is death of body tissue. It occurs when there is not enough blood flowing to the tissue, whether from injury, radiation, or chemicals. Necrosis is not reversible. When substantial areas of tissue die due to a lack of blood supply, the condition is called .

Necrotizing enterocolitis is the death of intestinal tissue. It primarily affects premature infants or sick newborns.

A granuloma is a small clump of dead cells that form when the immune system tries to fight off a harmful substance but cannot remove it from the body. A necrotizing granuloma refers to an area of inflammation in which tissue has died. Necrotizing means dying or decaying. See: Tuberculosis and ...

Necrotizing soft tissue infection is a rare but very severe type of bacterial infection that can destroy the muscles, skin, and underlying tissue. Necrotizing refers to something that causes tissue death.

Necrotizing vasculitis is a rare condition that involves inflammation of the blood vessel walls.

Neonatal abstinence syndrome (NAS) is a group of problems that occur in a newborn who was exposed to addictive illegal or prescription drugs while in the mother’s womb.

Neonatal conjunctivitis is swelling (inflammation) or infection of the tissue lining the eyelids in a newborn.

Neonatal cystic fibrosis screening is a blood test that looks for increased levels of immunoreactive trypsinogen (IRT), an enzyme produced by the pancreas. The test is performed on newborns to screen for (CF). Cystic fibrosis is an inherited disease that causes thick, sticky mucus to build up in ...

Neonatal hypoglycemia is low blood sugar (glucose) in the first few days after birth.

Neonatal hypothyroidism is decreased thyroid hormone production in a newborn. In very rare cases, no thyroid hormone is produced. If the baby was born with the condition, it is called congenital hypothyroidism. If it develops soon after birth, it is referred to as hypothyroidism acquired in the ...

Neonatal respiratory distress syndrome (RDS) is most commonly a complication seen in premature infants. The condition makes it difficult to breathe.

Neonatal sepsis is a blood infection that occurs in an infant younger than 90 days old. Early-onset sepsis is seen in the first week of life. Late-onset sepsis occurs between days 8 and 89.

Feeding and growing is one of the most important tasks of small babies in the hospital. It is important that babies receive the right nutrition so they reach a weight similar to that they would have gained if they were still inside the womb.

A neonate is a baby who is 4 weeks old or younger.

Nephrocalcinosis is a disorder in which there is excess calcium deposited in the kidneys.

Nephrotic syndrome is a group of symptoms including (more than 3.5 grams per day), low blood protein levels, high cholesterol levels, high triglyceride levels, and .

A nerve biopsy is the removal of a small piece of a nerve for examination.

Nerve conduction velocity (NCV) is a test of the speed of electrical signals through a nerve.

Neuralgia is pain that follows the path of a nerve. See also:

Neuroblastoma is a malignant (cancerous) that develops from nerve tissue. It occurs in infants and children.

Neurocognitive testing is used to find out about a person’s thinking abilities, and to determine whether these problems are improving or getting worse.

Neurofibromatosis 2 (NF2) is a genetic disorder in which tumors form on the nerves of the brain and spine (the central nervous system). See also: (NF1)

Neurofibromatosis-1 is an inherited disorder in which nerve tissue (neurofibromas) form in the skin, bottom layer of skin ( tissue), and nerves from the brain (cranial nerves) and spinal cord (spinal root nerves).

Neurogenic bladder is a urinary problem in which the bladder does not empty properly due to a neurological condition. See also:

Neuronal ceroid lipofuscinoses (NCLS) refers to a group of rare, inherited disorders of the nerve cells. There are three main types of NCLS: Adult (Kufs’ or Parry’s disease) Juvenile (Batten disease) Late infantile (Jansky-Bielschowsky)

Neuropathy secondary to drugs is a (or movement) in a part of the body due to a certain medicine.

Neuroretinitis is inflammation of the and optic nerve of the eye. Various bacteria and viruses can lead to neuroretinitis. Inflammation can occur in the absence of any infection.

Neurosarcoidosis is a complication of in which inflammation occurs in the brain, spinal cord, and other areas of the nervous system.

Neurosciences refers to the branch of medicine that focuses on the nervous system. The nervous system is made of two parts: The central nervous system consists of your brain and spinal cord. The peripheral nervous system consists of all your nerves outside of the brain and spinal cord including, ...

Neurosyphilis is an infection of the brain or spinal cord. It usually occurs in persons who have had untreated for many years.

Neutropenia is an abnormally low number of white blood cells called neutrophils. Neutrophils help the body fight infection. This article discusses neutropenia in infants.

Newborn head molding is an abnormal head shape that results from pressure on the baby’s head during childbirth.

Newborn jaundice is a condition marked by high levels of bilirubin in the blood. The increased bilirubin causes the infant’s skin and whites of the eyes (sclera) to look yellow.

Newborn screening tests look for serious developmental, genetic, and metabolic disorders so that important action can be taken during the critical time before symptoms develop. Most of these illnesses are very rare. In the United States, individual states regulate newborn screening, so the ...

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.

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 ...

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 ...

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 ...

This article discusses the primary team of caregivers that are involved in the care of your infant in the neonatal intensive care unit (NICU). The staff often includes the following: ALLIED HEALTH PROFESSIONAL This health care provider is a nurse practitioner or a physician assistant who ...

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 ...

Night terrors are a sleep disorder in which a person quickly awakens from sleep in a terrified state.

A nightmare is a dream that occurs during sleep that brings out strong feelings of fear, terror, distress, or . 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:

Nikolsky’s sign is a skin finding in which the top layers of the skin slip away from the lower layers when slightly rubbed.

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 breastfeeding or who have not just had a baby (postpartum).

Nitric acid is a poisonous clear-to-yellow colored liquid. This article discusses poisoning from swallowing or breathing in nitric acid. This is for information only and not for use in the treatment or management of an actual poison exposure. If you have an exposure, you should call your local ...

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.

Nitroglycerin is a medicine that helps relax the blood vessels leading to the heart. It is used to prevent and treat chest pain. Nitroglycerin occurs when someone accidentally or intentionally takes more than the normal or recommended amount of this medication. This is for information only and ...

Nocardia infection is a rare disorder affecting the lungs, brain, or skin. It occurs mainly in people with weakened immune systems.

Nodules are solid, raised bumps in or under the skin that are wider than 10 millimeters.

Noma is a type of that destroys mucous membranes of the mouth and other tissues. It occurs in malnourished children in areas of poor cleanliness.

Non-Hodgkin’s lymphoma is cancer of the lymphoid tissue, which includes the lymph nodes, spleen, and other organs of the immune system.

The term noninvasive can refer to diseases, procedures, or devices: Noninvasive diseases usually do not spread to or damage other organs and tissues. Noninvasive procedures do not involve tools that break the skin or physically enter the body. Examples include x-rays, a , , , , and . Noninvasive ...

Noonan syndrome is a genetic disorder that causes abnormal development of multiple parts of the body. It used to be called Turner-like syndrome because certain symptoms (webbing of neck and abnormally shaped chest) resembled those seen in .

A child’s growth and development can be divided into four periods: Infancy Preschool years Middle childhood years Adolescence Immediately after birth, an infant normally loses about 5 – 10% of his or her birth weight. However, by about age 2 weeks, an infant should start to gain weight ...

Hydrocephalus refers to a build-up of fluid inside the skull, leading to brain swelling. Hydrocephalus means “water on the brain.” Normal pressure hydrocephalus (NPH) is a rise in cerebrospinal fluid (CSF) in the brain that affects brain function. However, the pressure of the fluid is ...

Norpramin is a type of drug called a tricyclic antidepressant. It is used to treat depression. Norpramin overdose occurs when you accidentally or intentionally take too much of this medicine. This is for information only and not for use in the treatment or management of an actual poison ...

A nose fracture is a break in the bone or cartilage over the bridge, in the sidewall, or septum (line dividing the nostrils) of the nose.

A nosebleed is loss of blood from the tissue lining the nose. Bleeding most commonly occurs in one nostril only.

Thallium stress test is a nuclear imaging method that shows how well blood flows into the heart muscle, both at rest and during activity.

Nuclear ventriculography is a test that uses radioactive materials called tracers to show the heart chambers. The procedure is . The instruments do not directly touch the heart.

Numbness and tingling are abnormal sensations that can occur anywhere in your body, but are often felt in your fingers, hands, feet, arms, or legs.

Nummular eczema is an allergy-related disorder in which itchy, coin-shaped spots or patches appear on the skin.

A nurse practitioner (NP) is a nurse with a graduate degree in advanced practice nursing. See also:

Nursemaid’s elbow is a of a bone in the elbow called the radius. Dislocation means the bone slips out of its normal position at the elbow joint. The injury is also called radial head dislocation.

There is a connection between food consumption and athletic performance.

Nystagmus refers to rapid involuntary movements of the eyes that may be: Side to side (horizontal nystagmus) Up and down (vertical nystagmus) Rotary Depending on the cause, these movements may be in both eyes or in just one eye. The term “dancing eyes” has been used in regional dialect ...