n-o
Nail psoriasis: Characterized by pitting, onycholysis, hyperkera-
tosis, and an oil-drop sign.1586 APPENDICES
Nasal scotoma: An area of blindness in the nasal portion of
peripheral vision.
Nasolacrimal occlusion: The closing of the tear duct to decrease
systemic absorption of a drug.
Natriuresis: Excretion of sodium in the urine.
Necrotizing enterocolitis: Medical condition seen in premature
infants, where portions of the bowel undergo necrosis.
Nelson syndrome: A condition characterized by the aggressive
growth of a pituitary tumor and hyperpigmentation of the skin.
Neoadjuvant therapy: Treatment given before the primary
modality to downsize the tumor.
Nephrolithiasis: A condition marked by the presence of renal
calculi (stones) in the kidney or urinary system.
Nephron: The working unit of the kidney that filters blood
to remove fluid, toxins, and drugs. Each kidney contains
approximately 1 million nephrons.
Nephrostomy: An artificial opening created between the kidney
and the skin which allows for the urinary diversion directly
from the upper part of the urinary system (renal pelvis).
Neuritic plaques: Extracellular deposits of amyloid beta with
concentration markedly increased in the hippocampus, amyg-
dala, and cerebral cortex. The plaque is thought to be formed
through a cascade involving the formation of abnormally
folded amyloid beta from amyloid precursor protein.
Neuritis: Inflammation of a nerve.
Neurofibrillary tangles: Aggregates of hyperphosphorylated tau
protein which can disrupt cellular function and lead to cellular
degeneration and death.
Neuropathic pain: Pain resulting from a lesion or dysfunction of
the nervous system.
Neuropathy: An abnormal and usually degenerative state of
the nervous system or nerves. Damage to the small and large
nerves due to glycation end products, lack of blood and
nutrients to the nerves, or chemical imbalances.
Neurotransmitters: Chemicals in the brain that allow the passage
of a message between neurons or nerve cells.
Neutralizing antibodies: Antibodies that develop in response to
a therapeutic agent that decrease the efficacy of the agent.
Nidus: A place in which something is formed or deposited; often
used to refer to the site in which bacteria have lodged and multiply.
Nociception: Encoding and processing of noxious stimuli to the
nervous system.
Nociceptors: Receptors for pain caused by injury from physical
stimuli (mechanical, electrical, or thermal) or chemical stimuli
(toxins); located in the skin, muscles, or in the walls of the
viscera.
Nocturia: Urination that occurs during sleep, causing patients to
awaken overnight.
Nocturnal polysomnography: Electrophysiologic assessment
of human sleep minimally composed of electroencephalogram,
electrooculogram, and electromyogram that allows determination
of sleep stage, breathing events, and muscle movements.
Nodule: An abnormal small swelling or aggregation of cells in
the body. When seen with rheumatoid arthritis, nodules are
subcutaneous knobs over bony prominences or extensor surfaces.
Non-rapid eye movement (REM) sleep: A state of usually
dreamless sleep that occurs regularly during a normal period
of sleep with intervening periods of REM sleep and that
consists of four distinct substages and low levels of autonomic
physiological activity.
Nonbacterial thrombotic endocarditis: Endocarditis which
consists of a sterile or noninfectious vegetation that has developed
on the heart valve and may be visible on imaging tests.
Nonmyeloablative preparative regimen: Chemotherapy
or chemotherapy/radiation regimens that cause minimal
cytopenias and do not require hematopoietic stem cell support
for hematopoietic cell recovery.
Nonpolyposis: Absence of polyps.
Nonprotein kilocalorie to nitrogen ratio: Numerical value
derived from dividing kilocalories from carbohydrate plus fat
by the number of grams of nitrogen in the diet (1 g of nitrogen
represent about 6.25 g of protein).
Non–ST-segment elevation myocardial infarction: A type of
myocardial infarction that is limited to the sub-endocardial
myocardium and is smaller and less extensive than an
ST-segment elevation myocardial infarction.
Noradrenergic: Neurons or receptors whose primary
neurotransmitter is norepinephrine.
Nuchal rigidity: Inability to flex the neck forward due to neck
muscle rigidity.
Nuclear factor kappa B (NF kappa B): Regulates cytokine
production.
Nulliparity: Condition of not having given birth to a child.
Nystagmus: Rapid, involuntary movements of the eyes.
Odynophagia: Pain on swallowing solid food and fluids, which is
often due to esophageal disease.
Off time: The time when the patient has poor control of their
symptoms.
Off-label use: Use of a medication outside the scope of its
approved, labeled use.
Oiling out: Continued coalescence of lipid emulsion particles,
resulting in irreversible separation of the emulsion (also called
“breaking” or “cracking” of the emulsion).
Oligoclonal immunoglobulin G bands: Small discrete bands in
the gamma globulin region of fluid electrophoresis.
Oligohydramnios: Decreased amniotic fluid.
Oliguria: Reduced urine output; usually defined as less than
400 mL in 24 hours or less than 0.5 mL/kg/hour.
Omentumectomy: Excision of the double fold of peritoneum
attached to the stomach and connecting it with abdominal
viscera (omentum).
On time: The time when patient has good control of their
symptoms.
Oncogenes: Genes found in the chromosomes of tumor cells
whose activation is associated with the initial and continuing
conversion of normal cells into cancer cells. Genes that cause
transformation of normal cells into cancer cells by promoting
uncontrolled cell growth and multiplication leading to tumor
formation.
Open comedo: A plugged hair follicle of sebum, keratinocytes,
and bacteria that protrudes from the surface of the skin
and appears black or brown in color. Also referred to as a
“blackhead.”
Opsonization: The process by which an antigen is altered so
as to become more readily and more efficiently engulfed by
phagocytes.
Optic neuritis: Usually monocular central visual acuity loss and
ocular/periorbital pain caused by demyelination of the optic nerve.
Oral glucose tolerance test: Used to measure the body’s response
to glucose; may be used to screen for type 2 diabetes and
gestational diabetes.
Orchiectomy: Surgical removal of the testes.
Organification: Binding of iodine to tyrosine residues of
thyroglobulin.
Orthopnea: Difficulty in breathing that occurs when lying down
and is relieved upon changing to an upright position
Nail psoriasis: Characterized by pitting, onycholysis, hyperkera-
tosis, and an oil-drop sign.1586 APPENDICES
Nasal scotoma: An area of blindness in the nasal portion of
peripheral vision.
Nasolacrimal occlusion: The closing of the tear duct to decrease
systemic absorption of a drug.
Natriuresis: Excretion of sodium in the urine.
Necrotizing enterocolitis: Medical condition seen in premature
infants, where portions of the bowel undergo necrosis.
Nelson syndrome: A condition characterized by the aggressive
growth of a pituitary tumor and hyperpigmentation of the skin.
Neoadjuvant therapy: Treatment given before the primary
modality to downsize the tumor.
Nephrolithiasis: A condition marked by the presence of renal
calculi (stones) in the kidney or urinary system.
Nephron: The working unit of the kidney that filters blood
to remove fluid, toxins, and drugs. Each kidney contains
approximately 1 million nephrons.
Nephrostomy: An artificial opening created between the kidney
and the skin which allows for the urinary diversion directly
from the upper part of the urinary system (renal pelvis).
Neuritic plaques: Extracellular deposits of amyloid beta with
concentration markedly increased in the hippocampus, amyg-
dala, and cerebral cortex. The plaque is thought to be formed
through a cascade involving the formation of abnormally
folded amyloid beta from amyloid precursor protein.
Neuritis: Inflammation of a nerve.
Neurofibrillary tangles: Aggregates of hyperphosphorylated tau
protein which can disrupt cellular function and lead to cellular
degeneration and death.
Neuropathic pain: Pain resulting from a lesion or dysfunction of
the nervous system.
Neuropathy: An abnormal and usually degenerative state of
the nervous system or nerves. Damage to the small and large
nerves due to glycation end products, lack of blood and
nutrients to the nerves, or chemical imbalances.
Neurotransmitters: Chemicals in the brain that allow the passage
of a message between neurons or nerve cells.
Neutralizing antibodies: Antibodies that develop in response to
a therapeutic agent that decrease the efficacy of the agent.
Nidus: A place in which something is formed or deposited; often
used to refer to the site in which bacteria have lodged and multiply.
Nociception: Encoding and processing of noxious stimuli to the
nervous system.
Nociceptors: Receptors for pain caused by injury from physical
stimuli (mechanical, electrical, or thermal) or chemical stimuli
(toxins); located in the skin, muscles, or in the walls of the
viscera.
Nocturia: Urination that occurs during sleep, causing patients to
awaken overnight.
Nocturnal polysomnography: Electrophysiologic assessment
of human sleep minimally composed of electroencephalogram,
electrooculogram, and electromyogram that allows determination
of sleep stage, breathing events, and muscle movements.
Nodule: An abnormal small swelling or aggregation of cells in
the body. When seen with rheumatoid arthritis, nodules are
subcutaneous knobs over bony prominences or extensor surfaces.
Non-rapid eye movement (REM) sleep: A state of usually
dreamless sleep that occurs regularly during a normal period
of sleep with intervening periods of REM sleep and that
consists of four distinct substages and low levels of autonomic
physiological activity.
Nonbacterial thrombotic endocarditis: Endocarditis which
consists of a sterile or noninfectious vegetation that has developed
on the heart valve and may be visible on imaging tests.
Nonmyeloablative preparative regimen: Chemotherapy
or chemotherapy/radiation regimens that cause minimal
cytopenias and do not require hematopoietic stem cell support
for hematopoietic cell recovery.
Nonpolyposis: Absence of polyps.
Nonprotein kilocalorie to nitrogen ratio: Numerical value
derived from dividing kilocalories from carbohydrate plus fat
by the number of grams of nitrogen in the diet (1 g of nitrogen
represent about 6.25 g of protein).
Non–ST-segment elevation myocardial infarction: A type of
myocardial infarction that is limited to the sub-endocardial
myocardium and is smaller and less extensive than an
ST-segment elevation myocardial infarction.
Noradrenergic: Neurons or receptors whose primary
neurotransmitter is norepinephrine.
Nuchal rigidity: Inability to flex the neck forward due to neck
muscle rigidity.
Nuclear factor kappa B (NF kappa B): Regulates cytokine
production.
Nulliparity: Condition of not having given birth to a child.
Nystagmus: Rapid, involuntary movements of the eyes.
Odynophagia: Pain on swallowing solid food and fluids, which is
often due to esophageal disease.
Off time: The time when the patient has poor control of their
symptoms.
Off-label use: Use of a medication outside the scope of its
approved, labeled use.
Oiling out: Continued coalescence of lipid emulsion particles,
resulting in irreversible separation of the emulsion (also called
“breaking” or “cracking” of the emulsion).
Oligoclonal immunoglobulin G bands: Small discrete bands in
the gamma globulin region of fluid electrophoresis.
Oligohydramnios: Decreased amniotic fluid.
Oliguria: Reduced urine output; usually defined as less than
400 mL in 24 hours or less than 0.5 mL/kg/hour.
Omentumectomy: Excision of the double fold of peritoneum
attached to the stomach and connecting it with abdominal
viscera (omentum).
On time: The time when patient has good control of their
symptoms.
Oncogenes: Genes found in the chromosomes of tumor cells
whose activation is associated with the initial and continuing
conversion of normal cells into cancer cells. Genes that cause
transformation of normal cells into cancer cells by promoting
uncontrolled cell growth and multiplication leading to tumor
formation.
Open comedo: A plugged hair follicle of sebum, keratinocytes,
and bacteria that protrudes from the surface of the skin
and appears black or brown in color. Also referred to as a
“blackhead.”
Opsonization: The process by which an antigen is altered so
as to become more readily and more efficiently engulfed by
phagocytes.
Optic neuritis: Usually monocular central visual acuity loss and
ocular/periorbital pain caused by demyelination of the optic nerve.
Oral glucose tolerance test: Used to measure the body’s response
to glucose; may be used to screen for type 2 diabetes and
gestational diabetes.
Orchiectomy: Surgical removal of the testes.
Organification: Binding of iodine to tyrosine residues of
thyroglobulin.
Orthopnea: Difficulty in breathing that occurs when lying down
and is relieved upon changing to an upright position