Caffeine is a drug that stimulates the central nervous system.

California Achievement Tests

The California Achievement Tests (CAT) are among the most widely used tests of basic academic skills for children from kindergarten through grade 12. The most recent edition of the CAT (the sixth) is also called TerraNova, Second Edition (or alternately, Terra-Nova CAT).


Cancer is a group of diseases characterized by uncontrolled growth of tissue cells in the body and the invasion by these cells into nearby tissue and migration to distant sites.


Candidiasis is an infection caused by a species of the yeast Candida, usually the Candida albicans fungus. Candida is found on various parts of the bodies of almost all normal people but causes problems in only a few.

Canker Sores

Canker sores (aphthous ulcers) are small shallow sores or ulcers that appear inside the lips, inside the cheeks, or on the gums. They begin as small, reddish swellings.

Carbohydrate Intolerance

Carbohydrate intolerance is the inability of the small intestine to completely process the nutrient carbohydrate (a classification that includes sugars and starches) into a source of energy for the body. This is usually due to deficiency of an enzyme needed for digestion.

Carbon Monoxide Poisoning

Carbon monoxide (CO) poisoning occurs when carbon monoxide gas is inhaled. CO is a colorless, odorless, highly poisonous gas that is produced by incomplete combustion.

Cardiopulmonary Resuscitation

Cardiopulmonary resuscitation (CPR) is a procedure to support and maintain breathing and circulation for an infant, child, or adolescent who has stopped breathing (respiratory arrest) and/or whose heart has stopped (cardiac arrest).

Cat-Scratch Disease

Cat-scratch disease is an uncommon infection that typically results from a cat's scratch or bite. Most sufferers experience only moderate discomfort and find that their symptoms clear up without any lasting harm after a few weeks or months.

Celiac Disease

Celiac disease is a disease of the digestive system in which the inside lining of the small intestine (mucosa) is damaged after eating wheat, rye, oats, or barley, resulting in interference with the absorption of nutrients from food.

Cerebral Palsy

Cerebral palsy (CP) is the term used for a group of nonprogressive disorders of movement and posture caused by abnormal development of, or damage to, motor control centers of the brain. CP is caused by events before, during, or after birth.

Cerebrospinal Fluid (CSF) Analysis

Cerebrospinal fluid (CSF) analysis is a set of laboratory tests that examine a sample of the fluid surrounding the brain and spinal cord. This fluid is an ultrafiltrate of plasma.

Cerumen Impaction

Cerumen impaction refers to the buildup of layers of earwax within the ear canal to the point of blocking the canal and putting pressure on the eardrum. Ironically, cerumen impaction is often caused by misguided attempts to remove earwax.

Cesarean Section

A cesarean section (also referred to as c-section) is the birth of a fetus accomplished by performing a surgical incision through the maternal abdomen and uterus. It is one of the oldest surgical procedures known throughout history.

Charcot-Marie-Tooth Disease

Charcot-Marie-Tooth disease (CMT) is the name of a group of inherited disorders of the nerves in the peripheral nervous system. These are the nerves throughout the body that communicate motor and sensory information to and from the spinal cord.


Chemotherapy, sometimes referred to as "chemo," is the treatment of cancer with anticancer drugs.

Chest Physical Therapy

Chest physical therapy is the term for a group of treatments designed to improve respiratory efficiency, promote expansion of the lungs, strengthen respiratory muscles, and eliminate secretions from the respiratory system.

Chiari Malformation

Chiari malformation is a congenital anomaly (a condition that is present at birth), in which parts of the brain protrude through the opening in the base of the skull into the spinal column.


Chickenpox (also called varicella) is a common, extremely infectious, rash-producing childhood disease that also affects adults on occasion.

Chickenpox Vaccine

Chickenpox vaccine or varicella zoster vaccine (VZV) is an injection that protects children from contracting chickenpox (varicella), one of the most common childhood diseases.

Child Abuse

Child abuse is the blanket term for four types of child mistreatment: physical abuse, sexual abuse, emotional abuse, and neglect.

Child Custody Laws

Child custody laws are federal and state laws that govern a parent's legal authority to make decisions affecting a child (legal custody) and to maintain physical control over the child (physical custody). Child custody laws also pertain to the visitation rights of the non-custodial parent.


Childbirth is formally divided by the medical field into three stages. The first stage is labor, which has three phases: early, active, and transitional.

Childhood Vaccine Injury Act

The Childhood Vaccine Injury Act established a federal program for compensating victims of vaccine-related injuries or death.


About 2 million children are injured or killed by hazards in the home each year. Many of these incidents are preventable simply by taking precautions and by using simple, relatively inexpensive child safety products widely available.

Children's Apperception Test

The Children's Apperception Test (CAT) is a projective personality test used to assess individual variations in children's responses to standardized stimuli presented in the form of pictures of animals (CAT-A) or humans (CAT-H) in common social situations. In a supplement to the CAT—the CAT-S—the stimuli include pictures of children in common family situations such as prolonged illnesses, births, deaths, and separations from parental figures.


Choking is a condition caused by inhalation of a foreign object that partially or fully blocks the airway.

Cholesterol, High

High cholesterol (hypercholesterolemia or hyperlipidemia) refers to the presence of higher than normal amounts of total cholesterol circulating in the bloodstream. Cholesterol is a fatty substance (lipid) that is essential to the body as protection for the walls of the vasculature (veins and arteries) and linings of body organs, a component in the manufacture of hormones, and a factor in the digestion of consumed fats in foods.


The surgical removal of the foreskin of the penis in a male or the prepuce of a clitoris in a female.

Cleft Lip and Palate

A cleft lip and/or palate is a birth defect (congenital) of the upper part of the mouth. A cleft lip creates an opening in the upper lip between the mouth and nose and a cleft palate occurs when the roof of the mouth has not joined completely.


Clubfoot is a condition in which one or both feet are twisted into an abnormal position at birth. The condition is also known as talipes.

Coagulation Disorders

Coagulation disorders (coagulopathies) are disruptions in the body's ability to control blood clotting, an essential function of the body designed to prevent blood loss. The most commonly known coagulation disorder is hemophilia, a condition in which a critical component of blood coagulation is missing, causing individuals to bleed for long periods of time before clotting occurs.

Coarctation of the Aorta

Coarctation of the aorta (COA) is a congenital heart defect that develops in the fetus. It involves a constricture of the aorta, the main artery that delivers blood from the left ventricle of the heart to the rest of the body.

Cochlear Implants

A cochlear implant is a surgical treatment for hearing loss that works like an artificial human cochlea in the inner ear, helping to send sound from the ear to the brain. It is different from a hearing aid, which simply amplifies sound.

Cognitive Development

Cognitive development is the construction of thought processes, including remembering, problem solving, and decision-making, from childhood through adolescence to adulthood.

Cold Sore

Cold sores are small red blisters, filled with clear fluid, that form on the lip and around the mouth. Rarely, they form on the roof of the mouth.


Colic is defined as when a baby cries for longer than three hours every day for more than three days a week. It is the extreme end of normal crying behavior.

Color Blindness

Color blindness is an abnormal condition characterized by the inability to clearly distinguish different colors of the spectrum. The difficulties can range from mild to severe.

Common Cold

The common cold, also called a rhinovirus or coronavirus infection, is a viral infection of the upper respiratory system, including the nose, throat, sinuses, eustachian tubes, trachea, larynx, and bronchial tubes. Over 200 different viruses can cause a cold.

Common Variable Immunodeficiency

Common variable immunodeficiency (CVID) is a disorder of the immune system characterized by low levels of specific immunoglobulins, antibodies produced by the immune system to fight infection or disease. In CVID, immunoglobulin G (IgG) antibodies, one of several classes of antibodies, are either absent or produced in lower than normal numbers.

Communication Skills

Communication is the process by which information is exchanged between individuals. It requires a shared understanding of symbol systems, such as language and mathematics.

Computed Tomography

Computed tomography (CT), formerly referred to as computerized axial tomography (CAT), is a common diagnostic imaging procedure that uses x rays to generate images (slices) of the anatomy.


Concussion is a trauma-induced change in mental status, with confusion and amnesia, and with or without a brief loss of consciousness.


A condom is a device, usually made of latex, used to avoid pregnancy and/or sexually transmitted diseases such as gonorrhea, syphilis, and human immunodeficiency virus (HIV). Condoms are also known as prophylactics, as well as the popular slang term "rubbers." There are male and female versions of condoms.

Conduct Disorder

Conduct disorder (CD) is a behavioral and emotional disorder of childhood and adolescence. Children with conduct disorder act inappropriately, infringe on the rights of others, and violate the behavioral expectations of others.

Congenital Adrenal Hyperplasia

Congenital adrenal hyperplasia (CAH) is a genetic disorder characterized by a deficiency in the hormones cortisol and aldosterone and an over-production of the hormone androgen. CAH is present at birth and affects the sexual development of the child.

Congenital Amputation

Congenital amputation is the absence of a limb or part of a limb at birth.

Congenital Bladder Anomalies

The two most common congenital bladder abnormalities are exstrophy and congenital diverticula. An exstrophic bladder is one that is open to the outside and turned inside out, so that its inside is visible at birth, protruding from the lower abdomen.

Congenital Brain Defects

Congenital brain defects are a group of disorders of brain development that are present at birth.

Congenital Heart Disease

Congenital heart disease, or congenital heart defect, includes a variety of structural problems of the heart or its major blood vessels, which are present at birth.

Congenital Hip Dysplasia

Congenital hip dysplasia is a condition of abnormal development of the hip, resulting in hip joint instability and potential dislocation of the thigh bone from the socket in the pelvis. This condition has been in the early 2000s been termed developmental hip dysplasia, because it often develops over the first few weeks, months, or years of life.

Congenital Ureter Anomalies

The ureter drains urine from the kidney into the bladder. Not simply a tube, the ureter is an active organ that propels urine forward by muscular action.


Conjuctivitis is an inflammation resulting in redness of the lining of the white part of the eye and the underside of the eyelid (conjunctiva) that can be caused by infection, allergic reaction, or physical agents like infrared or ultraviolet light.


Constipation is an acute or chronic condition in which bowel movements occur less often than usual or consist of hard, dry stools that are painful or difficult to pass. Although constipation is a relative term, with normal patterns of bowel movements varying widely from person to person, generally an adult who has not had a bowel movement in three days or a child who has not had a bowel movement in four days is considered constipated.

Contact Dermatitis

Contact dermatitis is the name for any skin inflammation that occurs when the skin's surface comes in contact with a substance originating outside the body. There are two major categories of contact dermatitis, irritant and allergic.


Contraception (birth control) prevents pregnancy by interfering with the normal process of ovulation, fertilization, and implantation. There are different kinds of birth control that act at different points in the process.

Corneal Abrasion

A corneal abrasion occurs when there is a loss of cells from the epithelium or surface of the cornea. It is usually due to trauma but may occur without trauma such as with the overuse of contact lenses.


A cough is a forceful release of air from the lungs that can be heard. Coughing protects the respiratory system by clearing it of irritants and secretions.

Cough Suppressants

Cough suppressants are medicines that prevent or stop a person from coughing.


Craniosynostosis is one of a diverse group of deformities in the head and facial bones called craniofacial anomalies. An infant or child with craniosynostosis has improperly fused or joined bones (sutures) in the skull.


Crawling is a slow creeping mode of locomotion, consisting of forward motion with weight supported by the infant's hands (or forearms) and knees. It is the primary means of mobility in infants.


Creativity is the ability to think up and design new inventions, produce works of art, solve problems in new ways, or develop an idea based on an original, novel, or unconventional approach.

Cri du Chat Syndrome

Cri du chat (a French phrase that means "cry of the cat") syndrome is a group of symptoms that result when a piece of chromosomal material is missing (deleted) from a particular region on chromosome 5. Children born with this chromosomal deletion have a characteristic mewing cat-like cry as infants that is thought to be caused by abnormal development of the larynx (organ in the throat responsible for voice production).


Croup is one of the most common respiratory illnesses in children. It is an inflammation of the larynx and the trachea.

Crying and Fussing in an Infant

All babies cry and fuss. Many infants spend a considerable amount of time being fussy.

Cyclic Vomiting Syndrome

First described in 1882, cyclic vomiting syndrome (CVS) is a rare idiopathic disorder characterized by recurring periods of vomiting in an otherwise normal child. The word, idiopathic, means that the origin of the disorder is unknown.

Cystic Fibrosis

Cystic fibrosis (CF) is an inherited disease that affects the lungs, digestive system, sweat glands, and male fertility. Its name derives from the fibrous scar tissue that develops in the pancreas, one of the principal organs affected by the disease.


Cystitis is inflammation of the urinary bladder. Urethritis is an inflammation of the urethra, which is the tube that connects the bladder with the exterior of the body.

Cytomegalovirus Infection

Cytomegalovirus (CMV) is a virus related to the group of herpes viruses. Infection with CMV can cause no symptoms or can be the source of serious illness in people with weak immune systems.