All Diseases

A concussion is a traumatic brain injury that alters the way your brain functions. Effects are usually temporary but can include headaches and problems with concentration, memory, balance and coordination.

Although concussions usually are caused by a blow to the head, they can also occur when the head and upper body are violently shaken. These injuries can cause a loss of consciousness, but most concussions do not. Because of this, some people have concussions and don't realize it.

Concussions are common, particularly if you play a contact sport, such as football. But every concussion injures your brain to some extent. This injury needs time and rest to heal properly. Most concussive traumatic brain injuries are mild, and people usually recover fully.

Congenital adrenal hyperplasia (kun-JEN-ih-tul uh-DREE-nul hi-pur-PLAY-zhuh) is a collection of genetic conditions that limit your adrenal glands' ability to make certain vital hormones. In most cases of congenital adrenal hyperplasia, the adrenal glands don’t produce enough cortisol. The production of two other kinds of hormones also may be affected, including mineralocorticoids (for example, aldosterone) and androgens (for example, testosterone).

Congenital adrenal hyperplasia can cause problems with normal growth and development in children — including normal development of the genitals. It affects both males and females.

Although congenital adrenal hyperplasia can be life-threatening, most people with it can lead normal lives with proper treatment.

If your child has a congenital heart defect, it means that your child was born with a problem in the structure of his or her heart.

Some congenital heart defects in children are simple and don't need treatment, such as a small hole between heart chambers that closes on its own. Other congenital heart defects in children are more complex and may require several surgeries performed over a period of several years.

The news that your child has a congenital heart defect can leave you worried about your child's health now and in the future. But, learning about your child's congenital heart defect can help you understand the condition and know what you can expect in the coming months and years.

Congenital heart disease (congenital heart defect) is an abnormality in your heart's structure that you're born with. Although congenital heart disease is often considered a childhood condition, advances in surgical treatment mean most babies who once died of congenital heart disease survive well into adulthood.

While medical advances have improved, many adults with congenital heart disease may not be getting proper follow-up care. If you had a congenital heart defect repaired as an infant, you likely still need care as an adult.

Find out if and when you should check with your doctor, if you're likely to have complications, or if you're at greater risk of other heart problems as an adult.

Conjoined twins are two babies that are born physically connected to each other.

Conjoined twins develop when an early embryo partially separates to form two individuals. Although two fetuses will develop from this embryo, they will remain physically connected — most often at the chest, pelvis or buttocks. Conjoined twins may also share one or more internal organs.

Most conjoined twins are stillborn or die shortly after birth. Some surviving conjoined twins can be surgically separated. The success of surgery to separate conjoined twins depends on where the twins are joined and how many and which organs are shared, as well as on the experience and skill of the surgical team.

Chronic constipation is infrequent bowel movements or difficult passage of stools that persists for several weeks or longer.

Constipation is generally described as having fewer than three bowel movements a week.

Though occasional constipation is very common, some people experience chronic constipation that can interfere with their ability to go about their daily tasks. Chronic constipation may also cause excessive straining to have a bowel movement and other signs and symptoms.

Treatment for chronic constipation depends on the underlying cause. Though, in some cases, a cause for chronic constipation is never found.

Constipation in children is a common problem. Constipation in children is often characterized by infrequent bowel movements or hard, dry stools.

Various factors can lead to constipation in children. Common causes include early toilet training and changes in diet. Fortunately, most cases of constipation in children are temporary.

Encouraging your child to make simple dietary changes — such as eating more fiber-rich fruits and vegetables and drinking more fluids — can go a long way toward alleviating constipation. If your child's doctor approves, sometimes constipation in children can also be treated with laxatives.

Contact dermatitis is a red, itchy rash caused by a substance that comes into contact with your skin. The rash isn't contagious or life-threatening, but it can be very uncomfortable.

Possible causes include soaps, cosmetics, fragrances, jewelry, and plants, such as poison ivy or poison oak. Some people are exposed to substances at work that may cause contact dermatitis.

To treat contact dermatitis successfully, you need to identify and avoid the cause of your reaction. If you can avoid the offending substance, the rash usually clears up in two to four weeks. You can try soothing your skin with cool, wet compresses, anti-itch creams and other self-care steps.

Convergence insufficiency occurs when your eyes don't work together while you're trying to focus on a nearby object. When you read or look at a close object, your eyes need to turn inward together (converge) to focus. This gives you binocular vision, enabling you to see a single image.

Convergence insufficiency can cause difficulty with reading. This may make parents or teachers suspect that a child has a learning disability, instead of an eye disorder.

Treatments for convergence insufficiency are usually effective.

Conversion disorder, also called functional neurological symptom disorder, is a condition in which you show psychological stress in physical ways. The condition was so named to describe a health problem that starts as a mental or emotional crisis — a scary or stressful incident of some kind — and converts to a physical problem.

For example, in conversion disorder, your leg may become paralyzed after you fall from a horse, even though you weren't physically injured. Conversion disorder signs and symptoms appear with no underlying physical cause, and you can't control them.

Signs and symptoms of conversion disorder typically affect your movement or your senses, such as the ability to walk, swallow, see or hear. Conversion disorder symptoms can vary in severity and may come and go or be persistent. The outcome may be better in younger children than in teenagers and adults. According to some experts, most people get better with immediate and proper management.