All Diseases

Cryptosporidium infection (cryptosporidiosis) is an illness caused by tiny cryptosporidium parasites. When cryptosporidia (krip-toe-spoe-RID-e-uh) enter your body, they travel to your small intestine and then burrow into the walls of your intestines. Later, cryptosporidia are shed in your feces.

In most healthy people, a cryptosporidium infection produces a bout of watery diarrhea and the infection usually goes away within a week or two. If you have a compromised immune system, a cryptosporidium infection can become life-threatening without proper treatment.

You can help prevent a cryptosporidium infection by practicing good hygiene and avoiding swallowing water from pools, recreational water parks, lakes and streams.

Cushing syndrome occurs when your body is exposed to high levels of the hormone cortisol for a long time. The most common cause of Cushing syndrome, sometimes called hypercortisolism, is the use of oral corticosteroid medication. The condition can also occur when your body makes too much cortisol.

Too much cortisol can produce some of the hallmark signs of Cushing syndrome — a fatty hump between your shoulders, a rounded face, and pink or purple stretch marks on your skin. Cushing syndrome can also result in high blood pressure, bone loss and, on occasion, diabetes.

Treatments for Cushing syndrome can return your body's cortisol production to normal and noticeably improve your symptoms. The earlier treatment begins, the better your chances for recovery.

Cyclic vomiting syndrome is characterized by episodes of severe vomiting that have no apparent cause. Episodes can last for hours or days and alternate with relatively symptom-free periods of time. Each episode is similar to previous ones, meaning that episodes tend to start at the same time of day, last the same length of time and occur with the same symptoms and level of intensity.

Once thought to affect only children, cyclic vomiting syndrome occurs in all age groups. Research suggests that cyclic vomiting syndrome may affect almost 2 percent of school-age children and that the number of cases diagnosed in adults is increasing.

Cyclic vomiting syndrome may be related to migraines. Episodes can be so severe that the person has to stay in bed for days.

The syndrome is difficult to diagnose because vomiting is a symptom of many disorders. Treatment generally involves managing symptoms and lifestyle changes to help prevent the events that can trigger vomiting episodes. Medications, including anti-nausea and migraine therapies, may help lessen symptoms.

Cyclospora infection causes watery, and sometimes explosive, diarrhea. The one-celled parasite that causes cyclospora infection can enter your body when you ingest contaminated food or water. Fresh produce is the culprit in many cases of cyclospora infection.

Because diarrhea can be caused by many things, it can be difficult to diagnose cyclospora infection unless a specialized stool test is done. Treatment for cyclospora infection is antibiotics. Food safety precautions may help prevent the disease.

Cyclothymia (si-klo-THIGH-me-uh), also called cyclothymic disorder, is a mood disorder. Cyclothymia causes emotional ups and downs, but they're not as extreme as in bipolar disorder type I or II.

With cyclothymia, you experience periods when your mood noticeably shifts up and down from your baseline. You may feel on top of the world for a time, followed by a low period when you feel somewhat blue. Between these cyclothymic highs and lows, you may feel stable and fine.

Compared with bipolar disorder I or II, the highs and lows of cyclothymia are less extreme. Still, it's critical to seek help managing these symptoms because they increase your risk of bipolar disorder I or II. Treatment options for cyclothymia include talk therapy (psychotherapy), medications and close, ongoing follow-up with your doctor.

Cystic fibrosis is a life-threatening disorder that causes severe damage to the lungs and digestive system.

An inherited condition, cystic fibrosis affects the cells that produce mucus, sweat and digestive juices. These secreted fluids are normally thin and slippery. But in cystic fibrosis, a defective gene causes the secretions to become thick and sticky. Instead of acting as a lubricant, the secretions plug up tubes, ducts and passageways, especially in the lungs and pancreas.

Cystic fibrosis is most common in white people of Northern European ancestry, but also occurs in Hispanics, African-Americans and some Native Americans. It is rare in people of Asian and Middle Eastern origin.

Although cystic fibrosis requires daily care, most people with the condition are able to attend school and work, and have a better quality of life than in previous decades. Recent improvements in screening and treatments mean most people with cystic fibrosis now live into their 20s and 30s, and some are living into their 40s and 50s.

Cystitis (sis-TI-tis) is the medical term for inflammation of the bladder. Most of the time, the inflammation is caused by a bacterial infection, and it's called a urinary tract infection (UTI). A bladder infection can be painful and annoying, and it can become a serious health problem if the infection spreads to your kidneys.

Less commonly, cystitis may occur as a reaction to certain drugs, radiation therapy or potential irritants, such as feminine hygiene spray, spermicidal jellies or long-term use of a catheter. Cystitis may also occur as a complication of another illness.

The usual treatment for bacterial cystitis is antibiotics. Treatment for other types of cystitis depends on the underlying cause.

Cytomegalovirus (CMV) is a common virus that can infect almost anyone. Most people don't know they have CMV because it rarely causes symptoms. However, if you're pregnant or have a weakened immune system, CMV is cause for concern.

Once infected with CMV, your body retains the virus for life. However, CMV usually remains dormant if you're healthy.

CMV spreads from person to person through body fluids, such as blood, saliva, urine, semen and breast milk. CMV spread through breast milk usually doesn't make the baby sick. However, if you are pregnant and develop an active infection, you can pass the virus to your baby.

There's no cure for CMV, but drugs can help treat newborns and people with weak immune systems.

Dandruff is a common chronic scalp condition marked by flaking of the skin on your scalp. Although dandruff isn't contagious and is rarely serious, it can be embarrassing and sometimes difficult to treat.

The good news is that dandruff usually can be controlled. Mild cases of dandruff may need nothing more than daily shampooing with a gentle cleanser. More stubborn cases of dandruff often respond to medicated shampoos.

De Quervain's tenosynovitis (dih-kwer-VAINS ten-oh-sine-oh-VIE-tis) is a painful condition affecting the tendons on the thumb side of your wrist. If you have de Quervain's tenosynovitis, it will probably hurt every time you turn your wrist, grasp anything or make a fist.

Although the exact cause of de Quervain's tenosynovitis isn't known, any activity that relies on repetitive hand or wrist movement — such as working in the garden, playing golf or racket sports or lifting your baby — can make it worse.