Acromegaly is an uncommon hormonal disorder caused by the overproduction of growth hormone. It typically causes signs such as enlarged hands and feet.

Acute kidney failure

Acute lymphocytic leukemia

Acute myelogenous leukemia (AML)

Acute sinusitis

Acute sinusitis occurs when your sinus cavities become inflamed. Antibiotics, decongestants and corticosteroids may relieve pain and congestion and prevent development of chronic sinusitis.



Anaphylaxis is the most serious type of allergic reaction. It often occurs rapidly after exposure to an allergen and may be life-threatening.



Anorexia nervosa



Aortic valve regurgitation

Aortic valve stenosis

Aplastic anemia

Aplastic anemia occurs when your bone marrow stops producing enough new blood cells. It's a serious problem, but treatments are available.


Arteriovenous fistula



Atrial septal defect

Atrioventricular canal defect

Autoimmune hepatitis

Autoimmune hepatitis — Early detection, medications can help.

Bipolar disorder

Blastocystis hominis infection

A microscopic parasite causes Blastocystis hominis infection. Experts disagree as to whether this infection causes diarrhea and other associated signs and symptoms.



Bronchitis often develops after a cold. Learn how to prevent this potentially serious lung infection.


Brucellosis is an infectious disease that spreads from animals to people, mainly via unpasteurized dairy products. Travelers should take special care to avoid infection.

Brugada syndrome



Castleman disease

Celiac disease

Celiac disease is an immune reaction to gluten, a protein found in certain foods. As a result, the body is unable to absorb some important nutrients.

Chagas disease

Chemo brain

Chemo brain causes thinking and memory problems in cancer survivors. Find out how to cope.


Cholera causes severe diarrhea and can kill in a matter of hours, yet can be easily treated with oral or intravenous fluids.

Chronic fatigue syndrome

Chronic kidney disease

Chronic kidney disease, often caused by diabetes or high blood pressure, is the gradual loss of kidney function. Early detection and treatment can help.

Chronic lymphocytic leukemia

Chronic lymphocytic leukemia is a cancer of the blood and bone marrow. Unlike other cancers, this form of leukemia doesn't always initially require treatment.

Chronic myelogenous leukemia

Chronic myelogenous leukemia (CML) is a rare type of blood cancer. New treatments may be improving the prognosis for many people with CML.

Chronic sinusitis

Chronic sinusitis involves long-term inflammation or infection of the sinus cavities. Medications can help, and in rare cases surgery can treat this painful condition.

Churg-Strauss syndrome

Churg-Strauss syndrome is a rare disorder marked by blood vessel inflammation that affects organs throughout the body. Asthma is the most common sign.


Colon cancer

Colon cancer and rectal cancer combined are the second-leading cause of cancer-related deaths in the United States. Regular screening tests can help reduce your risk.

Common cold

You've got a cold, or you're trying to prevent getting one. Here are some timely tips.


Concussions can be serious injuries that need sufficient time to heal.

Crohn's disease

Cushing syndrome

Cushing syndrome is caused by an excess of the hormone cortisol, originating from your adrenal glands or from corticosteroid medications you're taking for another illness.

Cyclospora infection

Cyclothymia (cyclothymic disorder)




Diabetes affects how your body uses blood sugar. Too much blood sugar over long periods can cause serious health problems, but treatments are available.

Diabetic coma

Diabetic ketoacidosis

Dilated cardiomyopathy

Dumping syndrome


Dysthymia is a mild but long-term form of depression that can greatly reduce your quality of life. Learn about dysthymia symptoms and treatment options.

Ebstein's anomaly

Ebstein's anomaly is a rare heart defect. Some people may not have any symptoms, but others may need treatment, including surgery.


Encephalitis is inflammation of the brain usually caused by a viral infection. Severe cases can cause brain damage, even death.



Endometriosis is a common and often painful disorder in which tissue that normally lines the inside of your uterus grows outside your uterus.

Enlarged liver

Enlarged spleen

An enlarged spleen is usually a sign of an underlying problem. Treatment varies, depending on what's causing the enlargement.

Esophageal cancer

Reduce your risk of esophageal cancer by eating more fruits and vegetables.


Fatigue and widespread pain are common with fibromyalgia, a condition affecting mainly women. Treatment often focuses on managing symptoms with medication and self-care.

Gaucher's disease

Generalized anxiety disorder



Glomerulonephritis affects your kidneys' filtering function. Complications include high blood pressure, protein in the urine (proteinuria) and kidney failure.

Grand mal seizure

Graves' disease

Hairy cell leukemia


Hashimoto's disease

Hashimoto's disease (chronic lymphocytic thyroiditis) causes thyroid gland inflammation and often an underactive thyroid (hypothyroidism). Treatment may involve thyroid hormone replacement medication.

Heart arrhythmias

Heart attack

Heart disease

Heart disease, usually thought of as blockages in the arteries that can cause a heart attack, can describe any medical condition affecting your heart.

Heart failure

Heat exhaustion


Hemochromatosis causes your body to store large amounts of iron, which can cause life-threatening complications. The simple treatment is to regularly remove blood.

Hemolytic uremic syndrome (HUS)

Hemolytic uremic syndrome is an uncommon condition that can cause life-threatening kidney failure, especially for children and older adults.


Hepatitis A

Hepatitis B

Hepatitis C

Hiatal hernia

Hirschsprung's disease

Hirschsprung's disease, a disease of the colon, is present at birth and can cause serious problems passing stool.


Hodgkin's lymphoma

Huntington's disease


Hyperglycemia in diabetes

Hyperglycemia in diabetes — Comprehensive overview covers causes, symptoms and treatments of high blood sugar.






In hypopituitarism, your pituitary gland produces too little — or none — of one or more hormones. Disruption of any number of routine body functions can result.


Inflammatory bowel disease (IBD)

Influenza (flu)


Sleepless nights? Insomnia includes difficulty going to sleep, staying asleep or going back to sleep after you awaken. Insomnia may be temporary or chronic.

Iron deficiency anemia

Iron deficiency anemia may leave you feeling sapped of energy. This condition is especially common in women. Iron supplements usually help.

Jet lag disorder

Kidney cancer

Lead poisoning

Legionnaires' disease

Legionnaires' disease, a severe form of pneumonia, is caused by bacteria that can live in water in air conditioning systems, showers and spas.


Liver cancer

The risk of liver cancer may be reduced by protecting yourself from serious liver diseases such as cirrhosis and hepatitis B and C.

Long QT syndrome

Low blood pressure (hypotension)

Low blood pressure (hypotension) can be a sign of good health or of a life-threatening condition. Find out more about hypotension's causes and treatment options.


Lyme disease

Male hypogonadism

Membranous nephropathy


Mental illness

Mitral valve prolapse

Mitral valve prolapse occurs when the valve separating two of your heart's chambers malfunctions. The disorder usually isn't serious and often doesn't require surgical treatment.

Mitral valve stenosis

Mixed connective tissue disease


Mononucleosis — also called kissing disease because it can be spread by kissing — causes fatigue, fever and swollen lymph glands.

Multiple myeloma


Myelodysplastic syndromes


In myelofibrosis, healthy bone marrow is replaced with scar tissue, leading to severe anemia and fatigue.


Nonalcoholic fatty liver disease

Nonalcoholic fatty liver disease is associated with obesity and diabetes. Lifestyle changes may prevent it from becoming serious.

Non-Hodgkin's lymphoma

Parvovirus infection

Pectus excavatum

Pelvic inflammatory disease (PID)




Plague is a disease carried by rats and other rodents. The risk of developing plague is low, and most cases occur in Africa.



Pneumonitis is a general term for lung inflammation. It can cause difficulty breathing, often accompanied by a cough.


One of the most feared diseases of the 20th century, polio has been eradicated from the developed world but remains a threat in less developed nations.

Polycythemia vera

Polycythemia vera is a rare blood disorder in which a person's bone marrow makes too many blood cells.

Polymyalgia rheumatica


Post-concussion syndrome

Postpartum depression

Post-polio syndrome


Premenstrual syndrome (PMS)

Primary biliary cirrhosis

Primary sclerosing cholangitis

Pulmonary atresia

Pulmonary atresia is a heart defect that you're born with. Fortunately, treatment soon after birth and ongoing throughout childhood and adulthood greatly improve your prognosis.

Pulmonary edema

Pulmonary fibrosis

Pulmonary fibrosis results from scar tissue that forms in your lungs. This affects your ability to breathe and obtain enough oxygen.

Pulmonary hypertension

High blood pressure affecting only the arteries in your lungs is known as pulmonary hypertension. Discover the symptoms, risk factors and treatment for this condition.

Pulmonary valve stenosis

Q fever

Rheumatic fever

Rheumatic fever, an inflammatory disease triggered by untreated or poorly treated strep throat, can cause permanent heart damage.

Rheumatoid arthritis

Rocky Mountain spotted fever



Sarcoidosis starts in your lungs but can cause inflammation in any part of your body. It can last a lifetime, or disappear in a few years.

Sheehan's syndrome

Sheehan's syndrome is a rare pituitary gland disorder that occurs in women usually as a result of severe blood loss during childbirth.


Sick sinus syndrome

Sinus headaches

Sjogren's syndrome

Small vessel disease

If you have symptoms of heart disease, but your doctor doesn't see any blocked major arteries, small vessel disease may be the cause.


Somatic symptom disorder

Stomach cancer

Reduce your risk of stomach cancer by eating more fruits and vegetables.

Strep throat

Strep throat is a bacterial throat infection. It typically causes a very sore throat and is treated with antibiotics.

Sudden cardiac arrest

Sudden cardiac arrest is a medical emergency. Rapid treatment improves your chances of survival.

Sunburn: Soothing solutions

Swine flu (H1N1 flu)

Takayasu's arteritis

Takayasu's arteritis is an uncommon form of vasculitis that affects the large arteries.

Teen depression

All teens feel down from time to time. But if negative feelings persist or start to interfere with daily life, it might be depression.


Thalassemia is an inherited blood disorder, characterized by less hemoglobin and fewer red blood cells than normal. When necessary, treatment includes blood transfusions.

Toxic hepatitis

Toxic hepatitis is liver damage that occurs when your liver isn't able to break down certain toxins — including common pain relievers such as Tylenol.


Toxoplasmosis is an infection caused by a parasite. It doesn't make most people ill, but infants and people with HIV/AIDS are at risk of complications.

Trench mouth

Although trench mouth is much less common than in years past, some people still get this painful gum infection. Brushing and flossing are keys to prevention.

Tricuspid atresia


Type 1 diabetes

Type 1 diabetes in children

Type 1 diabetes is a lifelong — sometimes frightening — condition, but it doesn't need to slow your child down. Learn more about managing type 1 diabetes.

Type 2 diabetes

Type 2 diabetes in children

Typhoid fever

Ulcerative colitis

Valley fever


Viral hemorrhagic fevers

Ebola and Marburg viruses and yellow fever belong to a group of potentially deadly illnesses called viral hemorrhagic fevers. Find out about risk.

Vitamin deficiency anemia

Lacking certain vitamins can lead to vitamin deficiency anemia. Find out which vitamins are linked to this condition.

Von Willebrand disease

Von Willebrand disease is an inherited bleeding condition caused by a deficit in or impairment of a protein essential for blood clotting.

Wegener's granulomatosis

Wegener's granulomatosis is an uncommon disease that causes blood vessel inflammation that can damage lungs, kidneys and other organs. Untreated, it can be fatal.

West Nile virus

West Nile virus infection usually resolves on its own, but occasionally it can be serious.


Whipple's disease

Whooping cough

Wilson's disease

Feb. 27, 2013