Health Topics A-Z

Blood cholesterol is a waxy, fat-like substance your body needs, but only in the right amounts. When cholesterol levels become unhealthy, your risk of heart attack, stroke, and other serious conditions rises.

Human immunodeficiency virus (HIV) is the virus that causes HIV infection. Without treatment, HIV can progress to acquired immunodeficiency syndrome (AIDS), the most advanced stage of HIV infection.

Huntington's disease is an inherited neurological condition that causes nerve cells in the brain to gradually stop working properly and die. This leads to problems with movement, behavior, emotion, thinking, and personality.

Infections happen when germs invade and grow inside the body. When the body’s response to an infection gets out of control, it can lead to a life-threatening condition called sepsis.

Infertility is when a person, or a couple together, is unable to become pregnant or can become pregnant but cannot carry a pregnancy to term.

Influenza, also known as the flu, is a highly contagious respiratory illness caused by influenza viruses that infect the nose, throat, and lungs. Each year, influenza causes millions of illnesses worldwide.

People with insomnia have trouble falling asleep, staying asleep, or getting good-quality sleep.

Intellectual and developmental disabilities are differences usually present at birth that affect a person’s physical, intellectual, and emotional development. They may affect multiple systems in the body, and their symptoms extend throughout life.

Irritable bowel syndrome (IBS) is a common digestive condition that causes abdominal pain and changes in bowel movements over a long period of time. It affects both adults and children and is also called a disorder of gut-brain interaction.

Kidney cancer can develop in adults and children. The main types of kidney cancer are renal cell cancer, transitional cell cancer, and Wilms tumor.