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Patient-friendly health topic summaries from the US National Library of Medicine.
Blood pressure is the force of your blood pushing against the walls of your arteries. Each time your heart beats, it pumps blood into the arteries. Your blood pressure is highest when your heart beats, pumping the blood. This is…
Psoriasis is a skin disease that causes itchy or sore patches of thick, red skin with silvery scales. You usually get the patches on your elbows, knees, scalp, back, face, palms and feet, but they can show up on other parts of your…
Diabetes means your blood glucose, also called blood sugar, is too high. With type 1 diabetes, your body makes little or no insulin. Insulin is a hormone from your pancreas that helps glucose move from your body into your cells, where…
Sometimes, after eating a large meal or lying down too soon after eating, you might feel acid coming up into your throat. This is called gastroesophageal reflux (GER). It happens when the muscle at the end of your esophagus (the tube…
Rheumatoid arthritis (RA) is a form of arthritis that causes pain, swelling, and stiffness in your joints. RA is an autoimmune disease. Although it is most common in the wrist and fingers, this disease can cause your immune system to…
You have two kidneys, each about the size of your fist. Their main job is to filter your blood. They remove wastes and extra water, which become urine. They also keep the body's chemicals balanced, help control blood pressure, and…
Epilepsy is a brain disorder that causes people to have recurring seizures. The seizures happen when clusters of nerve cells, or neurons, in the brain send out the wrong signals. People may have strange sensations and emotions or…
Breast cancer is a cancer that starts in breast tissue. It happens when cells in the breast change and grow out of control. New cells grow even when you don't need them, and old cells don't die when they should. These extra cells can…
A cataract is a clouding of the clear lens inside your eye. This cloudiness blocks light from reaching the back of the eye, making it harder to see clearly. A cataract can affect one or both eyes, but it doesn't spread from one eye to…
Asthma is a chronic (long-term) lung disease. It affects your airways, the tubes that carry air in and out of your lungs. When you have asthma, your airways can become inflamed and narrowed. This can cause wheezing, coughing, and…
Coronary artery disease (CAD) is the most common type of heart disease in the United States and a leading cause of death for both men and women. CAD affects the coronary arteries, which are the blood vessels that carry blood and…
Eczema is a term for several different types of skin swelling. Eczema is also called dermatitis. Most types cause dry, itchy skin and rashes on the face, inside the elbows and behind the knees, and on the hands and feet. Scratching…
Type 2 diabetes is a disease in which your blood glucose, or blood sugar, levels are too high. Glucose is your main source of energy. It comes from the foods you eat. A hormone called insulin helps the glucose get into your cells to…
Irritable bowel syndrome (IBS) is a problem that affects the large intestine. It can cause abdominal cramping, bloating, and a change in bowel habits. Some people with the disorder have constipation. Some have diarrhea. Others go back…
Lupus is a chronic (long-lasting) type of autoimmune disease. Autoimmune diseases happen when your immune system attacks healthy cells and tissues by mistake. This attack causes inflammation. It can also damage many parts of the body,…
A kidney stone is a solid piece of material that forms in the kidney from substances in the urine. It may be as small as a grain of sand or as large as a pearl. Most kidney stones pass out of the body without help from a doctor. But…
Migraines are a recurring type of headache. They cause moderate to severe pain that is throbbing or pulsing. The pain is often on one side of your head. You may also have other symptoms, such as nausea and weakness. You may be…
Lung cancer is cancer that forms in tissues of the lung, usually in the cells that line the air passages. It is the leading cause of cancer death in both men and women. There are two main types: small cell lung cancer and non-small…
Glaucoma is a group of diseases that can damage the optic nerve of one, or both, of your eyes. This can result in vision loss. There are different types of glaucoma, but the most common type is open-angle glaucoma. Other less common…
COPD (chronic obstructive pulmonary disease) is a group of lung diseases that make it hard to breathe and get worse over time. Normally, the airways and air sacs in your lungs are elastic or stretchy. When you breathe in, the airways…
A heart attack, also called a myocardial infarction, is a type of heart disease. It happens when blood flow to the heart suddenly becomes blocked. Without the blood coming in, the heart can't get oxygen. If not treated quickly, the…
Acne is a common skin disease that causes pimples. Pimples form when hair follicles under your skin clog up. Most pimples form on the face, neck, back, chest, and shoulders. Anyone can get acne, but it is common in teenagers and young…
Hyperthyroidism, or overactive thyroid, happens when your thyroid gland makes more thyroid hormones than your body needs. Your thyroid is a small, butterfly-shaped gland in the front of your neck. It makes hormones that control the…
Crohn's disease is a chronic (long-lasting) disease that causes inflammation in your digestive tract. It can affect any part of your digestive tract, which runs from your mouth to your anus. But it usually affects your small intestine…
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