DEFINITION Renal artery stenosis is the narrowing of one or more arteries that carry blood to your kidneys (renal arteries). Narrowing of the arteries prevents normal amounts of oxygen-rich blood from reaching your kidneys. Your kidneys need adequate blood flow…
DEFINITION Rapid eye movement (REM) sleep behavior disorder is a sleep disorder in which you physically act out vivid, often unpleasant dreams with vocal sounds and sudden, often violent arm and leg movements during REM sleep — sometimes called dream-enacting…
DEFINITION Prescription drug abuse is the use of a prescription medication in a way not intended by the prescribing doctor, such as for the feelings you get from the drug. Prescription drug abuse or problematic use includes everything from taking…
DEFINITION Preterm labor occurs when regular contractions begin to open your cervix before 37 weeks of pregnancy. A full-term pregnancy should last about 40 weeks. If preterm labor can’t be stopped, your baby will be born early. The earlier premature…
DEFINITION Priapism is a prolonged erection of the penis. The unwanted, persistent erection isn’t caused by sexual stimulation or arousal, and priapism is usually painful. Priapism is an uncommon condition that needs immediate medical attention. Prompt treatment for priapism is…
DEFINITION Primary aldosteronism (al-DOS-tuh-ro-niz-um) is a type of hormonal disorder that leads to high blood pressure. Your adrenal glands produce a number of essential hormones. One of these is aldosterone, which balances sodium and potassium in your blood. In primary…
DEFINITION Primary biliary cirrhosis, sometimes called PBC, is a disease in which the bile ducts in your liver are slowly destroyed. Bile, a fluid produced in your liver, plays a role in digesting food and helps rid your body of…
DEFINITION Primary lateral sclerosis (PLS) causes weakness in your voluntary muscles, such as those you use to control your legs, arms and tongue. Primary lateral sclerosis is a type of motor neuron disease that causes muscle nerve cells to slowly…
DEFINITION Primary progressive aphasia (uh-FAY-zhuh) is a rare nervous system (neurological) syndrome that impairs language capabilities. People with primary progressive aphasia may have trouble expressing their thoughts and comprehending or finding words. Symptoms of primary progressive aphasia begin gradually, sometimes…
DEFINITION Primary sclerosing (skluh-ROHS-ing) cholangitis (koh-lan-JIE-tis) is a disease of the bile ducts, which carry the digestive liquid bile from your liver to your small intestine. In primary sclerosing cholangitis, inflammation causes scars within the bile ducts. These scars make…
DEFINITION Primary immunodeficiency disorders — also called primary immune disorders or primary immunodeficiency — weaken the immune system, allowing infections and other health problems to occur more easily. Many people with primary immunodeficiency are born missing some of the body’s…
DEFINITION Progressive supranuclear palsy, also called Steele-Richardson-Olszewski syndrome, is an uncommon brain disorder that causes serious problems with walking, balance and eye movements. The disorder results from deterioration of cells in areas of your brain that control body movement and…