This congenital heart defect affects the valve between the heart and lungs and includes a hole in the heart. Learn the symptoms and how it's treated.
Disease
Pulmonary valve stenosis
When the valve between the heart and lungs is narrowed, blood flow slows. Know the symptoms of this type of valve disease and how it's treated.
Disease
Pyloric stenosis
In this condition, a valve between an infant's stomach and small intestine fails to open enough for food to pass through. Surgery is the treatment.
Disease
REM sleep behavior disorder
REM sleep behavior disorder is a sleep disorder in which you physically and vocally act out vivid, often unpleasant dreams during REM sleep.
Disease
Radiation sickness
Read about what happens when someone is exposed to high doses of radiation, and what you can do to prevent such exposure in an emergency.
Disease
Ramsay Hunt syndrome
A shingles outbreak can affect the facial nerve near one of your ears, potentially causing facial paralysis and hearing loss.
Disease
Renal artery stenosis
Learn about what happens when the arteries leading to the kidneys narrow, as well as treatments for this condition.
Disease
Respiratory syncytial virus (RSV)
This common illness affects the lungs. It can seem like a cold, but may be severe, especially in children. Know the symptoms and treatment.
Disease
Restless legs syndrome
Uncomfortable sensations in your legs can interrupt your sleep — making you drag through your day. These therapies calm the restlessness and improve sleep.
Disease
Rett syndrome
This rare genetic disorder affects the way the brain develops, causing a progressive inability to use muscles for eye and body movements and language.
Disease
Reye's syndrome
Learn about the causes and treatment of this rare but serious condition causing swelling in the liver and brain.
Disease
Ringworm (scalp)
Learn more on causes, symptoms, treatments of this easily spread, itchy fungal skin infection and how to prevent it.