Amenorrhea (uh-men-o-REE-uh) is the absence of menstruation — one or more missed menstrual periods. Women who have missed at least three menstrual periods in a row have amenorrhea, as do girls who haven't begun menstruation by age 15.
The most common cause of amenorrhea is pregnancy. Other causes of amenorrhea include problems with the reproductive organs or with the glands that help regulate hormone levels. Treatment of the underlying condition often resolves amenorrhea.
Amnesia refers to the loss of memories, such as facts, information and experiences. Though having no sense of who you are is a common plot device in movies and television, real-life amnesia generally doesn't cause a loss of self-identity.
Instead, people with amnesia — also called amnestic syndrome — are usually lucid and know who they are, but may have trouble learning new information and forming new memories.
Amnesia can be caused by damage to areas of the brain that are vital for memory processing. Unlike a temporary episode of memory loss (transient global amnesia), amnesia can be permanent.
There's no specific treatment for amnesia, but techniques for enhancing memory and psychological support can help people with amnesia and their families cope.
An amniotic fluid embolism is a rare but serious condition that occurs when amniotic fluid — the fluid that surrounds a baby in the uterus during pregnancy — or fetal material, such as hair, enters the maternal bloodstream.
An amniotic fluid embolism is most likely to occur during childbirth or immediately afterward.
An amniotic fluid embolism is difficult to diagnose. If your doctor suspects you might have an amniotic fluid embolism, you'll need immediate treatment to prevent potentially life-threatening complications.
Amyloidosis (am-uh-loi-DO-sis) is a rare disease that occurs when a substance called amyloid builds up in your organs. Amyloid is an abnormal protein that is usually produced in your bone marrow and can be deposited in any tissue or organ.
Amyloidosis can affect different organs in different people, and there are different types of amyloid. Amyloidosis frequently affects the heart, kidneys, liver, spleen, nervous system and digestive tract. Severe amyloidosis can lead to life-threatening organ failure.
There's no cure for amyloidosis. But treatments can help you manage your symptoms and limit the production of amyloid protein.
Amyotrophic lateral sclerosis (a-mi-o-TROE-fik LAT-ur-ul skluh-ROE-sis), or ALS, is a nervous system (neurological) disease that causes muscle weakness and impacts physical function.
ALS is often called Lou Gehrig's disease, after the famous baseball player who was diagnosed with it. ALS is a type of motor neuron disease that causes nerve cells to gradually break down and die. In the United States, ALS is sometimes called motor neuron disease.
In most cases, doctors don't know why ALS occurs. A small number of cases are inherited.
ALS often begins with muscle twitching and weakness in an arm or leg, or sometimes with slurring of speech. Eventually, ALS can affect your ability to control the muscles needed to move, speak, eat and breathe. ALS can't be cured and eventually leads to death.
Anal cancer is an uncommon type of cancer that occurs in the anal canal. The anal canal is a short tube at the end of your rectum through which stool leaves your body.
Anal cancer can cause signs and symptoms such as rectal bleeding and anal pain.
Most people with anal cancer are treated with a combination of chemotherapy and radiation. Though combining anal cancer treatments increases the chance of a cure, the combined treatments also increase the risk of side effects.
An anal fissure is a small tear in the thin, moist tissue (mucosa) that lines the anus. An anal fissure may occur when you pass hard or large stools during a bowel movement. Anal fissures typically cause pain and bleeding with bowel movements. You also may experience spasms in the ring of muscle at the end of your anus (anal sphincter).
Anal fissures are very common in young infants but can affect people of any age. An anal fissure usually heals on its own within four to six weeks. If it doesn't, medical treatment or surgery usually can relieve discomfort.
Anal itching is a common condition. The itch, situated in your anus or on the skin just around your anus, is often intense and may be accompanied by a strong urge to scratch. You may find anal itching to be embarrassing and uncomfortable.
Also called pruritus ani (proo-RIE-tus A-nie), anal itching has many causes, such as skin problems, excessive washing or hemorrhoids.
If anal itching is persistent, talk with your doctor. With proper treatment and self-care measures, most people get complete relief from anal itching.
Anaphylaxis is a severe, potentially life-threatening allergic reaction. It can occur within seconds or minutes of exposure to something you're allergic to, such as a peanut or the venom from a bee sting.
The flood of chemicals released by your immune system during anaphylaxis can cause you to go into shock; your blood pressure drops suddenly and your airways narrow, blocking normal breathing. Signs and symptoms of anaphylaxis include a rapid, weak pulse, a skin rash, and nausea and vomiting. Common triggers of anaphylaxis include certain foods, some medications, insect venom and latex.
Anaphylaxis requires an immediate trip to the emergency department and an injection of epinephrine. If anaphylaxis isn't treated right away, it can lead to unconsciousness or even death.