Medical dictionary

What is amyotrophic lateral sclerosis? Amyotrophic lateral sclerosis (ALS) is a degenerative disease. It is a disease of neurones in the brain, the brain stem, and the spinal cord that control the movement of voluntary muscles, leading to disability. ALS attacks the motor neurones, which are the longest cells in the body connecting electric signals from the brain to muscles. The cells do not

What is anaemia?   Anaemia is a condition in which there is a low concentration of haemoglobin in red blood cells, or a deficiency in the number of red blood cells themselves. Red blood cells carry oxygen from the lungs to cells throughout the rest of the body, and haemoglobin is an iron-rich protein that gives the blood its red colour and binds to oxygen molecules, allowing red bl

What is an anal abscess? An anal abscess is an infected, pus-filled cavity near the anus, often appearing as a painful, boil-like swelling. They are most commonly small anal glands that have become infected.   What are the symptoms of an anal abscess? Superficial anal abscesses usually cause one or more of the following symptoms: Constant, throbbing pain, which is accent

What is an anal fissure? An anal fissure (fissures) is a tear or crack in the lining of the anal canal (anus), which causes extreme pain during bowel movements. It is the most common cause of rectal bleeding in infancy. A fissure tends to occur when passing hard or large stools during a bowel movement. There may also be spasms in the ring of muscle at the end of the anus.   What

What is an anal fistula? An anal fistula is a small channel or tunnel that develops between the end of the bowel and the skin near the anus (i.e. where stool leaves the body). These can result in bleeding when passing stool and cause pain and discomfort. Often anal fistulas won’t get better on their own and will usually require treatment. Surgery is a common recommendation for treating an

What is anal fistula surgery? An anal fistula is a tunnel or channel that develops between the skin near the anus and the bowel. This can have a number of unpleasant symptoms, and surgery, known as anal fistula surgery, is often undertaken to correct this. It is performed under general anaesthetic. Why would you do it? Anal fistula surgery is usually needed to treat anyone suffering f

What is laser anal surgery? Lasers are becoming used more and more frequently in various surgical procedures as a less invasive option. One novel technique that can be used as an option for treating anal fistulas is the FiLaC™ (Fistula Laser Closing) technique. This involves using a laser fibre to seal the fistula.   Why is it done? The FiLaC technique is used to close a

What is anaphylaxis? Anaphylaxis, also called anaphylactic reaction or anaphylactic shock, is a serious, life-threatening allergic reaction. What are the symptoms of anaphylaxis? Symptoms occur in a severe and rapid way throughout the body. The most common symptoms include: abdominal pain discomfort or tightness in the chest diarrhoea difficulty swallowing difficulty bre

What is anaplastic large cell lymphoma? Anaplastic large cell lymphoma (ALCL) is a rare type of non-Hodgkin lymphoma (NHL) that develops from white blood cells called T-cells and causes the lymph nodes to swell. There are four types of ALCL, which have complicated names that are based on their features and proteins. These include: ALK-positive ALCL – which is the most common type