Medical dictionary

What is aneuploidy? Aneuploidy is any chromosomal condition that results from having an unusual number of chromosomes in a cell, such as having either a missing (monosomy) or extra chromosome (trisomy). The most common type of aneuploidy is trisomy, which means there is an extra chromosome (e.g. trisomy 21 is Down's syndrome). A common monosomy, in which a chromosome is missing, is Tur

What is angina? Angina, or angina pectoris, is chest pain that occurs when the blood supply to the muscles of the heart is restricted. This is because the arteries supplying the heart become hardened and narrowed. An angina attack has been described as a dull and tight pain in the chest, which can spread to the left arm, neck or b

What is angioedema? An angioedema is an irritation which causes an inflammation on your skin, similar to that caused by hives. However, while hives only affects the superficial layers of your skin, an angioedema affects the subcutaneous layers of the epidermis. The skin, mucosa and subcutaneous tissues are swollen but there are no welts, which are a sign of hives. While it’s not usuall

What is an angiography? An angiography is a type of X-ray which examines the blood vessels, particularly the arteries, veins and heart chambers.  What happens during an angiography? First, a catheter is inserted into one of your arteries, depending on the area which needs to be examined. Through the catheter, a dye is administered to contrast the area that needs to be v

What are angiomas? Angiomas are tumours which are non-cancerous (benign), made up of small blood vessels. They appear on the surface of the skin and can be located on any part of the body. There are different types of angioma including cherry angioma, spider angioma, and angiokeratomas. These tumours are harmless but patients may wish to have them removed for aesthetic reasons. What are

What is angiopathy? Angiopathy is a generic term which means disease of the blood vessels, but commonly refers to conditions where small blood vessels are damaged and burst open. There are two main types of angiopathy corresponding to the ways that the disease manifests: Congophilic angiopathy - this condition involves the accumulation of amyloid proteins in the walls of cere

What is being analysed? Angiotensin-converting enzyme (ACE) is an essential enzyme primarily found in endothelial cells, particularly within the lungs. It plays a crucial role in the renin-angiotensin-aldosterone system (RAAS) by converting angiotensin I to angiotensin II. This conversion leads to vasoconstriction and aldosterone secretion, contributing to blood pressure regulation and electrol

What is angle-closure glaucoma? Angle closure glaucoma is a serious condition that makes the pressure inside the eye rise suddenly, within a matter of hours. It is not as common as other types of glaucoma that cause pressure to build-up much more slowly over a longer period of time. The rapid increase in pressure inside the eye is called intraocular pressure.   What causes angl

What is aniridia? Aniridia is a hereditary and congenital eye disorder characterised by incomplete development of the iris, usually occurring in both eyes. Although etymologically speaking the term “aniridia” suggests that no iris is present, it actually means that part of the iris is not fully formed because of incomplete development. Prognosis It is quite difficult to