Vascular occlusion is a blockage of a blood vessel, usually with a

clot A thrombus (plural thrombi), colloquially called a blood clot, is the final product of the blood coagulation step in hemostasis. There are two components to a thrombus: aggregated platelets and red blood cells that form a plug, and a mesh of c ...

. It differs from

thrombosis Thrombosis (from Ancient Greek "clotting") is the formation of a blood clot inside a blood vessel, obstructing the flow of blood through the circulatory system. When a blood vessel (a vein or an artery) is injured, the body uses platelets (thro ...

in that it can be used to describe any form of blockage, not just one formed by a clot. When it occurs in a major

vein Veins are blood vessels in humans and most other animals that carry blood towards the heart. Most veins carry deoxygenated blood from the tissues back to the heart; exceptions are the pulmonary and umbilical veins, both of which carry oxygenated b ...

, it can, in some cases, cause

deep vein thrombosis Deep vein thrombosis (DVT) is a type of venous thrombosis involving the formation of a blood clot in a deep vein, most commonly in the legs or pelvis. A minority of DVTs occur in the arms. Symptoms can include pain, swelling, redness, and enla ...

. The condition is also relatively common in the

retina The retina (from la, rete "net") is the innermost, light-sensitive layer of tissue of the eye of most vertebrates and some molluscs. The optics of the eye create a focused two-dimensional image of the visual world on the retina, which then ...

, and can cause partial or total loss of vision. An occlusion can often be diagnosed using

Doppler sonography Doppler ultrasonography is medical ultrasonography that employs the Doppler effect to perform imaging of the movement of tissues and body fluids (usually blood), and their relative velocity to the probe. By calculating the frequency shift of ...

(a form of

ultrasound Ultrasound is sound waves with frequency, frequencies higher than the upper audible limit of human hearing range, hearing. Ultrasound is not different from "normal" (audible) sound in its physical properties, except that humans cannot hea ...

). Some medical procedures, such as

embolisation Embolization refers to the passage and lodging of an embolus within the bloodstream. It may be of natural origin (pathological), in which sense it is also called embolism, for example a pulmonary embolism; or it may be artificially induced (t ...

, involve occluding a blood vessel to treat a particular condition. This can be to reduce pressure on

aneurysm An aneurysm is an outward bulging, likened to a bubble or balloon, caused by a localized, abnormal, weak spot on a blood vessel wall. Aneurysms may be a result of a hereditary condition or an acquired disease. Aneurysms can also be a nidus (s ...

s (weakened blood vessels) or to restrict a

haemorrhage Bleeding, hemorrhage, haemorrhage or blood loss, is blood escaping from the circulatory system from damaged blood vessels. Bleeding can occur internally, or externally either through a natural opening such as the mouth, nose, ear, urethra, vagi ...

. It can also be used to reduce blood supply to tumours or growths in the body, and therefore restrict their development. Occlusion can be carried out using a

ligature Ligature may refer to: * Ligature (medicine), a piece of suture used to shut off a blood vessel or other anatomical structure ** Ligature (orthodontic), used in dentistry * Ligature (music), an element of musical notation used especially in the me ...

; by implanting small coils which stimulate the formation of clots; or, particularly in the case of

cerebral aneurysm An intracranial aneurysm, also known as a brain aneurysm, is a cerebrovascular disorder in which weakness in the wall of a cerebral artery or vein causes a localized dilation or ballooning of the blood vessel. Aneurysms in the posterior circul ...

s, by

clipping Clipping may refer to: Words * Clipping (morphology), the formation of a new word by shortening it, e.g. "ad" from "advertisement" * Clipping (phonetics), shortening the articulation of a speech sound, usually a vowel * Clipping (publications) ...

References

Medical terminology Hematology {{Symptom-stub

See also

References