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Venous Thromboembolism
Venous thrombosis is blockage of a vein caused by a thrombus (blood clot). A common form of venous thrombosis is deep vein thrombosis (DVT), when a blood clot forms in the deep veins. If a thrombus breaks off (embolizes) and flows to the lungs to lodge there, it becomes a pulmonary embolism (PE), a blood clot in the lungs. The conditions of DVT only, DVT with PE, and PE only, are all captured by the term venous thromboembolism (VTE). The initial treatment for VTE is typically either low-molecular-weight heparin (LMWH) or unfractionated heparin, or increasingly with direct acting oral anticoagulants (DOAC). Those initially treated with heparins can be switched to other anticoagulants (warfarin, DOACs), although pregnant women and some people with cancer receive ongoing heparin treatment. Superficial venous thrombosis or phlebitis affects the superficial veins of the upper or lower extremity and only require anticoagulation in specific situations, and may be treated with anti-inf ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
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 blood to the heart. In contrast to veins, arteries carry blood away from the heart. Veins are less muscular than arteries and are often closer to the skin. There are valves (called ''pocket valves'') in most veins to prevent backflow. Structure Veins are present throughout the body as tubes that carry blood back to the heart. Veins are classified in a number of ways, including superficial vs. deep, pulmonary vs. systemic, and large vs. small. * Superficial veins are those closer to the surface of the body, and have no corresponding arteries. *Deep veins are deeper in the body and have corresponding arteries. *Perforator veins drain from the superficial to the deep veins. These are usually referred to in the lower limbs and feet. *Communic ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Blood
Blood is a body fluid in the circulatory system of humans and other vertebrates that delivers necessary substances such as nutrients and oxygen to the cells, and transports metabolic waste products away from those same cells. Blood in the circulatory system is also known as ''peripheral blood'', and the blood cells it carries, ''peripheral blood cells''. Blood is composed of blood cells suspended in blood plasma. Plasma, which constitutes 55% of blood fluid, is mostly water (92% by volume), and contains proteins, glucose, mineral ions, hormones, carbon dioxide (plasma being the main medium for excretory product transportation), and blood cells themselves. Albumin is the main protein in plasma, and it functions to regulate the colloidal osmotic pressure of blood. The blood cells are mainly red blood cells (also called RBCs or erythrocytes), white blood cells (also called WBCs or leukocytes) and platelets (also called thrombocytes). The most abundant cells in vertebrate blo ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Hepatic Portal System
In human anatomy, the hepatic portal system is the system of veins comprising the hepatic portal vein and its tributaries. It is also called the portal venous system (although it is not the only example of a portal venous system) and splanchnic veins, which is ''not'' synonymous with ''hepatic portal system'' and is imprecise (as it means ''visceral veins'' and not necessarily the ''veins of the abdominal viscera'').Splanchnic circulation. Online Medical Dictionary. URLhttp://cancerweb.ncl.ac.uk/cgi-bin/omd?splanchnic+circulation Accessed on: October 22, 2008. Structure Large veins that are considered part of the ''portal venous system'' are the: *Hepatic portal vein * Splenic vein * Superior mesenteric vein *Inferior mesenteric vein The superior mesenteric vein and the splenic vein come together to form the actual hepatic portal vein. The inferior mesenteric vein connects in the majority of people on the splenic vein, but in some people, it is known to connect on the p ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Hepatic Vein
In human anatomy, the hepatic veins are the veins that drain venous blood from the liver into the inferior vena cava (as opposed to the hepatic portal vein which conveys blood from the gastrointestinal organs to the liver). There are usually three large upper hepatic veins draining from the left, middle, and right parts of the liver, as well as a number (6-20) of lower hepatic veins. All hepatic veins are valveless. Structure All the hepatic veins drain into the inferior vena cava. The hepatic veins are divided into an upper and a lower group. Upper group The upper group consists of three hepatic veins - the right, middle, and left hepatic veins - draining the central veins from the right, middle, and left regions of the liver and are larger than the lower group of veins. The veins of the upper group drain into the suprahepatic part of the inferior vena cava (i.e. part superior to the liver). Right hepatic vein The right hepatic vein is the longest and largest of all the h ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Subclavian Vein
The subclavian vein is a paired large vein, one on either side of the body, that is responsible for draining blood from the upper extremities, allowing this blood to return to the heart. The left subclavian vein plays a key role in the absorption of lipids, by allowing products that have been carried by lymph in the thoracic duct to enter the bloodstream. The diameter of the subclavian veins is approximately 1–2 cm, depending on the individual. Structure Each subclavian vein is a continuation of the axillary vein and runs from the outer border of the first rib to the medial border of anterior scalene muscle. From here it joins with the internal jugular vein to form the brachiocephalic vein (also known as "innominate vein"). The angle of union is termed the venous angle. The subclavian vein follows the subclavian artery and is separated from the subclavian artery by the insertion of anterior scalene. Thus, the subclavian vein lies anterior to the anterior scalene while the su ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Axillary Vein
In human anatomy, the axillary vein is a large blood vessel that conveys blood from the lateral aspect of the thorax, axilla (armpit) and upper limb toward the heart. There is one axillary vein on each side of the body. Structure Its origin is at the lower margin of the teres major muscle and a continuation of the brachial vein. This large vein is formed by the brachial vein and the basilic vein. At its terminal part, it is also joined by the cephalic vein. Other tributaries include the subscapular vein, circumflex humeral vein, lateral thoracic vein and thoraco-acromial vein. It terminates at the lateral margin of the first rib, at which it becomes the subclavian vein. It is accompanied along its course by a similarly named artery, the axillary artery In human anatomy, the axillary artery is a large blood vessel that conveys oxygenated blood to the lateral aspect of the thorax, the axilla (armpit) and the upper limb. Its origin is at the lateral margin of the first ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Paget–Schroetter Disease
Paget–Schroetter disease (also known as venous thoracic outlet syndrome) is a form of upper extremity deep vein thrombosis (DVT), a medical condition in which blood clots form in the deep veins of the arms. These DVTs typically occur in the axillary and/or subclavian veins. Signs and symptoms The condition is relatively rare. It usually presents in young and otherwise healthy patients, and also occurs more often in males than females. The syndrome also became known as "effort-induced thrombosis" in the 1960s, as it has been reported to occur after vigorous activity, though it can also occur due to anatomic abnormality such as clavicle impingement or spontaneously. It may develop as a sequela of thoracic outlet syndrome. It is differentiated from secondary causes of upper extremity thrombosis caused by intravascular catheters. Paget–Schroetter syndrome was described once for a viola player who suddenly increased practice time 10-fold, creating enough repetitive pressure again ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Branch Retinal Vein Occlusion
Branch retinal vein occlusion is a common retinal vascular disease of the elderly. It is caused by the occlusion of one of the branches of central retinal vein. Signs and symptoms Patients with branch retinal vein occlusion usually have a sudden onset of blurred vision or a central visual field defect. The eye examination findings of acute branch retinal vein occlusion include superficial hemorrhages, retinal edema, and often cotton-wool spots in a sector of retina drained by the affected vein. The obstructed vein is dilated and tortuous. The quadrant most commonly affected is the superotemporal (63%). Retinal neovascularization occurs in 20% of cases within the first 6–12 months of occlusion and depends on the area of retinal nonperfusion. Neovascularization is more likely to occur if more than five disc diameters of nonperfusion are present and vitreous hemorrhage can ensue. Risk factors Studies have identified the following abnormalities as risk factors for the development ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Central Retinal Vein Occlusion
Central retinal vein occlusion, also CRVO, is when the central retinal vein becomes occluded, usually through thrombosis. The central retinal vein is the venous equivalent of the central retinal artery and both may become occluded. Since the central retinal artery and vein are the sole source of blood supply and drainage for the retina, such occlusion can lead to severe damage to the retina and blindness, due to ischemia (restriction in blood supply) and edema (swelling). CRVO can cause ocular ischemic syndrome. Nonischemic CRVO is the milder form of the disease. It may progress to the more severe ischemic type. CRVO can also cause glaucoma. Diagnosis Despite the role of thrombosis in the development of CRVO, a systematic review found no increased prevalence of thrombophilia (an inherent propensity to thrombosis) in patients with retinal vascular occlusion. Treatment Treatment consists of Anti-VEGF drugs like Lucentis or intravitreal steroid implant (Ozurdex) and Pan-Retinal Lase ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Cavernous Sinus Thrombosis
The cavernous sinus within the human head is one of the dural venous sinuses creating a cavity called the lateral sellar compartment bordered by the temporal bone of the skull and the sphenoid bone, lateral to the sella turcica. Structure The cavernous sinus is one of the dural venous sinuses of the head. It is a network of veins that sit in a cavity. It sits on both sides of the sphenoidal bone and pituitary gland, approximately 1 × 2 cm in size in an adult. The carotid siphon of the internal carotid artery, and cranial nerves III, IV, V (branches V1 and V2) and VI all pass through this blood filled space. Both sides of cavernous sinus is connected to each other via intercavernous sinuses. The cavernous sinus lies in between the inner and outer layers of dura mater. Nearby structures * Above: optic tract, optic chiasma, internal carotid artery. * Inferiorly: foramen lacerum, and the junction of the body and greater wing of sphenoid bone. * Medially: pituitary gla ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Cerebral Venous Sinus Thrombosis
Cerebral venous sinus thrombosis (CVST), cerebral venous and sinus thrombosis or cerebral venous thrombosis (CVT), is the presence of a blood clot in the dural venous sinuses (which drain blood from the brain), the cerebral veins, or both. Symptoms may include severe headache, visual symptoms, any of the symptoms of stroke such as weakness of the face and limbs on one side of the body, and seizures, which occur in around 40% of patients. The diagnosis is usually by computed tomography (CT scan) or magnetic resonance imaging (MRI) to demonstrate obstruction of the venous sinuses. After confirmation of the diagnosis, investigations may be performed to determine the underlying cause, especially if one is not readily apparent. Treatment is typically with anticoagulants (medications that suppress blood clotting) such as low molecular weight heparin. Rarely, thrombolysis (enzymatic destruction of the blood clot) or mechanical thrombectomy is used, although evidence for this therap ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
