What exactly happens to the blood vessels when you say the following? * a. Thrombosis b. Embolism c. Spasm d. Atheroma e. Compression f. Vasculitis g. Steal h. Hyperviscosity


a. THROMBOSIS :- The term thrombosis describes the formation of a blood clot in a blood vessel. The blood vessel can be a vein (venous system) or an artery (arterial system). The symptoms that occur with a clot depend on where the clot occurs, the size of the clot, and whether the clot breaks off and travels to another part of the body (a process called embolization). For example, a blood clot in the leg can break off and travel to the lungs (called a pulmonary embolism) or travel to the brain (called an embolic stroke). ....... b. EMBOLISM :- Definition : An embolism is an obstruction in a blood vessel due to a blood clot or other foreign matter that gets stuck while traveling through the bloodstream. The plural of embolism is emboli. Description : Emboli have moved from the place where they were formed through the bloodstream to another part of the body, where they obstruct an artery and block the flow of blood. The emboli are usually formed from blood clots but are occasionally comprised of air, fat, or tumor tissue. Embolic events can be multiple and small, or single and massive. They can be life-threatening and require immediate emergency medical care. There are THREE general CATEGORIES OF EMBOLI : ARTERIAL, GAS, and PULMONARY. Pulmonary emboli are the most common. ........ c. SPASM :- Vasospasm typically occurs 4-10 days after subarachnoid hemorrhage. Reversible Cerebral Vasoconstriction Syndromes – A condition in which the arteries of the brain develop vasospasm (a blood vessel spasms causing less blood flow) without a clear cause, such as hemorrhage or trauma. Vascular spasms temporary limit blood flow to tissue supplied by that vessel. The most common symptom is pain. Causes : Vascular spasms can be caused by tobacco or drug use (especially cocaine), trauma, irritation to the blood vessels, exposure to cold weather, extreme emotional stress, or inflammation disorders affecting the blood vessels etc. ....... d. ATHEROMA :- An atheroma is an accumulation of degenerative material in the inner layer of an artery wall. The material consists of mostly macrophage cells, or debris, containing lipids, calcium and a variable amount of fibrous connective tissue. The accumulated material forms a swelling in the artery wall, which may intrude into the channel of the artery, narrowing it and restricting blood flow. ATHEROMA occurs in atherosclerosis, which is ONE OF the THREE SUBTYPES OF ARTERIOSCLEROSIS (which are ATHEROSCLEROSIS, MONCKEBERG'S ARTERIOSCLEROSIS and ARTERIOLOSCLEROSIS). In the context of heart or artery matters, atheromata are commonly referred to as atheromatous plaques. It is an unhealthy condition found in most humans. VEINS DO NOT DEVELOP ATHEROMATA, unless surgically moved to function as an artery, as in bypass surgery. The accumulation (swelling) is always in the tunica intima, between the endothelium lining and the smooth muscle middle layer of the artery wall. e. COMPRESSION :- The effects of external compression on venous blood flow and tissue deformation in the lower leg..... Results show that A compression produces greater vessel collapse and generates larger blood flow velocities and shear stresses than C compression..... f. VASCULITIS :- Vasculitis (plural: vasculitides) is a group of disorders that destroy blood vessels by inflammation. Both arteries and veins are affected. Lymphangitis is sometimes considered a type of vasculitis. Vasculitis is primarily caused by leukocyte migration and resultant damage. Although both occur in vasculitis, inflammation of veins (phlebitis) or arteries (arteritis) on their own are separate entities. Classification : Vasculitis can be classified by the cause, the location, the type of vessel or the size of vessel. Underlying cause. For example, the cause of syphilitic aortitis is infectious (aortitis simply refers to inflammation of the aorta, which is an artery.) However, the causes of many forms of vasculitis are poorly understood. There is usually an immune component, but the trigger is often not identified. In these cases, the antibody found is sometimes used in classification, as in ANCA-associated vasculitides. ........ g. STEAL :- As for example : In nephrology, vascular access steal syndrome or dialysis-associated steal syndrome (DASS) is a syndrome caused by ischemia (not enough blood flow) resulting from a vascular access device (such as an arteriovenous fistula or synthetic vascular graft–AV fistula) that was installed to provide access for the inflow and outflow of blood during hemodialysis. Signs : Pallor, Diminished pulses (distal to the fistula), Necrosis, Decreased wrist-brachial index (ratio of blood pressure measured in the wrist and the blood pressure measured in the upper arm), especially if below 0.6 ....... Reference : Zanow J, Kruger U, Scholz H (2006). "Proximalization of the arterial inflow: a new technique to treat access-related ischemia". J Vasc Surg. 43 (6): 1216–21. h. HYPERVISCOSITY :- As for example : Hyperviscosity syndrome is a group of symptoms triggered by increase in the viscosity of the blood. Symptoms of high blood viscosity include spontaneous bleeding from mucous membranes, visual disturbances due to retinopathy, and neurologic symptoms ranging from headache and vertigo to seizures and coma. What causes increase in blood viscosity? Hyperviscosity syndrome can also be caused by conditions that affect the bones, including: leukemia, which is a cancer of the blood. polycythemia vera, which occurs when bone marrow produces too many red blood cells. What are some things that can cause blood to become more viscous? Blood viscosity is the thickness and stickiness of blood. It is a direct measure of the ability of blood to flow through the vessels..... Blood viscosity is defined as the inherent resistance of blood to flow.....
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In one way all are same that they produce features of ischaemia in supplied territory.( Incase of vein - impaired drainage) - The basic pathophysiology:-- 1. Mechanical- thrombosis, Embolism, atheroma, compression & Vasculitis. 2. Functional- spasm 3. Both - steal 4. Neither- ( rheology) hyperviscosity THROMBOSIS- Formation of clot in situ ( Virchow' triad) . Ex. ACS - coronary thrombosis , DVT EMBOLISM- Formation of clot at a proximal site and lodged distally. Ex. CVA- cardioembolic stroke. SPASM- Constriction of vessel either due to local or circulating vasoactive substances. Ex. Vasospastic angina, Renaud's phenomena. ATHEROMA- A collection of fibrous & fatty material in intima protruding in to the lumen.Ex. atherosclerotic coronary artery and aortic disease. COMPRESSION- pressure on vessel from outside. Ex. Cervical rib, thoracic outlet syndrome. VASCULITIS- inflammation of intima or all three layers- leading to thrombosis, stenosis or Aneurism. Ex. Takayasu's arteritis, polyarteritis nodosa. STEAL- diversion of blood flow from a relatively disease segment to a normal segment .The basic mechanism is excessive vasodilation in one segment steals blood from other segment. Ex. Subclavian steal syndrome, coronary steal- produced by vasodilator such as nifedipine & dipyridamole. HYPERVISCOSITY- change in rheology leads to hypoxia due to impaired uptake & release of oxygen. Manifested by headache, visual impairment ,seizure, thrombosis or hemorrhage. Ex. Polycythemia.
That's wonderfully explained Sir Thank you
Very outstanding information in vascular emergencies .
Thank you Sir

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