Blood circulation disorders Normal functioning of a body is possible only in condition of normal functioning of blood circulation organs, i. e. the heart and vessels. Metabolism, oxidation, restoration, enzymatic and other processes that are taking place in the body cannot be affected without extraction of waste products. This transport and metabolic function is performed by both blood circulation and lymphatic system, which are functioning together. Blood circulatory system coordinates and connects functionally different organs and systems. This homeostasis coordination function is provided by both blood circulatory and lymphatic systems. Disorders of blood circulation and lymphatic circulation occur not only due to disturbance in the systems, but also due to disorders of heart function and other organs at any level. Disorders of blood circulation 1. Disorder of blood supply 2. Disorders of vascular wall permeability 3. Disorders of blood flow and its condition Disorders of blood circulation may be general, regional, and local in character. Such disorders are specific not only for pathology: they are frequently observed in physiologic condition as well, as adaptation or particular reflection of a physiologic change. Hyperemia and anemia are related to blood-circulation disorders. Hyperemia may be: arterial venous Arterial hyperemia Arterial hyperemia is a process of increased blood supply, as a result of larger amount of incoming blood and unchanged blood outflow. This process is usually local, but it may be generalised with an increase of circulating blood amount or when the number of circulating erythrocytes is increased. We differentiate: angioneurotic (neuroparalitic, vasomotor) arterial hyperemia collateral hyperemia postanemic hyperemia vacate hyperemia inflammatory hyperemia and hyperemia on the basis of arterio- venous fistula The signs of arterial hyperemia are temperature rise and increase of arterial blood pressure. The importance of pathologic arterial hyperemia is defined by its types and is usually insignificant, however rupture of a blood vessel may occur. Termination of arterial hyperemia depends on its time period and vascular condition. Venous hyperemia Venous hyperemia is a process of increased blood supply in veins as a result of impaired venous outflow. We differentiate general and local venous hyperemia (plethora). Local venous plethora appears as a result of impaired blood outflow from some organ. General venous plethora develops during cardiac decompensation. The signs of venous plethora are temperature decrease, increase of venous blood pressure, cyanosis, decrease in organ function. Changes in organs in venous hyperemia are: in the lungs: diapedesis and disintegration of erythrocytes happens, then hemosiderin is formed from hemoglobin. It stains the lungs brown- red color, growth of connective tissue starts at once (brown induration of the lungs). Similar process takes place in kidneys and spleen, it leads to organ insufficiency. Acute local venous plethora in the lungs in the liver: venous blood is accumulated in central veins (so-called nutmeg liver) «Nutmeg» liver in case of venous plethora Centrilobular necrosis of liver caused by venous plethora Anemia Anemia (oligohemia, ischemia) is process of blood cell amount lowering in the tissues. We differentiate general and local anemia. The cause of general anemia is lowering of the blood cells amount in the whole body. The causes of local anemia are the same as its types. They are: angiospastic obturational compressive anemia as result of blood redistribution The signs of local anemia are: pallor lowering of blood quantity temperature lowering decreased function of an organ Termination depends on the degree of anemia, its time period, its temperature, organ functional conditions, age. They can be insignificant as well as severe, including dystrophy and necrosis. Prolonged anemia leads to atrophy and sclerosis. Tubular necrosis in ischemia Hemorrhage Hemorrhage (bleeding) is a process of blood outflow from the lumen of a blood vessel or the heart. If the blood flows into surrounding environment, it is external hemorrhage. If blood outflows into surrounding tissues, it is internal hemorrhage. Formation of hematoma is result of internal bleeding. Hemorrhage mechanisms are: vessel rupture ulceration of vascular walls bleeding by diapedesis Some types of bleeding have their own names: blood spitting - hemoptysis or blood expectoration bleeding out of the nose - epistaxis or nasal bleeding blood vomiting - hematenesis or black vomit blood excretion with feces - fecal blood pathologic bleeding out of the uterus - metrorrhagia or uterine bleeding Hematoma is the blood that is accumulated in tissues outside the vascular lumen as result of bleeding. Types of hematoma Hematoma - hemorrhage with formation of a new cavity Bruise - hematoma under and flat surface Hemorrhagic infiltration - various hematomas Petechias and ecchimoses - spot-like hemorrhages Petechial hemorrhages on surface of endocardium Epidural hematoma Hematomas in natural cavities have their own terms: hemathorax - collection of blood in pleural cavity hemopericardium - effused blood in pericardium cavity hemoperitoneum - effused blood in peritoneal cavity hematocele - effused blood into tunica propria testis Hematoma outcomes are: blood resorbtion cyst formation on place of hematoma (as in the brain) encapsulation growth of connective tissue infection suppuration Plasmorrhagia Plasmorrhagia is the process of plasma outflow from the vascular fed. The result of plasmorrhagia is infiltration into vascular wall and of the surrounding tissues, that is plasmic infiltration. During this process the arteriolar walls become homogenous and thick. Fibrinoid necrosis may develop. Importance of plasmorrhagia lies in the disturbance of transcapillary metabolism and in the structural changes in tissues and organs. Usually plasmorrhagia is a reversible process, but sometimes in cases of recurrence or prolonged and massive plasmorrhagia fibrinoid necrosis and vascular wall hyalinization take place. Stasis Stasis is the process of slowing down or total stop of blood circulation in microcirculatory vessels. Sludge is a phenomenon which is variety of stasis. Its main peculiarity is that the erythrocytes, thrombocytes or leukocytes are agglutinated to each other. The increase of blood viscosity is observed. Stasis is caused by intoxication, infection, venous plethora, vasomotor paralysis. The stasis importance is defined by its time length, the organ or tissue sensitivity to hypoxia. So stasis is a reversible process. Prolonged stasis leads to thrombosis and necrosis. Stasis dermatitis is seen here. Years of poor circulation from poor cardiac function leads to chronic edema and venous stasis of blood with extravasation of red blood cells that leads to collection of hemosiderin to give the skin a brown appearance. This is a more advanced example of stasis dermatitis with brownish discoloration from hemosiderin deposition along with a thickened, rough appearance to the skin. Ulceration is possible as well. Shock Shock is an acute pathologic process caused by strong agents, which is characterized by disorder of activity of CNS, metabolism, and autoregulation of microcirculatory system, which leads to destructive changes in the organs and tissues. Classification 1. Hypovolemic shock - during acute decrease of quantity of circulating blood 2. Traumatic 3. Cardiogenous 4. Septic, or toxicoinfectious Morphologically, typical signs of shock are: hemocoagulation disorders hemorrhagic diatesis liquid blood in a corpse In internal organs there are common changes, such as dystrophy and necrosis. In shock kidney, the most affected by pathologic changes are proximal tubules; necrotic nephrosis develops, which causes acute renal insufficiency. In shock liver develop hydropic dystrophy of hepatocytes, centrilobular necrosis. When shock changes in kidneys and liver combine we speak of hepatorenal syndrome. Kidneys - necrosis of crimped tubules In shock lung develops atelectasis, serous- hemorrhagic plethora, formation of thrombi in microcirculation vessels, which causes development of acute respiratory insufficiency. Shock in myocardium is represented by necrobiotic changes of cardiomyocytes - disappearence of glycogen, appearance of lipids, possibly appearance of small zones of necrosis. Shock lung Sludge in myocardium (shock heart) Shock liver - empty central vein Thrombosis For the complete definition of this process we have to take into account following issues: 1. Thrombosis is a process of live blood coagulation. Dead blood coagulation isn’t called a thrombus but coagulation masses. 2. Thrombus is a firm mass and may consist only of blood cells 3. Thrombus must be attached to the vascular wall; when it is torn off it is called thromboembolus So, thrombosis is a process of firm masses formation from blood in live person, which is attached to the vascular wall. Thrombogenesis consists of 4 successive stages: 1. Thrombocytes agglutination 2. Fibrinogen coagulation and fibrin formation 3. Erythrocytes agglutination 4. Plasma protein precipitation Thrombogenesis may be protective and pathologic. This defines the importance of thrombosis and its outcome for the body. The most frequent localization of a pathologic thrombus is: veins of the small pelvis (parametral, hemorrhoid, vas deferens) deep and superficial leg veins In relation to the vascular wall thrombus can be parietal, that is attached to the vascular wall obstructive (occlusive, congestive) thrombus. A special form is a ball thrombus. It is freely located in the cavity of the left atrium and is “polished” by the blood flow. The pathogenesis of thrombosis is very complicated. We can conventionally differentiate local and common factors, promoting thrombogenesis. The local factors are: impairment of vascular wall, slowing down of blood flow. The common factors are: disturbance in regulation of coagulation and anticoagulation systems which support the liquid state of blood in the vascular lumen changes in the blood constituent part Termination of thrombosis may be various. Local thrombus may undergo aseptic autolysis vessels may germinate into thrombus (this process is called thrombus vascularization) thrombus may be replaced by connective tissue (thrombus organization) shriveling thrombus may acquire cracks (thrombus canalization) or getting smaller in size it can move away from the wall (vascular recanalization) Thrombus may be hialinized or calcified. It is possible for the thrombus to be torn off and turned into an embolus. Also septic lysis of the thrombus is possible. The importance of such termination is to be defined for every patient separately in every given situation. Clinical importance of pathologic thrombosis or thromboembolism is that they have fatal complications in many diseases. Coronary thrombosis Coronary thrombosis causing ischemia or infarction of myocardium Coronary thrombosis, microscopically Embolism Embolism is a process of transferring particles by blood and lymph flow, which are not normally found in the body. These particles are called emboli. Often these emboli are carried by blood (ortograde embolism). Sometimes because of the thrombi weight we can observe the thrombus moving up the blood flow (retrograde embolism) due to gravity. Finally, if there is a defect in interatrial or interventricular septum, the embolus from the veins of systemic circulation occurs in the arteries, part of the lungs (paradoxical embolism). The emboli may be single and multiple. The most frequent embolism type is thromboembolism, that occurs when the thrombus or its part is torn away. Fat embolism occurs in the long tubular bone fracture or in crushing of the fatty tissue. Air embolism occurs when air penetrates into the blood. Normally there is negative pressure in some veins. In pathologic conditions and blood losses it is increased (for instance, in uterus veins, etc). Accidental introduction of air is possible during injections. Gas embolism happens during rapid lowering of atmospheric pressure (Caisson disease). Tissue embolism is brough about during traumatic destruction of tissues and due to pathologic processes. Tumor cells, pieces of heart valves and other particles may become emboli. Microbial embolism is a frequent process, too. It may arise due to microorganisms entering the blood vessels or during the thrombus septic lysis. Embolism with foreign bodies may happen in wounds, injuries. Special category of embolism is metastatic spreading. Metastatic process is a process of transference of living particles by the blood or lymph flow and formation of the metastasis in a new place (the same process as in the original place). Malignant tumor cells, microorganisms and some parasites (echinococcus) may metastasize. The metastatic processes have not yet been studied completely. There is a great number of factors and causes influencing this process. The importance of embolism: embolism itself may be a complication of many diseases and sometimes may be the cause of fatal termination. Large thromboembolus which is deadly for the patient Thromboembolus in the branch of pulmonary artery, microscopically Lymph circulation disorders Lymph circulation disorders are manifested as insufficiency. We differentiate: mechanic insufficiency dynamic insufficiency resorptive insufficiency Morphological manifestations of lymph circulation disorders do not depend on the type of the insufficiency, they are similar. The importance and outcome of the lymph circulation disorders are defined by the tissue metabolic disturbances. Tissue hypoxia is developed and then the dystrophic necrobiotic processes are observed.