5 DISTURBANCES IN CIRCULATION. Congestion / Hyperemia Haemorrhage Thrombosis Embolism Ischemia Infarction Oedema Shock Sludged blood Model Questions

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1 5 DISTURBANCES IN CIRCULATION Congestion / Hyperemia Haemorrhage Thrombosis Embolism Ischemia Infarction Oedema Shock Sludged blood Model Questions

2 CONGESTION/ HYPEREMIA Hyperemia is increased amount of blood in circulatory system. It is of two types, active and passive. In active hyperemia blood accumulates in arteries while in passive hyperemia the amount of blood increases in veins (Fig to 5.4). As a result of inflammation. Obstruction of blood vessels. Organ becomes dark red/cyanotic. Size of organ increases. Weight of organ increases. Blood vessels become distended due to accumulation of blood. Increased amount of blood in blood vessels. Veins/capillaries/arteries are distended due to accumulation of blood. Blood vessels become enlarged with blood and their number increases. HAEMORRHAGE Escape of all the constituents of blood from blood vessels. It may occur through two processes i.e. rhexis- break in wall of blood vessel or through diapedesis in which blood leaves through intact wall of blood vessel. It occurs only in living animals (Fig. 5.5). Mechanical trauma Necrosis of the wall of blood vessels Infections Toxins Neoplasm Organ becomes pale due to escape of blood As per size, the haemorrhage is classified as under: Pinpoint haemorrhage of about one mm diameter or pinhead size is known as petechiae (Fig. 5.6). More than one to 10 mm diameter haemorrhage are known as ecchymoses (Fig. 5.6). Irregular, diffuse and flat areas of haemorrhage on mucosal or serosal surfaces are known as suffusions. Haemorrhage appear in line in crests or folds on mucous membrane are known as linear haemorrhage (Fig. 5.7 & 5.8). Hematoma is the accumulation of blood in spherical shaped mass (Fig.5.9). According to location, the haemorrhage is classified as: Hemothorax: Blood in thoracic cavity. Hemopericardium: Blood in pericardial sac. When there is increased amount of blood in pericardial sac, it causes heart failure and is known as cardiac temponade (Fig. 5.10). Hemoperitonium: Blood in peritoneal cavity. Hemoptysis: Blood in sputum. Hematuria: Blood in urine. Epistaxis: Blood from nose. Metrorrhagia: Blood from uterus. Melena: Bleeding in faeces. Hematemesis: Blood in vomitus. Blood constituents are seen outside the blood vessels. Break in blood vessels. Presence of red blood cells in tissues outside the blood vessels (Fig. 5.11). THROMBOSIS Formation of clot of blood in vascular system in the wall of blood vessel. It occurs due to endothelial injury leading to accumulation of thrombocytes, fibrinogen, erythrocytes and leucocytes (Fig & 5.13). 47

3 A V 1 A V 2 A V 3 Fig Photomicrograph of lymph node showing congestion Fig Diagram showing congestion 1. Normal blood vessel A arterial and V-Venous end, 2. Active and 3. Passive congestion A Fig Photograph of testes showing congestion B Fig Diagram showing haemorrhage through (A) diapedesis (b) rhexis A Fig Photomicrograph of lung showing congestion B Fig Diagram showing (A) Petechial (B) Ecchymotic haemorrhage 48

4 Injury in endothelium of blood vessels. Alteration in blood flow. Alteration in composition of blood. Blood clot in wall of blood vessels. On removal of clot, rough surface exposed. Clot may be pale, red or laminated. Occlusive thrombus totally occlude blood vessels. Mural thrombus is on the wall of heart. Valvular thrombus is on valves of heart. Cardiac thrombus is in heart. Saddle thrombus is at the bifurcation of blood vessel just like saddle on back of horse. Septic thrombus contains bacteria. Blood clot in blood vessel. Attached with wall of blood vessel. Alternate, irregular, red and gray areas in thrombi. EMBOLISM Presence of foreign body in circulatory system which may cause obstruction in blood vessel (Fig. 5.14). Thrombus, Fibrin Bacteria Neoplasm Clumps of normal cells Fat, Gas Parasites Emboli causing obstruction of blood vessels lead to formation of infarct in the area. Organ/ tissue becomes pale. Parasitic emboli e.g. Dirofilaria immitis Presence of foreign material in blood. Dependent area necrotic due to absence of blood supply. ISCHEMIA Ischemia is deficiency of arterial blood in any part of an organ. It is also known as local anemia. External pressure on artery Narrowing/obliteration of lumen of artery Thrombi/emboli Necrosis of dependent part. Occurrence of infarction. Dead tissue replaced by fibrous tissue. Lesions of infarction INFARCTION Local area of necrosis resulting from ischemia. Ischemia is the deficiency of blood due to obstruction in artery (Fig & 5.16). Thrombi Emboli Poisons like Fusarium toxins Necrosis in triangular area Red infarct is observed as red triangle bulky surface. Pale infarct is gray in colour and seen as triangle depressed surface. Necrosis in cone shaped area. Obstruction of blood vessels. OEDEMA Accumulation of excessive fluid in intercellular spaces and / or in body cavity (Fig.5.17 to 5.20). 49

5 Fig Diagram of linear haemorrhage Fig Photomicrograph of kidney showing haemorrhage A Fig Photograph of Large intestine showing linear haemorrhage B Fig Diagram showing hematoma C Fig Diagram showing cardiac temponade Fig Diagram of thrombi formation in wall of blood vessel (A) Normal (B) Thrombi formation (C) Saddle thrombi 50

6 Deficiency of protein. Passive hyperemia. Increased permeability of capillaries. Obstruction of lymphatics. Swelling of tissue / organ / body. Weight and size of organ increased. Colour becomes light. Pitting impressions on pressure. Ascites is accumulation of fluid in peritoneum. It is also known as hydroperitonium. Hydropericardium is fluid accumulation in pericardial sac. Hydrocele is fluid accumulation in tunica vaginalis of the testicles. Anasarca is generalized oedema of body. Hydrocephalus is accumulation of fluid in brain. Hydrothorax is accumulation of fluid in thoracic cavity. Inter cellular spaces becomes enlarged. Serum/fluid deposits (pink in colour on H&E. staining) in intercellular spaces. Cells separated farther. SHOCK Shock is a circulatory disturbance characterized by reduction in total blood volume, blood flow and by hemconcentration. Primary shock Occurs immediately after injury. Injury / extensive tissue destruction. Emotional crisis. Surgical manipulation. Secondary shock Crushing injury involving chest and abdomen. Occurs after several hours of incubation. Release of histamine and other substances by injured tissue. Extensive haemorrhage. Burns Predisposing factors like cold, exhaustion, depression. Acute general passive hyperemia Dilatation of capillaries Cyanosis Numerous petechial haemorrhages Oedema and loose connective tissue Capillaries and small blood vessels are distended due to accumulation of blood. Number of engorged blood vessels increased. Focal haemorrhage. Oedema, cells separated farther due to accumulation of transudate in intercellular spaces. SLUDGED BLOOD Sludged blood is agglutination of erythrocytes in the vascular system of an animal. Fluctuation in blood flow Slow rate of blood flow Oedema Emboli Infarction Necrosis Clumping of erythrocytes in pulmonary capillaries. Infarction, necrosis. Oedema. Erythrophagocytosis by reticuloendothelial cells. 51

7 Fig Photomicrograph of thrombi in blood vessel of lung Fig Photograph of an elephant showing oedema in s/c region Fig Diagram of emboli in blood vessel Fig Diagram showing Hydropericardium Fig Diagram of infarction in kidney Fig Photograph of poultry showing Hydropericardium Fig Photograph of spleen showing infarction Fig Photograph of bullock showing oedema in mandibular region 52

8 MODEL QUESTIONS Q. 1. Fill in the blanks with suitable word(s). 1. Accumulation of increased amount of blood in blood vessels in known as. 2. Presence of blood in urine, sputum and faeces is known as, and, respectively. 3. haemorrhages in large intestine is example of rinderpest in animals. 4. is generalized oedema of body while is accumulation of fluid in tunica vaginalis. 5. occurs in poultry due to accumulation of fluid in pericardial sac which is also known as 6. Shock is circulatory disturbance characterized by decrease in.., and by 7. Agglutination of erythrocytes in blood vessels is known as, which may act as and leads to, and 8. Discharge of blood from uterus in known as while the presence of blood in vomitus is called as.. Q. 2. Write true or false against each statement. Correct the false statement Epistaxis is bleeding from mouth Cardiac temponade is failure of heart due to excessive accumulation of blood in pericardial sac In arteries the increased amount of blood as known passive hyperemia Hydrocephalus is accumulation of blood in brain Melena is the presence of blood in faeces Laminated thrombi are alternatively having red and gray colour deposits Hematoma is the accumulation of blood in spherical shaped mass Infarction is local area of necrosis as a result of oedema Sludged blood is agglutination of RBC after haemorrhage Hydrothorax is accumulation of fluid in thoracic cavity. Q. 3. Write short notes on. 1. Ischemia 2. Infarction 3. Primary shock 4. Oedema 5. Sludged blood Q. 4. Define the followings. 1. Hemoptysis 6. Acute general active hyperemia 2. Suffusions 7. Acute local passive hyperemia 3. Petechiae 8. Hydrocephalus 4. Hematoma 9. Valvular thrombi 5. Saddle thrombi 10. Hydropericardium 53

9 Q. 5. Select most appropriate word(s) from the four options given against each statement. 1. Petechial haemorrhage are of.. size. (a) 1 mm (b) 2 mm (c) 5 mm (d) 10 mm 2. Parasitic emboli are formed in dogs due to. (a) Strongylus spp (b) Dirofilaria immitis (c) Coccidia spp. (d)sarcoptes canis 3. Metrorrhagia is haemorrhage from (a) Intestine (b) Stomach (c) Oviduct (d) Uterus 4. Septic thrombus must have. in it. (a) Virus (b) Parasite (c) Fungi (d) Bacteria 5. Presence of foreign material in blood vessels is known as (a) Thrombus (b) Emboli (c) Ischemia (d) Infarction 6. Accumulation of fluid in peritoneal cavity is known as. (a) Anasarca (b) Hydropericardium (c) Hydrothorax (d) Ascites 7. Shock is circulatory disturbance characterized by (a) Reduced blood volume (b) Reduced blood flow (c) Hemoconcentration (d)all of the above 8. Active hyperemia is accumulation of blood in. (a) Veins (b) Lymphatics (c) Arteries (d) Intestines 9. Escape of all blood constituents through intact blood vessel is known as. (a) Rhexis (b) Ecchymosis (c) Petechiae (d) Diapedesis 10. Erythrophagocytosis is a feature of. (a) Congestion (b) Oedema (c) Sludged blood (d) Infarction 54