Derangements of blood circulation Part 2 thrombosis embolism

Derangements of blood circulation. Part 2. (thrombosis, embolism, DIC-syndrome, shock)

Thrombosis o o Process essence: it is a life- time (antemortem) blood coagulation in vessels lumen or heart cavities – thrombus. Postmortem coagulation - clot

Thrombus and postmortem clot differences o o The clinical thrombus is a dry, friable mass of gray-to-red color, with rough surface. It is attached to the vessel wall. The post mortem clot, in contrast, is smooth, rubbery and gelatinous, and is not attached to the underlying wall.

Stages of blood coagulation: 1. 2. 3. 4. Prothrombokinase + activators → thrombokinase (active thromboplastin) Prothrombin + Са + thrombokinase → thrombin Fibrinogen + thrombin → fibrinmonomer Fibrin-monomer + fibrin stimulative factor → fibrin-polymer

Thrombosis as a compensatoryadaptive process: o o o In postpartum uterus (after labor) In umbilical cord vessels In case of trauma In case of various medical manipulations In aortic and cardiac aneurysms

Conditions promoting formation of thrombi: o General: - changing of blood composition and rheological properties; - derangement of coagulative and anticoagulative systems ratio

Conditions promoting formation of thrombi: Local: - blood speed change; - blood turbulences; - vessel wall injury. o

Stages of thrombus formation: o o Thrombocytes agglutination Fibrinogen coagulation with formation of fibrin Erythrocytes agglutination Precipitation of plasma proteins

Types of thrombi according to composition: o o White Red Mixed Fibrinous (hyaline)

White thrombus is composed of platelets, fibrin and leucocytes (white cells) and forming slowly and chiefly where blood circulation is rapid, e. g. in arteries.

Red thrombus is composed of platelets, fibrin and erythrocytes and is forming where blood circulation is slow, chiefly in veins.

Mixed thrombus consists of elements of white and red thrombi and has a laminated structure. It has a head, a body and a tail. The head has a structure of a white thrombus and is attached to the vessel wall. The body has a mixed structure, and the tail has a structure of a red thrombus. These thrombi are commonly found in veins, aneurisms and heart chambers.

Fibrin thrombi consist mainly of fibrin and are formed in the vessels of microcirculatory bed.

Types of thrombi regarding the vessel lumen: o o o Obstructive (obturating) Parietal (mural) Free (ball-valve)

Thrombosis consequences: o o Obstructive: - venous hyperemia - acute ischemia - infarction Parietal: - prolonged ischemia with development of parenchyma atrophy and organs stroma sclerosis

Thrombosis outcomes: o o o Aseptic autolysis Organization, canalization, revascularization Petrification (phleboliths) Septic autolysis Detachment, turning into embolus

DIC- syndrome - disseminated intravascular blood coagulation. Is characterized by disseminated formation of small thrombi in microcirculatory system of the whole organism, combined with blood incoagulability, leading to multiple massive hemorrhages.

DIC-syndrome causes: o o o o infectious diseases; neonatal or intrauterine infections; gynecological disorders; liver diseases; malignant tumors; small vessels vasculitis; major trauma; intravascular hemolysis etc.

In case of DIC-syndrome the multiple thrombi appear in the vessels of microcirculatory system and lead to microinfarctions in many organs.

Disseminated thrombosis also leads to expenditure of blood coagulation factors and development of consumption coagulopathy. At the same time we can observe thrombocytopenia, which together with depletion of fibrinogen and other coagulation factors leads to development of pathologic bleeding sickness.

DIC-syndrome o o Importance — acute multiple organ failure is developing, causing the patients death. Prognosis is determined by the timeliness of diagnostics and initiation of treatment.

Embolism o Process essence: is a transportation by blood or lymph flow of particles, which normally are not present there, and obstruction of vessel lumen by these particles, named emboli.

Emboli translocation o o o Orthograde (with the blood flow) Retrograde (against the blood flow) Paradoxically (due to defects in ventricular of intertribal septum embolus can travel from the systemic (venous) circulation and, bypassing the lungs, again get into the greater circulation through the foramen ovale)

Embolism types according to embolus nature: o o o o Thromboembolism Gas embolism Air embolism Fat (oil) embolism Tissue, cellular embolism Microbial embolism Embolism by foreign bodies

THROMBOEMBOLISM is the most frequent kind of embolism, it is developing when the thrombus (blood clot) or it`s part detaches from the vessel wall. Thromboembolism of the pulmonary arterial tree pipe leads to immediate death. By embolism of smaller arteries there appear in organs the foci of necrosis (infarctions).

GAS EMBOLISM is the congestion of blood vessels by gas bubbles, more often nitrogen. It happens to caisson workers or divers by decompression, the quick transfer from the area of increased atmospheric pressure to the normal pressure. Nitrogen bubbles lead to congestion of brain capillaries and development of foci of necrosis.

AIR EMBOLISM is developing through the ingress of air in the blood flow. It can happen through neck veins wounds, by premature detachment of placenta in labour, by open-heart operations. Air bubbles in the blood flow cause embolism of the smaller circulation and lead to sudden death.

FAT EMBOLISM is developing through the ingress of fat drops in the blood flow. It occurs often by trauma (injury) and shock. Organs do not change macroscopically by fat embolism. The congestion of 2/3 of pulmonary capillaries or embolism of brain capillaries can cause death.

TISSUE (CELLULAR) EMBOLISM can develop through injuries, followed by tissue destruction. But more often emboli represent the parts of malignant tumor, which invades the vessels. The tumor cells tear off and are transferred to other organs, forming the metastases.

MICROBIAL EMBOLISM is developing by circulation of bacteria, parasites, protozoa in the blood. Such emboli are forming often by septic autolysis of thrombi. Around such emboli there appear in organs and tissues metastatic abscesses – foci of supporative inflammation.

EMBOLISM BY FOREIGN BODIES develops by vessel injuries with bullets and shell splinters, as well as by ingren of calcium particles from atherosclerosis plaque. o Bullets o Shell fragments o Fragments of medical instruments – needles, catheters etc.

Embolism consequences: o o o o Heart failure due to pulmonary embolism (thromboembolism) Infarctions Tumor dissemination (tissue embolism) Generalization of infection Metastatic abscesses (particles of infected thrombi) Aeroembolism/caisson disease (gas embolism) Acute pulmonary failure Heart failure (air, gas)

SHOCK Is a clinical state, connected with decrease of effective cardiac output, derangement of microcirculatory system autoregulation and characterized by generalized abatement of tissue blood supply, leading to destructive changes of internal organs.

Shock types according to etiology and pathogenesis: o o o Hypovolemic Neurogenic Septic Cardiogenic Anaphylactic

Stages of shock development: 1. 2. 3. Stage of compensation Stage of tissue blood flow derangement Stage of decompensation

Shock morphology: o o o Shock kidneys Shock lung Liver injury (lesion) Myocardium changes Changes in the stomach and intestines