03 - Hemodynamic disorders Flashcards
Accumulation of fluid in tissues or body cavities.
Edema (tissues) or effusion (body cavities)
Four main mechanisms of edema formation.
A. Increased hydrostatic pressure
B. Decreased oncotic pressure
C. Increased vascular permeability
D. Lymphatic obstruction
General morphologic appearance of edema.
Clearing and separation of ECM, and subtle cell swelling
It is an active process resulting from augmented blood flow due to arteriolar dilation; affected tissue is redder than normal, because of engorgement with oxygenated blood.
Hyperemia
It is a passive process resulting from impaired venous return out of a tissue; tissue has a blue-red color due to accumulation of deoxygenated hemoglobin in the affected tissue.
Congestion
Characterized by alveolar capillaries engorged with blood, with associated alveolar septal edema or focal minute intra-alveolar hemorrhage.
Acute pulmonary congestion
Pulmonary septa are thickened and fibrotic, with hemosiderin-laden macrophages in alveolar spaces.
Chronic pulmonary congestion
The central vein and sinusoids of the liver are distended with blood, with central hepatocyte degeneration; periportal hepatocytes are better oxygenated.
Acute hepatic congestion
The central regions of the hepatic lobules are grossly red-brown, slightly depressed, and are accentuated against the surrounding zones of uncongested tan, sometimes fatty liver (nutmeg liver); presence of centrilobular necrosis with hepatocyte drop-out, hemorrhage, and hemosiderin-laden macrophages.
Chronic hepatic congestion
Pathologic form of hemostasis.
Thrombosis
Components of Virchow triad (abnormalities that lead to thrombus formation).
Endothelial injury, Stasis, Hypercoagulability
It is a major contributor to the development of arterial thrombi.
Turbulence or endothelial injury
It is a major contributor to the development of venous thrombi.
Stasis
Any alteration of the coagulation pathway that predisposes to thrombosis; can be primary (e.g. Factor V Leiden, Protein C and S deficiency) or secondary (e.g. Cancer, atrial fibrillation, and prolonged immobilization)
Hypercoagulability
Laminations composed pale platelet and fibrin deposits alternating with darker red cell_rich layers; signifies formation of thrombus in flowing blood; present in antemortem thrombosis.
Lines of Zahn
Most common site of arterial thrombosis.
Coronary > cerebral > femoral
Most common site of venous thrombosis.
Superficial or deep veins of the leg (Note: thrombi in superficial leg veins rarely embolize, while thrombi in deep leg veins are the most common sources of venous emboli)
A detached, intravascular solid, liquid or gaseous mass that is carried by the blood distal to its point of origin.
Embolus
Most common and most dreaded sequelae of deep venous thrombosis.
Pulmonary embolism
Embolus occluding a bifurcation in the pulmonary tree; associated with sudden death due to acute right-sided heart failure.
Saddle embolus
A venous embolus, which entered the systemic circulation through an interarterial or interventricular defect.
Paradoxical embolus
Microscopic fat globules found in the circulation after fractures of long bones or after soft-tissue trauma; can lead to pulmonary insufficiency, neurologic symptoms, anemia, and thrombocytopenia.
Fat embolism
Gas bubbles within the circulation obstructing vascular flow and causes distal ischemic injury; example: Decompression sickness (bends, chokes)
Air embolism
Entry of amniotic fluid into the maternal circulation through a tear in the placental membranes and rupture of uterine veins; presence of marked pulmonary edema, diffuse alveolar damage, and presence of squamous cells in the pulmonary circulation shed from fetal skin, lanugo hair, fat, and mucin.
Amniotic fluid embolism
Area of ischemic necrosis caused by occlusion of the vascular supply to the affected tissue.
Infarct
Infarcts that tend to occur in loose tissues and in those with dual circulations, previously congested tissues, or when flow is reestablished after an infarction (i.e. after angioplasty of obstructed artery); examples: Pulmonary and Intestinal infarcts
Red infarct
Infarcts that tend to occur in solid organs with end-arterial circulations; examples: Myocardial and Splenic infarcts
White infarct
State of systemic tissue hypoperfusion due to reduced cardiac output and/or reduced effective circulating blood volume.
Shock
This type of shock results from failure of the cardiac pump, which maybe caused by MI, ventricular arrhythmias, cardiac tamponade or outflow obstruction.
Cardiogenic shock
This type of shock results from loss blood or plasma volume.
Hypovolemic shock
This type of shock is caused by microbial infection, caused by Gram-negative and Gram-positive bacteria and fungi.
Septic shock
Type of shock that occurs in the setting of an anesthetic accident or spinal cord injury as a result of loss of vascular tone and peripheral pooling of blood.
Neurogenic shock
This type of shock represents systemic vasodilation and increased vascular permeability caused by an IgE-mediated hypersensitivity reaction.
Anaphylactic shock