Hemodynamic Disorders 1 PDF

Fatima Obeidat MD University of Jordan, School of medicine  Hyperemia and Congestion  Edema  Hemorrhage  Infarction  Shock  Hemostasis and Thrombosis  Embolism  Hyperemia :  Is an active process resulting from arteriolar dilation and increased bloo...

Fatima Obeidat MD University of Jordan, School of medicine  Hyperemia and Congestion  Edema  Hemorrhage  Infarction  Shock  Hemostasis and Thrombosis  Embolism  Hyperemia :  Is an active process resulting from arteriolar dilation and increased blood inflow.  Examples:  1. At sites of inflammation.  2. In exercising skeletal muscle.  Hyperemic tissues are red, oxygenated blood  Is a passive process resulting from impaired outflow of venous blood from a tissue.  Examples:  1. Systemically, as in cardiac failure.  2. Locally as a consequence of an isolated venous obstruction.  Congested tissues have an abnormal blue-red color (cyanosis), deoxygenated blood.  Edema is an accumulation of interstitial fluid within tissues.  Extravascular fluid can also collect in body cavities such as:  1. The pleural cavity (hydrothorax),  2. The pericardial cavity (hydropericardium).  3. The peritoneal cavity (hydroperitoneum, or ascites).  Anasarca is severe, generalized edema  The fluid may be protein-poor (transudate) or protein-rich (exudate). Increased Hydrostatic Pressure 1. Impaired Venous Return (heart failure, DVT) 2. Arteriolar dilatation (heat, early inflammation)  Increased vascular permeability (e.g., inflammation)  Reduced Plasma Osmotic Pressure due to reduced plasma albumin 1. decreased synthesis (e.g., liver disease, protein malnutrition) 2. increased loss (e.g., nephrotic syndrome, Protein-losing gastroenteropathy)  Lymphatic Obstruction.  Sodium and Water Retention.  Local :impaired venous return—for example, a deep venous thrombosis in the lower extremity can cause edema restricted to the distal portion of the affected leg.  Generalized : with resultant systemic edema, occur most commonly in congestive heart failure.  Albumin is either lost from the circulation or synthesized in inadequate amounts.  In nephrotic syndrome loss of albumin in the urine >>>generalized edema.  Protein losing enteropathy (malabsorption)  Reduced albumin synthesis occurs in the setting of severe liver disease (e.g., cirrhosis) and protein malnutrition.  Localized obstruction caused by an inflammatory or neoplastic condition.  1. Parasitic infection filariasis can cause massive edema of the lower extremity and external genitalia (so-called elephantiasis) by lymph node fibrosis.  2. Infiltration of superficial lymphatics by breast cancer : edema of the overlying skin; called peau d’orange.  3. Lymphedema also may occur as a complication of therapy. (axillary lymph node resection and/or irradiation)  Can lead to edema by increasing hydrostatic pressure and reducing plasma osmotic pressure.  Most commonly in subcutaneous tissues, lungs, and brain.  Subcutaneous edema : legs and sacrum, dependent edema. (pitting edema)  Periorbital edema in nephrotic syndrome.  pulmonary edema, in left side heart failure.  The extravasation of blood from vessels.  External or accumulate within a tissue as a hematoma,  Large bleeds into body cavities : hemothorax, hemopericardium, hemoperitoneum, or hemarthrosis (in joints). Petechiae are minute (1 to 2 mm in diameter) hemorrhages into skin, mucous membranes, or serosal surfaces; causes : 1. low platelet counts (thrombocytopenia), 2. defective platelet function. 3. Loss of vascular wall support, as in vitamin C deficiency  Purpura are slightly larger (3 to 5 mm) hemorrhages. same disorders of petechiae, as well as: 1. trauma, 2. vascular inflammation (vasculitis). 3. increased vascular fragility.  Ecchymoses are larger (1 to 2 cm) subcutaneous hematomas (bruises). color changes of a bruise are due to the enzymatic conversion of hemoglobin (red-blue color) to bilirubin (blue-green color) then hemosiderin (golden-brown). Depends on:  1. The volume of blood lost.  2. The rate of bleeding.  Rapid loss of up to 20% of the blood volume, or slow losses of even larger amounts, may have little impact in healthy adults.  Greater losses, however, can cause hemorrhagic (hypovolemic) shock.  3. The site of hemorrhage trivial in the subcutaneous tissues but can cause death if in the brain.  4. Chronic or recurrent external blood loss (e.g., due to peptic ulcer or menstrual bleeding) leads to iron deficiency anemia.