Hemodynamic Disorders 1 PDF

Hemodynamic Disorders 1 Hyperemia and congestion Causes of edema Hyperemia : Increased Hydrostatic Pressure Is an active process resulting from arteriolar 1. Impaired Venous Return (heart failure, DVT) di...

Hemodynamic Disorders 1 Hyperemia and congestion Causes of edema Hyperemia : Increased Hydrostatic Pressure Is an active process resulting from arteriolar 1. Impaired Venous Return (heart failure, DVT) dilation and increased blood inflow. 2. Arteriolar dilatation (heat, early inflammation) Examples: 1. At sites of inflammation. Increased vascular permeability (e.g., inflammation) 2. In exercising skeletal muscle. -Hyperemic tissues are red, oxygenated blood Reduced Plasma Osmotic Pressure due to reduced plasma albumin Congestion 1. decreased synthesis (e.g., liver disease, protein Is a passive process resulting from impaired malnutrition) outflow of venous blood from a tissue. Examples: 2. increased loss (e.g., nephrotic syndrome, Protein- 1. Systemically, as in cardiac failure. losing gastroenteropathy) 2. Locally as a consequence of an isolated venous obstruction. Lymphatic Obstruction. Sodium and Water Retention. **Congested tissues have an abnormal blue-red color (cyanosis), deoxygenated blood. Edema -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 2. Infiltration of superficial lymphatics by Local :impaired venous return—for example, breast cancer : a deep venous thrombosis in the lower edema of the overlying skin; called peau d’orange. 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. Reduced Plasma Osmotic Pressure -Albumin is either lost from the circulation or synthesized in inadequate amounts. -In nephroticsyndrome loss of albumin in the urine >>>generalized edema. 3. Lymphedema also may occur as a complication -Protein losing enteropathy (malabsorption) of therapy. (axillary lymph node resection and/or - Reduced albumin synthesis occurs in the setting of irradiation) severe liver disease (e.g., cirrhosis) and protein malnutrition. Lymphatic Obstruction Sodium and Water Retention Localized obstruction caused by an Can lead to edema by increasing hydrostatic inflammatory or neoplastic condition. pressure and reducing plasma osmotic 1. Parasitic infection filariasis can cause pressure. massive edema of the lower extremity and external genitalia (so-called elephantiasis) by lymph node fibrosis.  Morphology Appearances of hemorrhage Most commonly in subcutaneous tissues, -Petechiae are minute (1 to 2 mm in diameter) lungs, and brain. hemorrhages into skin, mucous membranes, 1- Subcutaneous edema : legs and sacrum, or serosal surfaces; causes : dependent edema. (pitting edema) 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-Periorbital edema in nephrotic syndrome. 2. vascular inflammation (vasculitis). 3. increased vascular fragility. 3-Pulmonary edema, in left side heart failure. 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). Hemorrhage -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). Clinical significance of any hemorrhage 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.