hemodynamics part 1 Flashcards
define hydrothorax
- fluid in pleural space
- like in between lungs
defien hydropericardium
- fluid in the space between the heart and pericardium
define ascites or hydroperitoneum
- fluid in peritoneal space
What are some causes of edema (5)
- elevated hydrostatic pressure
- decreased plasma oncotic pressure (low protein)
- lymphatic obstruction
- sodium retention
- inflammation
what can cause elevated hydrostatic pressure
- CHF, constrictive pericarditis, ascites from liver cirrhosis, venous obstruction
define Edema
- increased fluid in the interstitial tissue spaces
- occurs when there is a greater movement of fluid out of the vasculature than is returned by venous absorption or lymphatic drainage, then edema results
define transudate
protein poor fluid with a specific gravity of < 1.012
what causes a decreased plasma oncotic pressure
- Low protein due to nephrotic syndrome, end stage liver disease, malnutrition, protein losing gastroenteropathy
- -> low albumin levels
what causes lympahtic obstruction
- inflammation, neoplastic, surgery, postirradiation
what causes sodium retention
- renin, angiotensin, aldosterone (sodium reabsorption, renal insufficiency
- water follows sodium causing increase in vascular volume
what causes inflammation
- acute and chronic, angiogenesis
describe how heart failure causes edema
- heart failure leads to an increase in hydrostatic pressure which directly leads to edema due to back up of blood
- heart failure decreases renal blood flow leading to the activation of renin-angiotensin system which causes retention of Na+ and H2O that results in an increase in blood volume (edema)
what is the cause of reduced plasma oncotic pressure
- ALBUMIN is the protein most responsible for maintaining colloid osmotic pressure
EXAMPLES - Reduced synthesis or production of albumin caused by liver failure or cirrhosis
- Loss of protein via glomerular injury caused by nephrotic syndrome
define anasarca
- severe generalized edema
- due to lack of oncotic pressures
- earliest sign is periorbital edema
describe sodium and water retention
- increased salt in circulation causes:
- -> shift of fluid in intravascular space
- -> increased hydrostatic pressure due to expansion of fluid volume
- -> increased plasma water content results in decreased oncotic pressure resulting from dilution of albumin (not as much reabsorption on venous end**)
- Secondary to renin-angiotensin- aldosterone system activation
- common in renal failure
describe inflammation
- edema caused by inflammation is due to increased passage of fluid into the extracellular space
- it is localized unless it is the result of a systemic inflammatory response
- e.g allergic reaction
- OFTEN EXUDATE
describe lymphatic obstruction
- impaired lymphatic drainage results in lymphedema, therefore it is usually localized
- common result of:
- -> inflammation
- -> neoplasia
- -> surgical removal of axillary lymph nodes during treatment of breast cancer may cause obliteration of lymphatic drainage
describe the microscopic appearance of endema
- depends on the amount of protein exudate
- just see clearing and separation of the ECM elements
- may see pink-staining if protein content is significant
- edema is most commonly seen in subcutaneous tissue, lungs and brain
describe subcutaneous edema
- important, but seldom of clinical significance
- edema may interfere with healing because fluid must be removed before healing can take place
- severe edema may compromise venous return and increase the risk of infection and ulceration (pooling fluid is bad and can cause infections)
what are the two site of clinically relevant edema
- LUNG AND BRAIN
- due to the increased risk of death
describe the clinical manifestations of pulmonary edema
- Dyspnea; sudden, orthopnea, cyanotic (central), “air hunger”, tachypnea
- Cough: copious sputum, frothy, blood tinged
- Pulse: tachycardic, bounding
- breath sounds: crackles (fine to course)
- Engorged neck vein
describe the radiographical findings of the two types of pulmonary edema
- Interstitial pulmonary edema
- -> poorly defined pulmonary vessels
- -> visible lung fissures
- -> septal lines
- -> thick bronchial walls
- -> see haziness on X-ray
- Alveolar pulmonary edema (more severe)
- -> bilateral symmetric perihilar lung consolidation
- -> you see densities on X-ray
- also look for enlarged heart and pleural effusion
describe cerebral edema
- extremely serious condition because when brain swells, skull prevents further expansion so tissue is compressed
- Parenchymal edema may shift brain due to increased pressure and if generalized may push the brainstem down into the foramen magnum (tonsillar herniation)
- if edema is more localized (focal), one part of the brain may herniate into adjacent compartments tearing brain tissue
what causes localized cerebral edema
- abscess
- neoplasm
- trauma
what causes generalized cerebral edema
- encephalitis
- hypertensive crisis
- obstruction of venous outflow
- trauma
describe the gross appearance of cerebral edema
- swollen brain has distended, flattened gyri and narrowed sulci due to compression of brain against skull
Define Hyperemia
- active process in which arteriolar dilatation results in INCREASED FLOW of blood to a tissue
- -> skeletal muscle during exercise
- -> inflammation
- -> Blushing
- Tissue is erythematous (red) due to engorgement with oxygenated blood
define congestion
- passive process due to IMPAIRED OUTFLOW of blood from a tissue
- caused by:
- -> systemic = CHF
- -> local venous obstruction
- blue-red coloration due to accumulation of deoxygenated hemoglobin (cyanosis)
- congestion and edema commonly occur together
describe chronic passive congestion
- long term congestion producing stasis of poorly oxygenated blood can result in cellular degeneration and death
- capillary rupture at these sites may result in small foci of hemorrhage
- if there is capillary rupture, breakdown and phagocytosis of the red cell debris results in accumulation of hemosiderin-laden macrophages at the site
describe the microscopic findings in acute pulmonary congestion
- alveolar capillaries engorged with blood
- alveolar septal edema
- focal intraalveolar hemorrhage
describe the microscopic findings in chronic pulmonary congestion
- thickened and fibrotic septa
- heart failure cells hemosiderin-laden macrophages in alveolar spaces
- MORE SEVERE
describe chronic hepatic congestion
- Nutmeg liver = central regions of hepatic lobules are grossly red/brown and depressed (due to cellular loss) surrounded by unaffected areas
- Microscopically
- -> centrilobular necrosis = hepatocelular death and accompanying hemorrhage with hemosiderin laden macrophages
- -> long standing hepatic congestion may result in hepatic fibrosis
Describe Hemorrhage
- Extravasation of blood due to ruptured vessel
- hemorrhage classified as external or internal
what does hemorrhage result from
- Trauma
- atherosclerosis
- aneurysm
- neoplasia or inflammation
- capillary bleeding can occur in chronic congestion
- hemorrhagic diathesis potentiates bleeding (fragility of vessels, platelet dysfunctions, coagulation defects etc)
define hematoma
- collection of blood under the skin
describe the various types of hematoma’s
- Petechiae = 1-2mm hemorrhage in skin, mucous membrane or serosal surfaces (pin point)
- Purpura = >3mm
- Ecchymoses = > 1-2cm (LARGE)
describe the common causes of ecchymoses
- usually occur due to trauma
- can also occur as a first sign of acute myelogenous leukemia due to a low platelet count (thrombocytopenia)
what is the clinical significance of hemorrhage
- RAPID loss of 0% of blood volume has an insignificant impact on healthy individual but can be lethal in the compromised patient
- sites where bleeding occurs has significant prognostic value (e.g. bleeding into the brain can be rapidly fatal)
- chronic or recurrent bleeding can result in iron deficiency
- internal blood loss may allow reuse of iron