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Hemodynamic disorders
Dr. Mehzabin Ahmed
Edema
Accumulation of excess fluid (protein poor transudate, with specific gravity below1.012) in the tissues
Normally very little fluid leaks from the vessels to form interstitial fluid
This is cleared up by the lymphatics Edema results when the leakage from the
vessels is excessive
Inflammatory edema
Alteration of the vascular
permeability- in acute inflammation
& in allergic reactions
Non inflammatory edema
hydrostatic pressure
plasma oncotic pressure
Lymphatic obstruction
Salt & water retention
Causes of edema
Edema
1. Hydrostatic pressure: or the capillary blood pressure (35mmhg)
2. Osmotic pressure: maintained by the plasma proteins (25mmhg)
3. Some fluid enters the lymphatic system before eventually returning to the blood stream.
Pressure gradients controlling the fluid movement:
hydrostatic pressure- increase in the capillary blood pressure
Causes include: Local increase in the pressure:results
from impaired venous outflow.E.g.,deep vein thrombosis of the lower
extremities leads to edema of the affected leg
Generalized increase in venous pressure,with resulting systemic venous pressure occurs more commonly with congestive heart failure
Non inflammatory edema
plasma oncotic pressure Reduction in plasma albumin concentration results in edema
Causes are: Nephrotic syndrome Liver failure Protein malnutrition Protein losing gastroenteropathy
Non inflammatory edema
Lymphatic obstruction prevent the normal drainage of fluids into the thoracic duct
Causes are; Inflammatory Neoplastic Postsurgical postirradiation
Salt and therefore the water retention are contributory factors for the development of edema. It occurs with any acute reduction of renal function, e.g.,poststreptococcal glomerulonephritis and acute renal failure
Non inflammatory edema
Terms • Edema:increased fluid in the interstitial tissue
spaces.
• Effusion:excess of fluid in the serous or coelomic cavities– Hydrothorax;excess fluid in the pleural cavity– Hydropericardium;excess fluid in the pericardial cavity– Hydroperitoneum(ascites):excess fluid in the peritoneum
• Anasarca:severe & generalized edema with subcutaneous tissue swelling
Type of edema
Condition
causing the
edema
Tissue where the
fluid collects
hydrostati
c pressure
is in
Pulmonary edema
Left sided heart failure
Alveoli of the lung
Pulmonary vascular bed
Subcutaneous edema
Right sided heart failure
Subcutaneous
Systemic venous system
Examples of edema
Pulmonary edema
Pink edema fluid in the alveoli
Elephantiasis (filariasis)
Subcutaneous pitting pedal edema
Hyperemia
It is the increase in the blood supply (inflow) to the tissues due to arteriolar dilation as during an exercise.
It is the increased pooling of the blood in the capillary bed as
a result of a decreased venous return as in cardiac failure.
In long-standing congestion, called chronic passive
congestion, the stasis of poorly oxygenated blood also causes
chronic hypoxia, which can result in parenchymal cell
degeneration or death, sometimes with microscopic
scarring.
Capillary rupture at these sites of chronic congestion may
also cause small foci of hemorrhage; breakdown and
phagocytosis of the red cell debris can eventually result in
small clusters of hemosiderin-laden macrophages
Congestion
Examples of chronic venous ( passive) congestion are seen in
Liver in cases of chronic right heart failure -there are
alternate regions of congestion and fatty change giving
the liver alternate dark and light bands - nutmeg liver
Lungs in cases of chronic left heart failure- longstanding
congestion causes the alveolar walls to become fibrosed
(makes the lung firm /indurated). Damaged capillaries
result in the extravasation of RBCs, which are
phagocytosed by the alveolar macrophages and the
hemoglobin is converted to hemosiderin (makes the lungs
brown in color) - brown induration of the lung.
Nutmeg liver- alternate light (area of fatty change) and dark regions (areas of congestion)
Hemorrhage
It is the extravasation of blood from ruptured blood vessels.
The rupture can occur in large arteries due to trauma, atherosclerosis, inflammation or neoplastic infiltration.
Capillary bleeding can occur in chronic congestion.
Types of hemorrhage Hematoma- the collection of extravasated blood in the tissues
after rupture of the blood vessels. Petechiae- they are pinpoint hemorrhages (1-2mm diameter)
in the skin, mucous membranes or serosal surfaces Purpura-these are larger hemorrhages (>3mm dia) occurring
in vascultis, trauma. Ecchymosis- larger hemorrhages (>1-2 cm dia) occurring in
the subcutaneous tissues. They are commonly called bruises. Hemothorax- the collection of blood in the pleural cavity Hemoperitoneum- the collection of blood in the peritoneal
cavity Hemopericardium- the collection of blood in the pericardial
cavity Hemarthrosis- the collection of blood in the joint space or
cavity
Petechiae
Subarachnoid hemorrhagePurpura
Cerebral hemorrhage
At the end of this unit, the student should be able At the end of this unit, the student should be able to:to:
Define the following termsDefine the following terms HemorrhageHemorrhage HematomaHematoma HemothoraxHemothorax HemoperitoneumHemoperitoneum HemarthrosisHemarthrosis PetechiaePetechiae PurpuraPurpura HematemesisHematemesis Epistaxis Epistaxis HemoptysisHemoptysis MelenaMelena MenorrhagiaMenorrhagia
Define the following termsDefine the following terms ThrombosisThrombosis EmbolismEmbolism DICDIC Shock Shock infarctioninfarction
Explain the pathogenesis of thrombus Explain the pathogenesis of thrombus formationformation
List the outcomes of a thrombusList the outcomes of a thrombus List some disorders commonly associated List some disorders commonly associated
with thrombus formationwith thrombus formation List the types of embolism and give examples List the types of embolism and give examples
of each typeof each type List the types of infarcts and give examples List the types of infarcts and give examples
of each typeof each type Classify shock with examples.Classify shock with examples.
