Hemodynamic Disorders L16,17 Flashcards
Fluid Distribution:
- 60% of lean body weight is water
- 2/3 intracellular
- 1/3 extracellular
- Majority is interstitial fluid
- 5% is in blood plasma
- What is the difference between anasarca and other types of edema?
Anasarca is a severe form of edema with extensive swelling of subcutaneous tissues and fluid accumulation in body cavities.
- What are the two main mechanisms of edema?
*Water extravasation (movement) out of the vascular wall into the interstitial spaces.
*imbalance between hydrostatic pressure forcing fluid out and colloid osmotic pressure pulling fluid in the capillaries.
- How do lymphatics contribute to edema?
Lymphatics drain excess interstitial fluid. A blockage in the lymphatic system can contribute to edema.
- What are the two main types of edema based on protein content?
*Inflammatory edema: protein-rich exudate, specific gravity > 1.020, caused by increased vascular permeability.
*Non-inflammatory edema: protein-poor transudate, specific gravity < 1.012, caused by reasons other than inflammation.
- What are the main forces influencing fluid movement across capillary walls?
Hydrostatic pressure (pushing fluid out) and osmotic pressure (pulling fluid in) are normally balanced, minimizing net fluid movement into the interstitial space
- What are the four main causes of non-inflammatory edema?
*Increased hydrostatic pressure
*Reduced plasma osmotic pressure
*Lymphatic obstruction (not covered in this excerpt)
*Sodium and water retention
- How can increased hydrostatic pressure cause localized edema?
*Deep vein thrombosis (DVT) in a leg hinders blood return, causing swelling in that leg.
*Portal hypertension due to liver cirrhosis leads to fluid buildup in the peritoneal cavity (ascites).
*Pressure from a pregnant uterus on iliac veins can cause congestion and edema in the lower limbs.
*Acute left ventricular failure causes acute pulmonary edema
How can increased hydrostatic pressure cause generalized edema?
Congestive heart failure reduces cardiac output, leading to:
*Increased venous pressure throughout the body.
*Reduced kidney perfusion, triggering sodium and water retention, ultimately causing edema.
Besides increased pressure, what can cause reduced plasma osmotic pressure leading to edema?
*A decrease in plasma proteins (like albumin) due to malnutrition or liver disease.
*Excessive fluid intake diluting plasma proteins.
What protein is most responsible for maintaining fluid balance in the bloodstream?
Albumin
What happens when albumin levels decrease?
Plasma osmotic pressure is reduced, causing a net fluid movement into the interstitial space and leading to edema.
What are three situations that can cause reduced albumin levels?
*Albumin loss from leaky glomerular capillaries (e.g., nephrotic syndrome).
*Decreased albumin synthesis due to liver diseases (e.g., cirrhosis).
*Protein malnutrition.
What is the typical effect of lymphatic obstruction on edema?
It usually causes localized edema.
It usually causes localized edema.
*Inflammatory lesions
*Neoplastic lesions (cancers)
How can breast cancer treatment lead to lymphedema?
Resection and/or irradiation of axillary lymph nodes can cause scarring and disrupt lymphatic drainage, leading to severe upper extremity edema.
What is peau d’orange and how is it related to lymphatic obstruction in breast cancer?
*Peau d’orange is a French term meaning “orange peel” and refers to a dimpled appearance of the skin.
*It can occur in breast cancer when tumor cells infiltrate and obstruct superficial lymphatic vessels, causing fluid buildup and a characteristic pitted texture in the overlying skin.
How does increased sodium and water retention contribute to edema?
It increases both hydrostatic pressure (due to more fluid in the blood vessels) and reduces osmotic pressure (diluting albumin’s effect).
- What are two situations where salt retention can occur and lead to edema?
*Poststreptococcal glomerulonephritis
*Acute renal failure
What are the two main ways to recognize edema?
*Macroscopic observation of swelling
*Microscopic observation of:
-Clearing and separation of extracellular matrix elements
-Individual cell swelling
In which tissues is edema most commonly encountered?
*Subcutaneous tissues
*Lungs
*Brain
- What is pitting edema and how is it caused?
*Pitting edema refers to a depression left in the skin after applying finger pressure.
*It occurs in edematous subcutaneous tissue where pressure displaces the interstitial fluid.
Where does edema due to renal dysfunction or nephrotic syndrome often appear first?
Loose connective tissues, particularly around the eyelids (periorbital edema).
How does the effect of edema vary depending on its location?
*It can have minimal effects in some locations.
*In subcutaneous tissue (e.g., with heart or kidney failure), it mainly indicates an underlying disease.
*In the lungs (pulmonary edema), fluid fills the air sacs and can cause life-threatening breathing difficulties.
*In the brain, edema can be localized (e.g., injury) or generalized (e.g., infections, high blood pressure).
