[03.16] Clinical Manifestations of Patients with Edema V2.pdf

Excessive accumulation of interstitial fluid, either localized or generalized

What is edema?

Anasarca

What is the term for a condition when the amount of generalized edema is great?

Edema in the peritoneal cavity

What is ascites?

Edema in the pleural cavity

What is hydrothorax?

Movement of fluid into the extravascular space

What is the most likely cause of generalized edema in a patient with Chronic Kidney Disease?

About one-third

Approximately how much of the total-body water is confined to the extracellular space?

75% interstitial fluid and the remainder is plasma

How is the extracellular space fluid divided?

Starling forces

What regulates the disposition of fluid between the interstitial fluid and plasma components of the extracellular compartment?

The movement of fluid out of the capillary space or into the extravascular space

What do Starling forces describe?

Hydrostatic pressure, colloid oncotic pressure, endothelial integrity, and lymphatic systems

What are the several factors that control the direction of flow of interstitial fluid, driven by Starling’s law?

Capillary permeability (σ)

What is fluid movement proportional to?

Hydrostatic (P) and oncotic pressures (π) within the capillary and tissue interstitium (T)

What determine the net driving force (NDF) for fluid movement?

Reabsorption

What is the term for fluid movement into the capillary?

Filtration

What is the term for fluid movement out of the capillary?

Reflection coefficient (σ)

What is the oncotic pressure difference multiplied by in the Starling force equation?

Permeability of the capillary barrier to the proteins responsible for generating the oncotic pressure

What does the reflection coefficient (σ) represent?

NDF = (PC - PT) - σ(πC - πT)

What is the equation for Starling's Law?

Transcapillary hydrostatic pressure differences

What does (PC - PT) represent in the Starling force equation?

Transcapillary oncotic pressure differences

What does (πC - πT) represent in the Starling force equation?

Filtration

When NDF > 0, what does this favor?

Fluid goes outside of the blood vessel

When NDF > 0, where does fluid go?

Reabsorption

When NDF < 0, what does this favor?

Fluid goes inside the blood vessel

When NDF < 0, where does fluid go?

Capillary Hydrostatic Pressure (PC)

What is the pressure built by the fluid against the vascular wall going out?

Tissue Hydrostatic Pressure (PT)

What is the force of the fluid outside the vasculature?

Capillary Plasma Oncotic Pressure (πC)

What is generated by proteins and functions to draw fluid inside?

Tissue Fluid Oncotic Pressure (πT)

What is the pressure created by the oncotic pressure from proteins outside the vasculature?

Capillary Hydrostatic Pressure (PC) and Tissue Fluid Oncotic Pressure (πT)

What two factors promote movement of fluid out of the capillary space?

Capillary Plasma Oncotic Pressure (πC) and Tissue Hydrostatic Pressure (PT)

What two factors promote movement of fluid into the capillary space?

Osmotic pressure

What refers to the general force that drives water across a semipermeable membrane?

Oncotic pressure

What specifically refers to the osmotic pressure exerted by proteins in the blood plasma?

Colloid osmotic pressure

What is another name for oncotic pressure?

Plasma proteins, notably albumin

What induces oncotic pressure in blood vessel's plasma?

Pulls fluid back to the vascular space, into the capillaries

What effect does oncotic pressure have on fluid movement?

Forces fluid from the capillaries

What is the effect of capillary pressure?

Arterial pressure

Which end of the capillary has higher pressure, promoting blood flow?

Density of tissues

What determines how interstitial pressure varies?

Fluid forced into capillary

What happens when interstitial pressure values are positive?

Fluid forced into interstitium

What happens when interstitial pressure values are negative?

Albumin

What is the most abundant plasma protein contributing to capillary plasma oncotic pressure?

Towards absorption

What direction does the osmotic effect exerted by proteins across capillary walls favor?

Small amount of proteins

What exists in the interstitium that contributes to tissue fluid oncotic pressure?

Forces some fluid out of capillary walls

What is the effect of tissue fluid oncotic pressure?

Elevation of venous pressure due to obstruction to venous and/or lymphatic drainage, and imbalance in Starling forces

What are the two main factors that may result in edema?

Imbalance in Starling forces due to reduced colloid oncotic pressure of the plasma

What specific Starling force imbalance leads to edema?

Hypoalbuminemia

What condition is linked to reduced colloid oncotic pressure of the plasma?

Severe malnutrition, liver disease, loss of protein into the urine or gastrointestinal tract, severe catabolic state

What factors can induce hypoalbuminemia?

The amount of fluid is proportional to its extent and thickness

What is a general principle regarding the amount of fluid in edema?

In the feet and ankles of an ambulatory patient, or over the posterior calves or sacrum of a supine patient

Where does edema first appear due to gravity?

The processes involved in edema formation are the same

Are the processes for generalized and localized edema different or the same?

One or more alterations in the Starling forces

What does the development of edema depend on?

Increased flow of fluid from the vascular system into the interstitium or into a body cavity

What alteration in Starling forces leads to edema?

Location, timing, setting of the swelling, associated symptoms, drug intake

What pertinent information is needed in the evaluation of edema?

Local anatomy of blood vessels, lymphatics, soft tissues, and signs of local inflammatory or structural disease

What should the examiner consider and look for to evaluate edema?

Pitting vs. Non-pitting, Localized vs. Generalized, Symmetric vs. Asymmetric

What are the characteristics to take note of when evaluating edema?

Soft, usually bilateral, with pitting on pressure

What are the general characteristics of pitting edema?

No skin thickening, ulceration, or pigmentation

What is usually absent in pitting edema?

Congestive heart failure, nephrotic syndrome, liver cirrhosis, malnutrition, drugs

In what states is pitting edema seen?

Protein spills out of the urine, decreasing protein concentration in the vasculature

Why does nephrotic syndrome cause pitting edema?

The liver is unable to produce enough proteins, causing hypoalbuminemia

Why does liver cirrhosis cause pitting edema?

Not enough proteins are taken or ingested due to lack of nutrition

Why does malnutrition cause pitting edema?

Press firmly but gently with your thumb for at least 5 seconds

How is pitting edema evaluated?

Over the dorsum of each foot, behind each medial malleolus, over the shins, over the sacrum

What areas are evaluated for pitting edema?

Soft in early stages, then becomes indurated, hard, non-pitting

What are the characteristics of non-pitting edema (lymphedema)?

Markedly thickened

What is the state of the skin in non-pitting edema?

No pigmentation

What is typically absent in non-pitting edema?

Unilateral or bilateral

How can non-pitting edema be distributed?

Pitting

Is edema from chronic venous insufficiency usually pitting or non-pitting?

Insufficiency of venous valves

What causes edema from chronic venous insufficiency?

Blood cannot go back up across the venous system into the right side of the heart

What is the consequence of venous valve insufficiency?

Venous pooling, usually in the legs due to gravity

What does venous valve insufficiency lead to?

Changes in skin pigmentation

What usually accompanies chronic venous insufficiency edema?

Decreased plasma oncotic pressure

What was the likely cause of bipedal edema in Case 2 (18-year-old male with proteinuria, anemia, hyperlipidemia)?

Spillage of protein out through the urine

Why would plasma oncotic pressure be decreased in Case 2?

Over the thighs

What area is NOT typically evaluated for pitting edema, according to the source's active recall questions?

True

Oncotic pressure specifically refers to the osmotic pressure exerted by proteins in the blood plasma. True or False?

Tissue Hydrostatic Pressure

What is the force of the fluid outside the vasculature called?

Anasarca

What is a condition when there is a great amount of generalized edema?

Heart failure, COPD, Glomerulonephritis, Cirrhosis, Hypothyroidism

Facial and periorbital edema can be secondary to what conditions?

Allergic or inflammatory dilatation of capillaries (capillary leak syndrome)

What can cause facial and periorbital edema due to increased capillary permeability?

Orbital cellulitis, urticaria, angioneurotic edema, orbital trauma

What other diseases can cause facial and periorbital edema?

Damage to capillary endothelium increases permeability

What is the mechanism of capillary damage leading to edema?

Allows protein to transfer into the interstitial compartment

What is the result of increased capillary permeability due to damage?

Drugs, viral or bacterial agents, thermal or mechanical trauma

What may cause capillary damage?

Hypersensitivity reaction characteristic of immune injury

What is capillary damage a consequence of?

Inflammatory edema

What type of edema is presumably responsible for capillary endothelium damage?

Non-pitting, localized, and accompanied by redness, heat, and tenderness

What are the characteristics of inflammatory edema?

Hypersensitivity Reaction

Which condition results in edema due to increased capillary permeability?

Edema limited to a single extremity or part of an extremity

What is localized edema?

Edema that affects the whole body rather than particular organs or body areas

What is generalized edema?

Inflammation (infection, angioedema, contact allergy), metabolic causes (gout), insufficiency of venous valves, venous thrombosis, venous or lymphatic compression, chemical burns or physical injuries

What are causes of localized edema?

Hypoalbuminemia (nephrotic syndrome, cirrhosis, protein-losing conditions), renal retention of salt and water from drugs (corticosteroids, NSAIDs), increased capillary permeability (sepsis)

What are causes of generalized edema?

Superior vena cava obstruction

What causes bilateral edema above the diaphragm?

Congestive heart failure, portal vein hypertension, inferior vena cava obstruction, loss of venous tone (from calcium-channel blockers or other vasodilators)

What can cause bilateral edema below the diaphragm?

Effective arterial blood volume

What parameter represents the filling of the arterial tree?

Retention of salt and water

What is a key element of the physiologic responses to restore effective arterial blood volume, ultimately leading to edema?

Renin-Angiotensin Aldosterone System (RAAS)

What system comes into play for any drop in blood pressure or fluid volume?

Drop in blood pressure or fluid volume

What triggers the RAAS?

Kidney

What organ releases renin in response to a drop in blood pressure or fluid volume?

Angiotensinogen from liver to Angiotensin I

What does renin convert?