Download Cardinal Manifestation of Disease: EDEMA

Cardinal Manifestation of Disease:
EDEMA
Dr. Meg-angela Christi Amores
Water in the body
• Total body water (TBW)
– Compartments:
1. Intracellular Fluid
- 75%
2. Extracellular Fluid (ECF) – 25%
– Plasma 25%
– Interstitial Fluid 75%
What is edema?
• clinically apparent increase in the interstitial
fluid volume
• weight gain of several kilograms usually
precedes overt manifestations of edema
Edema
• Anasarca - gross, generalized edema
• Ascites and hydrothorax -accumulation of
excess fluid in the peritoneal and pleural
cavities, respectively, and are considered to be
special forms of edema
Pathogenesis
• Starling Forces
– regulate the disposition of fluid between these
two components of the extracellular
compartment
– hydrostatic pressure within the vascular system
and the colloid oncotic pressure in the interstitial
fluid – promote movement out into interstitium
Starling Forces
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πi – Interstitial Oncotic pressure
πc – capillary oncotic pressure
Pi – interstitial hydrostatic pressure
Pc – capillary hydrostatic pressure
Starling Forces
• movement of water and diffusible solutes
from the vascular space at the arteriolar end
of the capillaries
• Fluid is returned from the interstitial space
into the vascular system at the venous end
and lymphatics
Pathogenesis
• Capillary Damage
– damage to the capillary
endothelium, which increases
its permeability and permits
the transfer of protein into the
interstitial compartment
– from drugs, viral or bacterial
agents, and thermal or
mechanical trauma
– hypersensitivity reaction and is
characteristic of immune injury
– Usually Inflammatory edema
Pathogenesis
• Reduction of Effective Arterial Volume
– by a reduction of cardiac output and/or systemic
vascular resistance
– retention of salt and, therefore, of water, ultimately
leading to edema
• Renal Factors and RAA System
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renal retention of Na+ is central
Diminished renal blood flow = renin release
Renin = release angiotensin I = angiotensin II
Angiotensin II - enhancing salt and water reabsorption
Pathogenesis
• Others:
– Argininine Vasopressin
– Endothelin
– Natriuretic peptides
Clinical Causes of Edema
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Obstruction of Venous Drainage of a limb
Congestive Heart Failure
Nephrotic Syndrome and Hypoalbuminemia
Cirrhosis
Drug-induced Edema
Idiopathic Edema
Obstruction of Venous Return
• hydrostatic pressure in the capillary bed
upstream (proximal) to the obstruction
increases
• Alternative route may also be blocked (lymph)
• there is trapping of fluid in the extremity
• displacement of fluid into a limb occur at the
expense of the blood volume in the remainder
of the body = dec arterial blood volume retention of NaCl and H2O
Congestive Heart Failure
• accumulation of blood in the venous
circulation due to:
1. impaired systolic emptying of the ventricle(s)
2. impairment of ventricular relaxation
• Low cardiac output leads to:
– a decrease in baroreflex-mediated inhibition of
the vasomotor center activates renal
vasoconstrictor nerves and the RAA system,
causing Na+ and H2O retention
Nephrotic Syndrome
• Proteinuria
• Hypoalbuminemia
• diminished colloid oncotic pressure due to losses
of large quantities of protein into the urine
• NaCl and H2O that are retained cannot be
restrained within the vascular compartment
• Impaired renal function contributes further to
the formation of edema
Nephrotic Syndrome
Cirrhosis
• hepatic venous outflow blockade
• expands the blood volume and increases
hepatic lymph formation
• as a potent stimulus for renal Na+ retention
• activation of the RAA system, of renal
sympathetic nerves, and of other NaCl- and
H2O-retaining mechanisms
Drug-Induced
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Nonsteroidal anti-inflammatory drugs
Antihypertensive agents
Direct arterial/arteriolar vasodilators
Calcium channel antagonists
A -Adrenergic antagonists
Steroid hormones
Cyclosporine
Growth hormone
What caused the edema?
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Ascites
jaundice, and spider angiomas
collateral venous channels
= CIRRHOSIS
What caused the edema?
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Gallop rhythm
Dyspnea
basilar rales
Venous distention
Hepatomegaly
Cardiomegaly
= HEART FAILURE
What caused the edema?
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Blood in urine
Proteinuria
Hypoalbuminemia
= NEPHROTIC SYNDROME
Distribution
• thrombophlebitis, chronic lymphangitis,
resection of regional lymph nodes, filariasis
• =LOCALIZED
• Heart failure, nephrotic syndrome, cirrhosis
• =GENERALIZED
• For the next meeting, read on Stroke Syndromes
• Harrison’s Principles of Internal Medicine 17th
edition