3. What is edema?
● Edema can be defined as the presence of excess fluid in the
interstitial space of the body.
● Edema is divided into two types, localized edema and
generalized edema.
● The formation of edema is associated with renal sodium
retention.
4. Mechanism of generalised edema
● a reduced intravascular volume leading to sodium and water retention, that
is, an underfilling edema
● sodium and water retention secondary to expanded plasma and intracellular
tissue fluid volume accompanied by a lack of natriuresis, that is, an
"overfilling edema"
● The generalized edema occurs in the presence of parenchymal renal
damage (nephrotic syndrome, acute and chronic glomerulonephritis and renal
failure) or in the absence of structural renal disease (heart failure, liver
cirrhosis).
5. Underfilling theory
● The mechanism of "underfilling edema" is initiated with an increased glomerular
permeability to albumin, that is, albuminuria.
● The subsequent hypoalbuminemia leads to decreased plasma oncotic pressure
accompanied by movement of water from intravascular space to the interstitium.
● The intravascular contracted volume in turn stimulates the following neuroendocrinological
factors, resulting in sodium and water retention:
(1) an increased renin-angiotensin-aldosterone (RAA) activity;
(2) an increased sympathetic nervous system (SNS) activity;
(3) antidiuretic hormone (ADH) release
● These forces and perhaps as yet unidentified factors give rise to the consequential water
and sodium retention, which promotes the development of edema.
● The sodium and water retention leads to further decreased plasma oncotic pressure,
setting up a vicious cycle perpetuating the edema formation.
● The movement of water from intracellular space to interstitial space by itself also
contributes to the development of edema formation
6. Overfilling theory
In contrast, the mechanism of "overfilling edema" is expanded extracellular volume
that results from primary renal sodium retention, possibly secondary to the renal
damage, The RAA system, SNS system and ADH secretion are depressed in the
"overfilling edema”.
12. Causes -Increased capillary permeability- due to release of
cytokines/histamine/PG/complement
-Burn
-Sepsis
-Dengue
-Iatrogenic cause – intravenous fluid
13. Localized edema
Increased hydrostatic pressure
❖ Venous obstruction SVC/IVC obstruction
Thrombosis DVT
External compression- lymphnodes
❖ Cirrhosis
Fibrosis of the liver obstructing venous blood flow in the portal venous
system/lower limbs
16. History
● Age
● Edema location – localised /generalised
● Duration of symptoms- acute onset/gradual /relapsing
● Associated complaints that suggest systemic disease or major organ dysfunction
➔ Liver/heart/bowel
➔ Kidney- change in color/frequency/frothy urine
● Additional concurrent illnesses . A streptococcal infection one to three weeks earlier may point to
post-streptococcal glomerulonephritis/recent skin infection
● Waxing and waning of the edema
● System review: headache/nocturnal cough
● Past medical and family history. A family history of recurrent angioedema, for example, may suggest
hereditary angioedema as a possible diagnosis./family hx of renal disease
● History of allergies and current medications. Allergies and adverse reaction to certain medications can
present as angioedema in childhood.
17. Physical examination
❖ General examination
-Anthropometry (height /weight)
-Vital signs, perfusion, bounding pulse, BP, RR,
-JVP
-Assessment of edema- generalised, pitting, extent
involvement of other areas – sacral, labial/scrotal
cervical lymphadenopathy
-Throat examination
-Skin – rash, signs of skin infection
22. Supportive Treatment
● Focused on reversing the underlying cause
● General:
Medication: Diuretic (Frusemide) to increased urine output; no response to diuretic> Dialysis
Rest in bed
Dietary Modification: Sodium Restriction
Water Restriction: Avoid IV saline & enteral feedings in cardiac/renal disease; Promote fluid intake if
fever/diaphoresis
● Monitor
Vital signs: BP
Fluid Intake, Urine Output, Proteinuria
Daily Weight
Serum Electrolyte: Sodium & Albumin level
