5 CAUSES OF OEDEMA

1. Renal failure
   1. Renal hypoperfusion
   2. Excessive salt intake
   3. ↑ Tubular absorption
   4. ↑ RAAS
2. ↑ Salt retention
   1. ↑ water > ↑ hydrostatic P + ↓ colloid osmotic P

1. Hypoprotonaemia, ↓ albumin in plasma
2. ↓ Absorption
   1. Malabsorption syndrome in GIT
3. ↓ Intake
   1. Malnutrition
4. ↓ Synthesis
   1. ** See note on Liver Cirrhosis with ascites
5. ↑ Loss
   1. GIT – protein losing gastroenteropthy
   2. Kidney – nephrotic syndrome leading to increased loss in urine

1. Impairs interstitial fluid clearance
2. Inflammation
3. Cancer
   1. Infiltration and obstruction of lymphatics by growth
   2. Treatment causing scarring/loss of lymph drainage
4. Parasite
   1. infection by Filariarsis causes obstruction of inguinal lymphatics (Elephantitis)

Nota:

• C;ljasL;KJAsc asclknas;CLKNasc as;LKC;Asckn

1. ↓ Venous return
2. Local
   1. Clot
      1. DVT causing oedema in distal part of lymb
   2. Mass
      1. Causing obstruction, leading to oedema
3. Systemic
   1. CCF
      1. **See CCF diagram, leading to activation of RAAS
   2. Constrictive pericarditis
      1. Blood backs up behind the heart and ↑ P
   3. Dilation of arteries
      1. Heat
   4. Ascites
      1. **See note on Liver Cirrhosis leading to ascites
4. **CCF
   1. ↓ Pump action of heart > ↓ cardiac output > ↓ Renal perfusion > activates RAAS
   2. ↑ Na+ and H2O to ↑ blood volume > ↑ hydrostatic P
   3. BUT heart cannot compensate and CO is still ↓ > ↑ Venous back P > ↑ oedema
5. **Liver Cirrhosis
   1. ↓ Liver function > Hypoprotonaemia > ↓ Colloid osmotic P
   2. H2O leaks from vessels > ↓ BV > ↓ Renal perfusion > activates RAAS
   3. ↑ Na+ and H2O to ↑ blood volume > ↑ hydrostatic P BUT ↓ Colloid osmotic P
   4. Will get progressively worse > kidney failure
6. RAAS
   1. Reduced renal perfusion d/t ↓ BF, ↓ BP, dehydration, renal aa stenosis
   2. Kidney releases Renin > Liver > Angiotensinogen > Angiotensin I
   3. Angiotensin II
      1. Vasoconstriction > ↑ BP
      2. Adrenals > Aldosterone> Na+ retention + H2O
      3. ADH > ↑ H2O reabsorption
      4. ↑ Thirst, liquid intake, BV

1. Inflammation
   1. Systemic
   2. Local
   3. Acute
   4. Chronic
   5. Exudate