It is also known as dropsy or hydropsy. It is defined as clinically apparent increase in interstitial fluid volume. Generally, the amount of interstitial fluid is determined by the balance of fluid homeostasis, and increased secretion of fluid into the interstitium or impaired removal of this fluid may cause edema.
Six factors can contribute to the formation of edema
1. increased hydrostatic pressure
2. reduced oncotic pressure within blood vessels
3. increased tissue oncotic pressure
4. increased blood vessel wall permeability e.g. inflammation
5. obstruction of fluid clearance via the lymphatic system
6. changes in the water retaining properties of the tissues themselves. Raised hydrostatic pressure often reflects retention of water and sodium by the kidney.
Causes of oedema
1. Increased total extracellular fluid
• Congestive heart failure
• Renal failure
• Other hypervolaemic states: iatrogenic, Conn’s syndrome etc.
2. High local venous pressure
• Deep venous thrombosis or venous insufficiency
• Pregnancy
• Pelvic tumour
3. Low plasma oncotic pressure/serum albumin
• Increased loss: nephrotic syndrome
• Decreased synthesis: liver failure
• Malnutrition/malabsorption
4. Increased capillary permeability
• Leakage of proteins into the interstitium, reducing the osmotic pressure gradient which draws fluid into the lymphatics and blood
• Local: infection/inflammation
• Systemic: severe sepsis
• Drug-related, e.g. calcium channel blockers
5. Lymphatic obstruction
• Infection: filariasis, lymphogranuloma venereum
• Malignancy
• Radiation injury
• Congenital abnormality
Treatment
Treatment involves in the underlying cause.
Six factors can contribute to the formation of edema
1. increased hydrostatic pressure
2. reduced oncotic pressure within blood vessels
3. increased tissue oncotic pressure
4. increased blood vessel wall permeability e.g. inflammation
5. obstruction of fluid clearance via the lymphatic system
6. changes in the water retaining properties of the tissues themselves. Raised hydrostatic pressure often reflects retention of water and sodium by the kidney.
Causes of oedema
1. Increased total extracellular fluid
• Congestive heart failure
• Renal failure
• Other hypervolaemic states: iatrogenic, Conn’s syndrome etc.
2. High local venous pressure
• Deep venous thrombosis or venous insufficiency
• Pregnancy
• Pelvic tumour
3. Low plasma oncotic pressure/serum albumin
• Increased loss: nephrotic syndrome
• Decreased synthesis: liver failure
• Malnutrition/malabsorption
4. Increased capillary permeability
• Leakage of proteins into the interstitium, reducing the osmotic pressure gradient which draws fluid into the lymphatics and blood
• Local: infection/inflammation
• Systemic: severe sepsis
• Drug-related, e.g. calcium channel blockers
5. Lymphatic obstruction
• Infection: filariasis, lymphogranuloma venereum
• Malignancy
• Radiation injury
• Congenital abnormality
Treatment
Treatment involves in the underlying cause.
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