Oedema** Flashcards
Oedema definition
Excessive fluid in the interstitium.
Causes of oedema.
- Acute inflammation
As well as haemodynamic causes:
- Increased hydrostatic pressure
- Reduced colloid osmotic pressure
- Sodium-water retention
- Lymphatic obstruction
Mechanisms by which acute inflammation causes oedema
Increased permeability to both protein and water results in an exudate (fluid with specific gravity >1.020).
Causes of increased hydrostatic pressure
Impaired venous return
- Congestive heart fialure
- Impaired venous return due to compression or obstruction
- Constrictive pericarditis
- Ascites due to liver cerrhosis
- Lower extremity inactivity with prolonged dependency
- Pregnancy
Causes of reduced colloid osmotic pressure
- Protein loss due to nephrotic syndrome
- Protein loss due to malabsorption/low intake
- Failure of protein synthesis due to liver disease
Causes of sodium/water retention
- Acute renal failure
- Disturbance of renin-angiotensin-aldosterone system
- Secondary to cardiac failure or hypoproteinaemia
Causes of lymphatic obstruction
- Inflammatory
- Neoplastic
- Post surgical
- Post irradiation
When do transudate and exudate occur? What is the difference.
Exudate is a fluid with a specific gravity >1.020 which contains protein and water. It occurs during accute inflammation.
Transudante has a specific gravity of <1.020 and has a low protein content. It occurs during haemodynamic disturbance.
Effects and outcomes of oedema
The effects depend on te location and the time course
Pulmonary and cerebral oedema are clinical emergencies.
