Oedema is caused by fall in plasma proteins below -

Edema may be caused by: increased hydrostatic pressure (e.g., hea failure) increased vascular permeability (e.g., inflammation) decreased colloid osmotic pressure, due to reduced plasma albumin decreased synthesis (e.g., liver disease, protein malnutrition) increased loss (e.g., nephrotic syndrome) lymphatic obstruction (e.g., inflammation or neoplasia). sodium retention (e.g., renal failure) ( Robbins Basic Pathology, 9 th edition, )