<s>[INST] context: Following conditions can cause edema:-
1) The increased hydrostatic pressure of capillaries: It causes an increase in outward driving force. It may be
due to impaired venous return e.g. in CHF or DVT.
2) Decreased plasma osmotic pressure of capillaries: It causes decrease in inward driving force.
It results from Hypoproteinemia. When total plasma protein is below 5 gm/dl (normal 6-8gm/dl) or
albumin is below 2∙5 gm/dl (normal 3.5-5 gm/dl) edema takes place. Conditions causing
hypoproteinemia are a nephrotic syndrome, liver cirrhosis, protein-losing enteropathy, and PEM.
3) Defective removal of interstitial fluid by lymphatics: It is due to lymphatic obstruction, which may be inflammatory, neoplastic, post-surgical and post-irradiation.
4) Increased vascular permeability: It occurs in acute and chronic inflammation, and during angiogenesis (new vessels are leaky).
5) Sodium (salt) and water retention: It causes expansion of plasma volume (hydrostatic pressure) and dilution of plasma proteins (↓ osmotic pressure). The conditions responsible for this type of edema are ARF, acute glomerulonephritis, renal hypoperfusion, and increase renin angiotensin aldosterone system (RAAS) activity. [/INST] question: Edema occurs when plasma protein level is below? | options: A: 5 mg/dl B: 15 mg/dl C: 10 mg/dl D: 20 mg/dl | answer: A </s>