signs/differention with Cardiac Failure

A rise in hydrostatic pressure occurs in cardiac failure. A fall in oncotic pressure occurs in nephrotic syndrome syndrome and liver failure (more complicated than that, but one of the key distinctions).

Oncotic pressure, or colloid osmotic pressure, is a form of osmotic pressure exerted by proteins in blood plasma that usually tends to pull water into the circulatory system.
Throughout the body, dissolved compounds have an osmotic pressure. Because large plasma proteins cannot easily cross through the capillary walls, their effect on the osmotic pressure of the capillary interiors will, to some extent, balance out the tendency for fluid to leak out of the capillaries. In other words, the oncotic pressure tends to pull fluid into the capillaries. In conditions where plasma proteins are reduced, e.g. from being lost in the urine (proteinuria) or from malnutrition, the result of low oncotic pressure can be excess fluid buildup in the tissues

Hydrostatic pressure within blood vessels tends to cause water to filter out into the tissue. This leads to a difference in oncotic pressure… etc

*Starling equation

Starling's equation states that the rate of leakage of fluid is determined by the difference between the two forces and also by the permeability of the vessel wall to water, which determines the rate of flow for a given force imbalance.

In terms of differences in signs of the disease, they’re hard to separate, as often chronic renal failure leads to cardiac failure, but the key distinctions can be found in the contents of the blood – tests demonstrating accumulation of sulfates, phosphates, uric acid, etc. being indicative of renal failure.