With chronic kidney disease we mean the progressive reduction of the capacity of the kidneys to filter waste. It is the progression of acute renal injury. The disease becomes chronic when the kidney does not recover its functions even after treatment.

In general, all diseases that can cause acute renal failure are possible causes, especially if not treated. Most of the time, however, chronic kidney disease is caused by diabetes and hypertension. Both diseases damage the renal vessels, causing the progressive degeneration of tissues.

The disease is also linked to obstruction of the urinary tract and to changes in the organ. One example is polycystic kidney disease and glomerulonephritis. It can also be caused by autoimmune diseases such as lupus, in which antibodies attack the blood vessels of the kidneys. Whatever the cause, the consequences of chronic kidney disease have repercussions on the whole organism.

The bad functioning of the kidneys prevents the body from eliminating the acids it produces. This increases the acidity of the blood and causes the accumulation of waste, which can damage the brain. Furthermore, a slowing in the production of red blood cells occurs, resulting in anemia.
For the diagnosis of chronic kidney disease, urinalysis and ultrasound are used. Renal failure causes an increase in the levels of pathological proteins and cells. The ultrasound instead serves to identify any obstructions and to control the size of the kidneys. If these occur small and with scar tissue, then the disease would be chronic.

The treatment includes a modification of the lifestyles, so as to avoid further deterioration. It also resorts to drugs and, in the most advanced cases, to dialysis.

Source: msdmanuals.com