What is cardiorenal syndrome?

What is cardiorenal syndrome?

Cardiorenal syndrome is worsening of kidney function secondary to heart disease. Reverse condition of worsening heart function secondary to kidney disease is known as renocardiac syndrome. In general, both these conditions are grouped together as cardiorenal syndrome meaning that both heart disease and kidney disease are present and related to each other in some way.

Cardiorenal syndrome has been classified into types I, II, III, IV and V by the Consensus Conference of the Acute Dialysis Quality Initiative. The table has been cited in an American Heart Association Scientific Statement as well. A simplified presentation of the five types of cardiorenal syndrome are as follows:
Type I: Acute cardiorenal syndrome is acute kidney injury (AKI) which is mediated by changes in blood circulation secondary to acute worsening of heart function. Acute means a condition with a rapid onset. Heart diseases like a heart attack which can cause acute heart failure may lead on to acute cardiorenal syndrome with associated kidney failure. This usually occurs due to poor blood circulation to the kidneys.

Type II: Chronic cardiorenal syndrome is secondary to chronic heart diseases like heart muscle disease, heart valve disease or coronary artery disease. Chronic means a condition which has been there for a long period. Coronary arteries are blood vessels supplying oxygenated blood to the heart. All these conditions, if severe, can cause severe heart failure and lead on to chronic cardiorenal syndrome. It is kidney failure secondary to chronic heart failure.

Type III: Acute renocardiac syndrome is acute worsening of kidney function leading to heart failure as in acute glomerulonephritis which can cause flash pulmonary edema. Acute glomerulonephritis is a kidney disease which usually occurs after an infection by bacteria known as streptococci as a delayed immune mediated condition. Antibodies developed by the body against the bacteria cross react with the cells of kidneys and produce damage to the kidneys in this condition. The condition is usually seen in young children. Flash pulmonary edema is sudden collection of fluid in the airspaces of the lungs producing severe breathlessness and fall in oxygen saturation of blood.

Type IV: Chronic renocardiac syndrome is heart disease secondary to chronic kidney disease with left ventricular hypertrophy, anemia, uremia and calcification of coronaries with atherosclerosis. Left ventricular hypertrophy is thickening of the heart muscle of the lower left chamber. Anemia is decrease in hemoglobin content of blood. Hemoglobin is the protein which carries oxygen in the blood. Uremia is accumulation of waste products of metabolism in blood, which are normally excreted by kidneys in urine. Atherosclerosis is deposition of fatty material within the walls of blood vessels. Calcification of coronaries means deposition of calcium compounds in the wall of blood vessels of the heart.

Type V: In secondary cardiorenal syndrome same disease process causes injury to both the heart and the kidneys as in diabetes mellitus and generalized infection. Type V cardiorenal syndrome can be acute or chronic. Certain drugs and toxin may also cause type V cardiorenal syndrome. Another important group of diseases which can cause type V cardiorenal syndrome are the connective tissue diseases like lupus, Wegener’s granulomatosis and sarcoidosis. These diseases involve groups of cells known as connective tissue, which connect other important cell groups together. They can involve the walls of blood vessels in many organs, including heart and kidneys in a condition known as vasculitis or inflammation of the blood vessels.