Chronic kidney disease
The kidneys are two bean-shaped organs of about 10-12 centimeters (as big as a knotted hand) placed on each side of the spine, below the lower ribs pair.
The kidneys have three tasks, firstly it is the body’s purification plant, secondly it is the body’s filter package and thirdly the body’s control station.
The kidneys work around the clock to cleanse the blood of unhealthy substances. More than a liter of blood in minutes flows through them and about 180 liters of body fluid are filtered per day. A healthy person urinates between one and three liters per day. The urine contains “waste” including toxins, drug residues and waste products from the food we eat. If the kidney function is disturbed, levels of waste products in the body can accumulate and lead to an accumulation in the blood (uremia).
In each kidney there are about one million small urine-producing units, so-called nephrons. Every nephron consists of a blood vessel cyst, glomerulus, and a kidney canal, the tubule. Glomerulus is a microscopic “filter package” whose task is to cleanse the blood from waste products. Tubules can be likened to “sewer pipes” where excess liquid and waste that have been filtered out drain away. Each nephron is connected to larger kidney channels. From there, the urine moves to the ureters and beyond to the bladder. All important substances that should remain in the body are separated in the filtration process and recovered back to the blood.
The function of the kidneys is to produce substances and regulate processes. The kidneys ensure that the cells function by regulating the degree of salt and acidity in the blood and control how much the body absorbs or secretes, among other things, hydrogen ions, sodium and potassium.
The kidneys produce two important hormones: erythropoietin, a hormone which stimulates the production of red blood cells in the bone marrow and renin, which regulates the resistance and tone of blood vessels and hence blood pressure. The kidneys are also important for the structure of the skeleton. The calcium we get through food can only be absorbed in the intestine using vitamin D, which is formed in the skin by the sun and activated by the kidneys.
The kidney depends on adequate contraction and relaxation of the heart to maintain kidney blood flow. Therefore, the interaction between the heart and kidney can often become deranged in heart failure. Heart failure and chronic kidney disease often co-exist and share common risk factors in their development. An impaired kidney function is associated with an increased risk of adverse outcomes. Having both heart and kidney disease can worsen prognosis and these patients require careful follow-up.
As many of the medications for heart failure have important direct effects on kidney function, it is important you have your kidney function checked (mainly through laboratory analysis) by your health care providers regularly during the treatment of acute and chronic heart failure.