Kidney Function

Our kidneys filter our entire blood volume about 300 times a day – a total of about 1,500 liters of blood. In the process, the kidneys rid the blood of a wide variety of waste products. Substances dissolved in the blood, such as urea, electrolytes, sugars, acids and bases, are first filtered thanks to the kidneys and then reabsorbed into the blood in a refined way – depending on how much the body needs. The rest is excreted from the body as urine, along with breakdown products from metabolism.

Kidney and nephrons

The kidneys are made up of about 1 million nephrons: These are small units into which all the liquid components of the blood are squeezed. These nephrons are arranged in a complicated pattern so that there is a concentration gradient of substances important to the body between the blood and the water mixture that is filtered out – so sugar molecules, electrolytes and also water get back into the blood. Other substances that are toxic or unimportant for the body, such as metabolic waste products (e.g. uric acid), are then collected with the remaining water in larger tubules and pass through the renal pelvis and ureter into the urinary bladder. Urine collects in the urinary bladder – and when we reach a certain amount of urine, we feel the urge to urinate. Urine is excreted through the urethra, and the closure of the urethra is controlled by several muscles. Below the bladder, a walnut-sized organ, the prostate, surrounds the urethra in men. It releases a secretion vital for sperm during ejaculation. The kidneys are normally located to the left and right of the lumbar spine – after severe weight loss, they can sometimes move lower.

Symptoms of complaints with the kidney

With inflammation, the kidneys can hurt – if you gently tap your back in the area of the lumbar spine, it hurts. In the case of renal pelvic inflammation – which occurs after a bladder infection has been carried over – fever often also occurs. Cramp-like pain occurs with a kidney or bladder stone – the body tries in batches to squeeze out the stone. When the kidney stops working, harmful substances and metabolic waste products are no longer excreted – fluid accumulation (edema) occurs and blood poisoning increases, which can lead to confusion and even coma. An enlarged prostate – and almost every older man has one – impedes bladder emptying: the urethral muscles have to work against higher pressure to force urine out of the bladder – dribbling urination and many trips to the toilet are the consequences. Conversely, bladder weakness with many trips to the toilet or the inability to hold urine or pass urine at the right time, i.e. urinary incontinence, is a very common symptom that can have many causes.

History, percussion, and inspection.

All complaints can be further narrowed down by asking specific questions (history taking). For example, fever and pain in the kidney area can often be found in advance of a bladder infection. Inspection (looking at) and percussion (tapping): urine is usually yellow: light yellow when we have drunk enough and darker in thirsty situations. If urine smells unpleasant, an infection is likely – if it becomes dark brown when left to stand, the metabolic disease porphyria is suspected. If there is blood in the urine, you should also think about cancer. If you have to go to the toilet much more often than usual, this may indicate diabetes – so-called polyuria (urinating a lot) is a common initial symptom. If kidneys hurt when you tap them, it’s usually due to a kidney pelvis infection. In renal colic (due to a stone), the kidney bed may be so painful that even a light touch is too much.

Urine tests, functional tests, and CT scan.

In addition to color, volume, and odor, urine tests determine the contents of the urine – sugar does not usually appear in urine, and only a few cells do. In gout, for example, the excretion of uric acid is maximally exhausted – the gout attack occurs because more uric acid is produced in the body than the kidney can excrete. Functional tests: These are primarily used to check kidney function or the ability of the bladder to hold urine and release it selectively with strong pressure. Blood tests and a kidney biopsy are necessary in cases of glomerulonephritis, because this helps to determine why inflammation of the kidney tissue has occurred.Ultrasound, X-ray, computed tomography and magnetic resonance imaging: Ultrasound can be used to assess the shape and size of the kidneys – even cysts, a tumor or calcified stones can be seen clearly. The bladder and prostate can also be easily visualized by ultrasound. Further imaging procedures are usually only used to determine the extent of a tumor. Cystoscopy (cystoscopy of the bladder) is performed to clarify blood in the urine.

Kidney and bladder

In addition to inflammation of the kidney tissue (glomerulonephritis) and kidney stones, kidney failure is particularly prominent. In most cases, diseases such as diabetes or hypertension lead to the gradual loss of kidney function. Conversely, the lower flow rate of the kidneys during inflammation leads to high blood pressure, because an important blood pressure regulator is located in the kidneys. Since the kidney determines blood pressure and also blood volume, kidney and cardiovascular diseases are often coupled. Very common is cystitis, which occurs more often in women, but especially older men with prostate enlargement are also a risk group. In addition, the bladder is also affected in Reiter’s disease – this is a secondary disease following an infection. Bladder weakness or urinary incontinence describes more a symptom, because it can have many causes and it is divided into different forms: Stress or strain incontinence (the most common form), urge incontinence (also called irritable bladder) and overflow incontinence (more common in men). Bedwetting is also part of incontinence – at a very early age, the wet bottom then leads to diaper dermatitis.

Kidneys and prostate

Benign prostate enlargement, which almost every older man has, can lead to bladder problems. To be distinguished from this is prostate cancer, which has a good chance of cure if detected early. Drinking plenty of fluids is the motto in the case of stone disease and infections. If the kidneys are only functioning to a limited extent, it is particularly important to control water intake and output, otherwise fluid retention may occur or the body may be poisoned with metabolic waste products. In the event of kidney failure, the affected person must undergo dialysis. Dialysis is a type of blood washing in which toxic substances are removed from the blood. Affected individuals should also eat an appropriate diet to relieve the body. The treatment of incontinence is varied. There are medicinal and surgical methods – and pelvic floor exercises with many helpful exercises. In the case of prostate enlargement, there is recently the possibility of using green laser light instead of surgery – a gentle alternative for those affected. Of course, there is a special procedure for each disease with medication or surgery – more details can be found at the respective disease.

Strengthen kidneys by drinking

You can support the kidney in its flushing function by drinking a lot. Whether mineral water, apple spritzer or tap water – even coffee in moderation is quite suitable. Slowly, schools are also catching on to the fact that drinking frequently throughout the day keeps your body and mind fit. There are many foods and medicinal plants that have a diuretic effect and thus prevent kidney stones and inflammation – asparagus, cranberry or nettle juice are just a few. The acid-base balance in the body can be influenced by the right diet – and take work off the kidney. Early detection plays an important role in many kidney and urinary tract diseases, because kidney damage caused by diabetes or high blood pressure impairs quality of life. Unfortunately, only about 15% of men take advantage of prostate cancer screening. Urinary incontinence can only be prevented to a limited extent with pelvic floor exercises. Affected individuals should try not to let the disease affect them too much – carefully planned vacations are even possible without fear of embarrassing mishaps.