Blood in the urine: causes and symptoms

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Extract from the article: ‘Haematuria’ is the medical term used to describe the presence of blood in the urine. Haematuria is a fairly common reason for consultation. Finding blood in your urine is something that frightens everyone. However, there are many causes and not...

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‘Haematuria’ is the medical term used to describe the presence of blood in the urine. Haematuria is a fairly common reason for consultation. Finding blood in your urine is something that frightens everyone. However, there are many causes and not all of them are serious. Although blood is sometimes visible to the naked eye, this is not always the case.

Under normal conditions, there is no blood in the urine. Haematuria is defined as the presence of more than 2 red blood cells per analysis in the sediment of centrifuged urine, observed using certain laboratory techniques. Haematuria occurs because the kidneys or other parts of the urinary tract allow blood cells to pass into the urine. The urine may then be red in colour or remain the same, hence the difference between macroscopic haematuria (the presence of blood visible to the naked eye) and microscopic haematuria (not visible to the naked eye).

Main causes

In many cases, it is not possible to find the specific cause of haematuria. The main processes involved in filtering red blood cells into the urine. These include urinary tract infections, especially in women. This is because the female urethra is very close to the anus and the bacteria it contains can easily spread into the urethra.

Bilharzia is an infection caused by a parasite that enters contaminated water through the skin. It is the second most common parasitic disease in the world after malaria.

Haematuria can also be caused by a kidney infection such as pyelonephritis, which indicates that bacteria can reach the kidneys through the blood or ureters. There are also prostate problems: when the prostate enlarges (usually with age), it compresses the urethra. The flow of urine can then become blocked, causing haematuria. The same thing happens with prostate infections. Certain minerals in the urine also tend to accumulate. They solidify and form crystals that turn into small stones, the famous bladder or kidney stones. When they pass through the urinary tract, they can obstruct it. Blood then usually appears in the urine.

Haematuria can be a sign of bladder, prostate or kidney cancer. However, it generally occurs in advanced stages, making diagnosis difficult.  It can also be the result of glomerulonephritis, a disease in which the glomeruli become inflamed. The glomeruli are the kidneys' filtration system. This condition can be triggered for a number of reasons, including diabetes, infection or blood disorders. Certain medications can also cause haematuria. In men, excessive shaking of the penis after urination (to squeeze out the last few drops) can cause minor trauma to the ureter, resulting in haematuria and minor pain during subsequent urination.

Scientists have even established a link between haematuria and intense physical exercise, trauma or dehydration. It is therefore important to consult a doctor to find out the cause.

Symptoms

Macroscopic haematuria appears as red or brownish urine. In general, it is not painful and is not often accompanied by other symptoms. Nevertheless, the presence of certain symptoms can help to diagnose the cause. For example, if there is a fever and the lower back is sore, this may indicate a kidney infection. If, on the other hand, haematuria is accompanied by an increased urge to urinate or itching, the cause is usually in the lower urinary tract. On the other hand, continuous asymptomatic haematuria with clots may indicate a kidney tumour. From the age of 40, it is essential for men to have a prostate check-up.

See a doctor

Haematuria can be linked to a number of pathologies. What's more, in some cases it cannot be detected at first sight. It is therefore important to visit the doctor regularly. Urine tests are recommended from time to time to detect the possible presence of blood.

It's important to keep a close eye on your urine at all times: pay attention to its colour, frequency and different sensations. Any change may indicate an unknown pathology.

By William O.

Article validated by Dr Jean-Claude Bakpatina, general practitioner at the ‘Floréal’ clinic in Lomé