The presence in blood in the urine is referred to in medicine by the term hematuria. Blood may be present in large quantities and visibly stain urine pink, red or brown (this is called gross hematuria) or be present in trace amounts (microscopic hematuria). It is then necessary to carry out an examination to detect its presence.

Blood in the urine is an abnormal sign, usually indicative of urinary tract involvement. It is therefore important to consult your doctor when the urine presents an abnormal color, or in the event of urinary signs (pain, difficulty in urinating, urgent need, cloudy urine, etc.). Usually, an ECBU or urine dipstick workup will be done to quickly find the cause.

Depending on the results, your doctor may possibly refer you to a urologist.

Hematuria can have several causes. If your urine turns red or pink, it is important to ask yourself whether it is blood. Several situations can indeed change the color of urine, including:

• the consumption of certain foods (such as beets or certain berries) or certain food colors (rhodamine B)
• taking certain medications (antibiotics such as rifampicin or metronidazole, certain laxatives, vitamin B12, etc.)

In addition, menstrual bleeding or vaginal bleeding can, in women, color urine in a “deceptive” way.

To determine the cause of hematuria, the doctor may perform a urine test (by strip) to confirm the presence of blood, and will be interested in:

• associated signs (pain, urinary disorders, fever, fatigue, etc.)
• medical history (taking certain treatments, such as anticoagulants, history of cancer, trauma, risk factors such as smoking, etc.).

The “timing” of the hematuria is also a good indicator. If blood is present:

• from the start of urination: the origin of the bleeding is probably the urethra or prostate in men
• at the end of urination: it is rather the bladder that is affected
• throughout urination: all urological and renal damage should be considered.

The most common causes of hematuria are:

• a urinary tract infection (acute cystitis)
• kidney infection (pyelonephritis)
• urinary / kidney lithiasis (“stones”)
• kidney disease (nephropathy such as glomerulonephritis, Alport syndrome, etc.)
• prostatitis or an enlarged prostate
• a “urothelial” tumor (bladder, upper excretory tract), or kidney
• rarer infectious diseases such as urinary tuberculosis or bilharzia (after a trip to Africa, for example)
• trauma (blow)

The presence of blood in the urine should always be the subject of a medical consultation, as it can be indicative of a serious pathology. However, the most common cause remains the urinary tract infection, which still requires rapid treatment to avoid complications. Generally, the associated signs (urinary disorders, pain or burning during urination) put on the track.

Note that a very small amount of blood (1 mL) is enough to stain urine intensely. The color is therefore not necessarily a sign of profuse bleeding. On the other hand, the presence of blood clots should alert: it is advisable to go to the hospital without delay for an evaluation.

The solutions obviously depend on the cause, hence the importance of quickly identifying the origin of the bleeding.

In the case of a urinary tract infection (cystitis), antibiotic treatment will be prescribed and will resolve the problem of hematuria quickly. In the event of pyelonephritis, hospitalization is sometimes necessary in order to administer sufficiently powerful antibiotics.

Kidney stones or urinary tract stones are often associated with severe pain (renal colic), but can also result in simple bleeding. Depending on the case, it is advisable to wait for the stone to dissolve on its own, then medical or surgical treatment will be prescribed.

Finally, if the bleeding is due to a tumor pathology, treatment in the oncology department will obviously be necessary.