Normally, urine is sterile. Most infections are caused by gut bacteria that travel up the urethra into the bladder: this is cystitis, which causes burning and frequent urination, without fever. In women, the urethra is short, which is why cystitis is more common.
If the bacteria keep climbing through the ureter to the kidney, the infection becomes pyelonephritis: fever, chills and back pain. It must be treated the same day.
In the diagram: A cystitis (bladder infection) · B pyelonephritis (kidney infection, with fever)
1 Kidney · 2 Ureter · 3 Bladder · 4 Urethra · 5 Bacteria
After several episodes per year, or for any urinary infection in a man, a urological work-up helps find a contributing cause and tailor prevention.
Blood in the urine (haematuria) should always be checked by a doctor, even if it happens once and without pain.
These signs should prompt a visit to a urologist:
Symptoms, how often episodes occur and what may trigger them.
Dipstick and urine culture to identify the germ and choose the right antibiotic.
To look for a stone, a blockage or incomplete bladder emptying, especially in men or with repeat infections.
If needed: uroflowmetry or other tests to find why infections recur.
Treatment is chosen together with you, based on the cause, how severe the symptoms are and what matters to you.
Chosen from the urine culture, for a length suited to the type of infection.
A stone, the prostate or poor bladder emptying: the cause is found and treated.
Lifestyle advice and, in some cases, preventive treatment.
A check-up after an infection with fever, in men or during pregnancy.
ConseilsCystitis that keeps coming back? Why women are more affected, how to tell cystitis from a kidney infection, when to see a urologist and the habits that really help prevent recurrences.
ConseilsRed or pink urine, even once: blood in the urine must always be investigated. Possible causes, emergency signs and what the work-up involves (ultrasound, CT urogram, cystoscopy).
ConseilsSudden back pain, nausea, blood in the urine… How to recognise renal colic, when to go to the emergency department, which treatments exist and how to stop stones coming back.
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Learn moreThe information on this website is for general information only and does not replace a medical consultation.
