Urinary tract infections are among the most common bacterial infections in childhood. In babies and young children the only sign is often a high temperature without a cough, a runny nose or any other obvious cause, so they are easily mistaken for a viral infection.
Recognising them in time matters, because an infection that has reached the kidney (pyelonephritis) can leave a scar on the growing organ, and recurrent urinary infections are often the first sign of a congenital abnormality. Dr Penev sees children with urinary infections in Plovdiv and Karlovo in cooperation with the child’s paediatrician.
What is a urinary infection in children?
A urinary infection means that bacteria are multiplying in the normally sterile urine and inflaming the organs it passes through. Cystitis affects the bladder, causes no fever or only a low one, and mainly causes problems when passing urine. Pyelonephritis affects the kidney and causes a high temperature and feeling generally unwell; in young children every urinary infection with a fever is treated as pyelonephritis until proven otherwise.
Symptoms
In babies and children up to two or three years old the symptoms are non-specific:
- a temperature above 38 °C with no other explanation, often with shivering;
- irritability, drowsiness, refusing food, vomiting, poor weight gain;
- in newborns – jaundice (yellowing of the skin), floppiness, a low rather than a raised temperature;
- smelly or cloudy urine, crying when passing urine.
In older children the symptoms are like those in adults: burning, passing small amounts of urine often, urgent needs to go, new daytime wetting or bedwetting that has come back, pain low in the tummy; with pyelonephritis – a high temperature and pain in the back.
When it is urgent: a baby under three months old with a temperature; a child who is vomiting, is floppy or is passing very little urine; a high temperature with shivering and back pain; a seizure (fit). These are situations for the emergency department or 112 (the European emergency number), not for a booked appointment.
Causes and risk factors
The most common cause is gut bacteria, above all Escherichia coli (E. coli), which get into the urethra from the skin around the anus. The risk factors are:
- bladder and bowel dysfunction – constipation, holding on to urine and incomplete emptying, the leading cause after the age of three;
- vesicoureteric reflux – a congenital backflow of urine from the bladder up towards the kidneys;
- congenital narrowing and widening of the urinary tract – hydronephrosis, urethral valves in boys;
- a tight foreskin (phimosis) in babies and fused labia minora (labial adhesions) in little girls.
Diagnosis
The key to the diagnosis is a correctly collected urine sample: in children who use the toilet, a midstream sample after washing. In babies, a stick-on bag is suitable only as a rough guide, because it is often contaminated; for a reliable diagnosis a “clean-catch” sample in a sterile container or a catheter sample in hospital is used. The decisive test is the microbiological examination (urine culture), which shows the bacterium and which antibiotics will work against it.
At the paediatric urology consultation, Dr Penev examines the child and performs an ultrasound of the kidneys and bladder – according to European guidelines, it is recommended after a first urinary infection with a fever in a young child, because it detects dilatation, stones, a thickened bladder wall or incomplete emptying. With recurrent infections or abnormal ultrasound findings, further tests at a specialist paediatric unit are discussed – a micturating cystourethrogram (MCUG) for reflux and an isotope scan for scarring of the kidney.
Treatment
The mainstay is an antibiotic chosen according to the child’s age and the likely bacterium, and adjusted according to the urine culture. For cystitis in older children the course is usually three to five days; for pyelonephritis seven to ten days, depending on the doctor’s judgement, and in young babies, with vomiting or when the child is seriously unwell, the antibiotic is first given intravenously in hospital. The fever usually comes down within 48 hours; if it does not, the treatment is reassessed. Low-dose preventive antibiotics are used only in selected children – those with high-grade reflux or frequent recurrences.
Treating the cause is just as important: passing urine every two to three hours, enough fluids, sorting out constipation, and treating phimosis if infections keep coming back. With significant reflux or a narrowing, correction at a specialist paediatric unit is discussed, and Dr Penev follows the child up before and after it.
When to see a urologist
See a urologist after a first urinary infection with a fever in a baby or young child, with recurrent infections, with abnormal ultrasound findings, with difficult or infrequent urination, a weak stream or daytime wetting. The general principles are described in the article on urinary tract infections in adults.
Prevention
Regular urination without holding on, enough water, regular bowel movements, wiping from front to back in girls, cotton underwear, no bubble bath or perfumed soaps, changing nappies promptly, and treating phimosis when it keeps causing infections. You will find more steps in the advice on preventing urinary infections.
Urinary infections in children are treated successfully when they are recognised in time and their cause is looked for. If your child has an unexplained fever or keeps getting infections, book an appointment with Dr Penev for an examination and an ultrasound.
Frequently asked questions
Can urine from a stick-on bag confirm an infection?
No. Urine from a bag is very often contaminated by the skin and gives false-positive results. A clear result from a bag can rule out an infection, but a positive one must be confirmed with a sample collected cleanly or with a catheter.
Why does my child keep getting urinary infections?
The most common causes are constipation and the habit of holding on to urine, followed by congenital features such as urine flowing back up towards the kidneys (reflux) and, in baby boys, a tight foreskin. The urologist looks for the cause with an examination, an ultrasound and, if needed, further tests.
Should the urine be tested again after the antibiotic course has finished?
If your child has recovered and has no symptoms, a follow-up urine test is not routinely needed. A test is done if the fever has not come down within 48 hours of starting treatment or if the symptoms come back.
Does pyelonephritis leave lasting damage to the kidney?
In some children a scar remains after a kidney infection, especially when treatment started late or the infections keep coming back. Prompt treatment of every urinary infection with a fever and dealing with its cause reduce this risk.
Can my child go to nursery during treatment?
A urinary infection is not contagious. Once the fever has come down and your child feels well – usually a day or two after starting the antibiotic – they can return to their usual routine, as long as they finish the whole course.
The information on this website is for general education and does not replace an examination and consultation with a doctor. If you have urgent symptoms, seek medical help immediately or call 112.