What causes UTIs in children?

Urinary tract infections, or UTIs, are a very common type of infection that can lead to serious problems such as kidney damage if they are left untreated. In his latest article, renowned paediatric urologist Mr Alex Turner offers his expert insight into the condition, including their diagnosis, causes and treatment.

What are the causes of a UTI?

A UTI is a urinary tract infection caused by bacteria that get into the urinary tract. Bacteria can enter the urinary tract in different ways, but usually it comes from outside the urinary tract and ascends through the urethra.

UTIs can be divided into two groups:

• Lower tract urinary tract infections
• Upper tract urinary tract infections

Lower tract urinary tract infections are what we call cystitis, when bacteria are confined to the bladder. This has a separate set of symptoms.

Upper tract infections are when the bacteria move up the urinary tract and can damage the kidney. In very young babies it's more common in males due to anatomical problems. An abnormal urinary tract is more prone to infection because of poor bladder emptying, or stasis.

As children get older, it becomes more common in females, and the cause is much more likely to be due to things like bladder-bowel dysfunction. This poor emptying could be because of poor habits or constipation, for instance.

Another anatomical cause is the reflux of urine. This is when you pass urine and some wee goes back up to the kidney, resulting in dilation of the kidney and the ureter (the pipe from the kidney to the bladder) leading to incomplete emptying and bladder dysfunction. There are also several conditions which can obstruct the flow, which would also cause stasis of urine.

What are the most common symptoms of UTIs?

Lower tract urinary tract infections will often present with painful weeing, which is what we call dysuria, or high frequency of urine. Patients often have the feeling that they're not completely empty, so they keep going back for another dribble. Other symptoms include lower abdominal pain, and cloudy, smelly wee.

Upper urinary tract infections come with more systemic symptoms, so they complain of being unwell, lethargic, and nauseated. They vomit and typically they have high temperatures. It's really important to determine which sort of urinary tract infection it is because that then guides you as to what investigations to perform.

What complications can arise from a UTI?

Lower urinary tract infections and cystitis are very, very common and persist into adult life. Normally they cause discomfort and painful urination and don't tend to cause many complications. In severe cystitis, you may get blood in the urine, for instance.

It's the upper urinary tract infections that cause the most complications because infections that affect the kidney will scar the kidney and reduce its function. If it's affecting both kidneys, then that can result in reduced renal function, and in severe cases renal failure. You will then need renal replacement therapy.

What are the most effective treatments for UTIs?

The treatment really is related to the cause. So, if we're talking about lower urinary tract infections or recurrent cystitis, we would investigate all causes. If it’s just related to the bladder, then our priority is improving the health of the bladder.

This means that the patient would need bladder re-training. We would get the patient to make sure that they're drinking plenty and that they’re going to the toilet every three hours. They need to be doing something called double voiding, which means emptying the bladder, standing up, washing their hands and going back again to make sure they get that last bit.

We would also treat any constipation because that is one of the main causes of urinary tract infections.

And if these things didn't work, then we would begin antibiotic treatment. This needs to be done with caution, because the risk of resistance is always there and so the urine should be sent off to be tested to find out what bacteria it is so the appropriate antibiotic can be given.

Finally, we would need to investigate and correct anatomical abnormalities. For instance, reflux can be treated and reversed which would hopefully stop infections.

Why do UTIs keep coming back and how can that be prevented?

This is very much dependent on the nature and the reason for the UTIs coming back. Is there an anatomical abnormality, such as stasis of urine? Or could it be a type of bacteria that is good at staying in the urinary tract?

We can give antibiotics, but individual courses of antibiotics may not always work. An example would be E. Coli. E. Coli have microscopic “legs” and can bury themselves into the bladder walls.

However, we know that cranberry juice can disrupt the bacteria so that they can be easily flushed away.

There are some conditions where bacteria is always present and so the principles are to protect the kidneys. Whatever we do in terms of our treatment, we try to prevent upper tract infections.

Mr Alex Turner is a leading paediatric urologist and surgeon based in Leeds, with over 20 years of experience. If you would like to book a consultation with Mr Turner, you can do so today via his Top Doctors profile.