Urinary infections in children

Urinary tract infections (UTI) affect about 3 percent of children in the growing years. Throughout childhood, the risk of a UTI is about 2 percent for boys and 8 percent for girls. The symptoms are not always obvious to parents, and younger children are usually unable to describe how they feel. Recognizing and treating urinary tract infections is important as untreated urinary infections can lead to serious kidney problems with long term effects. In the first year of life urinary infections are more common in boys and after that they become considerably more common in girls.

  1. Function of the urinary system in normal health
  2. How does the urinary tract become infected in children?
  3. What are the signs of urinary tract infection in children?
  4. Treatment of urinary infections in children
  5. What tests may be needed in children after the infection is gone?
  6. What abnormalities lead to urinary infections in children?
  7. Do urinary tract infections have long-term effects in children?
  8. How can urinary tract infections be prevented?
  9. Points to Remember
  10. Cases links
Function of the urinary system in normal health
The kidneys filter and remove waste and water from the blood to produce urine. The urine travels from the kidneys down two narrow tubes called the ureters. The urine is then stored in an organ called the bladder. In a child, the bladder can hold about 1 to 1-1/2 ounces (each ounce= approx 30ml) of urine for each year of the child's age. So, the bladder of a 4-year-old child may hold about 4 to 6 ounces; an 8-year-old can hold 8 to 12 ounces When the bladder empties, a muscle called the sphincter relaxes and urine flows out of the body through the urethra, a tube at the bottom of the bladder. The opening of the urethra is at the end of the penis in boys and in front of the vagina in girls.
How does the urinary tract become infected?
Normal urine is free of bacteria (germs). Generally bacteria reach the urinary tract from nearby skin especially if the hygiene is poor. Once the bacteria reach the bladder, the bladder lining gets swollen and there is pain in the belly, fever and pain during passing urine. This bladder infection is called cystitis.
If the bacteria travel up through the ureters to the kidneys, a kidney infection can develop. The infection is called Pyelonephritis and is usually accompanied by pain in the side of belly below ribs, high grade fever and the child may be very sick. Kidney infections are much more serious than bladder infections.
In some children a urinary tract infection may be a sign of an abnormal urinary tract that may be prone to repeated problems. For this reason, when a child has a urinary infection, additional tests are often recommended. In other cases, children develop urinary tract infections because they are prone to such infections, just as other children are prone to getting coughs, colds, or ear infections. Or a child may happen to be infected by a type of bacteria with a special ability to cause urinary tract infections.
Children who frequently delay a trip to the bathroom are more likely to develop UTIs. Regular urination helps keep the urinary tract sterile by flushing away bacteria. Holding in urine allows bacteria to grow. Keeping the sphincter muscle tight for a long time also makes it more difficult to relax that muscle when it is time to urinate. As a result, the child’s bladder may not empty completely. This dysfunctional voiding can set the stage for a urinary infection.
What are the signs of urinary tract infection?
If the child is an infant or only a few years old, the signs of a urinary tract infection may not be clear, since children that young cannot tell you exactly how they feel. High fever, vomiting or lethargy may be the only features. Sometimes a child may have only a low-grade fever, experience nausea and vomiting, or just not seem healthy. The diaper urine may have an unusual smell. If the child has a high temperature and appears sick for more than a day without signs of a runny nose or other obvious cause for discomfort, he or she may need to be checked for a bladder infection.
An older child may complain of pain in the abdomen and pelvic area. Older kids may complain of need to go frequently to toilet for passing urine. Crying or complaining that it hurts to urinate and producing only a few drops of urine at a time are other signs of urinary tract infection. Your child may have difficulty controlling the urine and may leak urine into clothing or bedsheets. The urine may smell unusual or look cloudy or red.
Treatment of urinary infections
Antibiotics are the first line of therapy for urinary infections. Ideally, a urine culture should be ordered whenever a urinary infection is suspected. It would tell the kind of bacteria causing the infection and the best antibiotics to fight them. Additional medicines may be given for fever and pain like paracetamol.
While a urine sample is being examined, the treatment is started with a drug that is usually effective against the common bacteria causing the infection. Once culture results are known, the doctor may decide to switch to a better antibiotic. If the child is sick or not able to drink fluids, the antibiotic may need to be given via injections and the child may require admission in a hospital. Otherwise, the medicine (liquid or pills) may be given by mouth or by shots. The medicine is given for at least one week to ten days and the complete course of antibiotic must be given even if the child starts feeling better in 2-3 days. Otherwise infections may return, and germs can resist future treatment if the drug is stopped too soon.
What tests may be needed after the infection is gone?
Additional tests may be recommended to check for abnormalities in the urinary tract. The kinds of tests ordered will depend on your child and the type of urinary infection. Because no single test can tell everything about the urinary tract that might be important, more than one of the following tests may be needed:
  • Kidney and bladder ultrasound. An ultrasound test examines the kidney and bladder using high frequency sound waves. Kidneys and bladder structural abnormalities can be seen, however it cannot reveal all important urinary abnormalities. Most importantly, it cannot tell us about the kidney function.
  • Micturating cystourethrogram (MCU) also called- Voiding cystourethrogram (VCUG). This test examines the urethra and bladder while the bladder fills and empties. A liquid that can be seen on x rays is placed into the bladder through a catheter. The bladder is filled until the child urinates. This test can reveal abnormalities of the inside of the urethra and bladder. The test can also determine whether the flow of urine is normal when the bladder empties.
  • Intravenous pyelogram. This test examines the whole urinary tract. A liquid that can be seen on x rays is injected into a vein. The substance travels into the kidneys and bladder, revealing possible obstructions.
  • Nuclear scans. These tests use radioactive materials that are usually injected into a vein to show how well the kidneys work, the shape of the kidneys, and whether urine empties from the kidneys in a normal way. Each kind of nuclear scan gives different information about the kidneys and bladder. Nuclear scans expose a child to about the same amount of radiation as a conventional x ray. At times, it can even be less.
  • Computed tomography (CT) scans and magnetic resonance imaging (MRI). These tests provide 3-D images and cross-sections of the bladder and kidneys. With a typical CT scan or MRI machine, the child lies on a table that slides inside a tunnel where the images are taken. If the child’s infection is complicated or difficult to see in other image tests, a CT scan or MRI can provide clearer, more detailed images to help the doctor understand the problem.
What abnormalities lead to urinary infections?
Many children who get urinary tract infections have normal kidneys and bladders. But if a child has an abnormality, it should be detected as early as possible to protect the kidneys against damage. 30% of the children with urinary tract infections are found to have some abnormality on investigations.
Abnormalities that could occur include the following:
  • Vesicoureteral reflux (VUR). Urine normally flows from the kidneys down the ureters to the bladder in one direction. Vesicoureteral reflux is the abnormal backwash of urine into the ureter or kidney. This abnormality is common in children with urinary infections. As the urine is not emptied completely, it can lead to infections.
  • Urinary obstruction. Blockages to urinary flow can occur in many places in the urinary tract. The ureter or urethra may be too narrow or a kidney stone at some point stops the urinary flow from leaving the body. Occasionally, the ureter may join the kidney or bladder at the wrong place and prevent urine from leaving the kidney in the normal way.
  • Dysfunctional voiding. Some children develop a habit of delaying a trip to the bathroom because they don’t want to leave their play. They may work so hard at keeping the sphincter muscle tight that they forget how to relax it at the right time. These children may be unable to empty the bladder completely. Some children may strain during urination, causing pressure in the bladder that sends urine flowing back up the ureters. Dysfunctional voiding can lead to vesicoureteral reflux, accidental leaking, and urinary infections. Typical children with dysfunctional voiding leak urine during the day in drops and suddenly run to the toilet.
  • Constipation. The modern lifestyle has led to a spate of children coming with constipation. Loaded intestines behind the bladder disturb the emptying of the bladder and put pressure on the nerves. Some of these kids also have dysfunctional voiding. The kids with constipation are also at risk of developing urinary infections and the infections keep on recurring till the constipation has been tacked with dietary, behavioural and pharmacological means.
Do urinary tract infections have long-term effects?
Urinary tract infections in young children can lead to renal damage and lead to long term problems which include kidney scars, poor kidney growth, poor kidney function, high blood pressure, and other problems. For this reason it is important that children with urinary tract infections receive prompt treatment and careful evaluation. It is for this reason that follow-up imaging is a must for any child who had a urinary infection.
How can urinary tract infections be prevented?

If the investigations show that the urinary tract is normal:

  • Management of dysfunctional voiding.
  • Treatment of constipation.
  • Regular trips to the bathroom if the child has a habit of delaying urination
  • Teach your child proper cleaning techniques after using the bathroom to keep bacteria from entering the urinary tract.
  • Making sure that the foreskin in boys and vaginal area in girls is cleaned properly while bathing.

If the investigations show some abnormalities of the urinary tract:

  • All the above factors are as important as some of these abnormalities in the urinary tract correct themselves as the child grows, but some defects may require surgical correction. This is especially true of Vesicoureteral reflux. Only a handful of children with repeated infections or high grade reflux require surgery to correct the reflux. The primary aim in children with reflux is to prevent and treat infections timely as it is infections that cause damage and not the reflux itself. For low grade reflux, Endoscopic injection therapy for reflux has shown good results in curing reflux in suitable cases which otherwise would have been cases for open surgery. This injection creates a kind of valve that keeps urine from flowing back into the ureter. The injection is delivered to the inside of the bladder through a catheter passed through the urethra, so there is no need for a surgical incision.
  • Urinary obstruction is more dangerous than reflux and generally requires some form of surgery to take care of the obstruction. 
Points to Remember
  • Urinary tract infections affect about 3 percent of children.
  • Urinary infections may present with non-specific signs and symptoms; suspect urinary infection if no other site of infection is evident.
  • A urinary tract infection in a young child may be a sign of an abnormality in the urinary tract that could lead to repeated problems.
  • Symptoms of a urinary infection range from slight burning with urination or unusual smelling urine to severe pain and high fever.
  • Untreated urinary infections can lead to serious kidney damage.
  • Talk to a doctor if you suspect your child has a urinary tract infection.

Kushal, a 6 months old boy had high grade fever for 2 days. A doctor was consulted and he was diagnosed to have a viral infection- no tests were done. An antibiotic was prescribed for 5 days when the fever did not go away after another 2 days. The fever subsided for time being. But he developed frequent episodes of fever almost every 2-3 months, each time labeled as chest infection/ viral fever and received antibiotics. At 3 years of age, the mother noticed that Kushal was shorter than the other kids of his age and was taken to a doctor again. Doctor reassured that since everything else is well, the child need not be investigated further. At the age of four years, he became very sick with fever, vomiting and tummyache. He required admission and blood tests showed infection in the kidneys and early kidney failure. This sent the alarm bells ringing and he was investigated further. He was found to have a condition called Vesicoureteral reflux whereby urine goes back to kidneys and leads to infections. Each infection damages the kidneys and ultimately kidneys lose function. Over the years due to recurrent infections, the kidneys had been damaged. Now he is awaiting renal transplant.
All this could have been avoided, if a urinary infection had been suspected and a urine test was done. As the young children cannot complain of pain during urination and they pass urine into diapers, all that the parents can tell the doctor is that the child was cranky.
It is important to suspect urinary infection in any child with fever especially in the first few years of life. As seen the consequences of a missed urinary infections can be disastrous.

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