Evaluation of the Infant or Child with Urinary Tract Infection (UTI)

You have been referred to a pediatric nephrologist, a pediatrician who has sub-specialized in the evaluation and management of medical conditions of the urinary tract, such as UTI.  Sometimes, the services of a pediatric urologist (a specialist in the surgical conditions of the urinary tract in children) are also required, depending upon the results of the UTI evaluation.

The urinary tract consists of the two kidneys which make urine, each drained by tubes called ureters which drain the urine into the bladder, where it is stored until it leaves the bladder through the urethra in the act of urination (voiding). In the male, the urethra opens at the tip of the penis; in the female, just above the vaginal opening.

While infections of the respiratory tract (the “common cold,” ear infection, or sore throat) are very common during childhood, UTI is NOT a routine pediatric condition.  If untreated, UTI can cause permanent kidney damage.

The symptoms of UTI can be any one or more of the following, depending upon the age of the child:

• fever
• abdominal, flank, or back pain
• irritability
• nausea, vomiting, or diarrhea
• bad odor or cloudy urine
• painful or frequent urination
• wetting “accidents”

The diagnosis is made by testing the urine for bacteria (culture); this takes at least 24-48 hours.  Although sometimes examining the urine under a microscope can suggest UTI, the urine must be cultured (like a throat culture for strep) for proper diagnosis. Fortunately, UTI usually responds very quickly to antibiotics, and the patient is much better within a day or two. However, it is very important to determine why your child developed UTI, as frequently there is a specific reason which can be diagnosed (see below).  If this condition is ignored, UTI is very likely to happen again and again, with the risk of permanent kidney damage.

There are 4 main conditions that are likely to be associated with UTI

1. REFLUX: 

Normally, the ureter(s) drain urine into the bladder so that bladder urine can’t go back up the ureter and into the kidney(s).  If the valve between the ureter and bladder is not working right, usually as a result of a birth defect, germs (bacteria) which find their way into the bladder from the urethra can get up to the kidney(s) and cause infection, usually with high fever and the risk of permanent kidney damage.  Reflux is present in about one third of children with UTI; it may affect both sides of the urinary tract, and can range from mild to severe. A sonogram (ultrasound) cannot diagnose reflux.  The diagnosis is made by a bladder X-ray test called a voiding cysto-urethrogram (VCU or VCUG). The radiologist inserts a thin plastic tube (catheter) into the urethra; the catheter then enters the bladder. The radiologist slowly fills the bladder with X-ray dye (plain urine can’t be seen by X-ray). If there is no reflux, the dye stays in the bladder, as it should, until the bladder is full and child urinates it out.  If reflux is present, the dye is seen (by X-ray) to go up to one or both kidneys. The test takes 30-45 minutes. Young children have to be restrained, so that the proper X-ray pictures can be taken. A parent, wearing a protectiv e l ead apron, can be present with the child during the test.  Your pediatric nephrologist will discuss the test results with you, and recommend a treatment plan (usually either antibiotic prophylaxis until reflux disappears on its own or surgery) depending upon your child’s age, severity of reflux, and history of UTI.

2. HYDRONEPHROSIS:

This term refers to a number of conditions that interfere with the drainage of urine from the kidney(s) down the ureter(s), to the bladder, to the urethra.  The primary diagnostic test is a sonogram (ultrasound); a normal test usually excludes these conditions, but does not exclude reflux. If hydronephrosis is not due to reflux, other X-ray type tests may be necessary, such as the IVP or kidney “scan.” Both involve the intra-venous (IV) injection of either X-ray dye or a tiny amount of radioactivity, respectively. Both tests show how well each kidney is working, and how fast urine drains from the kidneys down the ureters into the bladder. Depending upon the results of these tests, sometimes the drainage is so poor that a surgical procedure is necessary to fix it.

3. VOIDING DYSFUNCTION:

This term describes children whose bladder does not function normally. Normally, the bladder stores urine until it is full; then a signal is sent from the nerves and muscles of the bladder, through the spinal cord to the brain, that tells us it is time to empty the our bladder (void).  Some children don’t know when their bladder is full, and thus void infrequently. Others get the signal of bladder fullness too late; if a toilet is not immediately available, they may wet themselves.  Still others have a bladder that thinks it’s full before it is, and contractions of the bladder muscle can make the child feel pain, wet themselves, or assume postures to prevent wetting. Such children are often difficult to toilet train and have frequent “accidents”, in addition to UTIs.  Parents sometimes think that they are “lazy,” but it is not their fault. These conditions can be diagnosed, and usually treated successfully with a combination of voiding by the clock (timed or scheduled voiding), behavior therapy, prophylactic antibiotics to prevent recurrences of UTI &/or bladder medications. Treatment of co-existing constipation is also important.

4. UNCIRCUMCISED INFANT BOYS: 

If urine is collected in a plastic bag from your uncircumcised boy baby, it is likely to be contaminated with bacteria that normally live under the foreskin. Only a catheterized urine specimen should be interpreted to diagnose UTI.  If the ultrasound of the baby’s kidney and bladder as well as the VCUG is normal, it is reasonable to assume that the UTI is due to bacteria from under the foreskin.  This is NOT a reason to have your baby circumcised.  It is uncommon for UTI to happen more than once and we simply advised that the baby’s urine be cultured (from a catheterized urine specimen) whenever there is an illness with fever that has no alternative source, such as a cold or ear infection.

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Regardless of the cause of UTI, the risk of recurrences can be reduced by:

• avoidance of constipation (a full rectum can interfere with bladder emptying)
• drinking a lot so that the child makes lots of urine, and empties the bladder frequently
• culturing the urine regularly to detect infection before the child becomes ill
• culturing the urine at the slightest sign that the child is unwell, especially fever
• if you doctor prescribes prophylactic antibiotics, make sure your child never misses a dose, even though they are well.  Prophylaxis means prevention !

Make sure that you don’t forget to keep follow-up appointments for tests (sonograms, X-rays, urine cultures, etc.).  Your doctor has many, many patients; you have only one child with UTI. You help your child and your child’s doctor by playing an active role in their management.