Dr. Kumud Mehta.
Consultant Pediatrician & Pediatric Nephrologist.
Jaslok Hospital & Research Centre.
Bai Jerbai Wadia Hospital for children.
Q.1) What is UTI?
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A.1) Urinary tract infection is a bacterial invasion of kidneys and the urinary tract. It is designated as pyelonephritis or upper UTI when the infection involves mainly renal parenchyma and pelvicalyceal system. Lower UTI involves infection of urinary bladder and urethra.
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Q.2) What are the causes of UTI?
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A.2) UTI is predominantly caused by enterococci like certain strains of E.Coli and other gram negative bacilli such as Proteus, Klebsiella, and Pseudomonas, which are uropathogenic. It is rarely caused by tubercular bacilli.
In children below the age of 3-4 years, UTI is associated with underlying congenital anomalies such as posterior urethral valves, PUJ obstruction, vesicoureteral reflux (VUR), bladder diverticuli or ureteroceles etc.
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Q3.) How does the child present?
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A.3) The clinical manifestations of UTI are non-specific and general. At younger age i.e. in new-borns and infants - fever, failure to thrive, vomiting or diarrhoea, convulsions, jaundice predominate, hence UTI can be missed at the early stage, when it is important to diagnose.
In older children above the age of 4-5 years, UTI manifests with fever, pain in abdomen especially loin pain, vomiting with urinary symptoms such as frequency, urgency, dysuria, painful micturition and foul smelling urine. The fever can be associated with chills and recurs frequently. When the UTI is recurrent there is failure to thrive, anaemia, listlessness and general malaise.
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Q.4) How do you diagnose UTI?
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A.4) The gold standard for diagnosis of UTI is: Urine culture, colony count and antibiotic sensitivity report in a clinical setting of UTI. The collection of urine under sterile conditions is an important point to remember. In very young infants, suprapubic bladder aspiration and in females or infants, use of urinary collection bags may be needed.
In older children midstream clean catch collection of urine in a sterile container and sending it within an hour or two to the lab are important points to get an accurate diagnosis of UTI. Presence of pus cells (more than 10/HPF in males and 25/hpf in female children) and gram staining of fresh sample of urine for Gram -ve bacilli support the diagnosis of UTI. 50% of cases of UTI may not have pyuria.
There are chemical tests like a) leukocyte esterase test and b) nitrite test, which can be used as screening test for UTI but the gold standard, is urine culture even in these children.
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Q5.) How do you investigate a child with UTI?
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A.5) Since there is a high incidence of congenital obstructive and non-obstructive malformations of kidney and urinary tract in 50-75% of infants with UTI, early diagnosis of these malformations is useful in preventing permanent kidney damage which occurs if congenital defects + UTI combine. Hence every child with UTI below the age of 3 years should be investigated as follows:
1) USG of kidneys, pelvicalyceal system, ureter and urinary bladder to detect dilatation (hydronephrosis, hydroureter, distended bladder and residual urine) which denotes either obstruction in subvesical region or VU reflux.
To detect the site of obstruction (like PU valves) or reflux, MCU should be performed in every child below the age of 2-3 years with UTI. It is done 3-6 weeks after the acute episode is over. Above the age of 3 years, MCU is indicated in those children with abnormal USG findings or renal scars detected on Tc DMSA renal scan which is the 3rd imaging test in a child with UTI. DMSA renal scan is ideally done 3-6 months after the acute episode is over. The aim of Tc99 DMSA renal scan is to detect acute infection of kidney and subsequently after 3-6 months of pyelonephritis to detect permanent renal scars.
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Q6) What is the treatment of UTI?
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A.6) Treatment of UTI is early institution of appropriate drug according to the antibiotic sensitivity report for a duration of 7-10 days. In sick children especially neonates and infants, intravenous antibiotics are required even before the culture report is available. The recommendation is to use Ampicillin and Gentamicin. This is the treatment given for sepsis. Delay of more than 72 hrs in starting the antibiotic can result in permanent renal damage. A 2nd urine culture after 3-5 days of antibiotic therapy should be sterile while the clinical features such as fever resolves within 2-3 days; raised ESR and CRP resolve over 2-3 weeks.
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Q.7) How do you prevent a recurrence? What precautions, monitoring is required? How do you treat a recurrence?
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A.7) The best way to prevent recurrence of UTI is to treat the first infection thoroughly as mentioned above and to detect underlying lesions that may require surgical corrections. Long term chemoprophylaxis using a single night dose of appropriate drug like cotrimaxazole or Furadantin or Nalidixic acid at 1/3rd dose prevents recurrent UTI in children with VUR or recurrent cystitis or in those in whom UTI follows urologic procedures.
Good perineal hygiene, treatment of threadworms, treatment of constipation, high fluid intake and toilet training for voiding periodically every 2-3 hours are some of the measures which help to prevent recurrent UTI. Monitoring for UTI includes periodic urine cultures initially every monthly and if cultures are negative in the first 3 months, regularly every 3 months or whenever there is fever without focus of infection.
The choice of drug for recurrent UTI depends on the culture and antibiotic sensitivity. Pyelonephritis is treated for 7-10 days while Lower UTI i.e. cystitis may be treated for 3-5 days followed by long term drug therapies mentioned above. On an average, 2-3 years of treatment is required for VUR and 6 months to 1-year treatment for post-urologic operations or procedures.
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Q.8) How do you manage a high risk UTI?
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A.8) A high risk UTI is the one, which can cause permanent renal scars. The long term consequences of recurrent pyelonephritis can be multiple bilateral renal scars resulting in end stage renal disease requiring renal transplant or hypertension in young adulthood. In young females, the risk of toxaemia of pregnancy is high in those who suffered from recurrent UTI in school age. Because of these long-term complications it is mandatory to follow every infant with UTI, both males and females and every school age girl with recurrent UTI for a minimum of 20-25 years.
Management of high risk UTI consists of monitoring growth, BP recording, renal function tests, size of the kidneys by USG and periodic urine cultures.
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Q.9) What are the complications of UTI, both short term and long term?
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A.9) Long term complications mentioned above. Short-term complications are progression to septicaemia in newborns and in those inadequately treated can result in recurrence.
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Q.10) Is urine culture or urine routine & microscopy more valuable for diagnosing UTI? If urine culture, then by what method should it be collected.
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A.10) For diagnosis of UTI, urine culture is the gold standard. While waiting for urine culture report, gram staining of fresh sample of urine for gm-ve bacilli may be useful in starting the treatment for UTI.
Innumerable pus cells can be treated as UTI but less than 10/hpf in males and 25/hpf in female children should not be treated as UTI, otherwise resistant strains of organisms may emerge.
Significant bacteriuria i.e. colony count of 105 or more of a pure growth of E.Coli or any other uropathogen is diagnostic of UTI with clinical manifestations. Sterile pyuria requires investigations for diagnosis of TB or fungal infections resulting in UTI. Fungal UTI is associated with Nephrotic Syndrome, chemotherapy, SLE or following urologic procedures/ operations.
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Q.11) What advice do you give the parents?
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A.11) The parents should be educated as regards the perineal hygiene especially use of diapers, cleaning the perineal region with water (not to use any antiseptics) and to toilet train the children at the age of 2-3 years, to give plenty of fluids and inculcate good habits of voiding every 3-4 hourly to prevent residual urine. These are some of the simple measures for prevention of recurrent UTI.
Children with constipation should be advised high fibre containing food and increased intake of fluids along with use of mild laxatives or suppositories because constipation is associated with recurrent UTI.
Recurrent diarrhoea can cause UTI due to the same organism because of the proximity of the rectum and the urethra.
Use of antibiotics for diarrhoea can result in resistant strains of organisms leading to recurrent UTI and since mostly the diarrhoeas are viral in origin, antibiotics should not be used indiscriminately for acute diarrhoeas of infants.
Compliance as regards the use of long term use of single night dose of cotrimaxozole or Furandantin should be observed closely by parents to prevent recurrences.
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Last created on 08-12-2000
Last updated on 01-07-2006
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