DR SIMON ATTARD MONTALTO
Urinary tract infection (UTI) is the most common bacterial infection of childhood, affecting 1-2% of school age children. The risk of UTI increases in girls and those with congenital anomalies, reflux and immunosuppression, and is due to E. Coli in 85% of cases. Classical symptoms of dysuria and frequency may be absent and children may be asymptomatic or present with fever without an obvious focus. Hence, a low threshold of suspicion must be maintained and appropriate urine samples collected for microscopy and culture. All confirmed cases below the age of 4 years are investigated with renal ultrasonography (US), micturating cystourethrogram (MCU) and renal isotope scanning (DMSA). Investigation may be less detailed in older children. UTI is treated with a 7 day course of trimethoprim or cephalosporin. Prophylactic trimethoprim or cotrimoxazole is administered whilst investigative results are pending, and in those with evidence of congenital anomalies on US, reflux on MCU or renal scarring on DMSA. Prophylaxis is usually continued, together with 3-4 monthly urine cultures, until the age of 4 years. The practice of prescribing antibiotics for presumed UTI before sending samples for culture may result in diagnostic confusion and potentially exposes the child to unnecessary investigation. Non-referral may result in missed diagnoses of underlying renal pathology including reflux nephropathy, a major cause of end stage renal failure in later life.
NOTES
1.4 per 1,000 newborns (M=F)
1-2% of schoolchildren (F>M)
increased risk in:
ureteric reflux
renal tract anomalies
immunosuppression
commonE. Coli (80%)Klebsiella speciesProteus
less common staph. saprophyticus pseudomonas viral agents
acute infection, cystitis, pyelonephritis
chronic infection, renal scars, fibrosis, tubular atrophy
sequelae, reflux nephropathy, renal failure, hypertension, secondary calculi
Ureteric reflux: grade:I to V
Infants asymptomatic, unexplained fever (8% UTI if >38.3C)dysuria, weight loss,
schoolchildren asymptomatic bacteruria, abdo pain, vomiting, jaundice, altered frequency
altered urine (cloudy, blood, smell), incontinence, bed wetting
Systemic none, rigors, poor perfusion, hypo/hypertension,
Local, none flank pain, perineal erythema, large kidneys
local symp/signs, chemical cystitis, vulvitis, local perineal infection,
other causes of abdo pain
generalised septicaemia
General: full blood count, urea, creatinine, electrolytes, blood culture
Specific Urinalysis: white cells, red cells, protein
Microscopy & culture:- bag<MSU<catheter<suprapubic sample
>105 single colonies/ml = >90% specificity
Ultrasound renal tracts: hydronephrosis, dilatation, calculi, abscesses
Micturating cystoureterography (MCU): after 3 weeks; reflux in 25%
DMSA scan: shows filling defects/renal scars
DTPA (or MAG3) scan: - dynamic scan showing differential renal uptake, function and obstruction
Others plain abdominal X-ray, IVU, CT scan: - rarely necessary
§ Antibiotics: 7-10 day course: oral cotrimoxazole or amoxycillin or nitrofurantoin or i.v cefotaxime plus gentamycin
§ Prophylaxis: oral, trimethoprim or septrin, for multiple UTI/recurrence, reflux, renal tract anomaly
§ Re culture urine: 1 week post infection; 3 monthly for 1-2 years
§ Catheterisation: those with residual volume, dysfunctional bladder
§ Surgery: reflux, dilatation, renal anomalies