Urinary tract infections
Terms Cystitis Pyelonephritis
Vesicoureteric reflux Male/ female
Any anatomical abnormality of the tract, eg tumour, scaring
Enlarged prostate Stasis
Catheters and instrumentation Stones - bacteria get into the stones
Glucosuria Start of sexual activity in women
Haematogenic infections are also possible
Coliform infection - Escherichia coli, Streptococcus faecalis, Proteus, Pseudomonas
Lower tract infection - detection of pus cells, detection of nitrite
Prevent contamination of MSU by preventing contact with adjacent tissues
EMU to look for TB MSU for C and S
Isotope studies Cystoscopy
Bacterial infection of the urothelial surface
Interstitial cystitis may develop in the bladder wall with clear cultures - mostly in middle aged
Asymptomatic bacteriuria occur in 5 - 10% of women and is probably caused by sex
Clinical features Blood and pus in urine
Cystitis frequency, dysuria, urgency
Acute Pyelonephritis loin pain, fever, malaise, usually bilateral
The end result of chronic infection often from childhood
Small, distorted asymmetrical kidneys Loin pain and tenderness
Possible hypertension Question about intake of NSAIDs
Culture, antibiotics, creatinine clearance tests
Adequate fluid intake Ensure bladder is fully emptied Empty bladder after sex
UTIs are common in pregnancy May ascend to the kidneys leading to premature delivery
Should be screened for bacteria in urine at first prenatal visit and given antibiotics if indicated
2% of boys and 8% of girls develop UTIs in childhood
Reflux may cause UTI
Vesicoureteric reflux present in 8 - 40% of cases
Renal scaring may develop
Always culture if any suspicion of UTI
Refer all children with UTI for investigations
High fluid intake Antibiotics Prophylactic antibiotics Surgery
UTI is defined by the presence of a pure growth of more than 105 colony forming units of bacteria per ml. Lower counts of bacteria may be clinically important, especially in boys and in specimens obtained by urinary catheter. Any growth of typical urinary pathogens is considered clinically important if obtained by suprapubic aspiration. In practice, three age ranges are usually considered on the basis of differential risk and different approaches to management: children under 1 year; young children (1–4, 5, or 7 years, depending on the information source); and older children (up to 12–16 years). Recurrent UTI is defined as a further infection by a new organism. Relapsing UTI is defined as a further infection with the same organism.
Boys are more susceptible before the age of 3 months; thereafter the incidence is substantially higher in girls. Estimates of the true incidence of UTI depend on rates of diagnosis and investigation. At least 8% of girls and 2% of boys will have a UTI in childhood.
The normal urinary tract is sterile. Contamination by bowel flora may result in urinary infection if a virulent organism is involved or if the child is immunosuppressed. In neonates, infection may originate from other sources. Escherichia coli accounts for about three quarters of all pathogens. Proteus is more common in boys (about 30% of infections). Obstructive anomalies are found in 0–4% and vesicoureteric reflux in 8–40% of children being investigated for their first UTI. Although vesicoureteric reflux is a major risk factor for adverse outcome, other as yet unidentified triggers may also need to be present.
first infection, about half of girls have a further infection in the first year
and three quarters within 2 years. We found no figures for boys, but a review
suggests that recurrences are common under 1 year of
age but rare subsequently. Renal scarring occurs in 5–15% of children within
1–2 years of their first UTI, although 32–70% of these scars are noted at the
time of initial assessment. The incidence of renal scarring rises with each
episode of infection in childhood. An RCT comparing oral versus intravenous
antibiotics found retrospectively that new renal scarring after a first UTI was
more common in children with vesicoureteric reflux than in children without
reflux (logistic regression model: AR of scarring 16/107 [15.0%] with reflux v
10/165 [6%] without reflux; RR 2.47, 95% CI 1.17 to 5.24). A study (287
children with severe vesicoureteral reflux treated
either medically or surgically for any UTI) evaluated the risk of renal scarring
with serial DMSA
scintigraphy over 5 years. It found that younger children (under 2 years) were at greater risk of renal scarring than older children regardless of treatment allocation for the infection (AR for deterioration in DMSA scan over 5 years 21/86 for younger children v 27/201 for older children; RR 1.82, 95% CI 1.09 to 3.03). Renal scarring is associated with future complications: poor renal growth; recurrent adult pyelonephritis; impaired glomerular function; early hypertension; and end stage renal failure. A combination of recurrent urinary infection, severe vesicoureteric reflux, and the presence of renal scarring at first presentation is associated with the worst prognosis.
To relieve acute symptoms; to eliminate infection; and to prevent recurrence, renal damage, and long term complications.
Short term: clinical symptoms and signs (dysuria, frequency, fever); urine culture; incidence of new renal scars. Long term: incidence of recurrent infection; prevalence of renal scarring; renal size and growth; renal function; prevalence of hypertension and renal failure.
UTIs in children
Vesicoureteric reflux is most common
Some forms of E. coli may adhere to the urinary endothelium so are not easily washed out
In neonates this is non-specific, e.g. poor feeding, vomiting, irratibility
May develop into sepsis with meningitis
In young children presentation may include fever, irritability, diarrhoea, vomiting.
Features may look like a GI rather than a GU problem.
Frequency and dysuria are not reliable symptoms.
May or may not be suprapubic or loin tenderness.
School age children
More classical adult type presentation
Inflammatory features around the urethral orifice
Microscopy and culture and sensitivity testing
Ward based tests for blood, protein, white cells and nitrite are indicative
Collect a clean specamine
Suprapubic samples being the most reliable, used under 1 year, best taken when the bladder is full
In young children i.v. antibiotics to reduce the risk of disseminated infection
While waiting for sensitivity consider trimethoprim, cephalosporins, amoxicillin with clavulinic acid
Repeat C and S at the end of the antibiotic course to confirm resolution
Follow-up investigations of the urinary tract such isotope scanning, ultrasound scanning
Renal scaring (reflux nephropathy) is most likely in the first 5 years of life, the younger the child the more sensitive the kidneys
Scaring may lead to chronic renal insufficiency and hypertension
Over the age of 5 pre-existing renal scars may enlarge with repeated infection but new scars rarely occur.
Recurrent infections over the age of 5 do not cause renal scar formation
If there is vesicoureteric reflex put the child on prophylactic antibiotics for at least 2 years, probably more, consider trimethoprim or nitrofurantoin, once at night
Treat acute infections promptly
Surgical re implantation of the ureters may be considered in extreme cases
Vesicoureteric reflex usually resolves with a rate of about 10% per year
Other causes of UTI
Other causes of infection below the age of 5 years may also lead to renal scaring,
Therefore children must be well investigated after UTIs
Remember chronic pyelonephritis is a common indication of renal dialysis in later life and almost certainly has its origins before the age of 5 years.
Haemolytic uraemic syndrome (HUS)
Intravascular haemolysis with red cell fragmentation (microangiopathic haemolysis).
Acute renal failure caused by thrombosis in small arteries and arterioles.
Microthrombi occlude small renal vessels.
Microthrombi may also occlude cerebral vessels leading to RICP with reduced GCS.
Usually Escherichia coli, usually 0157 which produce verocytotoxin.
Usually starts with a febrile illness, often with gastroenteritis, known as diarrhoea associated HUS, (D+HUS).
HUS develops after the febrile episode.
Most patients recover renal function.
Acute mortality is 5%.
5% develop chronic renal failure.
30% exhibit long term renal damage with persistent proteinuria.
Prevent cross infection.
Supportive therapy until renal function recovers.
Fluid end electrolyte balance, antihypertensive medication, nutritional support, probably dialysis.
If antibiotic or antimotility drugs are used to treat the diarrhoea there is a greater risk HUS and its complications.
Recurrent episodes have been described in the same individual.
Other forms of HUS
D-HUS HUS without diarrhoea may have a genetic aetiology and be a complement driven illness.
Sporadic cases may also present secondary to pregnancy or other disease processes.
Pneumococcus-assocaited HUS is a rare complication of Streptococcus pneumoniae infection.