Infection of the urinary tract is one of the most common bacterial infections of childhood.

It is important in young children as approximately half of children with a UTI will have a renal tract abnormality. If the infection ascends and develops to pyelonephritis this has further consequences, in a growing kidney it can cause scarring predisposing to hypertension and chronic renal failure (if bilateral) in later life.

Epidemiology

3% of girls and 1% of boys have a symptomatic UTI before the age of 11.

Before the age of one boys are affected more than girls. After one year of age this reverses and girls are more affected than boys.

50% will have a repeat UTI within a year

Infecting Organisms

The infecting organisms that cause a UTI usually come from the bowel - because of its close proximity bowel flora can easily enter the urinary tract.  The most common organism is therefore E. coli followed by Proteus and Pseudomonas.

The only exception is in the new born when it is caused by haematological spread.

Presentation

Infants under 3 months of age

  •  Fever/febrile convulsion
  •  Vomiting
  •  Lethargy and Irritabilitiy
  •  Poor feeding and failure to thrive
  •  Abdominal pain
  •  Jaundice
  •  Haematuria
  •  Offensive urine

Infants and children over 3 months of age

  •  Fever/febrile convulsion
  •  Frequency and Dysuria
  •  Abdominal pain and loin tenderness
  •  Vomiting and anorexia
  •  Dysfuntional voiding
  •  Haematuria
  •  Cloudy urine
  •  Reoccurance of enuresis

It is important when a diagnosis of UTI is made in a child to eliminate any risk factors that may have led to the UTI.

Incomplete bladder emptying - this may be due to any of the following:

  •  rushed micturition
  •  vulvitis
  •  infrequent voiding
  •  constipation causing obstruction
  •  neuropathic bladder

Vesicoureteric reflux- this is due to imcompetency of the the ureteric valves. When the bladder contracts urine is able to flow back up the ureters.

Diagnosis

Urine Collection Methods

  •  Clean catch sample - parent waits with a sample pot to catch a urine specimen
  •  Absorbent pad in the nappy
  •  Bag collection - an adhesive bag is attached to the perineum, skin contamination is assoiciated with this method.
  •  Suprapubic aspiration under ultrasound guidance.

 

In children under 3 years the specimen is always sent for microscopy and culture.

In children over 3 years dipstick testing is used first. If leukocyte and nitrite postive this is sufficent enough to diagnose a UTI. If it is a recurrent UTI the sample should be sent for microscopy and culture. If only either nitrites or leukocyte esterase are postive then the sample should be sent for microscopy and culture.

Acute Management of Upper and Lower UTI's

Antibiotic prophylaxis is not recommended after a first UTI. It is considered after recurrent UTIs or if a significant renal anomaly exsists.

Typical dose: Trimethoprim 2mg/kg at night

Follow Up

Ultrasound during acute infection if it is an atypical UTI in a child of any age OR in a child under the age of 6 months having a recurrent UTI.

Ultrasound within 6 weeks for recurrent UTI's

DMSA Scan 4-6 months after infection when the UTI is atypical or recurrent.

Micturating Urethrocystograms are only used to investigate children under 6 months with recurrent/atypical UTIs due the the uncomfortable and invasive nature of the test.

(A DMSA Scan will show up any renal scarring. It is done 4-6months later to give the kidney time to heal)

Atypical UTI

A child is said to have an atypical UTI when any of the following features are present:

  •  seriously ill
  •  palpable abdominal mass
  •  poor urine flow
  •  septicemia
  •  raised creatinine
  •  failure to respond to antibiotics within 48hrs
  •  infection not caused by E.coli

Recurrent UTI

2 or more episodes of an upper UTI

OR

1 episode of an upper UTI plus 1 or more episodes of a lower UTI

OR

3 or more episodes of a lower UTI.

Preventing Reccurance

  •  Encourage children who have had a UTI to drink adequate amounts of fluid.
  •  In children that have had a UTI give ready access to clean toilets. They should not be expected to delay micturition.
  •  Address causes of imcomplete voiding such as constipation/rushed micturition.

Further reading

Nice Clinical Guidelines CG54: Urinary Tract Infection in Children.

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