Further Imaging
Imaging is typically indicated for one of two reasons. Firstly, atypical infection may suggest obstruction that requires urgent intervention. Secondly, UTIs may arise from structural abnormalities such as vesicoureteric reflux (VUR), or cause renal scarring leading to renal dysfunction. [8]
Ultrasound is the first line imaging of choice. It is relatively easily accessible, non-ionising, non-invasive and can detect most anatomical abnormalities and hydronephrosis suggestive of obstruction or VUR.
Dimercaptosuccinic Acid (DMSA) scans are a nuclear isotope uptake scan. Reduced renal uptake can represent acute infection or longterm scarring.
Voiding Cystourethrograms (VCUG) use fluoroscopy where contrast is injected into the bladder via a catheter. It is the gold standard for assessing bladder function and ureteric reflux, but is resource and radiation intensive.
The full NICE guidance for imaging can be found here, however it is a key point for EM clinicians is to recognise those children that will require ultrasound imaging during the acute infection, thus requiring admission. These are [1]:
Any infant/child with an atypical infection, suggested by:
- Seriously ill
- Poor urine flow
- Abdominal or bladder mass
- Raised creatinine
- Sepsis
- Failure to respond to treatment with suitable antibiotics within 48hours
- Infection with non-E. coli organisms
Any infant <6 months old with recurrent UTI
- 2 or more episodes of UTI with acute pyelonephritis/upper urinary tract infection
- 1 episode of UTI with acute pyelonephritis/upper urinary tract infection plus one or more episode of UTI with cystitis/lower urinary tract infection
- 3 or more episodes of UTI with cystitis/lower urinary tract infection
If none of these apply, but the child is;
- Under 6 months old or
- Has an atypical UTI or
- Has recurrent UTIs
Then they are likely to need follow up outpatient imaging. If discharging these patients from ED, it is important to ensure they have appropriate follow up arranged.