Urinary Tract Infections

Microbiology

Enteric bacteria like Escherichia coli, other gram-negative organisms (P. aeruginosa, P. mirabilis, and Enterobacter) or Enterococcus
if underlying genitourinary abnormalities including Klebsiella spp, Enterobacter spp, and Pseudomonas aeruginosa

History and Examination

Consider UTI in an infant or child presenting with the following symptoms and signs:

Age <3 months:
- most common: Fever, Vomiting, Lethargy, Irritability, Poor feeding, Failure to thrive
- least common: Abdominal pain, Jaundice, Haematuria, Offensive urine
Age >3 months or older (preverbal):
- most common: Fever, Chillls, Abdominal pain, Loin tenderness, Vomiting, Poor feeding, Enuresis
- least common: Lethargy, Irritability, Haematuria, Offensive urine, Failure to thrive
Age >3 month or older (verbal):
- most common: Frequency, Dysuria, Dysfunctional voiding, Enuresis, Abdominal pain, Loin tenderness
- least common: Fever, Malaise, Vomiting, Haematuria, Cloudy urine

Remember

Older child with fever, flank pain and systemic problems suggest upper tract infection (e.g. pyelonephritis)
Neonates process to urosepsis rapidly

Important points in history

Chronic urinary symptoms (e.g. incontinence, poor stream, frequency, urgency, withholding maneuvers)
history suggesting previous UTI or confirmed previous UTI
(recurrent) fever of uncertain origin (suggesting upper UTI)
(family history of) vesicoureteric reflux (VUR) or renal disease), nephrolithiasis, neurogenic bladder in spinal lesions
chronic constipation
poor growth
high blood pressure
bladder catheter
sickle cell disease
Immunodeficiency, e.g. diabetes mellitus

Important points on examination

Temperature suggests upper UTI
Blood pressure as early sign of chronic kidney disease
Growth parameters (poor weight gain as indication of chronic or recurrent UTI)
Abdominal mass (eg, enlarged bladder or kidney, suggestive of anatomic abnormality)
Assessment of suprapubic tenderness (lower UTI), and costovertebral angle tenderness
genitalia abnormalities (phimosis or labial adhesions), signs of differential diagnosis (eg, vulvovaginitis, vaginal foreign body, sexually transmitted diseases)

Diagnosis

Try to get a clean catch sample of urine, preferable midstream
In sick infants in-out catheter or supra-pubic aspiration of urine may be required.
Dipstick the urine with a disptick that tests for both leucocyte esterase and nitrites. Use the table below to interpret results.
Alternatively carry out microscopy of a clean, fresh, uncentrifuged specimen of urine. In UTI >10 white cells per high-power field are present
If upper UTI with positive dipstick send urine for culture: submit a fresh sample before 10 am to the main lab. Significant bacteriuria
- midstream (clean catch) >100,000 CFU/mL
- catheterized samples > 50,000 CFU/mL
if severly sick, or poor urine output creatinine and urea

Interpretation of dipstick results

Leucocyte esterase	Nitrites	Interpretation and action
Positive	Positive	UTI Start antibtiotic treatment for UTI
Negative	Positive	Likely UTI Start antibiotic treatment for UTI if fresh sample was tested
Positive	Negative	Unlikely UTI If possible obtain urine microscopy Only start antibiotic treatment for UTI if there is good evidence of UTI Result may indicate infection elsewhere
Negative	Negative	Very unlikely UTI Do not start treatment for UTI Explore other causes of illness

Interpretation of dipstick results is less valid in younger children, especially infants, often false negative test

Complication

Ascending infection - pyelonephritis, urosepsis
scars in renal parenchym leading to hypertension and/or chronic kidney injury

Differential diagnossis

Schistosomiasis: Hematuria and cystitis in otherwise healthy children
Nephrolithiasis
Urethral strictures
interstitial nephritis
Neoplasms, such as neuroblastoma, or Wilms tumor
Vulvovaginitis
vaginal foreign body
sexually transmitted diseases

Admission criteria

Age <3 months
signs of systemic illness (fever >38 C, rigors or renal angle tenderness) especially if clinical in urosepsis (eg, toxic appearance, hypotension, poor capillary refill)
Immunocompromised patient
Vomiting or inability to tolerate oral medication
Failure to respond to outpatient therapy

Treatment

<3 months

Gentamicin and Benzylpenicillin
Or Ceftriaxone
Blood culture and LP if febrile

3 months or older and has signs of systemic illness

Gentamicin and Benzylpenicillin
Or Ceftriaxone
Change to oral antibiotic when fever settled and improving - to complete 10 days treatment

>3 months or older with no signs of systemic illness

Treat with oral antibiotics as outpatient
- 1st choice: Cotrimozazol for 3 days
- 2nd choice: Ciprofloxacin (if older than 1) or Nitrofurantoin for 5 days
If the child is still unwell after 24-48 hours reassess
If poor response or condition deteriorates admit

Supportive care

The child should be encouraged to drink or breastfeed regularly in order to maintain a good fluid intake, which will assist in clearing the infection and prevent dehydration.

Further investigations and Follow-up

Children with the following require further investigations:

Atypical UTI
- Seriously ill
- Poor urine flow
- Abdominal or bladder mass
- Raised creatinine (if measured)
- Septicaemia
- Failure to respond to treatment with suitable antibiotics within 48 hours
Recurrent UTI
- Two or more episodes of UTI with acute pyelonephritis/upper urinary tract infection
- One episode of UTI with acute pyleonephritis/upper urinary tract infection plus one more episode of UTI with cystitis/lower urinary tract infection
- Three or more episodes of UTI with cystitis/lower urinary tract infection
All males >1 year of age with UTI

Investigations:

renal tract ultrasound scan to look for structural abnormalities
Check for possiblility of arrangement for cystourethrogram to look for underlying structural abnormalities i.e.
- vesicoureteric reflux
- obstruction - posterior urethral valve (boys only, consider in male neonates), pelviureteric junction (PUJ) or vesico-ureteric junction (VUJ) obstruction
Consider X-ray to look for renal stones and calcification secondary to schistosomal bladder.

All children who have had a UTI should be advised to get their urine checked if they become unwell.

Children with abnormalities should be followed up in General Clinic - Wednesday 1:30pm.

Prophylactic treatment if

frequent recurrent UTIs (three febrile UTIs in six months or four total UTIs in one year
structural anomaly (than also refer to surgeons.)

Either Cotrim 2 mg TMP/kg as a single daily dose or Nitrofurantoin 1 to 2 mg/kg as a single daily dose for six months, than reasses