Urinary tract infection

Question 1

Common pathogens

Answer 1

Infecting Organism

UTI usually results from bowel flora entering the urinary tract via the urethra- although it can also be haematogenous e.g. in the newborn

MOST COMMON organisms:

1. Escherichia coli
2. Klebsiella
   * when there are stones, indwelling catheters
3. Proteus mirabilis
   * Predisposes to formation of phosphate stones by splitting urea to ammonia and thus alkalinising the urine
4. Pseudomonas
   * May indicate the presence of some structural abnormality in the urinary tract affecting drainage
   * More common in children with plastic catheters
5. Streptococcus faecalis
6. Enterococcus
7. Staph. epidermidis (indwelling catheter)

Question 2

Host factors that predispose to infection

Answer 2

Antenatally diagnosed renal or urinary tract abnormality

• Increases the risk of infection
• Investigation of a UTI may lead to urinary tract abnormality being detected if antenatal diagnosis was note made or missed to follow-up

Incomplete Bladder Emptying

• Infrequent voiding, resulting in bladder enlargement
• Vulvitis
• Incomplete micturition with residual postmicturition bladder volumes
• Obstruction by a loaded rectum from constipation
• Neuropathic bladder
• Vesicoureteric reflux

Question 3

Vesicoureteric reflux

Answer 3

The ureters are displaced laterally and enter DIRECTLY into the bladder (rather than at an angle)
* So more likely for urine to go back up into the ureters

It is familial (30-50% chance of occurrence in first-degree relatives)

It can occur with bladder pathology e.g. neuropathic bladder, urethral obstruction, after a UTI

Grades of VUR

• reflux into the ureter only, no dilation
• II- reflux into the renal pelvis on micturition, no dilation
• III- mild/ moderate dilation of the ureter, renal pelvis and calyces
• IV- dilation of the renal pelvis and calyces with moderate ureteral tortuosity
• V- gross dilation of the ureter, pelvis and calyces with ureteral tortuosity

The more severe forms of vesicoureteric reflux are associated with intrarenal reflux, which is the backflow of urine from the renal pelvis into the papillary collecting ducts

This is associated with a risk of renal scarring if UTIs occur

VUR tends to resolve with age, especially lower grade

Investigations

• Diagnosis- MCUG (micturating cystourethrogram)
• DMSA scan- may be performed to look for renal scarring

If bad but not bad enough for surgery, give prophylaxis AB

Question 4

Symptoms and signs

Answer 4

Infants
(non-specific symptoms)
* Fever, vomiting, lethargy or irritability
* Poor feeding/ faltering growth
* Jaundice
* Septicaemia
* Offensive urine
* Febrile seizure (> 6 months)

Children
(a bit more specific)
* Dysuria, frequency and urgency
* Abdominal pain or loin tenderness
* Fever +/- rigors (exaggerated shivering)
* Lethargy and anorexia
* Vomiting, diarrhoea
* Haematuria
* Offensive, cloudy urine
* Febrile seizure
* Recurrence of enuresis (bed wetting)

SIDE NOTE: constipation can make worse

NOTE: the classical symptoms of dysuria, frequency and loin pain become more common with increasing age

• Septicaemia can rapidly develop in infants

Dysuria ALONE is usually due to cystitis OR vulvitis (in girls) or balanitis (in uncircumcised boys)

Question 5

Symptoms and signs

Answer 5

Infants
(non-specific symptoms)
* Fever, vomiting, lethargy or irritability
* Poor feeding/ faltering growth
* Jaundice
* Septicaemia
* Offensive urine
* Febrile seizure (> 6 months)

Children
(a bit more specific)
* Dysuria, frequency and urgency
* Abdominal pain or loin tenderness
* Fever +/- rigors (exaggerated shivering)
* Lethargy and anorexia
* Vomiting, diarrhoea
* Haematuria
* Offensive, cloudy urine
* Febrile seizure
* Recurrence of enuresis (bed wetting)

SIDE NOTE: constipation can make worse

NOTE: the classical symptoms of dysuria, frequency and loin pain become more common with increasing age

• Septicaemia can rapidly develop in infants

Dysuria ALONE is usually due to cystitis OR vulvitis (in girls) or balanitis (in uncircumcised boys)

Features of pyelonephritis:

• Bacteriuria + fever > 38oC
• Bacteriuria + loin pain/ tenderness

**Features of cystitis/ lower UTI: Dysuria but NO systemic symptoms **

Question 6

Investigations

Answer 6

In infants: DDx meningitis, encephalits, viral URTI, pneumonia

Urine dipstick – used for ≥ 3 months- 3 years with suspected UTI

If both leukocyte esterase + nitrite NEGATIVE -> don’t culture unless:

• Suspected pyelonephritis
• Recurrent UTI
• Doesn’t respond to antibiotics within 24-48 hours
• Clinical symptoms and dipstick tests do not correlate

If both nitrite and/or leukocyte esterase POSITIVE -> send urine culture + start antibiotics

Urine MC&S

Urine should be sent for culture in:

• Infants and children with suspected UPPER urinary tract infection
• Infants and children with a high-intermediate risk of serious illness
• Infants < 3 months
• Infants and children with a positive result for either leukocyte esterase OR nitrites
• Infants and children with recurrent UTIs
• Infants and children with an infection that does NOT respond to treatment within 24-48 hours
• When clinical symptoms and urine dipstick do NOT correlate

Question 7

Management

Answer 7

<3m -> admit to hospital, IV ABx, 5-7 days, then switched to oral prophylaxis -> refer to paediatrician
* 1st Line: IV Co-amoxiclav for at least 5-7 days
* EMERGENCY
* Urgent USS should be booked (4-6w)

.
>3m, upper UTI -> consider hospital admission

• If urine dipstick is positive for either leukocyte esterase OR nitrites, send a urine sample for culture and start antibiotic therapy
• 1st Line: PO Cefalexin for 7-10 days
• IV Co-amoxiclav (if PO not feasible e.g. vomiting)
  * If IV: usually for 2-4 days, followed by PO antibiotics for 7-10 days
• Other options: Cephalexin, Ceftriaxone, Ciprofloxacin or ampicillin + gentamycin
• If <6m old when they have their first UTI, an urgent USS should be booked (4-6w)

.>3m, lower UTI -> oral ABx (local guidelines; i.e. trimethoprim, nitrofurantoin)

SAFETY NET: parents should bring the child back if they remain unwell after 48 hours (may be atypical)

o Recurrent UTI -> antibiotic prophylaxis, USS (during admission if <6m; urgent if >6m) and DMSA scan (routine)

IMPORTANT: the choice of antibiotic will depend on sensitivities- CHECK LOCAL GUIDELINES

DMSA scan

• Done 4-6 months after infection
• Detects renal parenchymal defects e.g. renal scarring
• NOTE: functional scans (e.g. DMSA) should be deferred unless the USS is suggestive of obstruction, to avoid missing a new scare and because false-positive results may be produced due to transient inflammation

MCUG scan (invasive)

• Looks for VUR and posterior urethral valves
• When MCUG is performed, prophylactic antibiotics should be given PO for 3 days with MCUG taking place on the 2nd day
• NOTE: in toilet trained children, USS should be performed with a full bladder with an estimate of bladder volume before and after micturition

Question 8

Advise

Answer 8

Seek medical attention if the child is still unwell for 24-48 hours of antibiotic treatment

• You are treating for E.coli so if they don’t respond to AB, you are thinking it may be non-E.coli (atypical)

Encourage adequate fluid intake

Regular voiding

Ensure bladder is completely empty

Good perineal hygiene

Treatment/ prevention of constipation (remember with that 8 y/o kid with UTI and constipation)

Advise use of paracetamol for pain relief where required

Question 9

Complications/ Prognosis

Answer 9

Complications

• Renal scarring/ damage
• Hypertension
• Renal insufficiency and failure
• Increased risk of bacteriuria and hypertension in pregnancy; pre-eclampsia when grow up

Prognosis

• Overall, good
• Progression to renal dysfunction is likely in those with urinary tract comorbidity
• Girls > boys for recurrent UTI
• Mild VUR usually resolves spontaneously

Question 10

PACES

Answer 10

Name of diagnosis
*  Anand has had something called a urine infection

Have you heard of this before?
Briefly explain what it is:

• A urine infection happens when bacteria (or germs) get into the urine
• This leads to babies feeling unwell with a fever, feeding less and can
  cause smelly urine

How is it managed:

• I would like to give Anand some antibiotics which he will need to take for a week
• This should clear the infection but it’s important to finish the whole course of antibiotics
• Please make sure you feed him regularly and keep him well hydrated
• You can give him some Calpol to help with the fever

Risks/Safety net:

• There is a risk that the antibiotics might not be enough to clear the infection, in which case we will need to give Anand different antibiotics through a drip at the hospital
• Please take Anand to A&E if he is still unwell after 2 days antibiotics. For example:
• Persistent fever > 38 degrees
• Starts vomiting
• Drowsy
• Feeding less than half

Leaflets/ Offer more info