Urinary Tract Infection

Question 1

What are the types of urinary tract infection

Answer 1

Cystitis (Lower UTI) = bladder and urethra
Pyelonephritis (upper UTI) = renal pelvis and kidneys

Question 2

What defines recurrent UTI

Answer 2

two or more episodes of UTI in 6 months or three or more episodes in one year

Question 3

What is the aetiology of UTI

Answer 3

Entry may be retrograde (ascension from urethra), via the blood stream, or direct i.e. catheter insertion
- E. Coli (70-95% of uncomplicated cases in females),
- Staphylococcus saprophyticus (5-20%)
- Enterobacteriaceae (Klebsiella)
- Enterococci
- group B streptococci
- Pseudomonas aeruginosa

Indwelling catheters: pseudomonas, Candida, resistant organisms
Worldwide: gram-negative strains (e.g., E coli, Enterobacteriaceae, Ps aeruginosa, or Acinetobacter genus infection)

Question 4

What are the risk factors for a UTI

Answer 4

Sexual activity
Spermicide use
Post-menopause - atrophic vaginitis, cystocoele, urinary incontinence
Positive family history of UTIs
History of recurrent UTIs
Presence of a foreign body e.g. catheter, stone, suture, surgical material
BPH
Urinary tract stones
Urological surgery or instrumentation
Urethral strictures
Catheterisation

Question 5

What is the epidemiology for UTIs

Answer 5

Lifetime incidence is 50-60% in adult women
20-30% of women who have had a UTI will have a recurrence
Prevalence of UTIs increases with age (Women aged 65 is approx. double the rate seen in the overall population)

Question 6

What are the symptoms of a urinary tract infection

Answer 6

Dysuria: Discomfort, pain, burning, tingling, stinging when passing urine
Urgency and frequency
New nocturia
Change in appearance (Cloudy urine or change in colour, Haematuria - red/brown discolouration or frank blood)
Suprapubic pain or tenderness, Flank pain
Incontinence
New or worsening delirium/debility
Loss of diabetic control
Malaise
Elderly: delirium, lethargy, reduced ability to carry out ADLs, anorexia
Pregnant: lower back pain, malaise, flu-like symptoms

Question 7

What are the symptoms and signs of pyelonephritis

Answer 7

UTI symptoms + fever, rigors, loin pain
Flank tenderness
Signs of sepsis/systemic illness

Question 8

What are the differentials for urinary tract infections

Answer 8

STIs e.g. chlamydia, gonorrhoea, herpes, candida
Atrophic vaginitis
Lichen sclerosis
Lichen planus
Urolithiasis
Psoriasis

Question 9

What are the signs of urinary tract infection on exam

Answer 9

Obs: fever, exclude systemic illness
Abdo: suprapubic tenderness

Question 10

What investigations should be done for urinary tract infection

Answer 10

Bedside:
- Urine dip: Nitrite + Leukocyte + RBC + (but unreliable >65 or catheterised)
- Urine sample for MC&S: >10^4 colony forming units/mL of pure growth
- urine pregnancy test

Bloods: FBC, WCC, CRP, blood cultures

other
- Renal USS: ?kidney stone, hydronephrosis, renal abscess, scarring
- Abdo/pelvic CT: ?kidney or bladder stone, renal abscess
- Post-void residual volume (for recurrent UTI)

Question 11

What does the white cell count and culture of a urine sample indicate

Answer 11

> 100 + e. coli: True UTI
100 + no growth: Patient may have taken antibiotics
10-50 + e. coli: Contamination
100 + mixed growth: Typical for catheterised patients

Question 12

Which patients require confirmation of UTI with urine MC&S

Answer 12

Pregnant women
Women >65
Symptoms do not resolve with treatment
Children
Recurrent/relapsing UTIs
Haematuria is present on the dipstick
Catheter in situ (Suprapubic tenderness or systemic symptoms → change catheter + antibiotics)
Male patients
Pyelonephritis

Question 13

What is the management for a UTI in women <65 with no catheter and no pregnancy

Answer 13

First line: Nitrofurantoin 100mg orally 2x daily for 3 days OR trimethoprim 200mg orally 2x daily
Second line: pivmecillinam

+ supportive: increase fluid intake, paracetamol/ibuprofen
+ safety net: symptoms worsen or significantly, fails to improve within 48h

Can prescribe a delayed (back-up) antibiotic if no improvement within 48 hours

Question 14

What is the management for a catheter UTI

Answer 14

1. Immediate antibiotics if severe - nitrofurantoin 100mg orally modified release 2x daily
2. Check catheter for blockage ± change or remove catheter
3. Supportive care and safety netting
   Pathogen targeted antibiotics after culture results

Question 15

What is the management for acute pyelonephritis

Answer 15

Cefalexin500mg BD or TDS (up to 1-1.5g TDS or QDS for severe infections) for 7-10 days
Co-amoxiclav(only if appropriate in line with culture and sensitivity results) 500/125 mg TDS for 7-10 days
Trimethoprim(if in line with culture and sensitivity results) 200mg BD for 14 days
Ciprofloxacin500 mg BD for 7 days- if penicillin allergy

Question 16

Why are pregnant women more likely to get UTIs in pregnancy

Answer 16

Increased urine stasis due to increased bladder volume and decreased detrusor tone
90% of pregnant women also develop ureteric dilatation
70% of pregnant women also develop glycosuria increasing risk of bacterial colonisation

Question 17

What proportion of pregnancies are complicated by a UTI

Answer 17

8%

Question 18

What is the management for UTIs in pregnancy

Answer 18

First line: PO nitrofurantoin 100mg BD 7 days (NOT at term)
Second line: PO amoxicillin 500mg TDS 7 days OR PO cefalexin 500mg BD 7 days

+ supportive: increase fluid intake, paracetamol
+ safety net: symptoms worsen or significantly, fails to improve within 48h
+ repeat MSU for MC&S once treatment is completed (if GBS identified → IV benpen intrapartum)
<12w→ can give trimethroprim

Question 19

What are the risks of medication for UTI in pregnancy

Answer 19

Nitrofurantoin: causes neonatal haemolysis at term
Trimethoprim: teratogenic before 12 weeks (folate antagonist)
NSAIDs: avoided (causes oligohydramnios, premature ductus arteriosus closure, maternal gastric mucosal ulceration and reduced renal perfusion)

Question 20

What are the complications of UTI

Answer 20

Sepsis
Ascending infection
- Renal and peri-anal abscess
- Acute Kidney injury
- Emphysematous pyelonephritis
- Xanthogranulomatous pyelonephritis
- Urosepsis
Renal failure
Pregnancy:
- Pyelonephritis (2%)
- Maternal morbidity
- Perinatal morbidity and mortality
- Premature delivery
- Low birthweight

Question 21

What is the prognosis for urinary tract infections

Answer 21

Prognosis for uncomplicated UTI is excellent
- Resolves within a few days - 3 days when treated, 5 days when not treated
- Unlikely to be long-term sequelae with appropriate antimicrobial treatment and resolution
- Recurrent infection occurs in 25-35% of women, within 3-6 months
Prognosis for complicated UTI is very good
UTIs and eradication may be more difficult
Indwelling catheters are associated with high risk of developing UTI. The risk exists as long as the catheter is in place. Catheters also increase the risk of bacteraemia. The prognosis remains poor, and recurrent infections are likely with chronic indwelling catheters.