T4-L5: Urinary Tract Infections

Question 1

What are predisposing factors to UTIs?

Answer 1

• Female - shorter urethra (10:1 compared to males)
• Sexual intercourse
• Urological instrumentation e.g. catheters
• Urinary stasis e.g. in obstruction
• Fistulae
• Congenital abnormalities e..g reflux

Question 2

What make up perineal flora?

Answer 2

• Skin flora - mainly coagulase negative staphylococci. Most coagulase staph are not an issue in UTIs
  
  • Lower GI flora - enteric flora will be found around the rectum, anus and perineum. You get more anaerobes as it is dark and moist. Gram negatives are particular issues in UTIs. Enterobacterales (coliforms) enteric gram negative bacteria - are the main issues from the gut.
  • Gram positive cocci e.g. enterococcus spp. - gut flora, not the most problematic

Question 3

What are the organisms that commonly cause UTIs?

Answer 3

• E.coli
• Staphylococcus saprophyticus (seen in young women particularly)
• Proteus (associated with kidney stones)
• Kliebsella spp,
• Enterococcus sp.
• Other coliform
• Pseudomonas aeruginisa

Question 4

Give common symptoms of UTIs.

Answer 4

• Frequency
• Urgency
• Burning
• Dysruira
• Supra-pubic Pain
• Fever, especially in systemic causes
• Haematuria, Polyuria, and nocturia

Question 5

Give symptoms of pyelonephritis.

Answer 5

Lower UTI symptoms plus some systemic symptoms such as fever, rigors and loin/abdominal pain or tenderness. Other symptoms inline nausea, vomiting, diarrhoea and elated CRP and WBC (inflammatory markers).

Question 6

What is a complicated UTI?

Answer 6

A complicated UTI is an infection associated with a condition, such as structural or functional abnormalities of the genitourinary tract or the presence of an underlying disease, which increases the risks of acquiring an infection or of failing therapy. Other factors could include the presence of a foreign body, UTI in men under 65 and in younger children.

Question 7

What is a CA-UTI?

Answer 7

Catheter-associated UTI.

To prevent this, take a catheter out as soon as it is not needed. Manipulation it catheter removal may result in bacteraemia. Antibiotic prophylaxis can be indicated for some patient group - traumatic catheterisation, previous Ca-UTI etc. A catheter will always grow symptoms. Do not dip stick catheter it will always be positive. It is the symptoms that will determine whether there is colonisation. Symptoms include irritation, systemic symptoms, pus formation and suprapubic pain.

Question 8

What are signs of urosepsis?

Answer 8

Systemic signs:

• Fever
• Rigors
• nausea, vomiting, diarrhoea
• Hameodynamic compromise
• Raised inflammatory markers

It is less common to get a urosepsis related to a LTI, it is more commonly UUTI. Treatment is similar to that of UUTI.

Question 9

Other an a UTI, give other causes of urethritis.

Answer 9

• Thrush
• STIs e.g. Gonorrhoea and Chlamydia
• Urethral syndorme - - symptoms of a lower UTI but you cannot demonstrate the infection. It may be hormonal, irritation etc. It mostly affects 30-50 year old women.

Question 10

What are common causes of perinephric and infrarenal abscesses?

Answer 10

Perinephric causes - Gram negative bacilli
These are an uncommon complication of stones and/or diabetes. It can also be secondary to obstruction of infected kidney. Normally gram-negative bacilli.

Infrarenal - Haematogenous spread - usually staph aureus.

Question 11

For prostatitis, give:

(a) Signs and Symptoms
(b) Pathogens
(c) Risk Factors

Answer 11

(a) Signs and symptoms:
- LUTI symptoms
- Fever
- Tender and tense prostate on PR palpation
- Acute retention
- Terminal dribbling, noctuia and stop start Flow issues
- Can result in an abscess

(b) Typically the normal urinary pathogens, e.g. E. coli. It can also be caused by S. aureus.

(c) - Procedures involving the prostate such as Trans-urethral resection of prostate (TURP) and rans-rectal ultra-sound guided (TRUS biopsy).
- Indwelling urinary catheter

Question 12

What is the most common cause of chronic prostatitis?

Answer 12

90% pelvic pain syndrome. It can also be a chronic bacteria prostatitis.

Question 13

How do we investigate a UTI?

Answer 13

• Urinanalysis
• Laboratory urine samples
• Blood cultures
• Microscopy and sensitivity testing

Question 14

Why do we use a mid-stream urine test?

Answer 14

The urethra is colonised so the initial stream of urine is flushing out the bacteria in the urethra. Using the midstream means that anything you grow is more likely to come from the bladder itself and causing problems.

Question 15

What does a raised WCC, RCC or the presence of Epithelial cells in the urine indicate?

Answer 15

Raised WCC - Indicated inflammation
Raised RCC- Indicated bleeding
Epithelial cells - Indicates contamination

Question 16

What is sterile pyuria?

Answer 16

This is a case where pus cells (raised WCC) in the urine is found but no organism is grown with standard lab methods. This may be due to:

- Inhibition of bacteria growth e.g. through antibiotics before sampling or the specimen is contaminated with antiseptic 
- It is a fastidious organism - it is hard to grow e.g. mycobacterium tuberculosis (not common in urine, we would expect it in BCG in the bladder as a complication of treatment for from specialist services), haemophilus spp, and anaerobes 
- There is urinary tract inflammation e.g. renal or bladder stones or renal disease 
- Urethritis (sexually transmitted pathogens) e.g. gonorrhoea and chlamydia

Question 17

What cases indicate further investigations?

Answer 17

• Recurrent UTI
  
  • Any UTI in male patient - think prostate
  • Any UTI in childhood - look for vesico-ureteric reflux
  • Pyelonephritis - underlying issue?

Question 18

Give non-antimicrobial management strategies of UTIs.

Answer 18

• More fluid
• NSAIDs
• Device removal if no longer indicated
• Drainage if obstruction/abscess
• Cranberry juice????

Question 19

What are typical antibiotics used in the treatment of UTIs?

Answer 19

• Nitrofurantoin
• Pivmecillinam
• Trimpethroprim
• Fosfomycin

Question 20

How is cystitis treated?

Answer 20

Females
• Treatment often pre-empts microbiology results
• Short course of antibiotics - 3-days
• In mild cases, a delayed prescription to take if increased fluids +/- ibuprofen don’t work may be an option.

Males or recurrence of symptoms
• Longer course - 7 days
• If recurrent think about the prostate

Question 21

How is pyelonephritis treated?

Answer 21

Empiric therapy
• Broad action against likely urinary pathogens required
• Need to be systemically active such as Cefuroxime, Aztreonam, Ciprofloxacin, Gentamicin. These are all available IV and can tackle most gram negative bacteria that could cause the infection.
Directed therapy
Based on sensitivity results – narrowest spectrum agent possible.

Duration- 14 days depending on antibiotic used.

Question 22

How do we treat prostatitis?

Answer 22

The prostates has its own blood prostate barrier so many antibiotics do not get into the prostate. Empirically it needs cover gram negatives but ideally some staph. aureus cover. Also if there is an abscess it needs to be aspirated.

Empirical options:
	• Piperacillin-tazobactam (IV only)
	• Ciprofloxacin (IV/PO)
Most common directed options:
	• As above
	• Trimethoprim or Co-trimoxazole
Duration: 2 - 4 weeks