Urinary tract infections Flashcards Preview

Clinical Pathology > Urinary tract infections > Flashcards

Flashcards in Urinary tract infections Deck (29):
1

What parts of the urinary tract are sterile in normal health?

Kidneys

Ureters

Bladder (usually, but my not always be the case)

2

What type of flora does the urethra contain?

Perineal flora

Skin/lower GI tract flora

3

What does skin flora consist of?

Predominantly coagulase-negative staphylococci

4

What does perianal flora consist of?

Skin flora

Lower GI tract flora
-Anaerobic bacteria
-Aerobic bacteria
--Enterobacteriaceae (“enteric Gram-negative bacilli”, “coliforms”)
-Gram-positive cocci
--Enterococcus spp.

5

What is cystitis?

Lower urinary tract infection syndrome
- Dysuria
- Urinary frequency
- Urgency
- Supra-pubic pain/tenderness
- Polyuria, nocturia, haematuria

6

What is pyelonephritis?

Upper urinary tract infection
- Infection of kidney and/or renal pelvis

7

What is the clinical presentation of pyelonephritis?

Symptoms of lower UTI

Loin/abdominal pain/tenderness

Fever

Other evidence of systemic infection
- Rigors, nausea, vomiting, diarrhoea
- Elevated CRP, WBC

8

What is 'urethral syndrome'?

Controversial term

a.k.a. abacterial cystitis, frequency-dysuria syndrome

Mostly affects 30-50 yr old women

Symptoms of lower UTI without demonstrable infection

9

What criteria is used to define 'significant bacteriuria'?

Kass criteria = 10^5 cfu/mL = “significant bacteriuria”

10

What are the limitations of the Kass criteria?

Bacterial count is on a normal curve

Many symptomatic females have bacterial counts of less

11

What is asymtomatic bacteriuria?

Significant bacteriuria
- With a single organism

No symptoms of urinary tract infection

12

What is sterile pyuria?

Pus cells in urine

No organisms grown

13

What are the risk factors for UTI?

Female sex - 10:1 female:male ratio

Urinary stasis - Pregnancy, prostatic hypertrophy, stones, strictures, neoplasia, residual urine

Instrumentation

Sexual intercourse - Associated with recent sexual intercourse and commoner in sexually active women

Fistulae - Recto-vesical, vesico-vaginal

Congenital abnormalities - Vesico-ureteric reflux (VUR)

14

What are the sources of infection in UTIs?

Perineum
- Movement of bacteria along a lumen

Fistulae
- Movement of bacteria from genital/GI tract to urinary tract

Haematogenous
- Seeding of infection from the blood (rare)

15

Which organisms commonly cause UTIs?

E. coli
S. saprophyticus
P.mirabilis
Enterococcus spp.
Klebsiella spp.
Other coliforms
P. aeruginosa

16

Which organism causes 70-80% of all GP UTIs and 50% of all hospital UTIs?

E.coli

17

What are the possible causes of sterile pyuria?

Inhibition of bacterial growth
- Unprescribed antibiotics
- Specimen contaminated with antiseptic

“Fastidious” (hard to grow) organisms
- e.g. Mycobacterium tuberculosis, Haemophilus spp., Neisseria gonorrhoeae
- Anaerobes

Urinary tract inflammation
- Renal or bladder stones
- Other renal disease

18

How do long-term indwelling catheters result in bacteriuria?

Biofilm colonisation (NB: colonisation does not equal infection)

19

At LTHT under what circumstances may antibiotic prophylaxis be used?

History of symptomatic urinary catheter-associated infection with previous catheter changes

Purulent urethral/suprapubic catheter exit site discharge

Catheter or meatal/suprapubic catheter exit site colonisation with Staphylococcus aureus (including MRSA).

20

What samples are taken for microbiological testing if a UTI is suspected?

Urine
- Mid-stream (MSU)
- Catheter urine (CSU)
- “Clean catch”
- Supra-pubic aspirate (SPA)

Blood
- Suspected pyelonephritis

- Microscopy, culture and sensitivity testing

21

Why would you perform an early morning urine (EMUx3) test?

For suspected urinary tuberculosis

22

What are the indications for further investigation?

Recurrent UTI

Any UTI in male patient

Any UTI in childhood

Pyelonephritis

23

What further investigations may be carried out?

Renal tract ultrasound scan

Specialised tests
- Isotope scans (DMSA, DTPA, MAG3)
- micturating cystourethrogram

24

What are the requirements for a UTI antibiotic?

Present in urine

Minimally toxic

Effective against likely organisms

Easily administered

Cheap

25

Give examples of some common UTI antibiotics?

- Nitrofurantoin
- Pivmecillinam
- Trimethoprim
- Fosfomycin

26

What is the treatment for cystitis in females?

Treatment pre-empts microbiology results

Short course of antibiotics - 3-days

27

What is the treatment for cystitis in males (or the recurrence of symptoms)?

- Longer course (7 days)

28

What is the treatment for pyelonephritis?

Empiric therapy
- Cefuroxime, ciprofloxacin
- Piperacillin-tazobactam (if >65 yrs old)

Targeted therapy
- Based on sensitivity results

Duration
- 7-14 days depending on antibiotic used

29

What is the treatment for asymtomatic bacteriuria?

Treat only specific groups:

- Pregnant
-- Association with upper UTI, pre-term delivery, and low birth weight babies

- Infant
-- Prevention of pyelonephritis and renal damage

- Prior to urological procedures
-- Prevention of UTI/bacteraemia

Elderly, catheterised etc. do not require antibiotics

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