Urinary Tract Infection Flashcards
Give the classic symptoms of urinary tract infection
Dysuria
- (burning) pain when urinating
Frequency of urination
- passing urine more frequently than usual (volume of
urine not necessarily increased)
Urgency
- sudden urge to urinate, due to involuntary
contractions of the bladder muscle
Polyuria
- too much urine being produced
Suprapubic tenderness
HaematuriaDefine cystitis and give its commonest cause
Inflammation of the bladder
Usually due to bacterial infection (bacterial cystitis)
Define bacteriuria
Presence of bacteria in the urine (not including urethral organisms which are washed out in the urine during micturition)
Define pyuria and describe its significance
Presence of pus cells (neutrophil polymorphs) in the urine
Represents and inflammatory response - supportive evidence of a UTI
What do neutrophil polymorphs look like down the microscope?
granulated cells with lobulated nuclei
What is meant by sterile pyuria?
when urine is negative on culture but significant numbers of pus cells (neutrophils) are present
Define acute pyelonephritis
Infection of the upper urinary tract involving the kidneys
Define chronic pyelonephritis. What causes it?
Pathological condition with renal scarring and potential loss of renal function.
Infection may contribute but is not necessarily ongoing for chronic pyelonephritis to be present.
Other contributory factors:
- diabetes
- vesico-ureteric reflux
- urinary obstruction
What is meant by uncomplicated UTI?
UTI occuring in healthy, sexually active young women
- clear correlation between sexual intercourse and episodes of UTI
What is meant by complicated UTI?
All types of UTI that are outwith the criteria for uncomplicated UTI, e.g.
- children
- men
- patients with renal tract abnormalities
- immunosuppression
- foreign body within the urinary tract (e.g. catheter, stent)
- bladder tumour
- chronic urinary retention
- abnormal bladder outflow tract
Give three examples of renal tract abnormalities that increase the risk of UTI (and would complicate a UTI)
pelvi-ureteric junction obstruction
vesico-ureteric reflux
renal tract stone
Give four examples of bladder outflow tract abnormalities that increase the risk of UTI (and would complicate a UTI)
benign prostatic enlargement
urethral stricture
meatal stenosis
phimosis (tight foreskin)
List six organisms that are known to cause UTIs
E.coli Proteus sp. Enterococcus faecalis Klebsiella sp. Psuedomonas sp. Staph. saprophyticus
Which two organisms are more likely to be the cause in uncomplicated UTI?
E.coli
Staph. saprophyticus
(most other organisms are more likely to be the cause cause in complicated UTI)
What is meant by empirical treatment in the context of UTI?
Treatment given before the exact cause is known, i.e. before the causative organism has been identified. In UTI, empirical treatment involves treating with broad-spectrum antibiotics, usually a 3-day course.
When is empirical treatment indicated in the management of uncomplicated UTI?
When the patient has 3 or more symptoms.
When symptoms are particularly severe.
When urine dipstick is positive for nitrate, protein AND leukocytes.
What should be done for women with mild or ≤2 symptoms of UTI?
Mid-stream sample of urine should be collected for inspection ± dipstick urinalysis
(dipstick urinalysis is only indicated if urine is cloudy)
What should be done for a man with suspected UTI?
MSSU should be collected and sent to the lab for culture and microscopy
In men, what is a potential underlying cause of recurrent UTI? What organisms are commonly involved in this condition?
Prostatitis and/or infection of the prostate (may be acute or chronic)
Older males - coliform organisms
Younger males - STIs e.g. Chlamydia trachomatis or Neisseria gonorrhoeae
Give the characteristic symptoms of acute pyelonephritis
Loin pain
Fever
(Urinary symptoms may be present but generally are less pronounced)
What is the biggest risk in patients with acute pyelonephritis? What symptoms may present in this condition?
Causative organism can spread to the bloodstream to cause bacteraemia, which can lead to sepsis.
Symptoms include rigors (uncontrolled shivering/shaking), nausea and vomiting
Describe the investigation/management for patients with suspected acute pyelonephritis
MSSU sent for culture and microscopy
Should be started on broad-spectrum antibiotics immediately, with the choice of antibiotic being reviewed once cultrue results are known.
If patient is systemically unwell, blood cultures should also be done.
Antibiotic treatment should be continued for at least 7 days.
Why is it important to screen pregnant women for bacteraemia?
Bacteraemia - including asymptomatic - in pregnant women is associated with an increased risk of pyelonephritis and premature delivery.
What is the “textbook” cause of sterile pyuria? How should this be investigated?
Renal tuberculosis
Collect three early morning urine samples for a ZN stain and TB culture
Give four examples of non-infectious pathologies that can cause recurrent sterile pyuria
Renal tract stone disease
Interstitial cystitis
Urological malignancy
Chronic prostatitis
What is the most significant cause of UTI in children? Why is it so important?
Vesico-ureteric reflux
Can lead to renal scarring in later life, particularly when combined with infection.
(Most cases of chronic pyelonephritis in adults are probably the result of damage done in early childhood)
Describe the clinical signs/symptoms of chronic pyelonephritis
Vague abdominal discomfort
Hypertension may be present
Renal function is usually normal, but may be seriously impaired in a small number of patients
Radiology (IVP) may show clubbing of calyces with scarring of cortical parenchyma.
Why is pregnancy a risk factor for UTIs?
Urine doesn’t flow as easily (becomes static) due to:
- progesterone dilates the ureters
- foetus puts physical pressure on the urinary tract
Give ten risk factors for UTIs
- Female sex (short urethra)
- Trauma to female urethra (e.g. during intercourse or childbirth)
- Sexual intercourse and poor voiding habits
- Congenital abnormalities (e.g. duplex kidney, horseshoe kidney)
- Stasis of urine (e.g. due to poor bladder emptying, obstruction)
- Foreign bodies (e.g. catheters, stones)
- Oestrogen deficiency in postmenopausal women
- Pregnancy
- Renal cysts
- Pre-existing renal parenchymal damage
- Immunosuppression
List the indications for laboratory diagnosis of UTI (i.e. culture and microscopy of urine)
- Women with mild/limited symptoms for whom dipstick testing is inconclusive
- Men with suspected UTI
- Children with suspected UTI
- Pregnant women with symptoms or for screening purposes
- Suspected acute pyelonephritis
- After failed antibiotic treatment or persistent symptoms
- Recurrent UTI
Name two methods of urine sampling for which any growth of organisms is considered significant
Suprapubic aspiration
Catheter specimens
What density of bacteria growth from a cultured MSSU usually signifies infection?
10^5 per ml = infection even if asymptomatic
10^3 - 10^4 + symptomes = probably infection
What course of treatment do the SIGN guidelines recommend for simple cystitis in non-pregnant women?
3 days of trimethoprim or nitrofuratoin
Which organism is not covered by nitrofuratoin?
Proetus
What course of treatment do the NHS Grampian guidelines suggest for men with lower UTI (if infection appears uncomplicated)?
7 days of trimethoprim or nitrofuratoin
Describe the treatment for acute pyelonephritis
At least 7 days of ciprofloxacin, with treatment being reviewed once the results of urine cultures and sensitivity tests are known.
Resolution of infection should be checked by obtaining a urine sample 1-2 weeks after the cessation of antibiotic therapy.
Which antibiotic should not be used in pregnancy?
Trimethoprim
What treatment is recommended in pregnancy?
Nitrofuratoin (safe during pregnancy but can cause neonatal haemolysis if used at term) or Cephalexin
- treatment should be guided by sensitivities
Describe the investigation and management of patients with recurrent infection
Detailed history to identify any risk factors.
Gynaecological examination.
IVP.
Long term antibiotic prophylaxis - one tablet of nitrofuratoin or trimethoprim per night for up to a year.
For uncomplicated recurrent UTIs, take a single dose of appropriate antibiotic immediately after intercourse.
How should severe and/or systemic infections be treated?
Intravenous antibiotics
Define septicaemia and bacteraemia
Bloodstream infection; presence of pathogen in the blood.
If the infection is bacterial, is it known as bacteraemia (i.e. bacteraemia is just bacterial septicaemia)
Define sepsis and septic shock
Sepsis: Inflammation throughout the body
Septic Shock: When the body goes into shock because of sepsis
- blood pressure drops due to vasodilation
- sats drop due to lack of tissue perfusion
