UTIs Flashcards
Define an urinary tract infection (UTI).
The inflammatory response of the urothelium to bacterial invasion, usually associated with bacteriuria (bacteria in urine) and pyuria (pus in urine).
What is numerically defined as an UTI?
Defined as >105 organisms/ml or fresh mid-stream urine
What are the 5 main pathogens account for nearly ALL ISOLATE from primary care?
KEEPS:
* K = Klebsiella spp.
* E = E.coli - MOST COMMON
* E = Enterococci
* P = Proteus spp.
* S = Staphylococcus spp. - coagulase negative
Name 3 UTI causative organisms.
- Uropathogenic strains of E.coli (UPEC) - 82%.
- CNS e.g. s.saprophyticus.
- Proteus mirabilis.
- Enterococci.
- Klebsiella pneumonia.
Give 5 risk factors for UTIs.
- Sexually active
- Catheterised
- Enlarged prostate
- Renal tract tumour
- Renal stones
- Urinary retention
- Woman
- Incontinence
- Poor hygiene
- Dehydration
What are the 3 different classifications of UTIs?
- Location:
* Lower urinary tract vs. Upper urinary tract - Clinical risk:
* Uncomplicated vs. Complicated - Timing:
* Single/isolated vs. Unresolved (persistent infection or re-infection)
* Acute vs. Chronic
Uncomplicated vs complicated UTI?
Uncomplicated - healthy non pregnant women
Everyone else - complicated
How to treat uncomplicated UTIs in young women?
3 days abx
E.G. nitrofurantoin or trimethoprim
What is the first line treatment for an uncomplicated UTI?
- Trimethoprim or nitrofurantoin for 3 days.
- Increased fluid intake and regular voiding.
How does trimethoprim work?
It affects folic acid metabolism.
How to manage ‘complicated’ UTI?
MSU for culture
7 days abx
Describe the management for a complicated UTI.
Same as for an uncomplicated UTI but a MCS MSU is essential! The patient would normally take a longer Abx course tailored to sensitivity.
3 things about UTI in pregnancy?
- Urinalysis is an unreliable test, always send for culture
- Asymptomatic bacteriuria is common
- Always treat, they are at much higher risk of pyelonephritis
What determines if a UTI is complicated or uncomplicated?
A UTI is deemed complicated if it affects:
- Someone with an abnormal urinary tract.
- A man.
- A pregnant lady.
- Children.
- The immunocompromised.
- If it is recurrent.
Give 3 bacterial virulence factors that aid their ability to cause UTI’s.
- Fimbriae/pili that adhere to urothelium.
- Acid polysaccharid coat resists phagocytosis.
- Toxins e.g. UPEC releases cytotoxins.
- Enzyme production e.g. urease.
Under what circumstances would you see higher rates of adhesion?
Why?
Oestrogen depletion due to the loss of lactobacilli and pH change:
- Seen post-menopause where the pH rises and thus there is increased colonisation by colonic flora and a reduction in vaginal mucus secretion
- Results in increased susceptibility to UTI
Give 5 host defence mechanisms against urinary tract infection.
- Antegrade flushing of urine (forward flow of urine).
- Tamm-horsfall protein -> has antimicrobial properties.
- GAG layer.
- Low urine pH.
- Commensal flora.
- Urinary IgA.
Give 3 methods of avoiding host defences.
- Capsule
- Enzyme production
- Toxins
Give an example of enzyme production as a method of avoiding host defences.
E.coli release cytokine that are directly toxic
Give an example of toxin production as a method of avoiding host defences.
Proteus spp. secrete urease:
* Increases risk of stone formation
Give an example of a gram negative bacteria that releases urease.
Gram-negative: Proteus, Klebsiella & Pseudomonas
Give an example of a gram positive bacteria that releases urease.
Gram-positive: Staphylococci & Mycoplasma
Give 2 reasons why a post menopausal woman is more susceptible to a UTI.
- pH rises -> increased colonisation by colonic flora.
- Reduced mucus secretion.
The vagina is heavily colonised with lactobacilli. What is the function of this?
Helps maintain a low pH = host defence mechanism.
Describe the pathophysiology of UTI’s.
Organisms colonise the urethral meatus and ascend via the transurethral route.
Briefly describe the epidemiology of UTIs.
More common in women
- Affects 1/3rd in lifetime
Why are women more susceptible to UTIs?
More common in women due to short urethra and its proximity to the anus.
What can facilitate bacteria ascent into the urinary tract via the urethra?
- Sexual intercourse.
- Catheterisation.
When would/wouldn’t you treat or test for a UTI?
3 UTI symptoms – empirical abx
2 UTI symptoms + nitrates – empirical abx
2 UTI symptoms + leucocytes – send MSU
Symptoms but no leuco/nitr in dipstick or it looks clear - unlikely to be a UTI
Name 4 lower urinary tract infections.
- Cystitis.
- Prostatitis.
- Epididymitis / Epididymo-orchitis.
- Urethritis.
Name 1 upper urinary tract infection.
Pyelonephritis.
Give 5 clinical presentations of UTIs.
Frequency
Dysuria
Urgency
Incontinence
Confusion
Suprapubic pain
Give 4 risk factors for UTIs.
- Female
- Sex
- Pregnancy
- Menopause
- Decrease in host defence
- Urinary tract obstruction resulting in urine stasis
- Catheter
Define pyelonephritis.
Inflammation secondary to infection of the renal parenchyma and soft tissues of the renal pelvis and upper ureter.
What can cause pyelonephritis?
UPEC. Typically P pili.
Infection is usually from the bladder.
What is the likely cause of pyelonephritis in children?
Reflux or structural/functional abnormalities.
Give 3 ways in which infection can spread to the upper urinary tract and cause pyelonephritis.
- Ascending from urethra, common in intercourse
- Haematogenous, in sepsis
- Lymphatic
Give 3 risk factors for pyelonephritis.
- Structural renal abnormalities
- Calculi (stones)
- Catheterisation
- Pregnancy
- Diabetes
- Immunocompromised patient
Give 3 symptoms of pyelonephritis.
- Loin pain.
- Fever.
- Pyuria.
May also have a severe headache and be fluid deplete.
What is pyuria?
The presence of leukocytes in urine.
3 features that suggest pyelonephritis over UTI?
1, Loin pain
2. Fever
3. Haematuria
What investigations might you do in someone with pyelonephritis?
- Urinalysis - urine dipstick.
- MSU MCS (midstream urine microscopy, culture + sensitivity)
- Bloods - raised WCC, ESR and CRP.
- Urgent ultrasound.
Investigations to diagnose pyelonephritis.
- Physical examination
- Tender loin - Urine dipstick:
* Detects nitrites - bacteria breakdown nitrates to release nitrites
* Detect leucocyte elastase
* Foul-smelling urine
* Dipstick positive for nitrites, leucocytes and protein - Midstream urine microscopy, culture and sensitivity
- GOLD STANDARD for diagnosis - Bloods:
* FBC - shows elevated white cell count
* CRP & ESR may be raised in acute infection - Urgent ultrasound:
* Detection of calculi, obstruction, abnormal urinary anatomy and
incomplete bladder emptying
Describe the treatment for pyelonephritis.
- Rest
- Cranberry juice and lots of water
- Analgesia
- Antibiotics:
* ORAL CIPROFLOXACILLIN or ORAL CO-AMOXICLAV
* If severe then: IV GENTAMICIN or IV CO-AMOXICLAV - Surgery to drain abscesses or relieve calculi that are causing infection
Differential diagnosis for pyelonephritis.
- Diverticulitis, abdominal aortic aneurysm, kidney stones, cystitis,
prostatitis
What is cystitis?
Inflammation of the bladder secondary to infection.
Give 4 risk factors for cystitis.
- Obstruction.
- Previous damage to bladder epithelium.
- Bladder stones.
- Poor bladder emptying.
Give 3 symptoms of cystitis.
- Dysuria.
- Frequency.
- Urgency.
What is the gold standard investigation for cystitis diagnosis?
MSU MCS
- (sterile) Midstream urine microscopy, culture and sensitivity
Investigations for cystitis.
- MSU MCS - gold standard
- Urinalysis - urine dipstick
- Positive leucocytes, blood and nitrites
Treatment for cystitis.
- Antibiotics:
- First-line:
- TRIMETHOPRIM or CEFALEXIN
- Second-line:
- CIPROFLOXACIN or CO-AMOXICLAV
Define prostitis.
Infection and inflammation of the prostate gland.
- Can be acute or chronic.
What are the 3 main causes of prostitis?
- Streptococcus faecalis
- E.coli
- Chlamydia
Give 5 symptoms of acute bacterial prostatitis (type 1).
- Systemically unwell, fever.
- Rigors and malaise.
- Voiding LUTS (straining, hesitancy, incomplete emptying, poor flow).
- Pelvic pain.
- Pain on ejaculation.
Give 4 symptoms of chronic bacterial prostatitis (type 1).
- Recurrent UTI’s.
- Pelvic pain.
- Voiding LUTS (straining, hesitancy, incomplete emptying, poor flow).
- Uropathogens in urine.
The patient should have had the symptoms for >3 months.
Give a symptom of type 3 prostatitis.
Chronic pelvic pain.
Describe the NIDDK classification for prostatitis.
- Type 1: acute bacterial prostatitis.
- Type 2: chronic bacterial prostatitis.
- Type 3a: Inflammatory chronic pelvic pain syndrome.
- Type 3b: non-inflammatory chronic pelvic pain syndrome.
- Type 4: asymptomatic inflammatory prostatitis.
What investigations might you do in someone with prostatitis?
- Digital rectal exam (DRE)
- Urinalysis - Urine dipstick - positive for leucocytes and nitrites
- Mid-stream urine microscopy, culture + sensitivity (MSU MCS)
- Blood cultures
- STI screen - for chlamydia in particular
- Trans-urethral ultrasound scan (TRUSS)
Describe the treatment for type 1 prostatitis (acute).
Type 1 = acute bacterial prostatitis.
First-line:
- IV GENTAMICIN + IV CO-AMOXICLAV or IV TAZOCIN or IV CARBAPENEM
* 2-4 weeks on a quinolone e.g. CIPROFLOXACIN (antibiotic) once a week
Second-line:
* Trimethorpin
- TRUSS guided abscess drainage if necessary
Describe the treatment for type 2 prostatitis (chronic).
Type 2 = chronic bacterial prostatitis.
- 4-6 weeks quinolone e.g. ciprofloxacin.
* BUT they don’t tend to respond as well to antibiotics
- +/- Alpha-blocker e.g. TAMSULOSIN
- NSAIDs e.g. IBUPROFEN
Give a complication of prostatitis.
Urinary retention.
Define urethritis.
Urethral inflammation due to infectious of non-infectious causes.
What is the most common cause of urethritis?
Chlamydia trachomatis
What can cause urethritis?
STI’s e.g. gonorrhoea, chlamydia.
A primarily sexually acquired disease.
Give 2 non-gonococcal causes of urethritis.
- Chlamydia trachomatis - MOST COMMON CAUSE
- Mycoplasma genitalium
- Ureaplasma urealyticum
- Trichomonas vaginalis
What is the main gonococcal cause of urethritis?
Neisseria gonorrhoea
Give 2 non-infective causes of urethritis.
- Trauma
- Urethral stricture
- Irritation
- Urinary calculi
Describe the clinical presentation of urethritis.
- May be asymptomatic (90-95% with gonorrhoea, 50% of patients with chlamydia)
- Dysuria (painful urination) +/- discharge; blood or pus
- Urethral pain
- Penile discomfort
- Skin lesions
- Systemic symptoms
Investigations for urethritis.
- Nucleic acid amplification test (NAAT):
* Female - self collected vaginal swab (best), endocervical swab, first void
urine
* Male - first void volume
* High specificity and sensitivity - Microscopy of gram-stained smears of genital secretions
- Blood cultures
- Urine dipstick - to exclude UTI
- Urethral smear
What is the treatment for urethritis caused by gonorrhoea?
- IM CEFTRIAXONE with ORAL AZITHROMYCIN
- Partner notification
What is the treatment for urethritis caused by chlamydia?
- ORAL AZITHROMYCIN STAT or 1 WEEK ORAL DOXYCYCLINE
- Tests for other STIs
What is the treatment for urethritis caused by chlamydia for a pregnant female?
ORAL ERYTHROMYCIN for 14 days or ORAL AZITHROMYCIN
STAT
What is epididymo-orchitis?
Inflammation of the epididymis and testicle.
Acute epididymo-orchitis is a clinical syndrome of pain, swelling and inflammation of the epididymis that can extend into the testis
Describe the aetiology of epididymo-orchitis.
- If <35 y/o = STI e.g. chlamydia.
- If >35 y/o = UTI (causes: KEEPS mnemonic).
Give 3 symptoms of epididymo-orchitis.
- Sudden onset tender swelling.
- Dysuria.
- Sweats/fever.
What investigations might you do on someone who you suspect has epididymo-orchitis?
- Nucleic acid amplification test (NAAT):
* Female - self collected vaginal swab (best), endocervical swab,, first void urine
* Male - first void volume
* High specificity and sensitivity
* If intracellular gram-NEGATIVE DIPLOCOCCI are present, then this is suggestive of GONORRHOEA - Urethral smear + swab.
- MSU dipstick - for UTI smptoms
- Ultrasound to rule out abscesses
- STD screening
Rule out testicular torsion!
Describe the treatment for epididymo-orchitis.
- If STI aetiology suspected; refer to GUM and maybe give doxycycline.
- If UTI aetiology suspected give quinolone (ciprofloxacin).
What is the treatment for epididymo-orchitis caused by chlamydia?
- ORAL DOXYCYCLINE 7 DAYS or STAT AZITHROMYCIN
What is the treatment for epididymo-orchitis caused by gonorrhoea?
- IM CEFTRIAXONE + STAT ORAL AZITHROMYCIN
- ORAL CIPROFLOXACIN or ORAL OFLOXACIN
Give a differential diagnosis of epididymo-orchitis, and symptoms that might suggest it.
TESTICULAR TORSION - UROLOGICAL EMERGENCY:
* MUST RULE THIS OUT
* If in any doubt then SURGICAL SCROTAL EXPLORATION
- Features suggestive of torsion:
- Short duration of pain - sudden onset
- Associated nausea/abdominal pain
- High-riding/bell-clapper testis
Define recurrent UTI.
> 2 episodes in 6 months of > 3 in 12 months.
Give 3 causes of recurrent UTI’s.
- Re-infection.
- Bacterial persistence.
- Unresolved infection.
What investigations might you do on someone who you suspect has a UTI?
- Take a good history.
- Urinalysis - multistix SG.
- Microscopy; culture and sensitivity of mid-stream urine.
- In recurrent/complicated UTI renal imaging is important.
Describe the management for someone who is having recurrent UTI’s.
- Increase fluid intake.
- Regular voiding.
- Void pre and post intercourse.
- Abx prophylaxis.
- Vaginal oestrogen replacement.
What do type P pili bind to?
Glycolipids on urothelium.
What do type 1 pili bind to?
Uroplakin.
What type of pili would you associate with a lower UTI?
Type 1.
What type of pili would you associate with an upper UTI?
Type P.
What do nitrates suggest?
Gram neg bacteria e.g. E coli
What do urine casts suggest?
Damage to epithelium/tubular necrosis/glomerulus
What does epithelium in MSU suggest?
Poorly taken sample, may be contaminated
What number of bacteria in an MSU is significant?
10^5
(10^4 may be contamination)
