Urinary tract infection (I) Flashcards
What is a UTI?
Inflammatory reaction of the urinary tract epithelium in response to pathogenic micro-organisms, most commonly bacteria
Describe UTIs in men.
- rarely occurs before 50y
- associated with abnormal structure/function of urinary tract e.g. prostate, catheters, surgeries, neurogenic
- also due to altered urinary flow
Describe UTIs in women.
- infectious cystitis is the most common type
- pyelonephritis is a kidney infection occurring via bacteria ascent
- urethritis is an infection causing inflammation of urethra
- colonisation of vagina first, then to urinary tract
Name a common causative agent for UTIs.
E. coli (gram -ve bacilli)
What is the difference between lower and upper UTIs?
- bladder & urethra = lower UTIs
- kidneys & ureters = upper UTIs
Why are females at higher risk of UTIs?
Women have shorter urethra (hence shorter distance to bladder from urethral opening) and anal and genital regions that are closer in proximity
What are some different types of UTIs? (4)
- uncomplicated UTI
- complicated UTI = presence of other factors hindering efficacy of therapy (e.g. structural/functional abnormalities, immunodeficiency, indwelling catheter, infection due to resistance, pregnancy UTIs)
- men more likely to have complicated UTIs
- recurrent UTI = due to persistence of infection that is inadequately treated/new infection
- 2 separate culture-proven episodes of acute UTIs within 6mo. or >3 in 12mo.
- asymptomatic bacteriuria = presence of bacteria in urine without any symptoms
What are the risk factors for UTIs? (6)
- abnormalities of urinary tract (e.g. benign prostatic hypertrophy, kidney stones)
- pregnancy
- postmenopause
- sexual activity (anal sex increases risk)
- urinary catheters
- anything causing urine stasis
What are the diagnostic criteria (AKA signs and symptoms) for UTIs in men?
- presence of risk factors
- dysuria
- urgency
- frequency
- hesitancy
- nocturia
- enlarged prostate
- tender prostate
UTI: >/=10^2 CFU/ml of a single/predominant organism with symptoms specific to urinary tract
Asymptomatic bacteriuria: >/=10^5 CFU/ml of a single organism by clean catch on one occasion without specific urinary tract symptoms
What are the diagnostic criteria (AKA signs and symptoms) for UTIs in women?
- dysuria
- new nocturia
- cloudy-urine
- presence of risk factors
- urgency
- visible haematuria
- frequency
- suprapubic pain/tenderness
10^4 to 10^5 CFU/ml indicate UTI
What are the three key symptoms of a UTI in women?
Dysuria, new nocturia, cloudy-urine
What are some signs and symptoms of UTIs in men?
- dysuria
- frequency
- urgency
- suprapubic pain (lower tummy)
What are the clinical features of a lower UTI (e.g. urethritis, cystitis)? (5)
- dysuria
- urinary frequency & urgency
- malodorous urine
- haematuria
- suprapubic tenderness (lower abdominal pain)
What are the clinical features of an upper UTI? (4)
- fever
- fatigue
- flank pain
- nausea and vomiting (may have pyelonephritis)
What are the clinical features of acute pyelonephritis? (5)
- flank (loin) pain
- fever
- rigors and vomiting
- white cell casts in urine
- may lead to haemodynamic instability
(To distinguish from cystitis: pyrexia, flank pain, abnormal vitals)
What extra features may elderly patients with a UTI have?
Delirium / acute confusion
What are the first line investigations (and results) for UTIs in men?
- urine dipstick (positive leukocyte esterase and/or nitrate)
- urine microscopy (WBCs and bacteria)
- urine culture (>/=10^2 colony forming units, use midstream clean-catch urine)
- gram stain
In an E.coli positive UTI, what does the E.coli appear like on MacConkey agar?
Intensely pink –> positive lactose fermentation
What imaging investigation modalities are considered for UTIs?
- ultrasound - only if complicated UTI, rule out obstruction
- CT renal tract - anatomical detail, complicated UTI, rule out obstruction (avoid if pregnant)
- XR-KUB - complicated UTI, find urinary tract stone/abscess
- intravenous urogram (IVU) - complicated UTI, rule out obstruction
What bloods can be done for UTIs?
FBC, U&Es (renal function, CRP, blood cultures)
What is the first line investigation for UTIs in women?
- urine dipstick (+ve nitrates/leukocytes/RBCs)
- perform when 1/3 symptoms are present OR other severe symptoms
- if 2/3 key symptoms OR positive dipstick OR risk of antibiotic resistance –> urine culture + sensitivity
- mid-stream, clean-catch urine specimen before giving antibiotics
What is seen in MC&S in pyelonephritis?
White cell casts
What are some differential diagnoses for UTIs in men?
- benign prostatic hypertrophy (BPH) - high PSA + enlarged prostate
- prostatitis - rectal pain, tender boggy prostate
- pyelonephritis - unilateral costovertebral angle pain, WBC casts on urinalysis
- urinary tract stones - loin to groin pain, IVU and CT confirm
- gonococcal/chlamydia urethritis
- bladder cancer - haematuria
- prostate cancer - obstructed flow
- renal cancer - haematuria
- epididymitis - lack of dysuria, urgency, frequency
- reactive arthritis - sterile urine culture
- Behcet’s Syndrome - sterile urine culture
What are some differential diagnoses for UTIs in women?
- overactive bladder - urgency, frequency
- non-infectious urethritis
- foreign body in bladder
- vaginitis, bacterial vaginosis and cervicitis
- interstitial cystitis
- urethral diverticulum
- pelvic organ prolapse
- urethral cancer
- asymptomatic bacteriuria
- radiation cystitis
What antibiotics are prescribed 1st line for uncomplicated lower UTI?
- nitrofurantoin OR trimethoprim
- course: 3 day (women) / 7 day (men)
- AVOID trimethoprim if pregnant in T1 (folate antagonist)
- AVOID nitrofurantoin near end of pregnancy (risk of haemolytic anaemia in baby)
What antibiotics are prescribed 2nd line for uncomplicated lower UTI?
Beta-lactams (amoxicillin) OR cefalexin
How is asymptomatic bacteriuria managed in pregnant women?
Still treat with nitrofurantoin (avoid near end term) or amoxicillin to avoid risk of progression to pyelonephritis
How is asymptomatic bacteriuria managed in catheterised patients?
Do not treat (could be colonisation of catheter)
If symptomatic - 7 day Abx course and change catheter
How could acute pyelonephritis be managed?
- hospital admission
- broad spectrum cephalosporin (e.g. ceftriaxone/cefuroxime) or quinolone (e.g. levofloxacin/ciprofloxacin) for 10-14 days
How do we treat initial asymptomatic bacteriuria before urological procedure in men?
- trimethoprim/sulfamethoxazole 160/800mg PO BD 1-2d
- OR nitrofurantoin 100mg PO QD 1-2d
- OR amoxicillin/clavulanate 500mg PO TD 1-2d
- OR cefalexin 500mg PO QD 1-2d
- OR levofloxacin 500mg PO OD 1-2d
- OR ciprofloxacin 500mg PO BD 1-2d
How do we treat acute but not severe and tolerating oral therapy UTI in men?
- trimethoprim/sulfamethoxazole 160/800mg PO BD 7-14d
- OR nitrofurantoin 100mg PO QD 7-14d
- OR amoxicillin/clavulanate 500mg PO TD 7-14d
- OR cefalexin 500mg PO QD 7-14d
- OR levofloxacin 500mg PO OD 7-14d
- OR ciprofloxacin 500mg PO BD 7-14d
How do we treat acute and severe / not tolerating oral therapy UTI in men?
Hospitalisation plus IV antibiotic therapy for 7-14 days
What is the treatment algorithm for women with UTIs?
Immediate empirical antibiotics or prescription for backup antibiotics
- 1st line: nitrofurantoin 100mg PO BD/50mg PO QD if eGFR>45 / trimethoprim 200mg PO BD if low risk of resistance and eGFR low
- 2nd line (no improvement in lower UTI Sx after 48h/not suitable): nitrofurantoin, pivmecillinam, fosfomycin
- NICE recommends 3 day course
Name some complications of UTIs.
- pyelonephritis
- prostatitis
- renal function impairment
- sepsis due to bacteraemia
- acute kidney injury
