UTI Flashcards
Definition
DEFINITION: the presence of a pure growth of > 105 organisms per mL of fresh MSU
Sub-Classification
- Lower UTI - affecting the urethra (urethritis), bladder (cystitis) or prostate (prostatitis)
- Upper UTI - affecting the renal pelvis (pyelonephritis)
NOTE: the laboratory classification mentioned above isn’t a complete necessity for the diagnosis of UTI - 1/3 women with symptoms of UTI will have negative MSU
Other Classification
- Uncomplicated UTI - normal renal tract and function
- Complicated UTI - abnormal renal/genitourinary tract, voiding difficulty/obstruction, reduced renal function, impaired host defences, virulent organism (e.g. S. aureus)
Causes
MOST UTIs are caused by Escherichia coli
Other causative organisms:
- Staphylococcus saprophyticus
- Proteus mirabilis
- Enterococci
Atypical organisms that can cause UTI (usually in immunocompromised individuals):
- Klebsiella
- Candida albicans
- Pseudomonas aeruginosa
Risk factors
FEMALE
Sexual intercourse
Exposure to spermicide
Pregnancy
Menopause
Immunosuppression
Catheterisation
Urinary tract obstruction
Urinary tract malformation
Epidemiology
VERY COMMON
1-3% of GP consultations
The majority of women will have a UTI in their lifetime
MUCH more common in FEMALES
Symptoms
Cystitis
- Frequency
- Urgency
- Dysuria
- Haematuria
- Suprapubic pain
Prostatitis
- Flu-like symptoms
- Low backache
- Few urinary symptoms
- Swollen or tender prostate on PR
Acute Pyelonephritis
- High fever
- Rigors
- Vomiting
- Loin pain and tenderness
- Oliguria (if AKI)
Signs
Fever
Abdominal or loin tenderness
Foul-smelling urine
Distended bladder (occasionally)
Enlarged prostate (if prostatitis)
Investigation
Urine Dipstick
- Positive leucocyte esterase and nitrites
Urine Microscopy
- Presence of leucocytes indicates infection
Urine Culture
- To exclude diagnosis or if the patient failed to respond to empirical antibiotics
Ultrasound
- Rule out obstruction
Bloods
- FBC
- U&Es - check renal function
- CRP
- Blood cultures - if systemically unwell and risk of urosepsis
Management
Empirical treatment of uncomplicated UTI: TRIMETHOPRIN or NITROFURANTOIN
- Treat for 3-6 days
- NOTE: men with UTI may need a longer course of antibiotics
Alternative Treatments: Co-amoxiclav or Cefalexin
Prophylactic antibiotics may be used in certain circumstances (e.g. recurrent cystitis associated with sexual intercourse)
Complications
Ascending infection can lead to:
- Pyelonephritis
- Perinephric and intrarenal abscess
- Hydronephrosis or pyonephrosis
- AKI
- Sepsis
Prostatic involvement (e.g. prostatitis) in men with UTIs is common
Prognosis
GOOD prognosis with appropriate treatment
