Urinary Tract Infection (UTI) (7.5) Flashcards
Define upper UTI
An infection of the upper part of the urinary tract, including the kidneys (pyelonephritis) and ureters
Define lower UTI
An infection of the lower urinary tract, including the bladder (cystitis) and urethra (urethritis)
Define uncomplicated UTI
Infection of the urinary tract by a ‘usual’ pathogen in a person with a normal urinary tract and normal kidney function
Define complicated UTI
A UTI where one or more factors predispose the patient to persistent or recurrent infection/treatment failure are present
Define recurrent UTI
Relapse - infection with the same strain, < 2 weeks after treatment
Reinfection - recurrent UTI > 2 weeks after treatment
Recurrent: >/= 2 in 6 months or >/= 3 in 12 months
Define asymptomatic bacteriuria
The presence of a specified quantified count of bacteria within urine WITHOUT UTI symptoms. The bacteria colonise the surrounding area. Positive urine dip and MC&S.
- Commonly observed in the elderly
- Does not indicate an UTI
HOWEVER - Must screen and treat pregnant women and those soon to undergo urological procedures
List the pre-disposing factors for UTIs
(include risk factors for complicated UTIs)
- Female gender - much more common (short urethra)
- Diabetes
- Sexual intercourse
- Spermicide use
- Pregnancy
- Catheterisation (‘plastic’ within the urinary system)
- Increasing age
- Immunocompromised
- Incomplete bladder emptying
Risk factors for complicated UTIs: Pregnancy, male gender, advanced age, diabetes, renal failure, Hx of UTIs, BPH, tract obstruction, immunosuppression, recent antimicrobial use
List common causative organisms of UTIs
- 95 % caused by infection via the ascending route
- GI tract is the main reservoir of uropathogens
- Gram negative bacillus: E. coli (90% of outpatient, 50 inpatient)
Others:
-
Enterobacteriaceae: Causes increased alkalinity to urine, increasing predisposition to kidney stones
- Proteus and Klebsiella: Associated with nephrolithiasis
- Staphylococcus saprophyticus: Related to sexual intercourse
- Enterococcus Faecalis: Elderly men with prostatism
- Fungal: Canadida Sp.
- Viral: Adenovirus
-
Catheter related:
- E. coli
- Proteus
- Pseudomonas Aeruginosa
- Candida
-
Haematogenous seeding to the UTI:
- Staph. aureus
- Pseudomonas Aeruginosa
- Salmonella Sp
Outline the clinical presentation and relevant hx for a patient with an UTI
Cystitis vs pyelonephritis
Clinical presentation:
Cystitis: Dysuria, polyuria, urgency, suprapubic pain
Pyelonephritis: Above symptoms + sudden onset, nausea/vomiting, malaise, chills, fever, flank pain, renal angle tenderness
Hx:
- Hx of UTIs (recurrent in childhood)
- Recent antibiotic treatment
- Regular medication - as some may affect choice of antibiotics (warfarin, contraceptive pill, statins, transplant medications)
- Systemic features? → suggestive of upper UTI or nephrolithiasis
Outline the methods and diagnostic criteria for UTIs
Urine dip
Urine dip:
- Performed for all suspected UTIs
- Nitrites indicates presence of gram negative bacilli (convert nitrates to nitrites)
- Leucocyte esterase: Indicates WBCs are present, sign of infection
- Positive for both > 90 % have UTI
When to use:
- Female with few or mild symptoms of cystitis
- Male with mild or non-specific symptoms of UTI - as a negative dipstick can exclude UTI
Outline the methods and diagnostic criteria for UTIs
Urine culture
Mainly used for patients who are susceptible to complicated UTI
When to use:
- Men
- Pregnant women
- Child < 3 y/o
- Suspected upper tract, recurrent or complicated infection
- If resistant organisms are suspected
- Symptoms persist or recur within 3 months
- Single positive result for leucocyte esterase or nitrite obtained from urine dip
- Symptoms do not correlate to dipstick result
Outline the methods and diagnostic criteria for UTIs
Other investigations
- FBC for systemically unwell patients
- Imaging may be used to assess for structural abnormalities
Outline modes of therapy for acute, chronic, and complicated UTI, including prophylaxis for recurrent infection.
Uncomplicated UTI:
- Nitrofuratoin, trimethoprim, pivmecillinam
Complicated UTI:
- Check urine culture and sensitivity
Upper UTI:
- Coamoxiclav
- Cefuroxime
- Ciprofloxacin
Prophylaxis:
- Standby antibiotics: Begin course as soon as symptoms appear
- Post coital antibiotics
- May rotate antibiotics to avoid resistance: Require low c.diff risk; review @ 6 months and consider ceasing treatment
Suggest possible differential diagnoses
Females and males
