UTI - Pathophysiology + Management Flashcards
Define uncomplicated (1) vs complicated UTI (5)
Uncomplicated
- cystitis in a healthy, premenopausal female (can treat post-menopausal women with no GU abnormalities)
Complicated UTI
- Pyelonephritis
- Male
- Pregnancy
- Child <12
- any structural or functional abnormalities in the GU tract
What is the more likely pathophysiology of UTI
Ascending infection
- UTI occurs when vaginal vestibule is colonized with colonic flora -> bacteria ascend urethra (causing cystitis) -> bacteria ascend ureter(s) to kidneys (causing pyelonephritis)
What are the defence mechanism of the GU tract (4)
- Length of Urethra in men
- Larger distance between rectum and urethral opening
- Forceful flushing through urination
- Lactobacillus colonization of vaginal vestibule
What are risk factors for UTI (5)
- Female
(Male risk is higher in <1 and 65+) - Sexual intercourse
- Use of spermicide/diaphragm (massages the urethra and makes it easier for bacteria to move upwards)
- Family/personal history of UTI
- Structural/functional abnormalities
What is defined as recurrent UTI (2)
2 episodes in 6 months
3 episodes in 1 year
What is the timeline where re-infection occurs?
Should return more than 2 weeks after therapy
What does it mean if symptoms come back less than 2 weeks after therapy and you relapse
Treatment failure, never treated the initial infection
What are clinical features of Cystitis
Common (3)
uncommon (2)
- Dysuria
- Urinary urgency
- Urinary frequency
May also experience
- hematuria
- Suprapubic pain or tenderness
What are clinical features of pyelonephritis
Common (3)
Uncommon (1)
- Fever, chills
- Nausea, vomiting
- Low back pain, flank pain, costovertebral angle tenderness
May also experience
- sx of cystitis
What is the costovertebral angle
The angle between the vertebrae and bottoms ribs, where the kidneys are located
What kind of symptoms is 90% indicative of cystitis
Females with dysuria and frequency WITHOUT vaginal symptoms
When would perform a urinalysis?
New incontinence
Gross hematuria (dark red blood in urine)
Urgency on it its own
When would you CONSIDER performing a urinalysis
In POSTmenopausal women with persistent urinary symptoms DESPITE adequate treatment, or have recurrences
What do urinalysis via dip sticks do a qualitative analysis of (3)
Which is the most common in UTI?
Hematuria
Leukocyte esterase
Nitrite
Most common: Microscopic hematuria
What does leukocyte esterase test for?
What do the results indicate?
Test for pus in urine (pyuria)
Non-specific for inflammation
It is present in all uncomplicated UTI
- low risk of false negative
- therefore a negative is more useful than a positive
- can have false positives
What does testing for nitrites identify for?
What do the results indicate in which type of bacteria is present?
Identifies nitrates formed by bacterial reduction of urinary nitrates
- indicates presence of Enterobacterales
Why are false negatives possible with nitrites? (2)
- Requires enough bacteria and contact time (4hrs)
- Not all bacteria are capable of nitrite redduction (gram pos eg. Enterococcus, saprophyticus)
What does the urinalysis nitrite test not differentiate between?
From UTI and Asymptomatic bacteriuria
- only perform on symptomatic patients
What do urinalysis via microscopy do a quantitative analysis of? (2)
Leukocytes and bacteria
What does leukocytes via microscopy test for?
What does a negative result suggest?
Pyuria = 10+ HPF
A negative result suggests alternate diagnosis
- NOT uncomplicated UTI
What is bacteria via microscopy presented as?
What does it indicate?
Presented as 1+ to 4+ (3+/4+) is high
Indicates quantity, not # of species
Is culture and susceptibility quantitative or qualitative?
Is it required for uUTI?
Quantitative
No
What is culture and susceptibility indicated for? (5)
- Recurrent UTI
- suspected pyelonephritis
- Patients at risk for infection with resistant pathogen
- Symptoms return within 2-4 weeks of effective therapy (elapse)
- symptoms not improved despite 48-72 hrs of antimicrobial
Which method of urine sampling is the lowest risk for contamination?
Suprapubic Aspiration
When is foley used? What is it?
Used for complicated UTI patients
A tube inserted into the urethra into bladder
T/F Bacteria in urine does not equal bacteria in bladder
True
T/F Bacteria in bladder equals infection
False
- could be asymptomatic bacteriuria
What is the most common pathogen in uUTI?
Less common?
Most common
- E. Coli
Less common
- S. Saprophyticus (more common in Cystitis than Pyelonephritis - doesn’t always have to be covered in UTI)
- Proteus spp. + Klebsiella spp. (Will likely be covered when E. Coli is covered)
Why is there selection bias with the data in antibiograms?
Overestimate/underestimate?
Cultures are only sent for patients that are more complicated, have higher resistance, treatment failure etc..
Overestimating for resistance + ESBL probability
Which pathogen do we consider covering in pyelonephritis?
Enterococcus
Which drugs would you be concerned about resistance if they used it in the last 3-6 months (2)
Septra
FQ (cipro)
Who is at risk for ESBL for E. coli + Klebsiella? (2)
- Recent urine culture (<3 months) positive for ESBL
- Travel to Africa, Asia in the last 3-6 months
**Only concerned with SEVERE illness such as ICU
Treating someone with suspected ESBL in:
Inpatient
Outpatient
For Inpatients:
- Must use CARBAPENEM for empiric treatment ESBL infections (empiric treatment)
- Once susceptibility data is confirmed -> then can step down to another ABX that works against that specific pathogen
For outpatients:
- Nitrofurantoin and Fosfomycin are ORAL agents that are effective against ESBLs
Do uncomplicated cystitis resolve on their own? How long?
Yes, 40% in 9 days
T/F it is not possible for uncomplicated cystitis to progress to pyelonephritis
False
What is the role of NSAIDs in uCystitis
NSAID group had symptom resolution by day 4 but still inferior to antibiotics
- slight higher risk of pyelonephritis though
What is a reasonable % resistance risk to avoid in an antibiogram when looking at E. coli for Ucystitis
20%
What are the preferred option uCystitis (3)
Nitrofurantoin 100mg BID for 5 days
Septra 1 DS tablet BID for 3 days
Fosfomycin 3g for 1 dose
What is the alternate treatment for uCystitis if they are allergic to sulfa?
Trimethoprim 100mg BID for 3 days
Nitrofurantoin efficacy (2)
- Risk for E. coli resistance is low
- effective against ESBL
Nitrofurantoin safety (2)
- decreased collateral damage
- GI side effects (more common with QID)
- can be lessened with milk or food
What are contraindications of nitrofurantoin (3)
- CrCl <30 mL/min
- G6PD deficiency (hemolytic anemia)
- 3rd trimester or breastfeeding <1mos or premature
What are the rare side effects with nitrofurantoin (2)
Pulmonary reaction
- acute cough, SoB, fever, infiltrate on CXR (reversible)
- Chronic with 6+ month use is irreversible fibrosis or pneumonitis
Peripheral neuropathy
- tingling, prickling, numbness
- more likely in older patients with decreased renal function taking longer than 5 days
Fosfomycin efficacy
- Inferior to nitrofurantoin when dosed TID
- Superior to nitrofurantoin in 60ml/min CrCl
- Low E. coli resistance and has activity against ESBL
(usually saved for antibiotic resistant organisms first)
Fosfomycin safety (2)
- Not indicated for <18
- Decreased collateral damage
What is an important counselling point for Fosfomycin monitoring
may still have symptoms for 24-48h and this is NOT a sign the drug’s not working (concentrations may remain elevated for a period of time)
Why are oral beta-lactams not preferred for uCystitis
- high resistance at baseline
- even those with lower resistance, does not work as well
- longer duration of therapy (5-7 days)
Which beta-lactams may be reasonable but not preferred (2)
Amoxi-clav
Cephalexin
Why are FQ not used frequently? (2)
Duration?
Similar effectiveness when pathogen is susceptible
Significant collateral damage and adverse effect profile
3 day duration
Which FQ is not used in UTI
Moxifloxacin
- not excreted in urine
When should symptoms improve for UTI
Within 72 hours
- often improve within the first hours of first dose
What are reasons for treatment failure (2)
non-adherence
Resistance (Urine culture)
Define relapse
symptom return within 2-4 weeks after therapy
What steps should you take if there is a relapse
- Urine culture
- physical exam to rule out complicated features
- retreat with different agent +/- longer duration of therapy
For minor ailments, what symptoms rule IN cystitis
Acute dysuria OR
At least 2 of:
- new urgency or frequency
- hematuria (not a lot)
- Suprapubic pain/discomfort
For minor ailments, what symptoms rule OUT pyelonephritis. (3)
How soon should you see a doctor if this is true?
- Fever/chills
- flank/back pain
- N/V
Should see ED within 24 hours
Minor ailments, what other causes can should you rule out for acute dysuria etc.. (5)
- Symptoms lasting 2+ weeks
- History of interstitial cystitis
- Vaginitis (vaginal symptoms)
- Gross hematuria
- Drug-induced cystitis (cyclophosphamide, allopurinol, danazol, tiaprofenic acid)
What are complicating features where you would have to refer in minor ailments (7)
- <12 years
- Pregnant
- LTC residence
- Immunocompromise
- Male
- return of symptoms within 4 weeks (2 in 6 months or 3 in 12 months)
- abnormal GU structure (BPH, kidney stones)
Define reinfection, most common reason for recurrent UTI
Symptoms return 4 weeks AFTER therapy
What are risk factors for premenopausal women for recurrent UTI (6)
- New sexual partner
- Frequency of intercourse
- Use of spermicide or diaphragm
- maternal history
- first episode before 15 years
- Abx use within the last month
What are risk factors for postmenopausal women for recurrent UTI (2)
- Loss of vaginal estrogen
- at risk for many more conditions that could lead to complicated cystitis
What are non-pharms for recurrent UTI
Avoid spermicides
Increase fluid intake (over 1L+/day)
Cranberry (only goof for prevention)
Post-coidal voiding (no evidence, not harmful)
What patient population should get continuous prophylaxis?
What is the preferred treatment?
3+ UTI/year NOT related to coitus
Septra 40/200mg HS or 80/400 3x weekly
- consider stopping in 6-12 months
What patient population falls under post-coital treatment prophylaxis?
Preferred treatment?
3+ UTI/year and related to coitus after 24-48 hrs
1 DOSE of septra within 2 hours of intercourse
What patient population should get acute self-rx?
Preferred treatment
Only for patients who can recognize symptoms well and can rule out pyelonephritis
Regular treatment doses and duration
Which antibiotic is not usually used for prophylaxis treatment
Fosfomycin
- long half-life
What is the monitoring for self-acute Rx treatment
Symptoms should resolve within 48 hours
- stricter than 72h cut off
Classify the following drugs in terms of safety in pregnancy
Nitrofurantoin
Fosfomycin
Sulfamethoxazole
Trimethoprim
FQs
Cepahalosporins
Amoxi-clav
Nitrofurantoin
- contraindicated in 3rd trimester
Fosfomycin
- Safe
Sulfamethoxazole
- contraindicated 3rd trimester
Trimethoprim
- contraindicated in 1st trimester (dec folic acid)
FQs
- Safer alternatives exist
Cephalosporins
- Safe
Amoxi-clav
- Safe
What is asymptomatic bacteriuria most common in? (4)
Elderly women
Sexual active women
Pregnant women
Diabetics with complications
- neuropathy and urinary retention
- poorly controlled glucose in urine
What are the negative effects of ABU in pregnancy? (3)
- 20-30 fold increase in pyelonephritis
- increased risk of premature delivery
- low body weight
- increased fetal mortality (controversy)
How do we treat for asymptomatic bacteriuria in pregnancy
Never empiric
- wait for culture results
only treat when ABU is associated with harm AND there’s benefit to treat
How to treat pyelonephritis and cystitis in pregnant people
- Always culture
- admit if pyelonephritis
