UTIs Flashcards
Lower tract UTI
Bladder, prostate, urethra
Mainly bladder = cystitis
Upper tract UTI
Kidney, ureter
Mainly kidney = pyelonephritis
Symptoms of cystitis
Dysuria Frequency Urgency Suprapubic pain/discomfort Cloudly/smelly urine Hematuria = blood in urine
Symptoms of pyelonephritis
Flank/back pain High fever, chills Headache Nausea/vomiting Maybe septic shock \+/- cystitis symptoms
What is the difference between uncomplicated and complicated UTI?
Uncomplicated = UTI in healthy patient with normal urinary tract
Complicated = UTI associated with factors that predispose to bacterial infection and decrease efficacy of therapy
What are some things that constitute a complicated UTI?
Abnormal GU tract (anatomic or functional)
Immunocompromised/unhealthy host
Multi-drug resistant bacteria
What is a UA?
Urinalysis
Chemical strip analysis = dipstick
-Screening for urinary blood, pus (leukocytes), bacteria, pH, specific gravity (concentration), protein, glucose
Microscopic analysis = definitive test for blood (RBC) and pus (leukocytes); can be false positive dipsticks so should always be confirmed by microscopic analysis
What is leukocyte esterase?
Detects pyuria (pus or WBC in urine) UTIs usually have pyuria -- but so does pregnancy, vaginal infection, inflammation, tumors and stones
What is the sensitivity and specificity of leukocyte esterase?
Sensitivity for UTI = high
Specificity for UTI = low
What does nitrites test for?
Some bacteria use nitrates for energy and convert them to nitrites by nitrate reductase
What is the sensitivity and specificity for nitrites?
Sensitivity = low Specificity = High
Positive nitrite test rules in UTI but a negative test doesn’t rule it out
Blood - microscopic hematuria
Dipstick detects the peroxidase activity of erythrocytes
Myoglobin and hemoglobin can catalyze this reaction –> false positives
Microscopy required for confirmation
Microhematuria noted in 50% of women with acute UTI
How long can microscopic hematuria hang around?
Could persist put o one week after successful treatment of UTI but if it persists beyond this –> 5-22% will have serious urologic disease (0.5-5% will have GU malignancy)
Persistent microhematuria after successful treatment of UTI requires urologic investigation
What does a urine culture do?
Determines growth of bacteria from urine sample
- Identifies and quantifies bacterial species
- Determines sensitivities to various antibiotics
What are some different collection methods for urine specimens?
Clean catch voided specimen
Catheterized specimen
Suprapubic aspirate
What counts as significant bacteria?
> 100,000 cfu/mL, especially if symptomatic
What are some common uropathogens in uncomplicated UTI?
E. coli (80%)
S. Saprophyticus
Enterbacteriaceae
Gram positives - S. aureus, GBBS, enterococci
What are some common complicated UTI uropathogens?
E. coli (20%) Enterobacteriaceae Pseudomonas Acinetobacter Gram positive bacteria - S. aureus, Coag - Staph Yeasts and fungi Parasites
Treatment for UTI
Antibiotics are mainstay
May start Abx based on best guess (empiric treatment)
Want Abx concentrations high in urine
Antibiotics – high to low urine concentrations
Cabrenicillin > Cephalexin > Ampicillin > TMP/SMX > Cipro > Nitrofurantoin
How long should Abx be administered for UTI treatment
Uncomplicated UTI in healthy female –> 3-5 days (sometimes up to 7)
Complicated UTI –> must correct any structural or functional urinary tract abnormality and treat with Abx for at least 7 d, often longer (10-14)
What are some tests that may function as adjuvant tests in UTI?
CBC – to see if WBC is elevated
Basic chem – creatinine, electrolytes
Imaging to determine if hydronephrosis, stones, abscess
When is imaging needed?
For complicated UTIs that have predisposing factors (GU anomalies, hx of stones), lack of response to appropriate therapy and recurrent pyelonephritis
What are some causes of bacterial persistence?
Inadequate/inappropriate/incomplete abx therapy Stones/foreign bodies Chronic bacterial prostatitis Urethral diverticula Fistula Urinary stasis
How are recurrent UTI’s managed?
Abx taken daily or every other day to prevent symptomatic recurrent
Prophylaxis - prevent outside re-infection
Suppression - prevent bacterial persistence
Recommended antibiotics for long-term prophylaxis
Nitrofurantoin Bactrim Trimethoprim Cipro *Typically used for 6 months of longer (years for pediatric vesicoureteral reflux)
UTIs still tend to recur once prophylaxis is discontinued :(
What are some forms of non-antibiotic prophylaxis?
Methenamine salts – converted to formaldyhyde and ammonia in acidic urine
Cranberry juice – prevention only
Ascorbic acid (vitamin C) – acidifies the urine
Who are some individuals that may have asymptomatic bacteriuria?
Elderly women Pregnancy Diabetes Use of catheters SC injury
Do you treat asymptomatic bacteriuria?
Generally not.
Treatment does not reduce incidence of symptomatic UTI, it recurs after treatment is stopped, overuse can lead to resistance
EXCEPT IN PREGNANCY – prevent preterm labor
