UTIs

Question 1

Lower tract UTI

Answer 1

Bladder, prostate, urethra

Mainly bladder = cystitis

Question 2

Upper tract UTI

Answer 2

Kidney, ureter

Mainly kidney = pyelonephritis

Question 3

Symptoms of cystitis

Answer 3

Dysuria 
Frequency 
Urgency 
Suprapubic pain/discomfort
Cloudly/smelly urine
Hematuria = blood in urine

Question 4

Symptoms of pyelonephritis

Answer 4

Flank/back pain
High fever, chills
Headache
Nausea/vomiting
Maybe septic shock 
\+/- cystitis symptoms

Question 5

What is the difference between uncomplicated and complicated UTI?

Answer 5

Uncomplicated = UTI in healthy patient with normal urinary tract

Complicated = UTI associated with factors that predispose to bacterial infection and decrease efficacy of therapy

Question 6

What are some things that constitute a complicated UTI?

Answer 6

Abnormal GU tract (anatomic or functional)
Immunocompromised/unhealthy host
Multi-drug resistant bacteria

Question 7

What is a UA?

Answer 7

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

Question 8

What is leukocyte esterase?

Answer 8

Detects pyuria (pus or WBC in urine) 
UTIs usually have pyuria -- but so does pregnancy, vaginal infection, inflammation, tumors and stones

Question 9

What is the sensitivity and specificity of leukocyte esterase?

Answer 9

Sensitivity for UTI = high

Specificity for UTI = low

Question 10

What does nitrites test for?

Answer 10

Some bacteria use nitrates for energy and convert them to nitrites by nitrate reductase

Question 11

What is the sensitivity and specificity for nitrites?

Answer 11

Sensitivity = low 
Specificity = High 

Positive nitrite test rules in UTI but a negative test doesn’t rule it out

Question 12

Blood - microscopic hematuria

Answer 12

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

Question 13

How long can microscopic hematuria hang around?

Answer 13

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

Question 14

What does a urine culture do?

Answer 14

Determines growth of bacteria from urine sample

• Identifies and quantifies bacterial species
• Determines sensitivities to various antibiotics

Question 15

What are some different collection methods for urine specimens?

Answer 15

Clean catch voided specimen
Catheterized specimen
Suprapubic aspirate

Question 16

What counts as significant bacteria?

Answer 16

> 100,000 cfu/mL, especially if symptomatic

Question 17

What are some common uropathogens in uncomplicated UTI?

Answer 17

E. coli (80%)
S. Saprophyticus
Enterbacteriaceae
Gram positives - S. aureus, GBBS, enterococci

Question 18

What are some common complicated UTI uropathogens?

Answer 18

E. coli (20%) 
Enterobacteriaceae 
Pseudomonas
Acinetobacter
Gram positive bacteria - S. aureus, Coag - Staph
Yeasts and fungi
Parasites

Question 19

Treatment for UTI

Answer 19

Antibiotics are mainstay
May start Abx based on best guess (empiric treatment)
Want Abx concentrations high in urine

Question 20

Antibiotics – high to low urine concentrations

Answer 20

Cabrenicillin > Cephalexin > Ampicillin > TMP/SMX > Cipro > Nitrofurantoin

Question 21

How long should Abx be administered for UTI treatment

Answer 21

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)

Question 22

What are some tests that may function as adjuvant tests in UTI?

Answer 22

CBC – to see if WBC is elevated
Basic chem – creatinine, electrolytes
Imaging to determine if hydronephrosis, stones, abscess

Question 23

When is imaging needed?

Answer 23

For complicated UTIs that have predisposing factors (GU anomalies, hx of stones), lack of response to appropriate therapy and recurrent pyelonephritis

Question 24

What are some causes of bacterial persistence?

Answer 24

Inadequate/inappropriate/incomplete abx therapy 
Stones/foreign bodies
Chronic bacterial prostatitis 
Urethral diverticula
Fistula
Urinary stasis

Question 25

How are recurrent UTI’s managed?

Answer 25

Abx taken daily or every other day to prevent symptomatic recurrent

Prophylaxis - prevent outside re-infection
Suppression - prevent bacterial persistence

Question 26

Recommended antibiotics for long-term prophylaxis

Answer 26

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 :(

Question 27

What are some forms of non-antibiotic prophylaxis?

Answer 27

Methenamine salts – converted to formaldyhyde and ammonia in acidic urine
Cranberry juice – prevention only
Ascorbic acid (vitamin C) – acidifies the urine

Question 28

Who are some individuals that may have asymptomatic bacteriuria?

Answer 28

Elderly women
Pregnancy 
Diabetes
Use of catheters
SC injury

Question 29

Do you treat asymptomatic bacteriuria?

Answer 29

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