Urinary Tract Infections

Question 1

Upper tract vs. lower tract infections:

Answer 1

Upper tract infection - above the level of the bladder, including the kidneys.
Lower tract infection - infections that involve only the bladder, urethra and/or prostate.

Question 2

Ascending route of infection vs. hematogenous spread:

Answer 2

Ascending route of infection - infection via the urethra

Hematogenous spread - via the blood

Question 3

Urine contamination vs. urine colonization:

Answer 3

Contamination - occurs when bacteria enter the urine after it has left the body from some sort of anatomic or environmental source.
Colonization - organisms are present in the urine, but are not causing symptoms.

Question 4

Complicated urinary tract infection implies one or more of the following:

Answer 4

1) obstruction of the urinary tract due to an anatomic abnormality or foreign body obstruction
2) functional disruption of urine flow (neuromuscular dysfunction)
3) systemic or local abnormalities of immune function

Question 5

Re-infection vs. relapsing infection:

Answer 5

Re-infection: multiple unique infections, often with different organisms. More common. Short treatment (3 days) is sufficient.
Relapsing infection: infection never completely clears, and thus the offending organism is the same with each bout. Less common. When UTI symptoms recur within two weeks, consider a relapsing infection. Long treatment (2-6 weeks) is often required.

Question 6

Staphylococcus in the urine:

Answer 6

Should raise concerns about bacteremia and other infections caused by Staph (endocarditis).

Question 7

UTIs in infants:

Answer 7

Consider some sort of anatomical abnormality. This group is most prone to kidney damage from recurrent UTIs.

Question 8

Epidemiology of UTIs:

Answer 8

Females > Males in childhood, adolescents, and adulthood.

Males > Females in old age (prostate enlargement).

Question 9

Organisms causing UTIs:

Answer 9

E. coli (95% of uncomplicated cases), due to type-1 pili (P-pili) which allows it to adhere to uroepithelial lining.
Staph saprophyticus in younger women.
Rarer causes: Pseudomonas, Klebsiella, Serratia, or other Enterobacteria. In these cases, consider the possibility of a complicated UTI.

Question 10

UTI diagnosis:

Answer 10

Urinalysis is always the first step.
Greater than 5-10 WBCs/HPF is indicative of infection, as is the presence of bacteria in the spun urine. Leukocyte esterase and nitrite test are also helpful. On gram-stain, the presence of one organism per HPF correlates with bacterial growth of 10^5 per cc.
If the patient is SYMPTOMATIC, the presence of 10^2 organisms is considered significant.
If the patient is ASYMPTOMATIC, the presence of 10^5 organisms in urine culture obtained on 2 separate days is considered significant.
Imaging of the urinary tract may also be useful.

Question 11

UTIs in young men:

Answer 11

Consider evaluation for STDs.

Question 12

UTIs in pregnant women:

Answer 12

Dilation of ureters predisposes them to ascending infections. Screen all pregnant women for bacteriuria, regardless of symptoms, and treat.

Question 13

UTIs in the elderly:

Answer 13

Treatment is only indicated for symptomatic or certain complicated UTIs. Do not treat asymptomatic bacteriuria. There is no increased morbidity or mortality associated with asymptomatic bacteriuria.

Question 14

Treatment for prostatitis:

Answer 14

Trimethoprim-sulfamethoxazole (TMP-SMX) or quinolones. (2+ weeks of treatment).

Question 15

Treatment for lower tract UTI (outpatient):

Answer 15

TMP-SMX (assuming E. coli resistance is low). Alternatives include nitrofurantoin or ciprofloxacin.

Question 16

Treatment for upper tract UTI (outpatient):

Answer 16

Ciprofloxacin (100% bioavailability).

Question 17

Prophylaxis for recurrent UTIs:

Answer 17

TMP-SMX, trimethoprim, nitrofurantoin, cephalexin, ciprofloxacin. (Most useful in women who have 3 or more infections of the re-infection type within a given year.)

Question 18

Treatment for upper tract UTI (inpatient):

Answer 18

Usually implies more serious infection.

Aminoglycosides plus ampicillin. Other choices include piperacillin/tazobactam or ciprofloxacin.

Question 19

Upper UTI vs. lower UTI symptoms:

Answer 19

Upper UTI symptoms: fever, flank pain, nausea, vomiting, clinical sepsis.
Lower UTI symptoms: dysuria, urgency, urinary frequency, and suprapubic pain.

Question 20

Relapse should be suspected:

Answer 20

When urinary symptoms recur within 2 weeks of the initial bout.