Urinary Tract Infections - Clinical Presentation

Question 1

What is defined as a significant bacteriuria and who gets a lower cutoff?

Answer 1

> 10^5 CFU/mL of urine

lower cut-off is used in sympomatic patients

Question 2

What is an asymptomatic bacteruria?

Answer 2

Significant bacteriuria in absence of any signs / symptoms suggestive of UTI

Question 3

What is a cystitis? How does this contrast with pyelonephritis?

Answer 3

Cystitis -> a lower UTI, where the infection is confined to the superficial bladder mucosa

Pyelonephritis = an upper UTI

Question 4

What is the definition of an uncomplicated UTI? Does it have anything to do with severity?

Answer 4

Cystitis OR pyelonephritis occurring in an otherwise healthy non-pregnant woman with no underlying structural or functional abnormalities of the urinary tract.

Has nothing to do with severity

Question 5

Is infection with a multi-drug resistant pathogen or health-care associated infection considered complicated or uncomplicated?

Answer 5

Complicated

Question 6

What is recurrence vs relapse vs reinfection?

Answer 6

Recurrence = another UTI (about 25% will have another UTI within 1 year)

Relapse = recurrence with same micro-organism (usually <2 weeks)

Reinfection = recurrence with different micro-organism
(usually >2 weeks)

Question 7

What is the most common source of bacteremia due to gram negative organisms?

Answer 7

UTI’s!

Question 8

In early infancy, do males or females get UTI’s more?

Answer 8

Males!, although prevalence is very low still

Question 9

At what age do UTI’s in men start to pick up and why?

Answer 9

> 36 years old, due to BPH (incomplete voiding)

Question 10

Why do pregnant women get UTI’s more? What is the prevalence?

Answer 10

The child can cause incomplete voiding. Asymptomatic bacteruria occurs in 5% of pregnant women. 40% will develop pyelonephritis if untreated

Question 11

Other than a shorter urethra, what is another reason why men get fewer UTI’s than women?

Answer 11

Prostatic secretions are antibacterial

Question 12

What is there a dose-response between UTI risk in in young women?

Answer 12

Higher frequency of sexual intercourse = increased risk of UTI (facilitates entry of micro-organisms into bladder)

Question 13

What are the characteristics of urine that make it hard to inhabit the UT?

Answer 13

High osmolality, low pH, presence of organic acids, and it’s constantly being flushed out

Question 14

How does cystitis present?

Answer 14

Dysuria, and urgency / frequency with possible hematuria

Suprapubic tenderness / lower back pain may be present. Systemic signs will be absent.

Question 15

How is cystitis differentiated from vaginitis and urethritis?

Answer 15

Vaginitis - will have vaginal discharge, and no frequency / urgency

Urethritis - caused by STI’s, no frequency / urgency

Question 16

What is the main clinical feature of pyelonephritis vs cystitis?

Answer 16

Pyelonephritis the patient will clearly be “sick” - systemic signs will be present (fever, chills, nausea, vomiting, hypotension if septic)

Physical exam may be notable for costovertebral tenderness, and there may be flank pain

Question 17

What is difficult about the diagnosis of UTI in the elderly?

Answer 17

Asymptomatic bacteriuria is very common - a change in mental status and unexplained fever / incontinence may be the presenting complaint

It must be a diagnosis of EXCLUSION - we want to treat the bigger underlying problem

Question 18

What is the presentation of UTI in infant patients?

Answer 18

Non-specific: poor feeding, failure to gain weight, GI symptoms, and unexplained fever

Question 19

How is UTI likely to present in preschoolers / toddlers?

Answer 19

A recurrence of daytime/nocturnal enuresis, and fever + lower tract symptoms

Question 20

What do you test for when you put a dipstick in a “midstream, clean catch” specimen?

Answer 20

Red blood cells, white blood cells, and bacteria

Question 21

What is pyuria and how much is needed to be supportive of a UTI?

Answer 21

WBCs in the urine - more than 5-10 leukocytes per high-power field is considered significant

Question 22

What corresponds to a CFU of greater than 10^5 per mL?

Answer 22

One or more bacteria per high power field in an unspun specimen

Question 23

Is it recommended to get a urine culture in all cases of UTI?

Answer 23

No, not in uncomplicated cystitis. It is recommended to treat these empirically

For an uncomplicated pyelonephritis you should get a urine culture!

Question 24

Some people have subclinical pyelonephritis. What is one specific but not sensitive test for determining this?

Answer 24

WBC casts in the urine - a WBC which is deformed by a renal tubule

Differentiation is usually done on clinical grounds

Question 25

What should never be used to diagnose a UTI?

Answer 25

The gross appearance and smell of urine - has more to do with patient’s hydration status and recent dietary intake

Question 26

What are the more rarer causes of cystitis?

Answer 26

PEK - facultative anaerobes. + Enterococcus - more likely nosocomial

Question 27

Who is most likely to get a UTI from coag-negative Staphylococci?

Answer 27

Pediatric population

Question 28

What are the treatments for uncomplicated cystitis? Complicated?

Answer 28

Nitrofurantoin or bactrim for 3-5 days

Complicated generally gets 7 days

Question 29

How is uncomplicated vs complicated pyelonephritis treated?

Answer 29

Uncomplicated - 7 day course

Complicated - 14-28 days

Question 30

What are the cases in which asymptomatic bacteriuria is treated?

Answer 30

1. Pregnancy (bad outcomes for child)
2. Prior to invasive instrumentation of urinary tract for a procedure (need to do a pre-culture)
3. Renal transplant patient (during first 6 months post transplant)

Question 31

When is radiologic imaging done for UTI and what are the modalities?

Answer 31

For recurrent pyelonephritis or pyelonephritis which is not responding (likely peri-renal / intranephric abscess), especially complicated infections

CT, ultrasound, and special imaging in children with vesicouteral reflex