Urinary Tract Infections - Clinical Presentation Flashcards
What is defined as a significant bacteriuria and who gets a lower cutoff?
> 10^5 CFU/mL of urine
lower cut-off is used in sympomatic patients
What is an asymptomatic bacteruria?
Significant bacteriuria in absence of any signs / symptoms suggestive of UTI
What is a cystitis? How does this contrast with pyelonephritis?
Cystitis -> a lower UTI, where the infection is confined to the superficial bladder mucosa
Pyelonephritis = an upper UTI
What is the definition of an uncomplicated UTI? Does it have anything to do with severity?
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
Is infection with a multi-drug resistant pathogen or health-care associated infection considered complicated or uncomplicated?
Complicated
What is recurrence vs relapse vs reinfection?
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)
What is the most common source of bacteremia due to gram negative organisms?
UTI’s!
In early infancy, do males or females get UTI’s more?
Males!, although prevalence is very low still
At what age do UTI’s in men start to pick up and why?
> 36 years old, due to BPH (incomplete voiding)
Why do pregnant women get UTI’s more? What is the prevalence?
The child can cause incomplete voiding. Asymptomatic bacteruria occurs in 5% of pregnant women. 40% will develop pyelonephritis if untreated
Other than a shorter urethra, what is another reason why men get fewer UTI’s than women?
Prostatic secretions are antibacterial
What is there a dose-response between UTI risk in in young women?
Higher frequency of sexual intercourse = increased risk of UTI (facilitates entry of micro-organisms into bladder)
What are the characteristics of urine that make it hard to inhabit the UT?
High osmolality, low pH, presence of organic acids, and it’s constantly being flushed out
How does cystitis present?
Dysuria, and urgency / frequency with possible hematuria
Suprapubic tenderness / lower back pain may be present. Systemic signs will be absent.
How is cystitis differentiated from vaginitis and urethritis?
Vaginitis - will have vaginal discharge, and no frequency / urgency
Urethritis - caused by STI’s, no frequency / urgency
What is the main clinical feature of pyelonephritis vs cystitis?
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
What is difficult about the diagnosis of UTI in the elderly?
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
What is the presentation of UTI in infant patients?
Non-specific: poor feeding, failure to gain weight, GI symptoms, and unexplained fever
How is UTI likely to present in preschoolers / toddlers?
A recurrence of daytime/nocturnal enuresis, and fever + lower tract symptoms
What do you test for when you put a dipstick in a “midstream, clean catch” specimen?
Red blood cells, white blood cells, and bacteria
What is pyuria and how much is needed to be supportive of a UTI?
WBCs in the urine - more than 5-10 leukocytes per high-power field is considered significant
What corresponds to a CFU of greater than 10^5 per mL?
One or more bacteria per high power field in an unspun specimen
Is it recommended to get a urine culture in all cases of UTI?
No, not in uncomplicated cystitis. It is recommended to treat these empirically
For an uncomplicated pyelonephritis you should get a urine culture!
Some people have subclinical pyelonephritis. What is one specific but not sensitive test for determining this?
WBC casts in the urine - a WBC which is deformed by a renal tubule
Differentiation is usually done on clinical grounds
What should never be used to diagnose a UTI?
The gross appearance and smell of urine - has more to do with patient’s hydration status and recent dietary intake
What are the more rarer causes of cystitis?
PEK - facultative anaerobes. + Enterococcus - more likely nosocomial
Who is most likely to get a UTI from coag-negative Staphylococci?
Pediatric population
What are the treatments for uncomplicated cystitis? Complicated?
Nitrofurantoin or bactrim for 3-5 days
Complicated generally gets 7 days
How is uncomplicated vs complicated pyelonephritis treated?
Uncomplicated - 7 day course
Complicated - 14-28 days
What are the cases in which asymptomatic bacteriuria is treated?
- Pregnancy (bad outcomes for child)
- Prior to invasive instrumentation of urinary tract for a procedure (need to do a pre-culture)
- Renal transplant patient (during first 6 months post transplant)
When is radiologic imaging done for UTI and what are the modalities?
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
