Urinary Tract Infections

Urinary Tract Infections
By:Lourdes Lozano Vargas

Urinary Tract Infections
* Leading cause of morbidity and health care expenditures in persons of all ages.
* An estimated 50 % of women report having had a UTI at some point in their lives.
* 8.3 million office visits and more than 1 million hospitalizations, for an overall annual cost > $1 billion.

Acute Uncomplicated Cystitis
* Sexually active young women.
* Causes: anatomy and certain behavioral factors, including delays in micturition, sexual activity, and the use of diaphragms and spermicides tract.
* Aggressive diagnostic work-ups are unwarranted in young women presenting with an uncomplicated episode of cystitis.

Acute Uncomplicated Cystitis
* The microbiology is limited to a few pathogens.
* 70%- 85% are caused by Escherichia coli
* 5-20%are caused by coagulase-negative Staphylococcus saprophyticus
* 5-12% are caused by other Enterobacteriaceae such as Klebsiella and Proteus.

Acute Uncomplicated Cystitis
* Clinical Features: dysuria, frequency, urgency, suprapubic pain, hematuria.
o Fever >38C, flank pain, costovertebral angle tenderness, and nausea or vomiting suggest upper tract infection.

Acute Uncomplicated Cystitis
* Diagnosis: direct history and PE
* PE: Temperature, abdominal exam, assessment of CVA tenderness, pelvic exam.
o H/o STD’s, new sexual partner, partner with urethral symptoms, gradual onset.

Acute Uncomplicated Cystitis
* Guidelines for tx of acute cystitis recommend empiric antibiotic tx.
* Unnecessary antibiotic use??
* Clinical criteria for Dx:

Dysuria, presence of > trace urine leukocytes, and presence of nitrites or...
Dysuria and frequency in the absence of vaginal discharge.
Acute Uncomplicated Cystitis
* UA: Evaluation of midstream urine for pyuria.
o White blood cell casts in the urine are Dx of upper tract infection.
* Urine Culture: Not necessary
o Warranted in: Suspected complicated infection, persistent symptoms following tx, symptoms recur < 1 mo after tx. Acute Uncomplicated Cystitis * Urine dipsticks: o Leukocyte esterase (pyuria), sensitivity 75-90%, specificity 95% o Nitrite (Enterobacteriacea), sensitivity 35-85%, specificity 95%, false positive with phenazopyridine, beets. o Microscopic evaluation for pyuria or a culture is indicated in pt with negative leukocyte esterase that have urinary symptoms. Acute Uncomplicated Cystitis * Susceptibility: o E.coli o S.saprophyticus Acute Uncomplicated Cystitis * Treatment: o Short course vs. prolonged tx + Short course preferred except with beta-lactam agents o TMP-SMX (160/800mg BID x 3) first-line tx if: no allergy to the drug, no antibiotics in the past 3 mo, no recent hospitalization. o Nitrofurantoin (100mg BID x 5 days) o Analgesia: Phenazopyridine 200mg TIDx2 Acute Urethral Syndrome * Acute symptomatic women with dysuria and frequency with a midstream culture containing < 10(5) CFU/mL. * > 10(2) CFU/mL in women with acute symptomatic pyuria = UTI
* Tx as an uncomplicated UTI
* Mycoplasma genitalium, Ureaplasma urealyticum

Acute Complicated Cystitis
* UTI when/with structural, functional or metabolic abnormalities (polycystic, solitary, transplant kidney;DM, CRF, indwelling cath, neurogenic bladder) or elderly, male, child, pregnant or h/o recurrent UTI)
* E.coli accounts for fewer than one third of complicated cases.
* Clinically, the spectrum of complicated UTIs may range from cystitis to urosepsis with septic shock.

Acute Complicated Cystitis
* Urine culture and susceptibility are necessary.
* These infections are usually associated with high-count bacteriuria (> 10(5) CFU/mL).
* MO: Proteus, Klebsiella, Pseudomonas, Serratia, and Providencia, enterococci, staphylococci and fungi AND E.coli

Acute Complicated Cystitis
* Empiric therapy for these patients should include an agent with a broad spectrum of activity against the expected uropathogens: fluoroquinolone, ceftazidime, cefepime, aztreonam, imipenem-cilastatin. (Obtain Ucx prior to Tx)
* Tx x 7-14 days
* Follow-up urine culture should be performed within 14 days after treatment???

Recurrent Cystitis
* Up to 27% of young women with acute cystitis develop recurrent UTIs.
* The causative organism should be identified by urine culture.
* Relapse: infection with the same organism (multiple relapses = complicated UTIs).
* Recurrence: infection with different organisms.

Recurrent Cystitis
* >3 UTI recurrences documented by urine Cx within one year can be managed using one of three preventive strategies:
* Acute self-treatment with a three-day course of standard therapy.
* Postcoital prophylaxis with one-half of a TMP-SMX double-strength tablet (80/400 mg).
* Continuous daily prophylaxis TMP-SMX one-half tablet per day (40/200 mg); nitrofurantoin 50 to 100 mg per day; norfloxacin 200 mg per day.

Uncomplicated Pyelonephritis
* Suspect if:
o Cystitis-like illness and accompanying flank pain
o Severe illness with fever, chills, nausea, vomiting, abdominal pain
o Gram-negative bacteremia.

Uncomplicated Pyelonephritis
* DX: Clinical, confirm with:
o UA: pyuria and/or WBC casts
o UCx with > 10 (5) CFU/mL (80%)
* Tx: 14 days total
o Oral: TMP/SMX, fluoroquinolones
o IV: 3rd gen cephalosporin, aztreonam, quinolones, aminoglycoside

Uncomplicated Pyelonephritis
* Pt with symptoms after 3 days of appropriate antimicrobial tx should be evaluated by renal US or CT for obstruction or abscess.

UTI in Men

* At risk: Older men with prostatic disease, UT instrumentation, anal sex, or partner colonized with uropathogens.
* UCx: 10 (3) CFU/mL sensitivity and specificity 97%.
* Additional studies?
o Not necessary in young healthy men who have a single episode.

UTI in Men
* Tx:
o Uncomplicated cystitis:
+ TMP/SMX or fluoroquinolones x 7 days
o Complicated cystitis:
+ Fluoroquinolones x 7-14 days
o Bacterial prostatitis:
+ Fluoroquinolone x 6-12 weeks

Catheter-Associated UTI
* Risk of bacteriuria is ~ 5%/day (long term catheter bacteriuria is inevitable).
* 40% of nosocomial infections
* Most common source of gram-negative bacteremia.
* Dx: Ucx 10 (2) CFU/mL
o MO: E.coli, Proteus, Enterococcus, Pseudomona, Enterobacter, Serratia, Candida

Catheter-Associated UTI
* Mild to mod: oral quinolones10-14days
* Severe infection: IV/oral 14-21days
* Asymptomatic bacteriuria in pt with an indwelling Foley should not be Tx unless they are immunosuppressed, have risk of bacterial endocarditis or pt who are about to undergo urinary tract instrumentation.

Asymptomatic Bacteriuria
* UCx: > 10(5)CFU/mL with no symptoms
* Three groups of pt with asymptomatic bacteruria have been shown to benefit from tx:
o Pregnant
o Renal transplant
o Pt who are about to undergo urinary tract procedures.

Pregnant patients

* Asymptomatic bacteriuria: two consecutive voided urine specimens with isolation of the same bacterial strain >10(5) or a single cath urine specimen.
o Nitrofurantoin 100mg BID x 5-7 days
o Amoxi/Clav 500mg BID or 250 TID x 7days
o Fosfomycin 3g PO x 1

Interstitial Cystitis
* Frequency, urgency, urge incontinence with periurethral and suprapubic pain on bladder filling that is improved by voiding. Terminal hematuria may be present.
* Etiology. Unclear (autoimmune, altered glycosaminoglycal layer, allergic)

Interstitial Cystitis
* TX
o Refer to urology for cystoscopy.
o Dietary modifications
o Behavioral modifications
o Rx:
+ Pyridium
+ Pentosan polysulfate 100mg TID x 6mo to 2 years.
+ Amitriptyline 10-75mg QHS

Interstitial Cystitis
* Intravesical therapies
o Dimethyl Sulfoxide instillations q1-2 wks
o BCG instilled q1wk x 6-8 wks
o Hyaluronic acid instilled q1wk x 4-6wk.

References

Urinary Tract Infections.ppt