Best Dx/Best Rx: Urinary Tract Infection

From: Subject: Best Dx/Best Rx: Urinary Tract Infection Date: Wed, 3 Jun 2009 21:34:25 -0700 MIME-Version: 1.0 Content-Type: multipart/related; type="text/html"; boundary="----=_NextPart_000_01C9_01C9E493.1144B250" X-MimeOLE: Produced By Microsoft MimeOLE V6.00.2900.5579 This is a multi-part message in MIME format. ------=_NextPart_000_01C9_01C9E493.1144B250 Content-Type: text/html; charset="Windows-1252" Content-Transfer-Encoding: quoted-printable Content-Location: http://www.acpmedicine.com/acp/newrxdx/rxdx/dxrx0723.htm Best Dx/Best Rx: Urinary Tract Infection

Urinary = Tract=20 Infection

Kalpana Gupta, M.D., M.P.H.
Walter E. Stamm, = M.D.=20
University of Washington School of Medical

Defin= ition/Key=20 Clinical Features
Best = Tests
Best = Therapy
Best = References

Definition/Key Clinical=20 Features

General

Includes the following:=20
- Asymptomatic bacteriuria=20
- Cystitis
- Prostatitis
- Pyelonephritis
Clinical symptoms do not always correlate with = site of=20 infection (bladder vs. kidney) or with degree of bacteriuria=20
No test differentiates bladder infections from = kidney=20 infections=20
May be acute, recurrent (repeated infections = with the=20 same or different organisms), or complicated=20
Usually affects females
Usually caused by gram-negative bacilli =

Cystitis

Dysuria=20
Urinary frequency=20
Urgency=20
Nocturia=20
Suprapubic or back pain=20
Urine cloudy, malodorous, or bloody =

Acute Pyelonephritis

Fever=20
Shaking chills=20
Nausea and vomiting=20
Symptoms often follow cystitis symptoms =

Prostatitis

Fever=20
Chills=20
Dysuria=20
Frequency, urgency=20
Perineal, back, or pelvic pain=20
Difficulty urinating=20
Prostate is enlarged, tender, and = indurated=20

Clinical Pearls

In men of any age with acute febrile = UTI=20
- Perform prostatic exam=20
- Assess postvoiding residual urine = volume=20
In women=20
- Restrict evaluations to those with = frequently=20 recurring infection and recurrent pyelonephritis despite adequate=20 therapy

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Best=20 Tests

No culture required before treatment in = otherwise=20 healthy women with typical symptoms of acute cystitis=20
Cultures should be obtained in all other = patient=20 groups

Urine Culture

In men or women with asymptomatic bacteriuria =
- Growth of >10⁵ colonies/ml of = single=20 bacterial species in 2 consecutive samples is diagnostic =
In children=20
- >10⁵ colonies/ml also = used=20
In men,=20
- Minimum diagnostic level is 10³=20 organisms/ml
Negative Gram stain does not rule out = infection=20
Cultures growing mixed bacterial species = should be=20 repeated

Urinalysis

Presence of squamous epithelial cells suggests = contamination
Dipstick for leukocyte esterase, nitrite, or = both has=20 about 90% sensitivity and 70% specificity for infection =

Imaging Studies

Rarely needed for the following:=20
- Acute cystitis=20
- Acute pyelonephritis
Reserve for evaluation of the = following:=20
- Abscess=20
- Tumor=20
- Stones
- Obstruction=20
- Relapsing infections
For I.V. pyelography,
ultrasound, or CT=20
- Use to rule out obstruction in urosepsis or = acute=20 pyelonephritis unresponsive to antimicrobial
- Ultrasound is preferred test =
For contrast-enhanced helical CT=20
- First choice for evaluating renal = infections=20
- Use noncontrast CT when renal calculi = suspected=20
I.V. pyelography + voiding = cystourethrography:=20
- Use to delineate surgically correctable = lesions that=20 might predispose to recurrent UTI or progressive renal = disease=20
- Obligatory to look for congenital anomalies = in young=20 children

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Best=20 Therapy

Acute Uncomplicated Cystitis

Empirical Regimens

Otherwise-healthy women
- 3-day regimens
  - Oral TMP-SMX
  - TMP
  - Fluoroquinolone=20
  - Cefixime
  - Cefpodoxime
- 7-day regimens=20
  - Nitrofurantoin monohydrate/macrocrystals =
  - Nitrofurantoin macrocrystals (see Oral=20 Regimens, below)
- Follow up after 3=967 days; if symptomatic, = order=20 urinalysis and urine culture=20
  - If pyuria is present with no bacteriuria, = evaluate=20 for cystitis or urethritis=20
  - If bacteriuria is present, treat with a=20 fluoroquinolone or TMP-SMX for 14 days
Pregnancy=20
- 7-day regimen=20
  - Oral amoxicillin
  - Nitrofurantoin monohydrate/macrocrystals =
  - Nitrofurantoin macrocrystals=20
  - Cefixime=20
  - Cefpodoxime proxetil
  - TMP-SMX (see Oral Regimens, = below)=20
For patients who have diabetes, who have = symptoms for=20 greater than 7 days, who have recently used antimicrobials, who are = older than=20 65 yr, or who are male=20
- 7-day regimen=20
  - Oral TMP-SMX
  - Fluoroquinolone
  - Cefixime
  - Cefpodoxime proxetil (see Oral = Regimens,=20 below)

Oral Regimens

TMP-SMX=20
- Efficacy: > 90%=20
- Can be used in pregnancy
- High resistance in some communities =
Fluoroquinolones:=20
- Efficacy: > 90%
- Avoid in pregnancy=20
- Men: 7=9614 days=20
  - Ciprofloxacin
    - Dose: 100=96250 mg q. 12 hr=20
    - Cost/mo: $257.48 (250 mg) =
  - Levofloxacin=20
    - Dose: 250 mg q.d.=20
    - Cost/mo: $222.98
  - Ofloxacin
    - Dose: 200 mg q. 12 hr=20
    - Cost/mo: $218.65
  - Norfloxacin
    - Dose: 400 mg q. 12 hr=20
    - Cost/mo: $235.97 =
Cefixime=20
- Efficacy: > 90%=20
- Dose: 400 mg q.d.=20
- Cost/mo: not available
Nitrofurantoin = monohydrate/macrocrystals=20
- Efficacy: > 75%=20
- Avoid in pregnancy=20
- Men: 7=9614 days=20
- Dose: 100 mg q. 12 hr=20
- Cost/mo: $108.98
Amoxicillin:
- Efficacy: >75%=20
- Dose: 100 mg q. 12 hr=20
- Cost/mo: = $15.10

Prophylaxis for recurrent UTI in = women

If more than 3 symptomatic episodes a year,=20 suggest=20
- Voiding after sexual intercourse,=20
- Use of contraception other than diaphragm +=20 spermicide,=20
- Drinking cranberry/lingonberry juice =
Prescribe continuous or postcoital low-dose=20 antimicrobial prophylaxis for 6 mo, then discontinue and observe=20 response=20
- Single-dose TMP-SMX=20
  - Efficacy: high=20
  - Dose: half a 20/300 mg tablet =
- Ciprofloxacin=20
  - Efficacy: high=20
  - Dose: 250 mg q.d.=20
  - Cost/mo: $128.74
- Nitrofurantoin=20
  - Efficacy: high=20
  - Dose: 50 mg or 100 mg macrocrystals=20

Acute Uncomplicated = Pyelonephritis

Immediate treatment with oral or parenteral=20 antimicrobial agent to which invading organism is presumed or known to = be=20 sensitive, followed by=20
- Oral therapy to eradicate residual tissue=20 infection

Antimicrobial Agents for = Pyelonephritis

Ciprofloxacin:=20
- Can be given orally or I.V. followed by oral =
- Resistance rare
- Efficacy: high=20
- Dose
  - Oral: 500 mg q. 12 hr x 7=9614 days =
  - I.V.: initially, 400 mg q. 12 hr =
- Cost/mo: $297.98
Ampicillin + gentamicin=20
- Particularly useful if urine Gram stain = shows 6PC=20 (enterococci) or in complicated UTI=20
- Reduce dose with renal failure=20
- Efficacy: high=20
- Dose:
  - Initially, ampicillin 1 g I.V. q. 6 = hr=20
  - Gentamicin, 1 mg/kg I.V. q. 8 hr=20
TMP-SMX=20
- Reduce dose with renal failure=20
- Efficacy: high
- Entire course of therapy for patients with = mild=20 disease who can tolerate oral
- 14-day course following initial parenteral = therapy is=20 very effective
- Resistance high enough in some areas to = preclude=20 empiric use=20
- Dose: 160/800 mg q. 12 hr x 14 days =
Third-generation cephalosporins=20
- Reduce dose with renal failure=20
- Efficacy: high=20
- Less published clinical experience=20
- Cefixime=20
  - Dose: Oral: 400 mg q.d. x 7=9614 = days
- Ceftazidime=20
  - Dose: I.V.: initially 500 mg q. 12 = hr=20
Imipenem/cilastatin:=20
- Reduce dose with renal failure=20
- Efficacy: high=20
- Useful in complicated UTI
- Dose: I.V.: initially 500 mg q. 6=20 hr

UTI in Pregnancy

Asymptomatic bacteriuria should be diagnosed = and=20 treated=20
The following are safe in early = pregnancy=20
- Sulfonamides=20
- Nitrofurantoin=20
- Ampicillin=20
- Cephalosporins
Avoid trimethoprim and fluoroquinolones =

Prostatitis

Treatment of acute prostatitis
- TMP-SMX, 160/800 mg b.i.d. for at least 4 = wk=20
- Ciprofloxacin, 250 mg b.i.d. for 2 wk =

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Best References

Kontiokari, et al: BMJ 322:1571, 2001

McCarty, et al: Am J Med 106:292, 1999

Talan, et al: JAMA 283:1583, 2000

Wing, et al: Obstet Gynecol 92: 249, = 1998

July=20 2004

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