URINARY TRACT INFECTION


See also "Pediatric Urinary Tract Infection"

I. Presentation of acute cystitis: Dysuria, increased urinary frequency, urgency, suprapubic/flank discomfort

II. Asymtpomatic bacteriuria in young women

  1. In a 6mo population study of 796 healthy young women who underwent monthly urine cultures, 5% of all cultures were positive (> 100,000 cfu/mL); 8% of which were follwed by a symptomatic UTI within 1wk (NEJM 343:992, 2000--JW)

III. Risk factors

  1. Sexual activity
  2. Use of condoms with spermicide (Arch. Int. Med. 158:281, 1998--AFP; J. Inf. Dis. 182:1177, 2000--JW)
  3. Diminished defenses (syst. illness or resid. urine)
  4. Pregnancy
  5. DM, SSA, analgesic abuse can all cause papillary necrosis with sloughing and consequent obstruction & UTI
  6. Pre- and post-coital voiding, use of hot tubs or tampons, wearing of pantyhose, douching, water consumption, and BMI in a case-control study of 482 pts (J. Inf. Dis. 182:1177, 2000--JW)

IV. Dangers of repeated UTI: If DM or VU reflux, can predispose to upper UTI; if preg, can cause fetal probs

V. Physical exam: Look for urethral d/c; vag erythema, d/c, atrophy; cervical erosions; vesicles

VI. Differential diagnosis

  1. 10-15% of women with sx of urethritis have neg U/A & Cx; of these, 70% have true inf with <10K bact, or chlamydia; 30% have no inf.
  2. Vaginitis (+ vag d/c, + dyspareunia, + ext. itching, -freq/urg; -Cx)
  3. Non-gram-neg urethritis (chlamyd,GC,trich, candida,HSV;+ pelvic pain, vag d/c, cervicitis, vesicles, gradual onset)
  4. "Acute urethral syndrome" from local trauma/irritation, esp in postmenopausal women
  5. Pyelonephritis (+ fever, flank pain, N/V, systemic sx, *but lower UTI can present with these too*)

VII. Treatment

  1. Antibiotics, increased fluid intake, (f/u for repeat urinalysis and culture--recommended by some in my experience but I'm not sure if there's evidence to support)
  2. Treatment of pyelonephritis
    1. Outpt tx may be appropriate for most upper-tract UTI's as evidenced by a randomized trial in 141 pts demonstrating similar outcomes with Cipro IV vs. PO (Arch. Int. Med. 159:53, 1999--JW)
    2. In 255 women with acute uncomplicated pyelonephritis randomized to Ciprofloxacin 500mg PO BID x 1wk vs. Trimethoprim-Sulfamethoxazole DS 1 PO BID x 2wks, cure rates at 22-48d f/u were 91% and 77% (summary doesn't say whether diff. was sig.; JAMA 283:1583, 2000--JW)
  3. Treatment of asymptomatic bacteriuria
    1. 105 non-pregnant women with Diabetes Mellitus and asymptomatic bacteriuria (2 positive urine cultures in 2 weeks) randomized to antibiotic treatment (14d of abx then repeat courses for recurrences of bacteriuria) vs. placebo.  Over mean 2y f/u, no sig. diffs between groups in frequency of symptomatic UTI's, time to first symptomatic UTI, # of hospitalizations for UTI's, or incidence of renal failure (NEJM 347:1576, 2002--JW)

VIII. Prophylaxis for recurrent UTI

  1. 135 premenopausal women with 3 or more UTI's in last 12mos randomized to Cipro 125 QD vs. Cipro 125 after each coitus; equally effective at preventing recurrence of UTI (only 2 women from eah group had a UTI in the 12mos of f/u; J. Urol 157:935, 1997-JW)
  2. Cranberry-Lingonberry juice concentrate 50cc QD was ass'd with sig. lower risk of recurrent UTI c/w placebo or Lactobacillus GG (16% vs. 39% and 36, respectively) in a 1y randomized trial in150 women with one episode of E. coli UTI (BMJ 322:1571, 2001--JW)

IX. Urinary Tract Infection in Pregnancy

  1. Preferred antibiotics to treat UTI in pregnancy: Amoxicillin, amoxicillin/clavulanate, nitrofurantoin, cephalexin
    1. Avoid trimethoprim-sulfamethoxazole because of antigolate activity of trimethoprim in first trimester and potential contribution to neonatal hyperbilirubinemia if used near delivery
    2. Avoid nitrofurantoin in patients with G6PD deficiency and/or near term
  2. Asymptomatic bacteriuria
    1. Overall incidence is 5% of pregnancies
    2. Strongest predictor is prior h/o UTI; also low socioeconomic status
    3. If untreated, 40% will progress to cystitis and 30% will progress to pyelonephritis
    4. Also associated with low birth weight and preterm delivery
    5. Commonly screened for with urinalysis and culture at 12-16wks gestation (or first prenatal visit if occurs later in pregnancy)
    6. E. coli is most common organism; also other gram-negative bacteria and Group B Streptococcus
  3. Acute cysitis
    1. Overall incidence is 1.3% of pregnancies
    2. Same common bacteria as asymptomatic bacteriuria (see above)
  4. Pyelonephritis
    1. Overall incidence is 1% of pregnancies
    2. Same common bacteria as asymptomatic bacteriuria (see above)
    3. Usually requires hospitalization for aggressive hydration and IV antibiotics (ampicillin/gentamicin most common; also third-generation cephalosporins) until afebrile x 48h then oral antibiotics for total 10-14d course
      1. Uterine contractions after initiation of antibiotics seen in 86% of patients in first hour and 50% for > 5h; rarely associated wiht cervical change
      2. In mild pyelonephritis may be safe to treat with initial dose of pareneteral antibiotics and observe 2-24h then treat as outpatient but requires ability to tolerate oral fluids, close follow-up, and no evidence of end-organ dysfunction (see below)
    4. Can result in hemolysis with anemia, sepsis with ARDS, and renal disease with hypertension; Also preterm labor, and low birth weight
  5. Secondary prophylaxis during the same pregnancy
    1. Recurrence rate is 25%, so should have...
    2. Urine culture to confirm cure within 2wks after starting treatment
    3. Monthly urine cultures advised for duration of the pregnancy
    4. Daily prophylaxis with nitrofurantoin 50-100mg/d or cephalexin 250-500mg/d until 4-6wks postpartum
(Sources include Core Content Review in Family Medicine, 2012)