Genitourinary infection

Background

Definitions

• UTI = significant bacteriuria in presence of symptoms
  • Described by location: urethritis, cystitis, or pyelonephritis
• Relapse
  • Recurrence of symptoms w/in month despite tx
    • Caused by same organism and represents treatment failure
• Reinfection
  • Development of symptoms 1-6mo after tx
  • Usually due to a different organism
  • If pt has >3 recurrences in 1 yr consider tumor, calculi, diabetes
• Men <50 yr: symptoms of dysuria or urinary frequency usually due to STI
• Men >50 yr: incidence of UTI rises dramatically d/t prostatic obstruction
• Uncomplicated UTI:
  • No structural or functional abnormalities w/in urinary tract or kidney
  • No relevant comorbidities that place pt at risk for more serious adverse outcome
  • Not associated with GU tract instrumentation

Risk factors for complicated UTI

1. Male sex
   1. In young males dysuria is more commonly d/t STI
   2. Suspect underlying anatomic abnormality in men with culture-proven UTI
2. Anatomic abnormality of urinary tract or external drainage system
   1. Indwelling urinary catheter, stent
   2. Nephrolithiasis, neurogenic bladder, polycystic renal disease, recent instrumentation
3. Recurrent UTI (three or more per year)
4. Advanced age in men (BPH, recent instrumentation, recent prostatic biopsy)
5. Nursing home residency (w/ or w/o indwelling bladder catheter)
6. Neonatal state
7. Comorbidities (DM, sickle cell disease)
8. Pregnancy
9. Immunosuppression (AIDS, immunosuppressive drugs)
10. Advanced neurologic disease (CVA w/ disability, Spinal Cord Injuries)
11. Known or suspected atypical pathogens (Non–E. coli infection)
12. Known or suspected abx resistance (resistance to Cipro predicts multidrug resistance)

Bacteriology

• Most common pathogen is E. coli
• Anaerobic organisms are rarely pathogenic (do not grow well in urine)
• Complicated UTIs more likely to be caused by pseudomonas or enterococcus

Diagnosis

Clinical Features

• UTI dx requires both bacteriuria and clinical symptoms
  • Cystitis = Dysuria, hematuria, frequency, urgency, suprapubic pain, CVAT
  • Pyelo = Cystitis sx AND fever/chills/nausea/vomiting
    • CVAT alone may be referred pain from cystitis
    • CVAT is only physical examination finding that increases likelihood of a UTI
• Urethritis
  • In males more likely due to chlamydia/GC
  • In females more likely due to chlam/GC if:
    • Stuttering urination symptoms
    • New sex partner or partner w/ urethritis
    • Signs/symptoms cervicitis
    • Sterile pyuria
• Complicated UTI
  • Pts may not have classic symptoms; may only have weakness, fever, abd pain, AMS

Labs

UA

WBC count

• WBC >5 in pt w/ appropriate symptoms is diagnostic
  • Lower degrees of pyuria may still be clinically significant in presence of UTI sx
    • False negative may be due to: dilute urine, systemic leukopenia, obstruction
  • WBC 1-2 w/ bacteriuria can be significant in men
    • More likely represents urethritis or prostatitis from STI

Nitrite

• Very high specificity (>90%) in confirming diagnosis of UTI
• Low sensitivity (enterococcus, pseudomonas, acinetobacter are not detected)

Urine Culture

• Indicated for:
  • Complicated UTI
  • Pyelonephritis
  • Pregnant women
  • Children
  • Adult males
  • Relapse/reinfection

Blood Culture

• Not indicated
  • Organisms in blood cx matched those in urine cx 97% of time

Imaging

• Consider if pyelonephritis and any of the following:

1. History of Renal Stone
2. Poor response to antibiotics
3. Male
4. Elderly
5. Diabetic
6. Severely ill

Management

• Consider local resistance patterns (if >10-20% use a different agent)
• Avoid use of fluoroquinolones for uncomplicated cystitis if possible
• Consider longer course of tx for uncomplicated cystitis if:
  • Symptoms >7d
  • DM
  • UTI in previous 4wk
  • Men
  • Age 65 yr
  • Women who use spermicides or diaphragm
  • Relapse

Women, uncomplicated cystitis

• Nonpregnant, few prior UTI episodes, symptoms <7d, no flank pain or fever

1. Nitrofurantoin ER 100mg BID x 5d OR
2. TMP-SMX DS (160/800mg) 1 tab BID x 3d OR
3. Cephalexin 250mg QID x 5d OR
4. Ciprofloxacin 250mg BID x3d

Women, complicated cystitis/pyelo

• Risks for complicated UTI or symptoms of pyelo

1. Ciprofloxacin 500mg BID x10-14d OR
2. Cefpodoxime 200 mg BID x10-14d

Women, uncomplicated cystitis AND urethritis

1. CTX 250mg IM x1 AND azithromycin 1gm PO x1 AND nitrofurantoin ER 100mg BID x5d OR
2. Levofloxacin 500mg QD x 14d (covers UTI pathogens, GC, and chlam)
   1. GC resistance to fluoroquinolones is increasing

Men, cystitis/pyelo

• Consider urethritis and prostatitis

1. Ciprofloxacin 500mg BID x10-14d OR
2. Cefpodoxime 200 mg BID x10-14d

Inpatient

• Ciprofloxacin 400mg IV q12hr OR
• Ceftriaxone 1gm IV QD OR
• Cefotaxime 1-2gm IV q8hr OR
• Gentamicin 3mg/kg/day divided q8hr +/- ampicillin 1–2 gm q4hr OR
• Piperacillin-tazobactam 3.375 gm IV q6hr OR
• Cefepime 2gm IV q8hr OR
• Imipenem 500mg IV q8hr

Disposition

Uncomplicated UTI

• Admit
  • Unable to tolerate PO
• Discharge
  • Consider phenazopyridine 100-200mg TID after meals x2d only (bladder analgesic)

Pyelonephritis

• Discharge
  • Consider if young, otherwise healthy, tolerating PO
• Admission
  • Consider if elderly, Renal Calculi, obstruction, recent hospitalization/instrumentation, DM

Complications

• Suspect in pts who have inadequate or atypical response to tx for presumed pyelonephritis

1. Acute bacterial nephritis
   1. CT shows ill-defined focal areas of decreased density
2. Renal/Perinephric Abscesses
   1. Sign/symptoms similar to pyelo (fever, CVAT, dysuria)
   2. Occurs in setting of ascending infection w/ obstructed pyelo
   3. Associated w/ DM and Renal Stones
   4. Also occurs due to bacteremia w/ hematogenous seeding (Staph)
3. Emphysematous pyelonephritis
   1. Rare gas-forming infection nearly always occurring in pts w/ DM and obstruction
      1. Pts appear toxic and septic; nephrectomy may be required

Special Populations

AIDS

• TMP-SMX resistance is increased due to its use in PCP PNA prophylaxis
  • Fluoroquinolones should be initial antibiotic of choice
• Most UTIs are caused by typical pathogens or common STI organisms

Pregnant Women

• Treat all cases of asymptomatic bacteriuria

See Also

• UTI (Peds)
• Dysuria (DDX)

Source

Tintinalli