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Acute Pyelonephritis & Complicated UTI

UTI

Source: IDMP View on spectrum chart →
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Patient
Clinical scenario / source

Annotations only — chart still shows the full chemistry of each drug.

1. Clinical Syndrome

Upper urinary tract infection — flank pain, fever, costovertebral angle tenderness, ± nausea/vomiting — with pyuria + bacteriuria on UA and culture. Includes: uncomplicated pyelonephritis (otherwise-healthy non-pregnant women) and complicated UTI (men, pregnancy, indwelling catheter, structural / functional anomaly, immunocompromise, recent urologic instrumentation).

Excludes: lower-tract cystitis without upper-tract signs (use uncomplicated-cystitis), urosepsis with hemodynamic instability (escalate to sepsis syndrome), prostatitis (separate management).

2. Pathogens

Consider the patient: Pregnancy (changes drug choice + need for IV initially), prior abx exposure (resistance risk), prior MDR isolate (ESBL, Pseudomonas), age, DM, immunocompromise, urologic anatomy / catheter / stent.

Consider the case: Local antibiogram (E. coli FQ-resistance often >20% — check before empiric cipro), recurrent infection (≥2 in 6 mo or ≥3 in 12 mo → urology workup), recent hospitalization (MDRO risk).

Less common

3. Empiric Therapy

TierFirst choiceAlternativesDurationComments
Outpatient
  • 500 mg · PO BID · PO · 7 days

    Only if local E. coli FQ-resistance <10%.

  • 1 DS tab (160/800 mg) · PO BID · PO · 14 days

    Only if susceptibility confirmed.

  • 1 g · single dose IV/IM · IV · single dose

    Single ED dose followed by oral β-lactam step-down (cefpodoxime 200 mg PO BID × 10–14 d).

7 days FQ; 14 days TMP-SMX or β-lactamOtherwise-healthy non-pregnant adult, hemodynamically stable, tolerating PO.
Admitted to ward
  • 1–2 g · q24h · IV · 7 days uncomplicated; 10–14 days complicated
  • 400 mg · IV q12h · IV · 7 days
  • 1 g · q24h · IV

    If ESBL risk or prior ESBL isolate.

Step down to PO once afebrile + tolerating PO; total 7 days uncomplicated, 10–14 days complicatedAdmitted for sepsis, dehydration, vomiting, or social factors. Always send blood + urine cultures.
Admitted to ICU
  • 4.5 g · q6h (extended infusion) · IV
  • 2 g · q8h · IV
  • 1 g · q8h · IV

    If ESBL risk.

10–14 daysSeptic shock, urosepsis. Add vancomycin if GP cocci on Gram stain or hemodialysis.

Add coverage if:

Pseudomonas coverage
  • Recurrent UTI on fluoroquinolone
  • Indwelling catheter or stent
  • Recent hospitalization
  • Prior Pseudomonas isolate

Add:

  • 2 g · q8h · IV

    Or pip-tazo. Replaces ceftriaxone.

ESBL coverage
  • Prior ESBL isolate
  • Recent broad-spectrum antibiotics ≤90 days
  • Travel to high-prevalence region
  • Recurrent UTI on TMP-SMX or fluoroquinolone

Add:

  • 1 g · q24h · IV

    Or meropenem if ICU. Avoid pip-tazo for severe ESBL infection (MERINO trial).

4. Directed Therapy

Once cultures back, narrow:

  • Pan-S E. coli / Klebsiella: cefazolin → cephalexin step-down, or amoxicillin
  • ESBL: ertapenem; PO step-down rarely viable
  • Enterococcus: ampicillin (preferred over vancomycin if susceptible)
  • Pseudomonas: cipro PO if susceptible, otherwise continue IV anti-pseudomonal

Repeat urine culture not routinely needed if symptoms resolve. Image (CT or US) if no defervescence by 72 h to exclude obstruction or abscess.

5. Monitoring

Resolution: afebrile within 48–72 h. Persistent fever / pain → image for obstruction, abscess, or emphysematous pyelonephritis (DM).

Toxicity: ceftriaxone biliary sludging in pregnancy; FQ tendinopathy + QTc; TMP-SMX K+ + Cr.

Pearls

Don't treat asymptomatic bacteriuria except in pregnancy or pre-urologic procedure. Recurrent uncomplicated UTI ≠ complicated — workup only if structural / functional concerns. Group B Strep in pregnancy urine = treat as UTI even if asymptomatic (vaginal colonization implied → intrapartum prophylaxis).

References