Renal & Urinary

Urinary tract infection in adults: uncomplicated vs complicated

Clinical Overview and When to Suspect UTI

— Uncomplicated UTI: premenopausal, non-pregnant, immunocompetent woman with normal GU tract and no recent instrumentation

— Complicated UTI: any UTI with structural/functional GU abnormality, indwelling catheter, recent urologic procedure, immunocompromise, pregnancy, diabetes with poor control, renal failure, transplant, or all UTIs in men (traditionally)

— Recurrent UTI: ≥2 in 6 months or ≥3 in 12 months

— Acute dysuria, frequency, urgency, suprapubic pain without vaginal discharge/irritation → >90% probability of cystitis

— Flank pain, fever ≥38°C, CVA tenderness, N/V → pyelonephritis

— Altered mentation alone in elderly is not sufficient to diagnose UTI — look for localizing GU signs

— Female sex, sexual intercourse, spermicide/diaphragm, prior UTI, postmenopausal estrogen deficiency, DM, immunosuppression, urinary stasis (BPH, neurogenic bladder), stones, catheters

Definition framework — UTI = symptomatic bacteriuria; asymptomatic bacteriuria (ASB) is colonization, not infection

Epidemiology — lifetime risk in women ~50%; E. coli causes 75–95% of uncomplicated cases; Staph saprophyticus 5–15% (young, sexually active women)

When to suspect in primary care

Step 3 management: In a healthy non-pregnant woman with classic dysuria + frequency and no vaginal symptoms, empiric treatment without urinalysis or culture is appropriate — this is a high-yield ambulatory pearl. Phone-triage prescribing is acceptable per IDSA/AAFP.

Risk factors

Board pearl: Pyuria + bacteriuria without symptoms = ASB. Do NOT treat ASB except in pregnancy and before urologic procedures with expected mucosal trauma. Treating ASB in elderly, diabetics, or catheter patients increases resistance and C. difficile risk without benefit — a recurring Step 3 stewardship vignette.

Presentation Patterns and Key History

— Dysuria, urinary frequency, urgency, suprapubic discomfort, sometimes gross hematuria (~30%)

— Afebrile, no flank/back pain, no systemic symptoms

— Symptom onset typically <3–5 days

— Fever, chills, flank pain, CVA tenderness, nausea/vomiting ± dysuria

— May progress to sepsis; bacteremia in ~20–30%

— Male sex, pregnancy, known GU abnormality, indwelling/intermittent catheter, recent stenting/instrumentation, immunocompromise, transplant, poorly controlled DM, advanced CKD, nephrolithiasis, neurogenic bladder

— Healthcare exposure → resistant organisms (ESBL, Pseudomonas, Enterococcus)

— Distinguish relapse (same organism <2 weeks after therapy → consider stones, abscess, prostatitis) vs reinfection (different organism, later → behavioral risk factors)

— Always ask about prostatitis symptoms (perineal pain, obstructive voiding, fever) — acute bacterial prostatitis requires longer therapy and different antibiotic penetration

— Sexually active men: consider urethritis (GC/CT) before labeling as UTI

— Atypical: anorexia, weakness, falls, delirium — but require GU localizing signs or systemic infection markers to attribute to UTI

— Functional decline alone with positive UA → likely ASB

Acute uncomplicated cystitis

Acute pyelonephritis

Complicated UTI clues from history

Recurrent UTI history

Men with UTI

Elderly

Key distinction: Dysuria + vaginal discharge or irritation → think vaginitis or cervicitis, not UTI. Dysuria + flank pain + fever → pyelonephritis. Dysuria + perineal pain + obstructive symptoms in a man → prostatitis.

Sexual & contraceptive history — spermicide, new partner, frequency of intercourse (honeymoon cystitis), postcoital voiding habits

Board pearl: A positive nitrite or leukocyte esterase on UA in an asymptomatic patient does not justify antibiotics. The exam repeatedly tests the discipline of "treat the patient, not the urinalysis."

Physical Exam Findings and Hemodynamic Assessment

— Often normal exam; mild suprapubic tenderness

— Afebrile, normal vitals

— No CVA tenderness, no peritoneal signs

— Fever ≥38°C, tachycardia

— Unilateral CVA tenderness (Murphy's punch/Lloyd's sign)

— Abdominal tenderness, especially flank

— Assess for sepsis: qSOFA ≥2 (RR ≥22, SBP ≤100, AMS) or SIRS criteria

— SBP <90 or MAP <65

— HR >120

— Lactate ≥2

— Altered mentation

— Oliguria

— These trigger sepsis bundle: blood cultures ×2, lactate, broad-spectrum antibiotics within 1 hour, 30 mL/kg crystalloid if hypotensive or lactate ≥4

— Palpable bladder → outlet obstruction/retention

— Enlarged tender prostate → acute bacterial prostatitis (avoid vigorous prostate massage — risk of bacteremia)

— Costovertebral mass or fluctuance → perinephric abscess

— Indwelling catheter — inspect for purulence, encrustation

— Indicated if vaginal discharge, irritation, or no clear cystitis pattern → rule out vaginitis, cervicitis, PID

— Urethral discharge → urethritis; testicular tenderness → epididymo-orchitis

Uncomplicated cystitis

Pyelonephritis

Hemodynamic red flags warranting ED/inpatient triage

Complicated UTI exam clues

Pelvic exam in women with dysuria

Genital exam in men

CCS pearl: On the CCS exam for suspected pyelonephritis with sepsis, the high-yield order set is — IV access, 2 large-bore IVs, blood cultures × 2 before antibiotics, urine culture, lactate, CBC/BMP, IV crystalloid bolus, empiric ceftriaxone or piperacillin-tazobactam, continuous monitoring, and admit to telemetry or ICU based on response. Move the clock forward 1 hour and reassess vitals/lactate.

Board pearl: Bilateral CVA tenderness is less specific — consider musculoskeletal cause or obstructing bilateral stones if severe. Unilateral CVA tenderness with fever and pyuria = pyelonephritis until proven otherwise.

Diagnostic Workup — Initial Labs and Urinalysis

— Leukocyte esterase (LE): sensitivity ~75%, specificity ~85% for pyuria

— Nitrites: specific (~95%) but insensitive (~50%) — positive only with nitrate-reducing Enterobacteriaceae (E. coli, Klebsiella); negative with Staph saprophyticus, Enterococcus, Pseudomonas

— Pyuria: ≥10 WBC/hpf on microscopy

— Bacteriuria on microscopy supports infection

— Hematuria common in cystitis; if persistent post-treatment in adults >35 or with risk factors → workup for malignancy

— Not required for uncomplicated cystitis with classic symptoms

— Required for: pyelonephritis, complicated UTI, men, pregnancy, recurrent UTI, failed empiric therapy, healthcare-associated, recent antibiotics, catheter-associated

— Threshold: ≥10⁵ CFU/mL midstream; ≥10² CFU/mL if symptomatic woman with pyuria; ≥10³ CFU/mL from catheter

— Midstream clean-catch; in/out catheterization if unable

— Avoid culturing from chronic indwelling catheter — replace catheter first, then culture from new catheter

— CBC (leukocytosis), BMP (AKI, electrolyte derangement), lactate, blood cultures × 2 (positive in 20–30% of pyelonephritis)

— CRP/procalcitonin generally not required for diagnosis

— Pregnancy test in all reproductive-age women — changes management entirely

Urinalysis (UA) — dipstick + microscopy

Urine culture indications

Specimen collection

Additional labs when complicated/pyelonephritis suspected

Step 3 management: In a non-pregnant healthy woman with classic dysuria/frequency and no risk factors, empiric antibiotics without UA or culture is endorsed. Cost-effective and time-efficient. Order UA only if diagnosis uncertain or vaginal symptoms present.

Board pearl: Squamous epithelial cells >5/hpf on UA = contaminated sample → repeat with proper clean-catch technique before acting on results. White cell casts on microscopy localize infection to the kidney (pyelonephritis or interstitial nephritis).

Diagnostic Workup — Advanced and Confirmatory Studies

— Pyelonephritis not improving after 48–72 hours of appropriate antibiotics

— Sepsis, severe pain, hematuria persisting

— Suspected obstruction, stone, abscess

— Recurrent pyelonephritis or known anatomic abnormality

— Diabetes (risk of emphysematous pyelonephritis), immunocompromise

— CT abdomen/pelvis with IV contrast = best for perinephric abscess, emphysematous pyelo, obstructing stone, complicated anatomy

— Non-contrast CT (stone protocol) if renal function poor or stone strongly suspected

— Renal US — first line in pregnancy, children, or contrast contraindicated; detects hydronephrosis, abscess

— DMSA scan — pediatric scarring assessment, rarely Step 3

— Recurrent UTI in men

— Persistent hematuria after treatment

— Recurrent UTI in women with risk factors (age, smoking) → exclude bladder cancer

— Failure of recurrent UTI prevention strategies

— Bladder scan; PVR >150 mL suggests retention as contributor — especially elderly men (BPH), neurogenic bladder, post-stroke

Imaging — generally NOT needed for uncomplicated UTI or first-episode pyelonephritis responding to therapy

Indications for imaging

Modality selection

Cystoscopy / urology referral

Post-void residual (PVR)

Urodynamics — for suspected neurogenic bladder or refractory recurrent UTI

Special test: prostate exam + expressed prostatic secretions — chronic bacterial prostatitis workup; avoid in acute prostatitis

Key distinction: Emphysematous pyelonephritis = gas within renal parenchyma on CT, classically in poorly controlled diabetics, mortality ~20%. Treatment: aggressive resuscitation, broad-spectrum antibiotics, percutaneous drainage, sometimes nephrectomy. Renal/perinephric abscess >5 cm typically needs drainage; <3 cm may respond to antibiotics alone.

Board pearl: Persistent fever beyond 72 hours on appropriate antibiotics for pyelonephritis → image to exclude obstruction or abscess. This is a classic Step 3 inpatient management branch point.

Risk Stratification and Management Logic

— Uncomplicated cystitis → outpatient oral antibiotics

— Uncomplicated pyelonephritis, hemodynamically stable, tolerating PO → outpatient oral antibiotics with close follow-up acceptable

— Pyelonephritis with N/V, dehydration, sepsis, pregnancy, comorbidities, or social barriers → admit for IV therapy

— Complicated UTI / urosepsis → admit, often ICU if shock

— Hemodynamically stable

— Tolerating oral intake/meds

— No pregnancy

— No severe comorbidities

— Reliable follow-up in 48–72 hours

— Initial dose of long-acting IV agent (ceftriaxone 1 g IV or IM, or single-dose aminoglycoside) often given before discharge

— Local E. coli resistance to TMP-SMX >20% → avoid empiric TMP-SMX

— Fluoroquinolone resistance rising; reserve for pyelo when possible

— Risk factors for ESBL/MDR: recent antibiotics (90 days), recent hospitalization, healthcare exposure, travel to endemic regions, prior MDR UTI → consider carbapenem empirically

— Pregnancy: treat ASB AND symptomatic UTI; avoid fluoroquinolones, TMP-SMX (1st/3rd tri), nitrofurantoin near term

— Men: longer duration, evaluate prostate

— Catheter: remove or replace catheter if possible; treat only if symptomatic

Triage decision tree

Outpatient pyelonephritis criteria (must meet ALL)

Resistance considerations driving empiric choice

Special populations alter the logic

Step 3 management: For a stable young woman with uncomplicated pyelonephritis, the correct outpatient regimen is ciprofloxacin 500 mg BID × 7 days OR levofloxacin 750 mg daily × 5 days, often preceded by a single IV/IM ceftriaxone 1 g dose, with 48-hour follow-up. If local FQ resistance >10%, give the IV dose first regardless.

Board pearl: Nitrofurantoin and fosfomycin are NOT adequate for pyelonephritis — poor renal parenchymal/tissue penetration. They are cystitis-only drugs. This is one of the most tested distinctions on Step 3.

Pharmacotherapy — First-Line Regimens

— Nitrofurantoin 100 mg BID × 5 days — avoid if CrCl <30, avoid in pyelo

— TMP-SMX DS BID × 3 days — avoid if local resistance >20%, sulfa allergy, recent use within 3 months

— Fosfomycin 3 g single dose — convenient, slightly lower efficacy

— Pivmecillinam (where available) 400 mg BID × 5–7 days

— Beta-lactams: cefpodoxime, cefdinir, cefadroxil, amox-clavulanate × 5–7 days — generally inferior to first-line; avoid amoxicillin/ampicillin alone (resistance)

— Fluoroquinolones: effective but reserved due to boxed warnings (tendinopathy, aortic dissection, neuropathy, QT, dysglycemia) and collateral damage

— Ciprofloxacin 500 mg PO BID × 7 days OR levofloxacin 750 mg daily × 5 days

— TMP-SMX DS BID × 14 days — only if susceptibility known

— Single IV dose of ceftriaxone 1 g, ertapenem 1 g, or gentamicin 5 mg/kg before PO if local FQ resistance >10%

— Ceftriaxone 1 g IV daily — standard empiric

— Piperacillin-tazobactam 3.375 g IV q6h — if MDR risk, healthcare exposure

— Carbapenem (meropenem, ertapenem) — ESBL risk, prior ESBL isolate

— Add vancomycin if MRSA/Enterococcus risk (catheter, prior +)

— Aminoglycoside (gentamicin) — adjunct for Pseudomonas or step-down

— Step down to PO based on susceptibilities once afebrile 24–48 h; total 7–14 days depending on organism, source control, and agent

— Phenazopyridine 100–200 mg TID × ≤2 days — turns urine orange, do NOT use longer (methemoglobinemia, hemolysis in G6PD)

Acute uncomplicated cystitis — first-line options (IDSA)

Second-line cystitis (when first-line contraindicated)

Acute uncomplicated pyelonephritis (outpatient)

Pyelonephritis / complicated UTI (inpatient IV)

Symptom relief

Step 3 management: Always check prior urine cultures in patients with recurrent UTI before choosing empiric therapy — past resistance patterns drive current selection. This is "personalized antibiogram" thinking.

Board pearl: Duration matters — cystitis 3–5 days, pyelo 5–14 days, men with febrile UTI/prostatitis 4–6 weeks (FQ or TMP-SMX for prostate penetration).

Expanded Pharmacology and Resistance Management

— Nitrofurantoin: concentrates in urine only; ineffective for tissue infection or pyelo; pulmonary fibrosis with chronic use; hemolysis in G6PD; avoid CrCl <30 (reduced efficacy and toxicity)

— TMP-SMX: hyperkalemia (esp. with ACEi/ARB, spironolactone), elevated Cr (competes with secretion, not true AKI), Stevens-Johnson, marrow suppression; avoid in 1st and 3rd trimester pregnancy (neural tube defects, kernicterus)

— Fosfomycin: single-dose convenience; resistance emerging; not for pyelo

— Fluoroquinolones: tendon rupture (esp. >60, steroids, transplant), QT prolongation, aortic aneurysm/dissection, dysglycemia, peripheral neuropathy, C. difficile; chelated by calcium/iron/antacids — separate doses

— Ceftriaxone: avoid in neonates (biliary sludging, displaces bilirubin); pseudolithiasis

— Aminoglycosides: nephrotoxicity, ototoxicity; once-daily dosing, monitor trough; avoid in pregnancy

— Diagnose only if symptoms + significant bacteriuria; pyuria alone insufficient

— Remove or replace catheter before/at start of treatment

— Duration 7 days if prompt response, 10–14 days if delayed

— Asymptomatic catheter bacteriuria — do not treat

— Behavioral: postcoital voiding, increased hydration, avoid spermicide

— Postcoital antibiotic (TMP-SMX or nitrofurantoin single dose after intercourse) if intercourse-associated

— Continuous low-dose prophylaxis (nitrofurantoin 50–100 mg nightly, TMP-SMX 40/200 nightly) × 6–12 months

— Topical vaginal estrogen in postmenopausal women — strong evidence, first-line non-antibiotic

— Cranberry, D-mannose, methenamine — modest/uncertain evidence; reasonable adjuncts

— Narrow per culture, de-escalate IV→PO, shortest effective duration

— Avoid empiric FQ for cystitis when alternatives exist

Drug-specific pearls

Catheter-associated UTI (CAUTI)

Recurrent UTI prophylaxis

Stewardship

Board pearl: A woman with 4 UTIs/year and atrophic vaginitis findings — vaginal estrogen is the highest-yield answer, not chronic antibiotics. Step 3 emphasizes non-antibiotic prevention.

Special Populations — Elderly and Renal/Hepatic Impairment

— ASB prevalence 15–50% in community/LTC elderly — do not screen, do not treat

— Delirium, falls, or "change in status" without GU localizing signs and without other infectious signs → look for alternative cause (dehydration, medication, hypoxia, MI, stroke); treating UA alone worsens outcomes

— When UTI confirmed, watch for AKI, drug interactions, C. difficile

— Nitrofurantoin — contraindicated CrCl <30 (some allow <60 short-course); inefficacy in low GFR

— TMP-SMX — dose-reduce CrCl 15–30, avoid <15; monitor K⁺, Cr

— Fluoroquinolones — renal dose adjustment (cipro), QT caution

— Beta-lactams — most require dose reduction; ceftriaxone unique (hepatobiliary excretion, no renal adjustment)

— Aminoglycosides — extend interval; monitor levels

— Vancomycin — trough-guided dosing or AUC-based

— Most UTI antibiotics renally cleared; ceftriaxone, tigecycline require caution

— Nitrofurantoin — hepatotoxicity (chronic active hepatitis with long-term use)

— Incontinence, mobility, cognitive impairment increase catheter use → reduce unnecessary catheter days

— Polypharmacy: TMP-SMX + warfarin → INR ↑↑; TMP-SMX + ACEi → hyperkalemia; FQ + QT-prolonging drugs

— Loeb criteria for initiating antibiotics: acute dysuria alone OR fever + at least one GU sign (new urgency, frequency, suprapubic pain, gross hematuria, CVA tenderness, incontinence)

Elderly patients

Drug adjustments in renal impairment

Hepatic impairment

Functional considerations

Long-term care facility patients

CCS pearl: An 82-year-old nursing home resident with "confusion and cloudy urine" without fever, dysuria, or CVA tenderness → order workup for alternative causes first (CBC, BMP, glucose, CXR, med review, pulse ox). Treating the UA reflexively is a wrong-answer trap.

Board pearl: Nitrofurantoin is on the Beers list as potentially inappropriate for elderly with CrCl <30 due to pulmonary and hepatic toxicity risk and reduced efficacy.

Special Populations — Pregnancy and Men

— Screen all pregnant women for ASB at first prenatal visit (12–16 weeks) with urine culture — USPSTF Grade A

— Treat ASB and symptomatic UTI to prevent pyelonephritis (occurs in 20–30% of untreated ASB), preterm labor, low birth weight

— Safe agents: nitrofurantoin (avoid 1st trimester if alternatives, avoid near term/38+ weeks — hemolytic anemia in newborn), cephalexin, amoxicillin-clavulanate, fosfomycin

— Avoid: fluoroquinolones (cartilage), TMP-SMX (NTDs in 1st tri, kernicterus near term), tetracyclines, aminoglycosides (relatively)

— Duration: 5–7 days for cystitis (longer than non-pregnant)

— Pyelonephritis in pregnancy = admit, IV ceftriaxone, monitor for preterm labor, ARDS

— Test of cure culture 1–2 weeks post-treatment; consider suppression if recurrent

— All male UTIs traditionally classified complicated

— Workup: assess prostate, consider STI in young men

— Acute bacterial prostatitis: fever, perineal/pelvic pain, tender boggy prostate → FQ or TMP-SMX × 4–6 weeks

— Chronic bacterial prostatitis: same agents × 6–12 weeks

— Recurrent UTI in men → urology referral, post-void residual, imaging

— Increased risk of UTI, pyelonephritis, emphysematous pyelo, perinephric abscess, fungal UTI, papillary necrosis

— SGLT2 inhibitors increase risk of genital mycotic infections and rare Fournier gangrene; do NOT increase serious UTI rates significantly but counsel patients

— Do NOT screen/treat ASB in diabetics

— Lower threshold for culture, broader empiric coverage; consider BK virus in renal transplant with hematuria

Pregnancy

Men with UTI

Diabetes mellitus

Immunocompromised / transplant

Key distinction: ASB is treated in only two scenarios — pregnancy and prior to urologic procedure with anticipated mucosal trauma (e.g., TURP). Diabetes, elderly, catheter, spinal cord injury → not treated.

Board pearl: Group B Strep bacteriuria in pregnancy at any colony count = treat the UTI AND give intrapartum penicillin prophylaxis regardless of late-pregnancy swab results.

Complications and Adverse Outcomes

— Urosepsis / septic shock — most common source of gram-negative bacteremia in elderly; mortality 20–40% with shock

— Acute kidney injury — pre-renal (sepsis), intrinsic (pyelonephritis, papillary necrosis), post-renal (obstruction)

— Perinephric or renal abscess — persistent fever despite antibiotics; CT diagnosis; drain if >3–5 cm

— Emphysematous pyelonephritis — diabetics; gas in renal parenchyma on CT; mortality ~20%; broad antibiotics + percutaneous drainage ± nephrectomy

— Emphysematous cystitis — gas in bladder wall; usually responds to antibiotics + catheter drainage

— Papillary necrosis — diabetics, sickle cell, analgesic use; passage of sloughed papilla → renal colic, hematuria

— Preterm labor, low birth weight, septic shock, ARDS (1–8% of pyelo in pregnancy)

— Chronic pyelonephritis — recurrent infections + reflux/obstruction → renal scarring, HTN, CKD

— Xanthogranulomatous pyelonephritis — chronic obstruction (often staghorn calculus) + Proteus → nonfunctioning kidney, often requires nephrectomy

— C. difficile colitis — especially FQ, clindamycin, broad-spectrum cephalosporins

— Drug rash, SJS/TEN (TMP-SMX), tendon rupture (FQ), nephrotoxicity (aminoglycosides), pulmonary fibrosis (chronic nitrofurantoin), QT prolongation

— CAUTI, bacteremia, urethral injury, encrustation, bladder stones, urethral strictures

— Untreated obstruction or stone → relapsing infection → progressive renal damage

Acute complications

Obstetric complications

Chronic complications

Antibiotic-related complications

Catheter-related complications

Recurrent infection cycle

CCS pearl: Pyelonephritis patient who remains febrile after 72 hours on appropriate antibiotic → CT abdomen/pelvis with contrast to rule out abscess or obstruction; consider urology consult for drainage if found. Do not simply escalate antibiotics without imaging.

Board pearl: A diabetic with pyelonephritis, gas in kidney on imaging, and septic shock → think emphysematous pyelonephritis — call urology/IR for percutaneous drainage; nephrectomy if drainage fails.

When to Escalate Care — ICU, Consult, Inpatient Triage

— Pyelonephritis with N/V (cannot tolerate PO)

— Pregnancy with pyelonephritis (always admit)

— Hemodynamic instability, sepsis, or signs of organ dysfunction

— Suspected obstruction, stone with infection, abscess

— Severe comorbidities (DM uncontrolled, immunocompromised, CKD)

— Failed outpatient therapy after 48–72 hours

— Inability to ensure follow-up or compliance

— Septic shock (vasopressors needed)

— Lactate ≥4 despite resuscitation

— Respiratory failure / ARDS

— Multi-organ dysfunction

— Severe AKI requiring CRRT

— Obstructing stone with infection — emergent decompression (ureteral stent or percutaneous nephrostomy) — this is a true urologic emergency

— Perinephric/renal abscess requiring drainage

— Emphysematous pyelonephritis

— Recurrent UTI in men or women with anatomic concern

— Persistent hematuria post-treatment

— Suspected prostatitis with retention

— Percutaneous nephrostomy for obstruction not amenable to retrograde stent

— Abscess drainage

— MDR organism (ESBL, CRE, KPC, Pseudomonas)

— Recurrent breakthrough on suppression

— Complex immunocompromised patient

— Unusual organism (fungal, mycobacterial)

Admit to hospital

ICU admission

Urology consultation

Interventional radiology

Infectious disease consult

Step 3 management: Obstructing pyonephrosis (infected hydronephrosis from obstructing stone) = OR/IR within hours. Antibiotics alone will not clear an obstructed system. The exam tests recognition of this surgical urgency — the answer is emergent decompression, not "broader antibiotics."

CCS pearl: For septic shock from UTI, the sequence is: IV access × 2 → blood + urine cultures → lactate → 30 mL/kg LR bolus → empiric piperacillin-tazobactam (or carbapenem if MDR risk) within 1 hour → reassess MAP → norepinephrine if MAP <65 after fluids → ICU transfer → source control imaging.

Key Differentials — Same-Category Causes

— Acute uncomplicated cystitis — dysuria, frequency, suprapubic pain, afebrile, no systemic signs

— Acute pyelonephritis — fever, flank pain, CVA tenderness, ± cystitis symptoms

— Acute bacterial prostatitis — male, fever, perineal/pelvic pain, obstructive voiding, tender boggy prostate; don't massage; long course FQ or TMP-SMX

— Chronic bacterial prostatitis — recurrent UTIs same organism, ± perineal discomfort; difficult to eradicate

— Chronic pelvic pain syndrome (CPPS) — sterile cultures; multimodal therapy

— Epididymitis/orchitis — testicular pain, scrotal swelling; <35 y → GC/CT (ceftriaxone + doxycycline); >35 y → enteric (levofloxacin)

— Urethritis — dysuria + discharge; gonorrhea/chlamydia; treat with ceftriaxone 500 mg IM + doxycycline 100 mg BID × 7 days

— Pelvic inflammatory disease — cervical motion tenderness, adnexal tenderness, fever; ceftriaxone + doxycycline + metronidazole

— Vaginitis — discharge, pruritus, no urinary urgency; bacterial vaginosis, candidiasis, trichomoniasis

— Atrophic vaginitis — postmenopausal dysuria without infection; topical estrogen

— UA with pyuria but sterile culture → think Chlamydia urethritis, TB, interstitial cystitis, urolithiasis, recent antibiotic

— Pyuria + hematuria without infection → stones, malignancy, GN, interstitial nephritis

Within urinary/genital infections

Distinguishing features

Catheter-associated bacteriuria (ASB) vs CAUTI — symptomatic distinction is mandatory; pyuria alone in catheterized patient is meaningless

Key distinction: Sterile pyuria in a young sexually active adult — get NAAT for gonorrhea and chlamydia. This is a high-yield Step 3 trap because patients are treated for "UTI" repeatedly with negative cultures.

Board pearl: Recurrent same-organism UTI in a man → think chronic bacterial prostatitis as the reservoir. Treat with prostate-penetrating antibiotic (FQ or TMP-SMX) × 4–6 weeks minimum, sometimes 12 weeks.

Key Differentials — Other-Category Causes

— Nephrolithiasis — flank pain, hematuria, often no fever; non-contrast CT; consider stone + infection (emergency)

— Renal cell carcinoma — painless hematuria, flank mass, weight loss

— Bladder cancer — painless hematuria; smoker, >40; cystoscopy

— Interstitial cystitis / bladder pain syndrome — chronic suprapubic pain, urgency/frequency, negative cultures, no infection

— Overactive bladder — urgency/frequency without dysuria or infection

— Ectopic pregnancy — lower abdominal pain in reproductive-age woman; β-hCG mandatory

— Ovarian torsion — sudden unilateral pelvic pain ± N/V

— Endometriosis — cyclical pelvic pain, dyspareunia

— Acute appendicitis — RLQ pain, anorexia, fever

— Diverticulitis — LLQ pain, fever; can fistulize to bladder → recurrent polymicrobial UTI with pneumaturia/fecaluria (colovesical fistula)

— Cholecystitis — RUQ pain, Murphy's sign

— Vertebral osteomyelitis / discitis / epidural abscess — back pain + fever; MRI spine; can mimic pyelo

— Herpes zoster prodrome in flank dermatome

— Acute interstitial nephritis (AIN) — rash, fever, eosinophilia, eosinophiluria, recent drug (beta-lactam, NSAID, PPI); AKI with sterile pyuria

— Glomerulonephritis — hematuria with dysmorphic RBCs, RBC casts, proteinuria, HTN

— Pelvic abscess, psoas abscess — fever + flank/groin pain

— Endocarditis with septic emboli to kidney

Renal/urologic non-infectious

Gynecologic

GI mimics of pyelonephritis

Spine/musculoskeletal

Renal parenchymal

Systemic

Key distinction: Pneumaturia or fecaluria + recurrent polymicrobial UTI = colovesical fistula (diverticulitis, Crohn's, malignancy) until proven otherwise. Order CT abdomen/pelvis and colonoscopy; surgical referral.

Board pearl: Painless gross hematuria in an adult >35 or with smoking history → cystoscopy + upper tract imaging (CT urogram) regardless of UA findings — do not dismiss as "UTI."

Secondary Prevention and Long-Term Plan

— Adequate hydration (~2–3 L/day) — RCT-proven reduction in recurrence

— Postcoital voiding (modest evidence)

— Wipe front-to-back; avoid douching

— Avoid spermicide and diaphragm if associated with recurrences — switch contraception

— Avoid prolonged catheter use; intermittent self-catheterization preferred over indwelling when possible

— Vaginal estrogen (cream, ring, tablet) — first-line in postmenopausal women with recurrent UTI; reduces recurrence ~50%

— Cranberry products — modest, inconsistent benefit; reasonable adjunct

— D-mannose 2 g daily — emerging evidence, low harm

— Methenamine hippurate 1 g BID — non-antibiotic urinary antiseptic; growing evidence in women with recurrent uncomplicated UTI

— Probiotics (Lactobacillus) — uncertain benefit

— Continuous daily prophylaxis — nitrofurantoin 50–100 mg or TMP-SMX 40/200 mg nightly × 3–12 months (only after non-antibiotic strategies fail or insufficient)

— Postcoital prophylaxis — single dose if clearly intercourse-related

— Self-start therapy — selected reliable patients with classic symptoms keep a prescription at home

— Glycemic control in diabetics

— Treat BPH (alpha-blocker, 5-ARI) to reduce retention

— Stone removal/prevention

— Treat prolapse, fistula

— Daily review of necessity; remove ASAP

— Avoid catheter for "convenience" or simply because of incontinence

— Closed drainage system, aseptic insertion

— No US-approved UTI vaccine yet; investigational

Behavioral measures (all patients with recurrent UTI)

Non-antibiotic prophylaxis

Antibiotic prophylaxis

Address modifiable factors

Catheter stewardship

Vaccination

Step 3 management: In a 65-year-old postmenopausal woman with 4 culture-confirmed UTIs in 12 months, the first-line preventive intervention is vaginal estrogen, not continuous antibiotics. This sequencing question is a recurring exam favorite.

Board pearl: Recurrent UTI does NOT require routine imaging or cystoscopy in otherwise healthy young women — reserve workup for atypical features, hematuria, or treatment failure.

Follow-Up, Monitoring, and Counseling

— Follow-up only if symptoms persist >48–72 hours or worsen

— No test of cure needed

— Phone or clinic check at 48–72 hours: defervescence, symptom improvement, tolerance

— If not improving → admit, image, consider resistant organism

— Complete full course; counsel about return precautions

— Daily clinical assessment; expect afebrile by 72 hours

— Step down IV→PO when afebrile 24–48 h, tolerating PO, susceptibilities known

— Discharge plan: oral antibiotic to complete 7–14 days total; PCP follow-up in 1–2 weeks

— Test of cure urine culture 1–2 weeks after completing therapy

— Monthly urine cultures through pregnancy if any history of UTI/ASB

— Consider suppressive nitrofurantoin if recurrent

— Urology referral after first febrile UTI or recurrence

— Post-treatment culture if prostatitis treated

— Complete full antibiotic course even if asymptomatic

— Hydrate, void frequently

— Phenazopyridine for ≤2 days only; urine/contact lens discoloration

— Return precautions: fever, flank pain, vomiting, worsening dysuria, hematuria persisting >1 week

— Postmenopausal: discuss vaginal estrogen

— Sexually active: discuss postcoital voiding, contraception choice

— Diabetics: glycemic control reduces recurrence

— Initial assessment with PVR, pelvic exam, post-treatment culture

— Trial behavioral/non-antibiotic prevention × 3 months → reassess

— Escalate to prophylaxis if persistent

— Hospital → outpatient: ensure susceptibilities communicated, PO regimen prescribed, follow-up within 1–2 weeks, repeat BMP if AKI occurred

Uncomplicated cystitis

Pyelonephritis (outpatient)

Pyelonephritis (inpatient)

Pregnancy

Men with UTI

Counseling points

Recurrent UTI clinic schedule

Transitions of care

CCS pearl: Always advance the clock and recheck vitals + repeat lactate/UA in a CCS pyelo case. Document a 48-hour reassessment. Failing to reassess after starting empiric therapy loses points and misses non-responders.

Board pearl: Don't routinely repeat urine culture after successful treatment of uncomplicated UTI in non-pregnant adults — it leads to overtreatment of ASB.

Ethical, Legal, and Patient Safety Considerations

— Inappropriate treatment of ASB → C. difficile, AKI, SJS, resistance, drug interactions; documented harm without benefit in elderly and catheterized patients

— Institutions track UA/culture ordering, narrow-spectrum prescribing as quality metrics; CAUTI is a CMS hospital-acquired condition with non-reimbursement for related costs

— CMS bundle: insert only for valid indication, document indication daily, remove ASAP, aseptic technique

— Foley placed without indication → never event from a stewardship perspective

— "Confusion + positive UA" trap — overdiagnosis of UTI leads to missed alternative diagnoses (sepsis from another source, stroke, MI, hypoglycemia, medication effect). Safety-net practice = full workup before attributing AMS to UTI

— Discuss FQ boxed warnings (tendon rupture, aortic dissection, neuropathy, dysglycemia, mental status) before prescribing — documented shared decision-making is increasingly expected

— Discuss long-term antibiotic prophylaxis trade-offs (resistance, side effects) before initiating

— STIs detected on UTI workup (GC/CT) are reportable to public health and require expedited partner therapy in most states

— UTI workup may reveal pregnancy or STI; understand state laws for minor consent and parental notification regarding reproductive/STI care

— High-risk handoff: ED to home with pyelonephritis — ensure clear return precautions, follow-up within 48–72 hours, susceptibilities reviewed when available, antibiotic adjusted if mismatch

— Hospital discharge of elderly with new antibiotic: review for QT drugs, warfarin (TMP-SMX), renal dosing, fall risk

— Patient preferences about prophylaxis vs episodic treatment vary; document discussion

Antibiotic stewardship as patient safety

Catheter safety

Diagnostic anchoring in the elderly

Informed consent

Pregnancy and reporting

Confidentiality in adolescents

Transition-of-care risks

Cultural competency / shared decision making

Step 3 management: A nurse calls you about a stable nursing home patient with cloudy urine and no localizing symptoms. The ethically and clinically correct response is decline reflexive antibiotics, evaluate for alternative causes, and educate staff about ASB — both right answer and right thing.

Board pearl: CAUTI is a publicly reported, non-reimbursed CMS hospital-acquired condition — institutional and physician-level stewardship is both safety and financial imperative.

High-Yield Associations and Rapid-Fire Facts

E. coli — 75–95% of uncomplicated UTI; uropathogenic strains with P fimbriae adhere to uroepithelium

Staph saprophyticus — young sexually active women; nitrite-negative; coagulase-negative, novobiocin-resistant

Proteus mirabilis — urease producer; alkaline urine pH >7, struvite (staghorn) stones, swarming motility

Klebsiella pneumoniae — diabetics, healthcare-associated; mucoid colonies; ESBL risk

Pseudomonas aeruginosa — catheter-associated, post-instrumentation, healthcare exposure; antipseudomonal coverage needed

Enterococcus — catheter, post-instrumentation, prior antibiotics; intrinsically resistant to cephalosporins

Candida — catheter, broad-spectrum antibiotics, diabetes; remove catheter, treat only if symptomatic or neutropenic; fluconazole

Adenovirus / BK virus — hemorrhagic cystitis in transplant, immunocompromised

Schistosoma haematobium — travel to Africa/Middle East; chronic hematuria; squamous cell bladder cancer risk

Mycobacterium tuberculosis — sterile pyuria, chronic symptoms, hematuria; consider in endemic areas, immunocompromised

Honeymoon cystitis — onset after intercourse in young women

Sweet/fruity urine + UTI in DKA — consider emphysematous pyelo on imaging

Pneumaturia/fecaluria + recurrent polymicrobial UTI — colovesical fistula (diverticulitis, Crohn's, malignancy)

White cell casts on UA — pyelonephritis or AIN (renal parenchymal source)

Sterile pyuria — Chlamydia, TB, stones, malignancy, interstitial cystitis, partially treated UTI, AIN

Nitrites positive — Enterobacteriaceae (E. coli, Klebsiella, Proteus); negative with Staph sapro, Enterococcus, Pseudomonas

Urease producers — PEKKSS: Proteus, E. coli (rare), Klebsiella, Klebsiella oxytoca, Staph saprophyticus, Serratia → alkaline urine, struvite stones

Phenazopyridine — orange urine/tears, methemoglobinemia, hemolysis (G6PD)

Nitrofurantoin pulmonary toxicity — acute (hypersensitivity pneumonitis) and chronic (interstitial fibrosis)

FQ + steroids — synergistic tendon rupture risk; avoid in transplant, elderly

TMP-SMX + warfarin — INR spike, bleeding

Single-dose ceftriaxone for outpatient pyelo — adequate empiric coverage prior to PO FQ when resistance ≥10%

Pregnant + GBS bacteriuria — treat UTI now + intrapartum penicillin prophylaxis regardless of swab

Step 3 management: Staghorn calculus + recurrent UTI = think Proteus + struvite; needs urology, often percutaneous nephrolithotomy (PCNL) + antibiotics

Board pearl: The single most tested distinction across this topic is treat ASB only in pregnancy and pre-urologic procedure — memorize it cold.

Board Question Stem Patterns

— 78-year-old nursing home woman with mild confusion, no fever, no dysuria, UA shows + LE, + nitrites. → Best next step: evaluate for alternative causes, do not start antibiotics

— 24-year-old woman, 2-day dysuria/frequency, no vaginal discharge, no fever, no prior UTI, sexually active. → Empiric nitrofurantoin × 5 days; UA/culture not required

— 30-year-old woman, fever 39°C, flank pain, vomiting, HR 110, BP 110/70. → Admit for IV ceftriaxone, blood + urine cultures

— 28-year-old at 14 weeks gestation, screening urine culture grows >10⁵ E. coli, asymptomatic. → Treat with nitrofurantoin or cephalexin × 5–7 days; test of cure

— Diabetic woman, fever, flank pain, hydronephrosis with obstructing 8-mm ureteral stone on CT. → Urgent decompression (ureteral stent or nephrostomy) + IV antibiotics

— 68-year-old, 4 culture-confirmed UTIs in past year, atrophic vaginitis on exam. → Topical vaginal estrogen first-line

— 45-year-old man, fever, dysuria, perineal pain, tender prostate. → Acute bacterial prostatitis: ciprofloxacin or TMP-SMX × 4–6 weeks; avoid prostate massage

— 60-year-old with diverticular disease, recurrent UTIs grow mixed enterics, occasional pneumaturia. → Colovesical fistula; CT, colonoscopy, surgical consult

— 65-year-old poorly controlled DM, septic, CT shows gas in right kidney. → Emphysematous pyelonephritis; resuscitation, broad antibiotics, percutaneous drainage; urology

— 22-year-old woman, dysuria, pyuria, culture negative, new partner. → NAAT for GC/CT; treat urethritis

— Chronic indwelling catheter, +UA, no fever, no symptoms. → Do not treat; reassess catheter need

— Stable young woman with pyelonephritis, tolerating PO. → Single-dose IV ceftriaxone + ciprofloxacin × 7 days outpatient with 48-hour follow-up

Stem 1 — "Don't treat the UA"

Stem 2 — Empiric cystitis

Stem 3 — Pyelonephritis disposition

Stem 4 — Pregnancy ASB

Stem 5 — Obstructed infected stone

Stem 6 — Recurrent UTI postmenopausal

Stem 7 — Male UTI

Stem 8 — Polymicrobial recurrent UTI

Stem 9 — Diabetic with gas

Stem 10 — Sterile pyuria

Stem 11 — CAUTI vs ASB

Stem 12 — Outpatient pyelo regimen

Board pearl: Recurring trap answer choices: "obtain urine culture" when empiric treatment is appropriate, "broaden antibiotics" when the right answer is imaging for source control, and "treat positive UA" when the patient is asymptomatic. Recognize the pattern.

One-Line Recap

Uncomplicated UTI in young, non-pregnant, immunocompetent women is treated empirically with short-course nitrofurantoin, TMP-SMX, or fosfomycin, while complicated UTI — pyelonephritis, pregnancy, male sex, structural/functional GU abnormality, immunocompromise, or catheter-associated — demands culture-guided therapy, longer duration, and source control with imaging and drainage when antibiotics alone fail.

Treat the patient, not the urinalysis — ASB is treated only in pregnancy and prior to urologic procedures with anticipated mucosal trauma; treating ASB in elderly, diabetics, or catheterized patients causes harm without benefit and is a recurring Step 3 trap.

Cystitis vs pyelonephritis drug selection — nitrofurantoin and fosfomycin are cystitis-only; pyelonephritis requires tissue-penetrating agents (fluoroquinolones, TMP-SMX with susceptibilities, ceftriaxone, piperacillin-tazobactam, carbapenems), with duration 5–14 days depending on agent and clinical course.

Recognize the urgent branch points — obstructing infected stone = emergent urologic decompression; emphysematous pyelonephritis in a diabetic = resuscitation + percutaneous drainage; persistent fever beyond 72 hours = image for abscess or obstruction; sepsis = 1-hour bundle with cultures, lactate, fluids, and empiric broad-spectrum antibiotics.

Prevention is durable management — postmenopausal recurrent UTI responds best to topical vaginal estrogen before chronic antibiotics; address modifiable factors (hydration, spermicide, glycemic control, catheter removal, BPH, stones, prolapse) and reserve continuous prophylaxis for refractory cases, always weighing resistance and adverse events in a documented shared decision.

Step 3 management: When in doubt on the exam — verify pregnancy status, check prior cultures for resistance, confirm symptoms before treating bacteriuria, and choose imaging plus source control over reflexive antibiotic broadening in non-responders.