One-liner#
Painful urination requiring differentiation between UTI, STI, and vaginitis/urethritis—management depends on sex, age, and risk factors.
Quick nav#
- Red flags / send to ED
- Key history
- Focused exam
- Differential (quick pattern recognition)
- Workup
- Initial management
- Management by diagnosis
- Follow-up
- Patient instructions
- Smartphrase snippets
Red flags / send to ED#
- Fever + flank pain + dysuria → pyelonephritis; if septic-appearing (hypotension, tachycardia, altered), send to ED
- Urinary retention → unable to void despite urge; needs catheterization
- Pregnant with UTI symptoms + fever → risk of preterm labor, needs urgent evaluation
- Immunocompromised + UTI symptoms → lower threshold for ED if any systemic symptoms
Key history#
Characterize the symptom:
- Location: internal (urethral) vs external (vulvar irritation from urine on inflamed tissue)
- Timing: throughout void vs at end of void (bladder spasm)
- Duration: acute (<7 days) vs recurrent
UTI risk factors:
- Sexual activity (new partner, frequency)
- Prior UTIs and frequency
- Postmenopausal (atrophic changes)
- Diabetes, immunosuppression
- Recent catheterization or instrumentation
- Incomplete emptying, retention
STI risk factors:
- New or multiple sexual partners
- Unprotected intercourse
- Partner with STI symptoms or diagnosis
- Age <25 (highest chlamydia prevalence)
- History of STIs
Associated symptoms:
- Frequency, urgency, hematuria → bladder involvement
- Vaginal discharge, odor, itching → vaginitis vs cervicitis
- Urethral discharge (men) → urethritis/STI
- Flank pain, fever, nausea → upper tract involvement
- Suprapubic pain → cystitis
Medication review:
- Recent antibiotics (resistance, yeast)
- Spermicides (UTI risk)
- New soaps, douches, hygiene products
Focused exam#
Vital signs:
- Fever suggests upper tract or systemic infection
- Tachycardia, hypotension → sepsis concern
Abdominal exam:
- Suprapubic tenderness → cystitis
- Flank/CVA tenderness → pyelonephritis
Pelvic exam (women with vaginal symptoms or unclear diagnosis):
- External: erythema, lesions, discharge at introitus
- Speculum: vaginal discharge (character, odor), cervical discharge/friability
- Bimanual: cervical motion tenderness, adnexal tenderness (PID concern)
GU exam (men):
- Urethral discharge (milk urethra if none visible)
- Testicular tenderness, swelling → epididymitis
- Prostate tenderness → acute prostatitis (avoid vigorous massage)
When to examine:
- Uncomplicated cystitis in young woman with classic symptoms: exam often not needed
- Vaginal symptoms, recurrent UTIs, unclear diagnosis, men: exam indicated
Differential (quick pattern recognition)#
Common/likely (outpatient)#
| Diagnosis | Keywords patients use | Key clues | Focused exam clues | Initial next step |
|---|---|---|---|---|
| Uncomplicated cystitis | “Burns when I pee,” “have to go all the time,” “just started” | Acute onset, frequency, urgency, no fever, sexually active woman | Suprapubic tenderness; no CVA tenderness | Empiric antibiotics; UA optional in classic presentation |
| Chlamydia urethritis/cervicitis | “Burns a little,” “some discharge,” “my partner got tested” | Young, sexually active, mild symptoms, may have discharge | Mucopurulent cervical discharge; urethral discharge in men | NAAT for CT/GC; treat empirically if high suspicion |
| Gonorrhea urethritis/cervicitis | “Yellow discharge,” “really burns,” “partner has something” | More symptomatic than chlamydia, purulent discharge | Purulent urethral/cervical discharge | NAAT for CT/GC; treat empirically if high suspicion |
| Vulvovaginal candidiasis | “Itchy down there,” “cottage cheese discharge,” “burns on the outside” | External dysuria, pruritus, thick white discharge, recent antibiotics | Vulvar erythema, thick white discharge, no odor | Treat empirically or confirm with wet prep/pH |
| Bacterial vaginosis | “Fishy smell,” “grayish discharge,” “burns a little” | Thin gray discharge, fishy odor (especially post-coital), external dysuria | Thin gray discharge, positive whiff test, pH >4.5 | Wet prep; treat with metronidazole |
| Atrophic vaginitis | “Dry down there,” “burns when I pee,” postmenopausal | Postmenopausal, vaginal dryness, dyspareunia | Pale, dry vaginal mucosa; petechiae; loss of rugae | Vaginal estrogen |
| Trichomoniasis | “Frothy discharge,” “smells bad,” “itchy and burning” | Yellow-green frothy discharge, vulvar irritation, partner with STI | Strawberry cervix (rare), frothy discharge | NAAT or wet prep; treat with metronidazole |
| Urethritis (non-gonococcal) | “Mild burning,” “little bit of discharge” | Men with mild symptoms, clear/white discharge | Scant clear urethral discharge | NAAT for CT/GC; treat for NGU |
Can’t-miss / urgent#
| Diagnosis | Keywords patients use | Key clues | Focused exam clues | Initial next step |
|---|---|---|---|---|
| Pyelonephritis | “Back pain,” “fever and chills,” “feel really sick” | Fever, flank pain, nausea/vomiting, systemic symptoms | CVA tenderness, fever, ill-appearing | UA/culture; if stable, outpatient fluoroquinolone; if toxic, ED |
| PID | “Pain during sex,” “lower belly pain,” “discharge” | Sexually active, bilateral lower abdominal pain, fever | Cervical motion tenderness, adnexal tenderness | NAAT, treat empirically; if severe, ED for IV antibiotics |
| Acute prostatitis | “Can’t pee,” “fever,” “pain down there” | Men, fever, perineal pain, difficulty voiding | Tender, boggy prostate (gentle exam); may have retention | UA/culture; fluoroquinolone 4-6 weeks; if retention/septic, ED |
| Epididymitis | “Testicle hurts,” “swollen down there” | Unilateral scrotal pain, may have dysuria | Tender, swollen epididymis; positive Prehn sign | NAAT if <35 or STI risk; treat for STI vs enteric organisms |
| Herpes simplex (primary) | “Blisters down there,” “really painful to pee” | Severe pain, vesicles/ulcers, may have systemic symptoms | Vesicles, ulcers on genitalia; inguinal lymphadenopathy | Clinical diagnosis; confirm with PCR/culture; start antivirals |
Workup#
Uncomplicated cystitis (non-pregnant woman, classic symptoms):
- UA with or without culture acceptable
- Many guidelines support empiric treatment without UA if classic symptoms
- Culture if: treatment failure, recurrent UTIs, recent antibiotics, atypical symptoms
Complicated UTI (men, pregnant, catheter, anatomic abnormality, diabetes, immunocompromised):
- UA AND urine culture with sensitivities
- Consider BMP if concern for AKI or need to dose-adjust
Suspected STI:
- NAAT for chlamydia and gonorrhea (urine in men; vaginal swab preferred in women, urine acceptable)
- Consider: HIV, syphilis, hepatitis B/C if new STI diagnosis
- Trichomonas NAAT if vaginal symptoms
Vaginitis workup:
- Wet prep (saline and KOH) if available
- Vaginal pH (>4.5 suggests BV or trich; <4.5 suggests yeast)
- If no microscopy: syndromic treatment or send vaginal swab for BV/yeast/trich panel
Pyelonephritis:
- UA and urine culture
- BMP (assess renal function)
- Consider CBC if diagnostic uncertainty
- Imaging NOT routine; consider CT if: no improvement in 48-72 hours, suspected abscess, anatomic abnormality
When NOT to order:
- Do NOT send urine culture for classic uncomplicated cystitis in young women—adds cost without changing management
- Do NOT image for uncomplicated cystitis or pyelonephritis responding to treatment
- Do NOT treat asymptomatic bacteriuria (except: pregnancy, pre-urologic procedure)
Initial management#
Uncomplicated cystitis:
- Empiric antibiotics (see medication table)
- Phenazopyridine for symptom relief (warn about orange urine)
- Hydration encouraged
Suspected STI:
- Treat empirically if high suspicion; don’t wait for results
- Treat partners (expedited partner therapy where legal)
- Counsel on abstinence until treatment complete and partners treated
Pyelonephritis (stable, non-pregnant, tolerating PO):
- Outpatient fluoroquinolone x 7 days (or TMP-SMX x 14 days if susceptible)
- Close follow-up in 24-48 hours
- ED if: unable to tolerate PO, pregnant, septic, not improving
Vaginitis:
- Treat based on diagnosis (see management by diagnosis)
Management by diagnosis#
Uncomplicated Cystitis#
Education:
- Common infection; antibiotics work quickly (symptoms improve in 1-2 days)
- Complete full course even if feeling better
- Cranberry has minimal evidence but low harm if patient wants to try for prevention
Treatment:
| Drug | Dose | Contraindications | Monitoring | Cost | Notes |
|---|---|---|---|---|---|
| Nitrofurantoin (Macrobid) | 100 mg BID x 5 days | CrCl <30; avoid at term pregnancy | None | $ | First-line; avoid if any pyelonephritis concern |
| TMP-SMX (Bactrim DS) | 1 DS tab BID x 3 days | Sulfa allergy; avoid if resistance >20% locally | None | $ | Check local resistance patterns; avoid in 1st trimester |
| Fosfomycin (Monurol) | 3 g single dose | None significant | None | $$ | Convenient but slightly less effective; good for resistant organisms |
| Ciprofloxacin | 250 mg BID x 3 days | Tendon disorders; avoid in elderly if alternatives exist | None | $ | Reserve for resistant organisms; not first-line |
Follow-up: No follow-up needed if symptoms resolve. Return if symptoms persist >48 hours or worsen.
Recurrent UTI (3 or more per year or 2 or more in 6 months)#
Education:
- Recurrence is common; doesn’t mean something is wrong anatomically (usually)
- Behavioral measures: post-coital voiding, adequate hydration, avoid spermicides
- Vaginal estrogen helpful in postmenopausal women
Treatment options:
- Post-coital prophylaxis: TMP-SMX SS or nitrofurantoin 50-100 mg after intercourse
- Continuous prophylaxis: TMP-SMX SS daily or nitrofurantoin 50-100 mg daily x 6-12 months
- Self-start therapy: Patient-initiated treatment at symptom onset (give prescription to keep on hand)
Follow-up: Urology referral if: anatomic abnormality suspected, persistent hematuria, not responding to prophylaxis.
Chlamydia#
Education:
- Curable with antibiotics; partners must be treated
- Abstain from sex for 7 days after treatment AND until partners treated
- Reinfection common if partners not treated
- Screen again in 3 months (high reinfection rate)
Treatment:
| Drug | Dose | Contraindications | Monitoring | Cost | Notes |
|---|---|---|---|---|---|
| Doxycycline | 100 mg BID x 7 days | Pregnancy | None | $ | Preferred; slightly more effective than azithromycin |
| Azithromycin | 1 g single dose | None significant | None | $ | Alternative if adherence concern; less effective for rectal infection |
Follow-up: Test of cure not needed unless pregnant or symptoms persist. Rescreen in 3 months.
Gonorrhea#
Education:
- Requires injection + oral antibiotic due to resistance
- Partners need treatment; abstain until both treated
- Report to public health (mandatory in most states)
Treatment:
| Drug | Dose | Contraindications | Monitoring | Cost | Notes |
|---|---|---|---|---|---|
| Ceftriaxone | 500 mg IM x 1 (1 g if 150 kg or more) | Severe cephalosporin allergy | None | $ | Must give IM; always co-treat for chlamydia |
| PLUS Doxycycline | 100 mg BID x 7 days | Pregnancy | None | $ | Covers chlamydia co-infection |
Follow-up: Test of cure if pharyngeal infection or symptoms persist. Rescreen in 3 months.
Trichomoniasis#
Education:
- STI caused by parasite; partners must be treated
- Can be asymptomatic, especially in men
- Increases HIV transmission risk
- Abstain from sex until both partners treated and asymptomatic
Treatment:
| Drug | Dose | Contraindications | Monitoring | Cost | Notes |
|---|---|---|---|---|---|
| Metronidazole | 500 mg BID x 7 days | Avoid alcohol x 24 hours after | None | $ | Preferred in women; better cure rate than single dose |
| Metronidazole | 2 g single dose | Avoid alcohol x 24 hours after | None | $ | Alternative; preferred in men |
| Tinidazole | 2 g single dose | Avoid alcohol x 72 hours after | None | $$ | Alternative if metronidazole fails |
Follow-up: Test of cure in 3 months (high reinfection rate). Treat partners.
Vulvovaginal Candidiasis#
Education:
- Not an STI; caused by yeast overgrowth
- Common after antibiotics, in diabetes, with immunosuppression
- OTC treatments work well for uncomplicated cases
Treatment:
| Drug | Dose | Contraindications | Monitoring | Cost | Notes |
|---|---|---|---|---|---|
| Fluconazole | 150 mg PO x 1 | Pregnancy (1st trimester); drug interactions | LFTs if recurrent use | $ | Most convenient; avoid in pregnancy |
| Miconazole 2% cream | Intravaginal daily x 7 days | None | None | $ | OTC; safe in pregnancy |
| Clotrimazole 1% cream | Intravaginal daily x 7 days | None | None | $ | OTC; safe in pregnancy |
Recurrent candidiasis (4 or more episodes per year):
- Fluconazole 150 mg every 72 hours x 3 doses, then weekly x 6 months
- Check HbA1c to rule out diabetes
- Consider HIV testing if not recently done
Follow-up: None needed if symptoms resolve. Return if recurrent.
Bacterial Vaginosis#
Education:
- Not an STI but associated with sexual activity
- Caused by imbalance in vaginal bacteria
- Recurrence common (30% within 3 months)
- Avoid douching
Treatment:
| Drug | Dose | Contraindications | Monitoring | Cost | Notes |
|---|---|---|---|---|---|
| Metronidazole | 500 mg PO BID x 7 days | Avoid alcohol (disulfiram reaction) | None | $ | First-line; warn about alcohol |
| Metronidazole gel 0.75% | 5 g intravaginally daily x 5 days | None | None | $$ | Alternative; less GI side effects |
| Clindamycin cream 2% | 5 g intravaginally at bedtime x 7 days | None | None | $$ | Alternative; may weaken condoms |
Follow-up: None needed if symptoms resolve. No need to treat male partners.
Pyelonephritis (Outpatient Management)#
Education:
- Kidney infection; more serious than bladder infection
- Must complete full antibiotic course
- Should feel better in 24-48 hours; if not, need reassessment
- Stay hydrated; rest
Treatment:
| Drug | Dose | Contraindications | Monitoring | Cost | Notes |
|---|---|---|---|---|---|
| Ciprofloxacin | 500 mg BID x 7 days | Tendon disorders | None | $ | First-line if local resistance <10% |
| Levofloxacin | 750 mg daily x 5 days | Tendon disorders | None | $ | Alternative fluoroquinolone |
| TMP-SMX DS | 1 tab BID x 14 days | Sulfa allergy | None | $ | Use if culture shows susceptibility |
Criteria for outpatient treatment:
- Non-pregnant
- Tolerating oral intake
- No sepsis criteria
- Reliable follow-up
- No urinary obstruction
Follow-up: Phone or visit in 24-48 hours. If not improving, reassess (may need imaging, IV antibiotics).
UTI in Pregnancy#
Education:
- UTIs more common and more serious in pregnancy
- Asymptomatic bacteriuria MUST be treated (unlike non-pregnant patients)
- Untreated UTI increases risk of pyelonephritis and preterm labor
- Some antibiotics are contraindicated
Treatment:
| Drug | Dose | Contraindications | Monitoring | Cost | Notes |
|---|---|---|---|---|---|
| Nitrofurantoin (Macrobid) | 100 mg BID x 5-7 days | Avoid at term (38+ weeks); G6PD deficiency | None | $ | Safe in 2nd/3rd trimester; avoid near delivery |
| Cephalexin | 500 mg BID x 7 days | Cephalosporin allergy | None | $ | Safe throughout pregnancy |
| Amoxicillin-clavulanate | 500 mg BID x 7 days | Penicillin allergy | None | $ | Safe throughout pregnancy |
| Fosfomycin | 3 g single dose | None | None | $$ | Safe in pregnancy; good for resistant organisms |
Avoid in pregnancy:
- TMP-SMX (1st trimester: neural tube defects; 3rd trimester: kernicterus)
- Fluoroquinolones (cartilage toxicity)
- Nitrofurantoin at term (hemolytic anemia in newborn)
Follow-up: Test of cure 1-2 weeks after treatment. Monthly urine cultures for remainder of pregnancy if history of UTI.
Male UTI (Complicated by Definition)#
Education:
- UTIs in men are uncommon and always considered complicated
- Often associated with anatomic abnormality, BPH, or recent instrumentation
- Longer treatment course required
- May need urology evaluation
Treatment:
| Drug | Dose | Contraindications | Monitoring | Cost | Notes |
|---|---|---|---|---|---|
| Ciprofloxacin | 500 mg BID x 7 days | Tendon disorders | None | $ | First-line; good prostate penetration |
| Levofloxacin | 500 mg daily x 7 days | Tendon disorders | None | $ | Alternative fluoroquinolone |
| TMP-SMX DS | 1 tab BID x 7-14 days | Sulfa allergy | None | $ | Use if culture shows susceptibility |
Workup:
- Always send urine culture
- Consider post-void residual if BPH suspected
- Urology referral if: recurrent UTIs, anatomic abnormality suspected, not responding to treatment
Follow-up: Repeat culture after treatment to confirm clearance. Urology referral for recurrent infections.
Atrophic Vaginitis#
Education:
- Due to low estrogen after menopause
- Vaginal estrogen is safe and effective (minimal systemic absorption)
- Takes 4-6 weeks to see full benefit
- Can use long-term
Treatment:
| Drug | Dose | Contraindications | Monitoring | Cost | Notes |
|---|---|---|---|---|---|
| Estradiol vaginal cream | 0.5-1 g intravaginally 2-3x/week | Unexplained vaginal bleeding; breast cancer (relative) | None | $$ | Most studied; use applicator |
| Estradiol vaginal tablet (Vagifem) | 10 mcg intravaginally 2x/week | Same as above | None | $$ | Less messy than cream |
| Estradiol vaginal ring (Estring) | Insert every 90 days | Same as above | None | $$$ | Most convenient; patient inserts |
| Ospemifene (Osphena) | 60 mg PO daily | VTE history; breast cancer | None | $$$$ | Oral option; SERM |
Follow-up: 4-6 weeks to assess response. Continue indefinitely if effective.
Follow-up#
Uncomplicated cystitis:
- No routine follow-up needed
- Return if symptoms persist >48 hours or recur within 2 weeks
Pyelonephritis:
- Phone check in 24-48 hours
- If not improving: office visit, consider imaging, possible hospitalization
STIs:
- Rescreen in 3 months for chlamydia/gonorrhea (high reinfection rate)
- Ensure partners treated
Recurrent UTIs:
- Follow-up in 1-3 months on prophylaxis
- Urology referral if not responding to prophylaxis or red flags present
Return precautions (all patients):
- Fever, chills, flank pain (suggests upper tract infection)
- Unable to keep fluids/medications down
- Symptoms worsening despite treatment
- Blood in urine (if not already present)
Patient instructions#
- Take all your antibiotic doses, even if you feel better before finishing
- Drink plenty of water to help flush out the infection
- You can take phenazopyridine (AZO) for pain—it turns your urine bright orange, which is normal
- Avoid sex until you finish treatment (and your partner is treated, if applicable)
- Call or return if: fever, back pain, vomiting, symptoms getting worse, or not improving after 2 days
- To help prevent future infections: urinate after sex, wipe front to back, stay hydrated
Smartphrase snippets#
Uncomplicated cystitis: “Symptoms and UA consistent with uncomplicated urinary tract infection. No red flags for upper tract involvement. Treated with [antibiotic] x [duration]. Return precautions given for fever, flank pain, or worsening symptoms.”
STI treatment: “NAAT sent for CT/GC. Given clinical suspicion, treated empirically with [regimen]. Partner treatment discussed; expedited partner therapy provided. Advised abstinence x 7 days. Will rescreen in 3 months.”
Pyelonephritis (outpatient): “Presentation consistent with acute pyelonephritis—fever, CVA tenderness, pyuria. Patient is hemodynamically stable, tolerating PO, and has reliable follow-up. Treated with [fluoroquinolone] x 7 days. Urine culture pending. Phone follow-up in 24-48 hours; return immediately if worsening or unable to tolerate PO.”