Renal, Fluids, Electrolytes & Acid-Base · Topic 9 of 23

Urologic Emergencies: Retention, BPH, Torsion & Priapism

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Renal & GU · urologic emergencies

Urologic Emergencies: Retention, BPH, Torsion & Priapism

Three urologic clocks: detorse a testis within hours, treat priapism beyond 4 hours, and decompress acute retention with a catheter now.

01 · Testicular torsionDetorse and call urology: ~90% salvage ≤ 12 h

02 · Ischemic priapismErection over 4 hours is an emergency

03 · Acute retentionCatheter decompression now

What causes it

Retention: stop offending drugs. Priapism in adults: erectile dysfunction drugs

Retention: drugs

Anticholinergics (many OTC)OpioidsSympathomimeticsAnestheticsAlcohol

Retention: other triggers

UTIImmobilizationFecal impactionNeurogenic bladder

Retention: often on top of

Prostate enlargementUrethral stricture

Priapism: adults

Erectile dysfunction drugs (most common)Other medications and substances

Priapism: children

Sickle cell diseaseOther hematologic disorders

Check a CBC when the cause of priapism is unclear.

What you'll see

Torsion is a clinical diagnosis: suspicion alone justifies acting

Torsion: sudden severe scrotal pain, nausea and vomiting call urology

Torsion: tender, high-riding, horizontal testis

Torsion: absent cremasteric reflex hallmark

Fever or urinary frequency does not exclude torsion

Bell-clapper deformity, usually bilateral, lets the testis twist → fix both testes

Ischemic priapism: painful, rigid corpora with a soft glans

Nonischemic priapism: painless, partially or fully rigid

Nonischemic priapism usually follows trauma forming an arterial fistula

Acute prostatitis: fever, chills, urinary symptoms

Acute prostatitis: exquisitely tender, boggy prostate

Diagnosis & labs

Reserve imaging for equivocal torsion; get a corporal blood gas in priapism

Equivocal scrotal pain: color Doppler

Partial torsion can mimic epididymitis

Priapism: obtain a corporal blood gas at presentation

Ischemic gas: dark blood, typically PO₂ under 30 mmHg

Ischemic gas: typically PCO₂ over 60 mmHg and pH under 7.25

Nonischemic gas: bright red, resembles arterial blood

Priapism still indeterminate: penile duplex

Postvoid residual in a patient who can void: normal under 50 mL

Residual under 100 mL: usually acceptable over 65, abnormal if younger

Acute prostatitis: diagnose from midstream urine

Red flags

Suspected testicular torsion: salvage falls with every hour detorse + urology

Erection over 4 hours: fibrosis and erectile dysfunction aspirate + phenylephrine

Acute urinary retention catheter

Output over 200 mL/h for 2 h or over 3 L in 24 h after decompression check electrolytes

Priapism beyond 36–48 hours: injections unlikely to respond surgery earlier

Prostatitis with suspected sepsis admit + culture

Prostate massage in acute prostatitis: unnecessary, possibly dangerous avoid massage

Treatment: the three clocks

Three emergencies, right now

Torsion: manual detorsion, call urologyrotate the testis outward; emergent exploration

→

Priapism: aspiration + phenylephrineintracavernosal; monitor BP and HR

→

Retention: catheter decompressionthen treat the cause

Torsionsalvage falls by the hour

Manual detorsion, rotating the testis outward, plus emergent exploration

Salvage ~90% by 12 h, 54% at 13–24 h, 18% after

Ischemic priapismfirst-line

Phenylephrine 100–500 mcg per dose

Corporal aspiration, with or without irrigation, plus intracavernosal phenylephrine

Doses at least 5 min apart for up to 1 hour; monitor BP and HR

Persistent erectionafter aspiration and phenylephrine

Urology: distal corporoglanular shunt

Add corporal tunneling if it still persists

Nonischemic priapismconfirm the subtype emergently

Ice and analgesics, then selective embolization or surgery

Retentiondecompress

Standard urethral catheter, then coudé tip, then flexible cystoscopy

Transurethral routes fail: suprapubic percutaneous decompression

Postobstructive diuresisafter decompression

Check electrolytes; if pathologic, replace about 75% of hourly output

Rapid complete drainage is safe

Torsion age, post-injection erection, Fournier, drainage evidence

Torsion peaks at age 12–18 and is uncommon after 30

Erection of 4 hours or less after intracavernosal injection: phenylephrine first

Established ischemic priapism: conservative measures unlikely to workobservation, cold compresses, exercise and oral drugs

Severe scrotal pain with fever or toxicity suggests Fournier gangrenealso necrotic lesions or subcutaneous gas; management is on the necrotizing soft tissue infection sheet

Older teaching of gradual drainage with clamping has no supporting evidenceNyman 1997 review

Postobstructive diuresis: the 75% replacement figure is level III evidence

Treatment: BPH, epididymitis, prostatitis

BPH retentionbefore a trial without catheter

Oral alpha-blocker

Complete at least 3 days of alpha-blocker first

BPH symptomsalpha-blocker, 5-ARI, or both

Tamsulosin Terazosin Doxazosin Alfuzosin Finasteride Dutasteride

The combination beats either alone; 5-ARIs shrink glands over 30 mL over months

Tadalafil helps with coexisting erectile dysfunction

Alpha-blockerswarn the patient

Orthostatic hypotension, dizziness, intraoperative floppy iris syndrome

Tell the ophthalmologist before cataract or glaucoma surgery

Epididymitislikely chlamydia or gonorrhea

Ceftriaxone 500 mg IM once Doxycycline 100 mg BID × 10 days

Ceftriaxone 1 g if 150 kg or more

After insertive anal sex: levofloxacin 500 mg daily replaces doxycycline

Prostatitisnontoxic

Ciprofloxacin 500 mg BID

Duration differs: about 30 days (Merck), 10–14 days may benefit (IDSA 2025)

Sources differ, evidence is thin

Prostatitissuspected sepsis

Ampicillin IV Gentamicin IV

Admit, culture, IV until afebrile 24–48 hours

Then oral therapy for about 4 weeks (Merck)

PSA on 5-ARIs, enteric epididymitis, prostatitis duration, alpha-blocker timing

5-ARIs lower PSA by about 50%double an isolated PSA after 6 months of finasteride when comparing with normal ranges

Investigate any confirmed PSA rise from the lowest on-treatment value

Enteric epididymitis alone: levofloxacin 500 mg daily for 10 dayswith scrotal elevation, ice and analgesics

In epididymitis, severe pain or fever suggests another diagnosistorsion, testicular infarction, abscess or necrotizing fasciitis

Prostatitis duration: Merck gives about 30 days to prevent chronic prostatitis

IDSA 2025 (and the UTI sheet) says men may benefit from 10–14 dayswith febrile, bacteremic UTI and suspected acute bacterial prostatitis, while noting evidence on the optimal duration is lacking

Alpha-blocker timing is the AUA 2021 statement, read in an open summarya 2026 AUA revision exists and its full text was not checked

Testicular torsion or epididymitis?

Swelling can blur them: when equivocal, use color Doppler

	Testicular torsion	Epididymitis
Onset	Sudden and severe	More gradual
Location	Testis, high-riding and horizontal	Epididymis first
Cremasteric reflex	Usually absent	Present
Associated	Nausea and vomiting	Sometimes dysuria or urethral discharge
Treatment	Detorsion and emergent surgery	Antibiotics

Pearl

Testicular salvage falls from about 90% within 12 hours to 54% at 13–24 hours and 18% after, so clinical suspicion alone justifies treatment.

Sources · Merck Manual Professional: Urinary Retention · Merck Manual Professional: Benign Prostatic Hyperplasia · Merck Manual Professional: Testicular Torsion · Merck Manual Professional: Scrotal Pain · Merck Manual Professional: Epididymitis · CDC STI Treatment Guidelines 2021: Epididymitis · Merck Manual Professional: Priapism · AUA/SMSNA Guideline: Acute Ischemic Priapism (2021) · Merck Manual Professional: Prostatitis · AUA 2021 LUTS/BPH guideline statements (open summary) · Halbgewachs & Domes: Postobstructive diuresis (Can Fam Physician 2015) · DailyMed: Tamsulosin Hydrochloride Capsules Label · DailyMed: Proscar (finasteride) Label · IDSA 2025 Guideline Update on Complicated Urinary Tract Infections · Follow your institution's protocols.