What is the appropriate workup for a patient presenting with scrotal edema?

Workup for Scrotal Edema

Begin immediately with scrotal ultrasound with Doppler to differentiate surgical emergencies (testicular torsion, Fournier's gangrene) from benign causes, while simultaneously assessing for life-threatening necrotizing infection through clinical examination. 1, 2

Immediate Clinical Assessment

Rule Out Surgical Emergencies First

Fournier's Gangrene (Life-Threatening)

• Examine for crepitus, skin necrosis, or systemic toxicity 2
• If suspected clinically, proceed directly to surgical debridement without waiting for imaging 2
• In stable patients only, CT scan may help determine disease extent 2
• Obtain: CBC, serum creatinine, glucose, inflammatory markers, and lactate 2

Testicular Torsion (Time-Sensitive)

• Assess for acute onset of scrotal pain accompanying edema 2
• Abrupt onset strongly suggests torsion versus gradual onset suggesting epididymitis 1
• Age matters: prepubertal boys more commonly have torsion of testicular appendage; adults over 25 typically have epididymitis 1
• Critical: If high clinical suspicion exists, proceed to surgical exploration within 6-8 hours even with normal Doppler (false-negative rate up to 30%) 2

Primary Diagnostic Modality: Duplex Doppler Ultrasound

The American College of Radiology recommends scrotal ultrasound with Doppler as the primary diagnostic modality for all scrotal abnormalities. 1

Three-Component Ultrasound Protocol

Grayscale Examination 1

• Assess testicular homogeneity and size
• Look for "whirlpool sign" of twisted spermatic cord (96% sensitivity for torsion) 1
• Evaluate scrotal wall thickening and hydrocele

Color Doppler Assessment 1

• Evaluate testicular perfusion compared to contralateral side (96-100% sensitivity for torsion) 1
• Decreased or absent flow indicates torsion requiring immediate surgical consultation 2

Power Doppler 1

• More sensitive for slow flow states
• Particularly useful in prepubertal boys with normally reduced intratesticular blood flow 3

Differential Diagnosis Based on Ultrasound Findings

Epididymitis/Epididymo-orchitis (Most Common in Adults)

• Enlarged epididymis with increased blood flow on color Doppler 2
• Scrotal wall thickening with reactive hydrocele 2
• Gradual onset of pain 1
• Management: bed rest, scrotal elevation, analgesics, age-appropriate antibiotics 2

Acute Idiopathic Scrotal Edema (Self-Limited)

• Marked scrotal wall thickening with heterogeneous striated appearance 2
• Increased peritesticular blood flow but normal testicular vascularity 3
• More common in prepubertal boys but can occur in adults 3, 4, 5
• Usually painless or minimally painful 3
• Expectant management with NSAIDs; resolves within 72 hours 4

Testicular Torsion (Surgical Emergency)

• Decreased or absent testicular blood flow 2
• Whirlpool sign on grayscale 1
• Requires surgical exploration within 6-8 hours 2

Lymphatic Obstruction/Systemic Causes

• Consider in patients with volume overload states (heart failure, renal failure, peritoneal dialysis) 6
• Bilateral presentation more common 6

Critical Pitfalls to Avoid

• Never assume isolated scrotal edema is simply "fluid overload" requiring diuretics without investigating for surgical emergencies 2
• Normal urinalysis does not exclude testicular torsion 1
• False-negative Doppler can occur with partial torsion or spontaneous detorsion 1
• Do not delay surgical consultation for Fournier's gangrene to obtain imaging 2
• Clinical examination alone is unreliable due to significant overlap in presentations 1

Advanced Imaging

MRI may be appropriate for: 1

• Very large scrotal masses where ultrasound is limited
• Equivocal ultrasound findings when testicular torsion remains suspected
• Shows decreased or absent perfusion on dynamic contrast-enhanced sequences

Immediate Urological Consultation Required For:

• Any suspicion of testicular torsion (within 6-8 hours window) 1, 2
• High TWIST score (≥6) even without imaging 1
• Suspected Fournier's gangrene 2