What are the possible causes of scrotal swelling in a patient with a history of spinal issues and chronic back pain?

Causes of Scrotal Swelling

Scrotal swelling requires immediate evaluation to exclude testicular torsion, which is a surgical emergency demanding intervention within 6-8 hours to prevent testicular loss. 1

Acute Causes (Surgical Emergencies)

Testicular Torsion

• Presents with abrupt onset of severe unilateral scrotal pain and swelling developing within minutes to hours, often accompanied by nausea and vomiting. 1, 2
• Pain is NOT relieved when elevating the testis (negative Prehn sign), which distinguishes it from epididymitis. 1
• More common in adolescents with bimodal distribution (neonates and postpubertal boys), but can occur at any age. 1, 2
• Duplex Doppler ultrasound shows decreased or absent testicular blood flow, "whirlpool sign" of twisted spermatic cord, and enlarged heterogeneous testis. 1, 2
• Requires immediate urological consultation and surgical exploration within 6-8 hours—imaging should NEVER delay surgery when clinical suspicion is high. 1

Fournier's Gangrene

• Necrotizing fasciitis of the scrotum requiring urgent surgical debridement and broad-spectrum antibiotics (piperacillin-tazobactam plus vancomycin, or carbapenem-based regimens). 3
• Presents with severe pain, rapidly progressive scrotal swelling, skin necrosis, and systemic toxicity. 3

Infectious/Inflammatory Causes

Epididymitis/Epididymo-orchitis

• Most common cause of scrotal pain and swelling in adults, representing approximately 600,000 cases annually in the United States. 1
• Gradual onset of pain over hours to days, unlike the abrupt presentation of torsion. 1
• Ultrasound shows enlarged epididymis with INCREASED blood flow on color Doppler (opposite of torsion), scrotal wall thickening, and hydrocele. 1
• Obtain midstream urine culture, urethral swab for gonorrhea/chlamydia testing (first-voided urine for NAAT), and consider blood cultures if severe. 3
• Treatment depends on likely pathogen: ceftriaxone 1000 mg IV/IM plus doxycycline for sexually transmitted infections; fluoroquinolones or cephalosporins for enteric organisms in older men. 3

Genitourinary Tuberculosis (GUTB)

• Presents with non-specific symptoms including scrotal swelling, along with hematuria, urinary frequency, and suprapubic pain. 3
• Requires combination drug therapy: 2 months of isoniazid, rifampicin, pyrazinamide, and ethambutol, followed by 4 months of isoniazid and rifampicin. 3
• More than 50% may require surgical intervention due to destructive nature of infection. 3

Orchitis

• Can cause rapid testicular damage and swelling, particularly in severe cases. 2
• Often viral (mumps) or bacterial, with ultrasound showing diffusely enlarged testis with increased vascularity. 1

Non-Acute Causes

Hydrocele

• Fluid collection between layers of tunica vaginalis, appearing as anechoic fluid surrounding the testis on ultrasound. 4, 5
• Most extratesticular lesions causing painless scrotal swelling are benign. 5

Varicocele

• Dilated pampiniform plexus veins, typically on the left side, with "bag of worms" appearance on examination. 4, 6
• Ultrasound shows dilated veins >3mm that increase with Valsalva maneuver. 4

Spermatocele/Epididymal Cyst

• Benign extratesticular cystic lesions appearing as well-defined anechoic structures on ultrasound. 5

Testicular Tumor

• Most intratesticular lesions are malignant—any solid intratesticular mass should be considered cancer until proven otherwise. 5
• Presents as painless, hard testicular swelling in most cases. 7, 5
• Critical pitfall in spinal cord injury patients: orchitis is common in this population, leading to delayed diagnosis when testicular tumors are mistakenly treated as infection. 7
• If clinical examination reveals hard testicular swelling without typical urinary infection features, perform urgent scrotal ultrasound. 7

Inguinal Hernia

• Bowel or omentum extending into scrotum, diagnosed clinically and confirmed with ultrasound if needed. 5

Torsion of Testicular Appendage

• Most common cause of testicular pain in prepubertal boys. 1
• "Blue dot sign" is pathognomonic but only present in 21% of cases. 1
• Ultrasound shows normal testicular perfusion with localized hyperemia near the appendage. 1

Acute Idiopathic Scrotal Edema

• Rare, self-limiting condition with marked scrotal wall thickening but minimal pain. 1
• Diagnosis of exclusion showing increased peritesticular blood flow but normal testicular vascularity. 1

Segmental Testicular Infarction

• Presents as wedge-shaped avascular area on ultrasound, may also appear as round lesions with variable Doppler flow. 1

Special Consideration: Referred Pain from Spine

Chronic Scrotal Pain with Spinal Pathology

• Etiologies of chronic scrotal content pain include referred pain from spine, abdomen, and retroperitoneum. 8
• In patients with chronic back pain and spinal issues, consider referred pain as a cause of scrotal discomfort, though this typically presents as pain rather than visible swelling. 8
• Requires thorough evaluation to exclude primary scrotal pathology before attributing symptoms to referred pain. 8

Critical Diagnostic Algorithm

For ANY acute scrotal swelling:

1. Immediate clinical assessment focusing on onset (abrupt vs. gradual), pain severity, and Prehn sign. 1
2. If high suspicion for torsion (TWIST score ≥6): proceed directly to surgical exploration without imaging. 1
3. If intermediate suspicion (TWIST score 1-5): urgent Duplex Doppler ultrasound with grayscale, color Doppler, and power Doppler. 1
4. Compare affected testis to contralateral side as internal control—asymmetry in blood flow is key. 1
5. Remember: 30% false-negative rate for Doppler in partial torsion—when clinical suspicion remains high despite normal imaging, proceed to surgical exploration. 1