What is the differential diagnosis (ddx) for a 27-year-old male with intermittent scrotal pain for 10 months, provoked by physical activity, with a history of lumbar injury, multiple negative urine Sexually Transmitted Disease (STD) screenings, and previous treatments for bacterial epididymitis, who has only found relief with lower abdominal acupuncture?

Differential Diagnosis and Work-Up for Chronic Intermittent Scrotal Pain

Most Likely Diagnosis: Referred Pain from Lumbar Spine

Given the 10-month duration, provocation by physical activity, history of lumbar injury, and relief with lower abdominal acupuncture, this presentation is most consistent with referred pain from the lumbosacral spine rather than a primary scrotal pathology. The negative STD screenings, absence of urethral discharge/dysuria, unremarkable initial ultrasound, and lack of response to multiple courses of antibiotics effectively rule out infectious etiologies 1, 2.

Key Differential Diagnoses to Consider

Primary Considerations

• Referred pain from lumbar spine/nerve root irritation - The combination of lumbar injury history, activity-provoked pain, and response to acupuncture strongly suggests radiculopathy or nerve entrapment affecting the genitofemoral or ilioinguinal nerves 2, 3

• Chronic orchialgia (idiopathic) - Defined as scrotal pain lasting ≥3 months without identifiable cause, this affects quality of life significantly and may represent neuropathic pain 4, 3

• Varicocele - Can cause intermittent, activity-related scrotal discomfort, though typically presents with visible/palpable findings 2

• Post-inflammatory chronic pain - Following the multiple episodes of treated epididymitis, chronic pain may persist even after infection resolution 4

Less Likely but Important to Exclude

• Intermittent testicular torsion - While the 10-month duration makes this unlikely, the bell-clapper deformity can cause recurrent torsion-detorsion episodes; however, this typically presents with acute severe pain episodes rather than chronic intermittent discomfort 1

• Inguinal hernia - Can cause activity-related scrotal pain, though usually accompanied by palpable bulge 5

Recommended Work-Up Algorithm

Immediate Clinical Assessment

• Detailed neurological examination - Assess for lumbar radiculopathy signs including straight leg raise, sensory deficits in L1-L2 distribution (genitofemoral nerve), and lower extremity reflexes 2, 3

• Focused scrotal examination - Palpate for varicocele (perform Valsalva maneuver), assess cremasteric reflex, evaluate for masses or tenderness, and check for inguinal hernias 1, 5

• Pain mapping - Document exact location, radiation pattern, and relationship to specific movements or positions 3

Diagnostic Testing

• Repeat scrotal ultrasound with Doppler - The initial ultrasound was performed 10 months ago; repeat imaging should specifically evaluate for varicocele, testicular masses, and epididymal changes that may have developed since 1, 6

• Lumbar spine imaging (MRI preferred) - Given the lumbar injury history and activity-provoked symptoms, evaluate for disc herniation, nerve root compression, or other structural abnormalities affecting L1-L2 nerve roots 2, 3

• Urinalysis - Repeat to definitively exclude ongoing infection, though this is likely negative given the clinical picture 1, 5

Diagnostic/Therapeutic Intervention

• Spermatic cord block with local anesthetic - This has a >90% success rate for diagnosis and can help differentiate true scrotal pathology from referred pain; if pain persists after the block, referred pain is more likely 4, 3

Management Approach Based on Findings

If Referred Pain from Spine is Confirmed

• Physical therapy focusing on lumbar stabilization and nerve mobilization 3
• Neuropathic pain medications (gabapentin or pregabalin) rather than antibiotics 4
• Consider epidural steroid injection if specific nerve root compression identified 3

If True Chronic Orchialgia Without Identifiable Cause

• Trial of tricyclic antidepressants (success rate up to 66.6%) 4
• Pelvic floor physical therapy may be beneficial 3
• If spermatic cord block provides temporary relief, consider microsurgical denervation of the spermatic cord (success rate up to 70%) 4

If Varicocele Identified

• Conservative management with scrotal support initially 2
• Surgical repair (varicocelectomy) if conservative measures fail and varicocele is clinically significant 2

Critical Clinical Pitfalls to Avoid

• Do not continue empiric antibiotic therapy - Three courses without improvement and negative STD screenings make bacterial infection extremely unlikely; continued antibiotics risk resistance and side effects without benefit 1, 4

• Do not dismiss the lumbar injury history - Referred pain from the spine is frequently overlooked in chronic scrotal pain evaluation, yet the genitofemoral and ilioinguinal nerves originate from L1-L2 and can cause isolated scrotal symptoms 2, 3

• Normal ultrasound does not exclude pathology - Ultrasound sensitivity is not 100%, and conditions like small varicoceles or nerve-related pain may not be visible on imaging 1, 6

• Activity provocation is a key distinguishing feature - This pattern is more consistent with musculoskeletal/neurological causes rather than infectious or torsion-related etiologies, which typically have different pain patterns 1, 2