Differential Diagnosis of Testicular Pain

🔴 Emergencies (Must Rule Out First)

1. Testicular Torsion (Spermatic Cord Torsion)

• Mechanism: Twisting of the spermatic cord cuts off arterial blood supply. The "bell clapper" deformity (tunica vaginalis enveloping the testis high on the cord) is the main predisposing anatomy.
• Presentation: Acute onset, severe unilateral scrotal pain ± nausea/vomiting; pain may radiate to the abdomen. High-riding, transverse testis; absent cremasteric reflex on the affected side.
• Peak ages: Neonatal period and adolescence.
• Time-critical: Salvage rates >90% if treated within 6 hours; drops to ~31% by 24 hours and only ~2.6% by 48 hours.
• Dx: Clinical first; confirm with color Doppler US (absent/decreased perfusion, "whirlpool sign" of the spermatic cord).
• Tx: Emergent surgical detorsion → orchiopexy or orchiectomy if non-viable.

🟠 Infectious / Inflammatory

2. Epididymitis

• Most common cause of acute scrotal pain in post-pubertal males.
• Infectious causes:
  • STI organisms (sexually active males): Chlamydia trachomatis, Neisseria gonorrhoeae
  • Gram-negative uropathogens (older men, prepubertal boys): E. coli
  • Viral
• Noninfectious: trauma, urine reflux into ejaculatory ducts, vasculitis
• Presentation: Acute or subacute pain in the epididymis ± testis, urinary frequency/dysuria, possible penile discharge, scrotal induration/erythema. Cremasteric reflex intact. Prehn sign (pain relief with elevation) may be present — but does NOT rule out torsion.
• Dx: UA + culture, NAAT for gonorrhea/chlamydia, scrotal US (increased vascular flow).
• Tx: Antibiotics per etiology; supportive care (analgesia, ice, scrotal elevation).

3. Orchitis

• Pain and swelling of the entire testicle (vs. just the epididymis).
• Viral (most common): mumps (can cause testicular atrophy in ~50%, oligospermia), EBV, HSV-2, dengue, HIV.
• Bacterial: usually via direct spread from epididymitis (epididymo-orchitis).
• Autoimmune: secondary to vasculitides (Behçet's, polyarteritis nodosa, Henoch-Schönlein purpura — HSP).
• Dx: Clinical ± scrotal US; urine culture positive in ~38%.
• Tx: Antibiotics if bacterial; supportive if viral.

🟡 Structural / Anatomical

4. Torsion of the Testicular Appendage (Appendix Testis)

• Torsion of a vestigial remnant (appendix testis or appendix epididymis).
• Typically prepubertal boys (ages 7–14).
• More gradual onset, less severe than spermatic cord torsion; pain at the superior pole.
• Blue dot sign: blue/black discoloration under scrotal skin at the superior testis.
• Cremasteric reflex present. Self-limiting; managed conservatively.

5. Varicocele

• Dilation of the pampiniform plexus ("bag of worms" on palpation).
• Typically causes a dull ache that worsens after exercise or prolonged standing.
• Usually left-sided. A new right-sided varicocele warrants workup for retroperitoneal pathology or renal vein thrombosis.
• Reactive hydrocele may co-exist.

6. Inguinal Hernia

• An early indirect inguinal hernia can produce referred testicular pain before a scrotal bulge is apparent.
• Incarcerated hernia: severe pain, irreducible mass, ± associated hydrocele.

7. Hydrocele

• Accumulation of peritoneal fluid within the tunica vaginalis.
• Typically painless, but a reactive hydrocele (secondary to torsion, epididymitis, orchitis, or tumor) may be tender.

🟢 Neoplastic

8. Testicular Tumor

• Uninfected testicular tumors generally do not cause pain — pain is uncommon and may signal hemorrhage into the tumor or advanced disease.
• Can be misdiagnosed as epididymitis → always arrange ultrasound with close follow-up if pain persists.

🔵 Referred Pain

9. Ureteral/Renal Stone

• Stone in the upper ureter can refer pain to the ipsilateral testis via shared T10–L1 innervation. The testis itself is non-tender on palpation.

10. Referred from Inguinal Region

• Inguinal tendonitis or muscle strain can produce apparent testicular pain.

🟣 Chronic / Idiopathic

11. Chronic Orchialgia (Idiopathic Testicular Pain)

• Defined as intermittent or constant unilateral/bilateral testicular pain >3 months that significantly interferes with daily activities.
• Evaluation is frequently negative. Associated with low testosterone or B12 deficiency in many screened patients.
• Diagnosis of exclusion.

Summary Table