What are the causes of testicular pain in males?

Causes of Testicular Pain

Primary Causes by Age Group

Testicular pain has three predominant causes that account for 85-90% of cases: epididymitis/epididymo-orchitis (most common in adults), testicular torsion (surgical emergency with bimodal distribution in neonates and adolescents), and torsion of testicular appendage (most common in prepubertal boys). 1

In Adults (>25 years)

• Epididymitis/epididymo-orchitis is overwhelmingly the most common cause, representing approximately 600,000 cases annually in the United States 2
• Urinary tract pathogens, particularly E. coli, are the predominant organisms in men over 35 years 3
• Characterized by gradual onset of pain, positive Prehn sign (pain relief with testicular elevation), and increased blood flow on Doppler ultrasound 1
• Often associated with bladder outflow obstruction, urinary tract infection, or prostatitis 3

In Adolescents and Young Adults (<35 years)

• Testicular torsion occurs more frequently in this age group, with peaks in neonates and postpubertal boys, at an estimated yearly incidence of 2.9 to 3.8 per 100,000 boys under 18 years 2
• Sexually transmitted infections (N. gonorrhoeae and C. trachomatis) are the most common causes of epididymitis in men under 35 years 3
• Testicular torsion is rare in patients over 35 years but can still occur 2, 4

In Prepubertal Boys

• Torsion of testicular appendage is the most common cause of testicular pain in this age group 2, 1
• May present with the pathognomonic "blue dot sign" visible through the skin, though this is only seen in 21% of cases 2

Critical Surgical Emergency: Testicular Torsion

Testicular torsion requires surgical intervention within 6-8 hours of symptom onset to prevent permanent testicular loss. 2, 1

Key Clinical Features

• Abrupt onset of severe scrotal pain, often without preceding trauma 2, 5
• Negative Prehn sign (pain is NOT relieved when the testicle is elevated) 2
• Nausea and vomiting are common systemic symptoms 5
• Red, swollen scrotum with acutely painful testicle 5
• Normal urinalysis does not exclude testicular torsion 2

Pathophysiology

• Complete torsion >450 degrees results in absent arterial and venous flow 2
• Venous obstruction occurs first due to thinner vessel walls and lower pressure, followed by arterial occlusion 2
• Partial torsion can present with diminished arterial velocity and decreased diastolic flow 2

Additional Causes

Traumatic Causes

• Testicular fracture, hematoceles, areas of hemorrhage, or testicular infarction may be demonstrated on ultrasound following scrotal trauma 6

Vascular Causes

• Segmental testicular infarction presents with a classic wedge-shaped avascular area on ultrasound, with median age of 37-38 years 2
• May also present as round lesions with variable Doppler flow 2

Rare Causes

• Acute idiopathic scrotal edema is a rare, self-limiting condition primarily affecting prepubertal boys but can occur in adults 2
• Usually painless or minimally painful with marked scrotal wall thickening 2
• Diagnosis of exclusion with heterogeneous striated appearance on ultrasound 2

Diagnostic Approach

Clinical Assessment

• Timing and onset of pain is critical: abrupt onset suggests torsion, while gradual onset suggests epididymitis 2
• Age of the patient helps narrow the differential diagnosis 2
• Prehn sign testing: positive (pain relief with elevation) suggests epididymitis; negative suggests torsion 2, 1

Imaging

• Duplex Doppler ultrasound is the first-line imaging modality with sensitivity of 69-96.8% and specificity of 87-100% 2, 1
• Key findings for torsion: decreased or absent blood flow, "whirlpool sign" of twisted spermatic cord, enlarged heterogeneous testis 2
• Key findings for epididymitis: enlarged epididymis with increased blood flow on color Doppler, scrotal wall thickening 2
• Power Doppler is particularly useful for prepubertal testes with slow flow 2

Critical Pitfalls to Avoid

• Significant overlap exists in clinical presentation between different causes of acute scrotal pain, making diagnosis challenging 2
• False-negative Doppler evaluations occur in 30% or more of cases, particularly with partial torsion, spontaneous detorsion, or early presentation 2
• Trauma history can be a red herring in testicular torsion cases, as progressive worsening pain suggests torsion rather than simple traumatic injury 1
• When clinical suspicion for torsion is high, immediate urological consultation and surgical exploration should proceed regardless of imaging findings, as delaying surgery risks testicular loss 2, 1
• Starting antibiotics for presumed epididymitis when torsion is possible delays correct diagnosis and treatment 1
• Prepubertal males have normally reduced intratesticular blood flow that can mimic torsion on Doppler, leading to false-positive evaluations 2