Orchitis: Symptoms and Workup
Orchitis typically presents with scrotal pain, swelling, and tenderness, often accompanied by fever (87%), and requires urgent scrotal ultrasound with Doppler to exclude testicular torsion, along with urinalysis, urine culture, and urethral testing for sexually transmitted infections to guide antibiotic therapy. 1, 2
Clinical Presentation
Cardinal Symptoms
- Scrotal pain and tenderness (present in 100% of cases) 2
- Fever (87% of cases) 2
- Scrotal swelling (83% of cases) 2
- Gradual onset over hours to days, distinguishing it from testicular torsion which has sudden onset 1, 3
Key Physical Examination Findings
- Swollen, tender epididymis and/or testis in normal anatomic position 3
- Intact cremasteric reflex (helps differentiate from torsion) 3
- Positive Prehn sign - pain relief when elevating the scrotum above the symphysis pubis (though not always reliable) 1
- Left-sided involvement more common (60%) 2
- Reactive hydrocele may develop (31% of cases) 2
Age-Specific Considerations
Epididymo-orchitis is the most common cause of acute scrotum in adolescent boys and adults 1. In men 18-50 years, it accounts for 1 in 44 outpatient visits 1. Peak incidence occurs in the 31-40 year age group 2.
Diagnostic Workup
Immediate Priority: Rule Out Testicular Torsion
The critical first step is excluding testicular torsion, which requires surgical intervention within 6-8 hours to prevent testicular loss 1. Any suspicion of torsion mandates immediate surgical referral 4.
Laboratory Studies
Essential tests include:
- Urinalysis and urine culture - pyuria present in 50%, positive cultures in 39% of cases 2
- Urethral Gram stain - to identify gram-negative intracellular diplococci (gonorrhea) 3
- Nucleic acid amplification testing (NAAT) for Chlamydia trachomatis and Neisseria gonorrhoeae 5, 6, 3
- Complete blood count - leukocytosis present in 51% 2
Imaging
Scrotal ultrasound with color Doppler is the primary imaging modality 1:
- Confirms inflammatory changes in 100% of cases 2
- Demonstrates increased blood flow (unlike torsion which shows decreased/absent flow)
- Identifies reactive hydrocele, abscess formation, or other complications
- Contrast-enhanced ultrasound can be used as a problem-solving technique when conventional Doppler fails to identify flow 1
- Microvascular imaging ultrasound is a newer technique that better differentiates slow flow 1
Etiology-Based Workup Strategy
For Men <35 Years Old
Primary concern: Sexually transmitted pathogens
- Chlamydia trachomatis and Neisseria gonorrhoeae are most common 3
- Obtain urethral swab for NAAT testing 5, 6
- Consider Mycoplasma genitalium testing if available 6
For Men >35 Years Old
Primary concern: Urinary tract pathogens
- Escherichia coli is the predominant organism 2, 3
- Focus on urine culture and sensitivity 3
- Examine for bladder outflow obstruction, perform digital rectal exam for BPH or prostatitis 4
Risk Factor Assessment
Identify predisposing conditions:
- Urinary tract infection (31% of cases) 2
- Obstructed uropathy or prior instrumentation (24%) 2
- Trauma (21%) 2
- Diabetes mellitus (23%) 2
- Insertive anal intercourse (enteric pathogens) 6
- Spinal cord injury/neurogenic bladder 7
Common Pitfalls
Critical warning: The overlapping clinical presentation between epididymo-orchitis and testicular torsion makes acute scrotum a diagnostic challenge 1. When in doubt, testicular torsion must be excluded first as it is a surgical emergency.
Prehn sign is not reliable - while classically described, it should not be used alone to differentiate orchitis from torsion 1.
Bilateral involvement can occur and should not exclude the diagnosis 7.
In endemic areas or patients with raw dairy consumption, consider brucellosis as a rare cause, especially if initial antibiotic therapy fails 8.
Complications to Monitor
Most patients (87%) have no complications with appropriate treatment 2. However, watch for:
- Scrotal abscess formation
- Testicular infarction
- Chronic pain
- Scrotal fistula formation 7
Patients with severe pain or systemic illness require hospital admission for IV antibiotics, analgesia, and hydration 4.