Caution: Exclude torsion by careful clinical examination, especially if sudden onset, young (less than 20yrs usually, but can occur at any age); seek urgent urology opinion.
This is a surgical emergency – salvage of affected testis under 6 hours offers best outcome.

• Gram stained urethral smear – even if urethral symptoms are absent – examined microscopically for the diagnosis of urethritis and presumptive diagnosis of gonorrhoea. Where facilities do not exist for immediate microscopy, consideration may be given to referring patients to another centre.
• The presence of nitrite and leukocyte-esterase on dipstick testing may suggest a UTI in men with urinary symptoms, but this is not diagnostic and its results should not preclude the other microbiological investigations above.

• Midstream urine specimen (MSU) for microscopy and culture.
• Urethral swab for N. gonorrhoeae culture.
• First pass urine for NAAT testing for N.gonorrhoeae and C.trachomatis.
• First pass urine for NAAT testing for M. genitalium infection.
• Screening for other STIs (syphilis and HIV testing - hepatitis testing based on sexual history).
• White blood cell count, CRP and ESR can be elevated.

• Surgical exploration when torsion cannot be confidently excluded.
• If torsion not considered a possible diagnosis but diagnostic uncertainty remains, seek advice from senior colleague.
• Ultrasound may help differentiate between epididymo-orchitis and other causes of testicular pain.
• Refer to BASHH when TB, Mumps or other rare infective or non-infective cause is suspected.

A clinical diagnosis presumptively made based on presenting history, risk of STIs, physical examination and preliminary investigations. A sexually transmitted cause should always be excluded.