Torsion of Appendix Testis

Torsion of the appendix testis is twisting of the embryonic remnant (a remnant of the paramesonephric duct) attached to the upper pole of the testis, causing ischaemic infarction of the appendage.

• It is the commonest cause of acute scrotum in prepubertal boys, with peak age 7 to 14 years (mean about 10).
• The appendage lies on the upper pole of the testis and is a pedunculated 3 to 5 mm structure; the appendix epididymis can twist in a similar way.
• Cause: unknown; often spontaneous, may follow trauma or exertion.

Gradual onset of pain localised to the upper pole of the testis, mild to moderate, with little systemic upset; nausea and vomiting are infrequent.

• Examination: tender small nodule at the upper pole; "blue dot sign" (blue-black discolouration seen through the scrotal skin) in a minority (about 20 percent); normal testis lie; cremasteric reflex is present; later secondary hydrocele, scrotal oedema and erythema.
• Differential diagnosis: testicular torsion (surgical emergency), epididymo-orchitis, torsion of appendix epididymis, incarcerated hernia, idiopathic scrotal oedema, trauma, scrotal swelling in IgA vasculitis, mumps orchitis, tumour, varicocele.
• Complications: persisting pain, infarction and sloughing (usually benign), secondary hydrocele and epididymitis, mistaken diagnosis delaying testicular torsion treatment (testis salvage depends on surgery within 6 hours).

Clinical, with a high index of suspicion for testicular torsion until excluded.

• Scrotal ultrasound with colour Doppler: normal or increased testicular blood flow, a small avascular hyperechoic, round nodule near the upper pole with reactive hydrocele and thickened epididymis.
• Urinalysis normal (to differentiate from epididymitis); infection screen if sexually active.
• If testicular torsion cannot be excluded (high-riding testis, absent cremasteric reflex, horizontal lie, severe pain), proceed straight to surgical exploration.

Supportive: scrotal support, rest, cold or warm compresses, avoid strenuous activity for 1 to 2 weeks; symptoms settle in 3 to 10 days.

Pharmacological

• Analgesia: ibuprofen 10 mg/kg every 8 hours (adults 400 mg three times daily with food) or diclofenac 1 mg/kg every 8 hours (adults 50 mg three times daily), plus paracetamol 15 mg/kg every 6 hours (adults 1 g).
• Antibiotics are not needed unless epididymitis is suspected.

Procedures

• Surgical exploration and excision of the necrotic appendage, performed through a scrotal incision, for severe or persistent pain beyond 7 days, equivocal diagnosis, or patient or family preference; fixing the contralateral testis is unnecessary.
• Excision gives immediate pain relief and short recovery.

Special groups: neonates and children (always exclude testicular torsion), adolescents (testicular torsion is more common than appendage torsion after puberty).

Red flags: severe pain, absent cremasteric reflex, high-riding testis, testicular swelling, abdominal pain with vomiting.

Follow-up: review at 1 week; ultrasound if pain persists; normal activity after pain resolves; no long term complications.