Atlas of pathophysiology, 2 Edition

Part II - Disorders

Genital Diseases

Testicular Torsion

Testicular torsion is an abnormal twisting of the spermatic cord due to rotation of a testis or the mesorchium; it may occur inside or outside the tunica vaginalis. Intravaginal torsion is most common in adolescents, extravaginal, in neonates. Onset may be spontaneous or follow physical exertion or trauma. Potential outcomes range from strangulation to eventual infarction of the testis without treatment. This condition is almost always (90%) unilateral.

Age Alert

The greatest risk of testicular torsion occurs during the neonatal period and again between ages 12 and 18 (puberty), but it may occur at any age. Infants with torsion of one testis have a greater incidence of torsion of the other testis later in life than do males in the general population. The prognosis is good with early detection and prompt treatment.

Causes

Intravaginal torsion

·   Abnormality of the coverings of the testis and abnormally positioned testis

·   Incomplete attachment of the testis and spermatic fascia to the scrotal wall, leaving the testis free to rotate around its vascular pedicle

Extravaginal torsion

·   Loose attachment of the tunica vaginalis to the scrotal lining causing spermatic cord rotation above the testis

·   Sudden forceful contraction of the cremaster muscle due to physical exertion or irritation of the muscle

Pathophysiology

Normally, the tunica vaginalis envelops the testis and attaches to the epididymis and spermatic cord. Normal contraction of the cremaster muscle causes the left testis to rotate counter-clockwise, and the right, clockwise. In testicular torsion, the testis rotates on its vascular pedicle and twists the arteries and vein in the spermatic cord, interrupting blood flow to the testis. Vascular engorgement and ischemia ensue, causing scrotal swelling unrelieved by rest or elevation of the scrotum. If manual reduction is unsuccessful, torsion must be surgically corrected within 6 hours after the onset of symptoms to preserve testicular function (70% salvage rate). After 12 hours, the testis becomes dysfunctional and necrotic.

Signs and symptoms

·   Excruciating pain in the affected testis or iliac fossa of the pelvis

·   Edematous, elevated, and ecchymotic scrotum

·   Loss of the cremasteric reflex (stimulation of the skin on the inner thigh retracts the testis on the same side) on the affected side

·   Abdominal pain; nausea and vomiting

·   Lightheadedness

Diagnostic test results

Doppler ultrasonography distinguishes testicular torsion from strangulated hernia, undescended testes, or epididymitis (absent blood flow and avascular testis in torsion).

Treatment

·   Manual manipulation of the testis counterclockwise to improve blood flow before surgery (not always possible)

·   Immediate surgical repair by:

§  orchiopexy—fixation of a viable testis to the scrotum and prophylactic fixation of the contralateral testis

§  orchiectomy—excision of a nonviable testis to limit risk for autoimmune response to necrotic testis and its contents, damage to unaffected testis, and subsequent infertility.

P.343

TESTICULAR TORSION

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