Pelvic Emergencies

Testicular Torsion

The testis and epididymis attach to the inner scrotal wall via a broad attachment. When this attachment is too narrow, it may function as a pedicle around which the testis may twist. This twisting, or torsion, compromises the blood supply to the testis, which may lead to infarction of the testis. Males with testicular torsion often present with acute scrotal pain, and this condition requires emergent treatment to maintain viability of the affected testis. Testicular salvage rates are greatest when surgery is performed within 6 hours of the onset of symptoms. After 24 hours the testis is usually no longer salvageable. Patients with the “bell clapper” deformity, in which the tunica vaginalis joins high on the spermatic cord, are more prone to testicular torsion compared with the general population.

Sonography is the preferred imaging examination for the diagnosis of testicular torsion because of its high sensitivity and specificity. Gray-scale ultrasound findings are often completely normal when torsion is present, and the testes may appear symmetric with respect to both size and echogenicity. A small hydrocele may be present on the affected side. Within a few hours of the onset of symptoms, the scrotal wall will appear thickened, and the testis and epididymis will appear enlarged and hypoechoic as a result of inflammation and/or hemorrhage. Color Doppler imaging is crucial for the diagnosis of torsion. The lack of demonstrable blood flow to the affected testis, assuming appropriate ultrasound settings are used, is virtually pathognomonic for torsion ( Fig. 10-1 ). In prepubertal patients, demonstrating the presence of blood flow often is difficult even in normal testes. Two potential false-negative scenarios must be considered when evaluating for torsion. First, a twisted testis may untwist spontaneously with resultant hyperemia on color Doppler imaging, and thus testicular torsion can be mistaken for epididymo-orchitis; and second, incomplete torsion may result in venous occlusion without arterial occlusion, which may result in arterial flow being detected in the testis despite the presence of torsion.

Testicular scintigraphy is often used as an adjunct to ultrasound when a diagnosis of torsion cannot be made with certainty. Given the added delay of scintigraphic examinations, however, some surgeons operate when findings of an ultrasound are equivocal. The treatment for testicular torsion is detorsion of the affected testicle and orchiopexy—that is, with fixture of the testis to the scrotal wall to prevent torsion from recurring.

Torsion of the Testicular Appendages

Although males have four testicular appendages, only two, the appendix testis and appendix epididymis, are commonly visible with ultrasound imaging. These appendages are remnants of embryonic ducts and serve no real function. Because they are attached by a small pedicle, they are prone to torsion. Torsion of these appendages is one of the most common causes of acute scrotal pain in children. The appendix testis is more commonly affected than the appendix epididymis, although it is often difficult to identify the offending appendage. Patients are usually young, prepubertal males who report acute-onset scrotal pain. Clinical examination may reveal a bluish discoloration of the skin at the site of pain, which is called the “blue dot” sign and is pathognomonic. Upon ultrasound imaging the twisted appendix is often identified as a round, extratesticular, extraepididymal mass lacking color Doppler flow ( Fig. 10-2 ). A reactive hydrocele may be present, along with scrotal wall skin thickening.

Epididymitis and Orchitis

Epididymitis or epididymo-orchitis is an infection of the epididymis and/or testis and is a common cause of acute-onset scrotal pain. Typically, scrotal pain associated with epididymitis or epididymo-orchitis is relieved when the testes are elevated over the symphysis pubis, a maneuver called the Prehn sign . In contradistinction, the pain associated with testicular torsion is not relieved by this maneuver. Although the causative agent in epididymitis is usually not identified in young children, the infection usually originates in the prostate gland or bladder and spreads to the epididymis and testis via the vas deferens and spermatic cord lymphatics. A congenital anomaly of the urinary tract may be present. In adolescents, the cause is usually a sexually transmitted infection.

Ultrasound examination of a patient with epididymitis demonstrates enlargement of the epididymis, primarily the head, with heterogeneous echotexture. Color Doppler evaluation shows increased blood flow to the epididymis and/or testis ( Fig. 10-3 ). A reactive hydrocele may be an associated finding. When the entire testis is involved, it often is enlarged and has altered echogenicity. On gray-scale imaging findings alone, the appearance of the testis may mimic a diffusely infiltrative disease such as leukemia or lymphoma, although the clinical presentation should suggest the correct diagnosis. Untreated epididymo-orchitis may progress to formation of a scrotal abscess or may result in testicular infarction, which may lead to testicular atrophy. In patients with epididymo-orchitis, a follow-up sonogram performed 4 to 6 weeks after the initial event is advised in all cases to ensure complete resolution of the imaging findings after appropriate interval therapy. A follow-up sonogram is important to exclude an underlying tumor as the cause for the patient’s symptoms. It is uncommon for a testicular tumor to present with acute scrotal pain; the accepted figure is that acute pain is a symptom in less than 10% of tumors. When such pain occurs, it is usually due to acute hemorrhage or infarction of the testis that contains the tumor. Orchitis as a result of infection with mumps occurs in approximately 25% of patients who contract the disease. The sonographic findings include an enlarged hypoechoic testis, a small hydrocele, and sometimes thickening of the scrotal wall. Infertility occasionally may result as a consequence of mumps orchitis. Severe scrotal infection may result in the rare condition called Fournier gangrene , which is a fulminant infectious process involving the scrotal wall and skin of the perineum that is in essence a fasciitis. The severe infection may result in gas formation along the fascial planes of the scrotal wall. Sonographic findings include the findings of epididymo-orchitis along with small echogenic ill-defined foci within the scrotal wall. These foci represent gas, and this finding requires urgent communication to the referring physician because surgical debridement may be required. In questionable cases, CT may be performed, which will clearly show the presence of any gas as hypoattenuating foci within the scrotal wall ( Fig. 10-4 ).

Inguinal Scrotal Hernia

An uncommon cause of acute scrotal pain is incarceration of an inguinal hernia that extends into the scrotum. Indirect inguinal hernias are not uncommon; however, extension into the scrotal sac is rare. The clinical findings are usually obvious with a large swelling in the scrotum, although the mass may not be easily reduced. Sonographically, the appearance may be nonspecific, with a heterogeneous mass identified in the scrotum. It is usually easy to identify the mass as being separate from the testis, although following the mass along the inguinal canal may not be easy. The presence of bowel may be detected if the two walls and lumen are clearly visible; however, it is not always clear that the mass represents bowel. Often the mass may merely be omental fat that has herniated into the scrotum. The presence of peristalsis may confirm the diagnosis. In cases in which doubt exists, a CT scan could be performed, which would show the hernia and its contents extending into the scrotum. Signs of incarceration on sonography include the absence of color flow on color Doppler evaluation. Although this sign may be easy to elicit in identifiable bowel wall, if the hernia consists of omental fat alone, it may be an unreliable sign. On CT, signs of incarceration include edema of the adjacent fat around the hernia and, possibly, decreased enhancement of the bowel wall of any bowel loops that may be present in the hernia.

Testicular Trauma

Trauma to the testis may be either penetrating or blunt. Penetrating trauma to the testis, as in many other locations, usually requires immediate surgical exploration. Blunt trauma to the testis in a hemodynamically stable patient should be evaluated with sonography. The key diagnosis to make after testicular trauma is the presence or absence of testicular rupture. A ruptured testicle requires immediate surgical repair, and early diagnosis is required to maximize the chances of testicular salvage. A ruptured testicle that is operated on within 72 hours of the trauma has a salvage rate approaching 80%, but this rate drops to 30% with subsequent delay. The sonographic findings suggesting testicular rupture include loss of clarity of the margins of the testis and abnormal structure of the testis; on occasion, testicular parenchyma protruding beyond the testicular capsule may be identified. Sonographic findings seen after trauma to the testes that does not result in testicular rupture include altered echogenicity with loss of the normal homogeneity and alternating foci of either increased or decreased echogenicity. Depending on the degree of trauma, the heterogeneity may be focal or more generalized. A focal area of heterogeneity may be mistaken for epididymo-orchitis or even tumor, and thus an accurate history of testicular trauma is required to help differentiate these conditions. Despite having an accurate history, when focal heterogeneity is seen as a result of trauma, a follow-up scan is advised in 4 to 6 weeks to ensure complete resolution. As with many testicular conditions, after trauma to the scrotum, a secondary hydrocele is commonly observed, which appears as a hypoechoic fluid collection within the scrotum. An associated scrotal hematoma may be present, which also may appear as a hypoechoic fluid collection when it is hyperacute. As the hematoma resolves, more complex elements may develop within the scrotum, and the presence of complex fluid in the scrotum after trauma represents a resolving hematoma. The long-term sequelae of testicular trauma include complete or incomplete infarction with a resultant smaller testicle, chronic fibrosis, and even calcification.