Role of US in acute scrotal pain

Transcription

1 World J Urol (2011) 29: DOI /s TOPIC PAPER Role of US in acute scrotal pain G. Liguori S. Bucci A. Zordani S. Benvenuto G. Ollandini G. Mazzon M. Bertolotto F. Cacciato S. Siracusano C. Trombetta Received: 4 March 2011 / Accepted: 5 May 2011 / Published online: 24 May 2011 Ó Springer-Verlag 2011 Abstract Background The acute scrotum is a common emergency department (ED) presentation and can be defined as any condition of the scrotum or intrascrotal contents requiring emergent medical or surgical intervention. Although rarely fatal, acute scrotal pathology can result in testicle infarction and necrosis, testicular atrophy, infertility, and significant morbidity. Methods Scrotal US is best performed with a linear 7.5- to 12-MHz transducer. In addition to imaging in the longitudinal and transverse planes, it is helpful to obtain simultaneous images of both testes for comparison. Color Doppler is used to evaluate for abnormalities of flow and to differentiate vascular from nonvascular lesions. Attention to appropriate color Doppler settings to optimize detection of slow flow is critical. Results The evaluation of acute scrotal pain can be challenging for the clinician initially examining and triaging the patient. Acute scrotal conditions due to traumatic, infectious, vascular, or neoplastic etiologies can all present with pain as the initial complaint. Additionally, the laboratory and physical examination findings in such conditions may overlap; this, coupled with potential patient guarding and lack of collaboration, may result in a limited, non-specific physical examination. Therefore, scrotal ultrasound has emerged to play a central role in the evaluation of the patient presenting with acute scrotal pain. G. Liguori S. Bucci A. Zordani (&) S. Benvenuto G. Ollandini G. Mazzon S. Siracusano C. Trombetta Department of Urology, University of Trieste, Cattinara Hospital, Strada di Fiume 447, Trieste, Italy alessio_zordani@hotmail.it M. Bertolotto F. Cacciato Department of Radiology, University of Trieste, Cattinara Hospital, Strada di Fiume 447, Trieste, Italy Conclusions In conclusion, we are firmly convinced that a scrotal ultrasound should always be performed in the presence of acute scrotal pain. Moreover, urologist should be able to perform a scrotal ultrasound but, if imaging does not supply a clear diagnosis, surgical exploration is still mandatory. Keywords Acute scrotum Color Doppler ultrasound Orchi-epididymitis Testicular trauma Testicular torsion Testicular infarction Introduction The acute scrotum is a common emergency department (ED) presentation and can be defined as any condition of the scrotum or intrascrotal contents requiring emergent medical or surgical intervention. Moreover, it can result in testicle infarction and necrosis, testicular atrophy, infertility, and significant morbidity. The evaluation of acute scrotal pain can be challenging for the clinician initially examining the patient, and scrotal ultrasound has emerged to play an essential role in the evaluation of patients presenting with acute scrotal pain. US technique Scrotal ultrasound is performed with the patient in the supine position with the scrotum supported by thighs or a rolled towel placed between the thighs. The Valsalva maneuver while scanning in the upright position should be always performed when evaluating for varicoceles. Scrotal US is best performed with a linear 7.5- to 12-MHz transducer. In addition to imaging in the

2 640 World J Urol (2011) 29: longitudinal and transverse planes, it is helpful to obtain simultaneous images of both testes for comparison. Color Doppler ultrasound (CDU) is used to assess flow abnormalities and to differentiate vascular from nonvascular lesions [1]. A correct CDU setting in order to optimize detection of slow flow is critical. Power Doppler increases the sensitivity for slow flow detection [2]. Epididymo-orchitis Epididymitis and epididymo-orchitis are the most frequent cause of acute scrotum in adults [3]. Clinically, epididymo-orchitis presents as acute scrotal pain and swelling of sudden onset. Symptoms of lower urinary tract infection associated with fever and leukocytosis are distinctive features in the differential diagnosis with testicular torsion. Typical gray scale US findings of epididymitis consist of an enlarged hypoechoic epididymis with parenchymal heterogeneity due to edema and hemorrhage [4]. Associated orchitis develops in 20% of epididymitis due to contiguous spread of infection [5]. Isolated orchitis is rare. Orchitis is characterized by an enlarged and heterogeneous testis, although findings may be focal or diffuse. When focal, orchitis is most often located adjacent to an inflamed epididymis. Focal orchitis can progress into abscess formation and a clear distinction between the two conditions is not simple. Associated findings of epididymo-orchitis may include skin thickening and reactive hydrocele. In case of tuberculous epididymo-orchitis, a more heterogeneous sonographic appearance can be demonstrated [6]. CDU has a sensitivity of quite 100% in detecting scrotal inflammation [7]. Color and power Doppler readily show a diffuse or focal areas of increased color signal of the epididymis (Fig. 1) and/or testis. While echogenicity may be variable, Doppler flow is invariably increased. Spectral Doppler patterns normally show increased peak systolic velocity with variable degree of diastolic flow. On pulsed Doppler, peak systolic velocity in intratesticular arteries increase fold on symptomatic side in epididymoorchitis [8]. A reversed diastolic flow suggests ischemia, a rare complication that may occur secondary to venous out flow obstruction. Demonstration of a normal spermatic cord and lack of avascular areas in the testis are important findings to exclude torsion [9]. Testicular trauma Blunt trauma is the most common mechanism of injury while penetrating scrotal injuries are less common. Direct blow or straddle injuries can result in contusion, Fig. 1 Acute epididymitis in a 31-year-old man. Longitudinal color Doppler US demonstrates normal testis and diffuse swelling of the right epididymis and increased blood flow hematoma, fracture, or rupture. Untreated testicular injuries may result in ischemic atrophy, chronic pain, or secondary infection. Physical examination is may be limited due to pain and often reveals varying degrees of edema; therefore CDU is essential for confirmation or exclusion of testicular rupture, differentiation of soft-tissue hematomas from hematocele and follow up of patients undergoing conservative therapy [3]. Testicular rupture Ultrasound shows heterogeneous echogenicity within the testis due to areas of hemorrhage or infarction. An irregular or indistinct testicular contour is suggestive of testicular rupture and a break in the continuity of the tunica albuginea confirms the diagnosis (Fig. 2). Guichard et al. [10] reported a sensitivity of 100% and specificity of 65% for US in the detection of testicular rupture when comparing with surgical findings. In addition, absence of normal vascularity within the testis may help characterize a rupture. Testicular fracture refers to a break in the normal testicular parenchyma. In testicular fracture without rupture of the albuginea, the capsule is intact (Fig. 3): a discrete fracture plane is visible in only 17% of cases. A testicular fracture line is identified at US as a linear hypoechoic and avascular area within the testis. Hematoma Scrotal trauma often results in hematomas which may be intratesticular or extratesticular [11]. They can involve the testis, epididymis, or scrotal wall. US appearance varies

3 World J Urol (2011) 29: diagnosis of testicular rupture or that may obscure a site of tunica disruption leading to an exclusion of a testicular rupture [8]. Testicular torsion Fig. 2 Testicular Rupture in a 34-year-old man. Longitudinal US image shows an abnormally shaped testis of the lower border, intratesticular hematoma, and scrotal hematoma with time because they can subsequently become complex with cystic components. Acute hematomas initially appear hyperechoic and avascular on color Doppler US scans [12], but subsequently become hypoechoic. Hematocele Extratesticular hematoceles, or collections of blood within the tunica vaginalis, are the most common finding in the scrotum after blunt injury [13, 14]. The appearance of hematoceles typically changes with time. In the early stages, they appear hypoechoic and markedly heterogeneous, and then become more echogenic. Large hematoceles can take several months to reabsorb and may results in testicular atrophy. Chronic hematoceles may become calcified. Moreover, a large hematocele may displace and obscure the underlying testis, leading to a false-positive Testicular torsion is the rotation of the testis along its longitudinal axis. This results in torsion of the spermatic cord with an initial blockage of venous drainage and subsequent reduction in arterial supply to the testis if complete rotation persist [3]. Patients with acute torsion present after a sudden onset of pain. Physical examination reveals a swollen, tender, and inflamed hemiscrotum [15]. The degree of venous engorgement, edema, hemorrhage, and arterial distress depends on the degree of torsion; basic literature has shown that there must be at least 720 torsions for occlusion of the testicular artery [16]. Venous obstruction occurs first, followed by obstruction of arterial flow and ultimately by testicular ischemia and infarction. The severity of torsion of the testis depends on the degree and length of torsion. If diagnosed in the first 6 h, torsion can be successfully treated surgically in nearly 100% of cases; the salvage rate drops to approximately 20% between 12 and 24 h after diagnosis [17]. Transient or intermittent torsion with spontaneous resolution sometimes occurs. Ultrasound is helpful to differentiate testicular torsion from other causes of acute scrotal pain and to identify testicular torsion promptly, ensuring the highest salvage rate (Fig. 4). One potential limitation with CDU is in the detection of an episode of torsion after spontaneous detortion has occurred: blood flow may be normal because of post-ischemic hyperemia. Real-time whirlpool sign is a key sign of testicular torsion that has been recently described as a snail shell, a doughnut shape, a target with concentric rings, and a storm on a weather map [18]. The presence of vascular flow in the testis can be readily detected by CDU with a sensitivity, specificity, and accuracy that has been reported to be 86, 100, and 97%, respectively [19]. Unilateral diminished or absent flow is the most accurate sign of testicular torsion, but the presence of blood flow does not exclude torsion. In these cases, spectral examination can show a decrease or inverted diastolic flow secondary to initial venous out flow obstruction. With time the testis becomes hypoechoic and swollen on gray scale images, and peritesticular hyperemia develops. Torsion of the testicular appendages Fig. 3 Testicular Fracture. CDU of the testis of 21-year-old man shows a wedge-shaped hypoechoic avascular area. A discrete fracture plane is visible into the testis, with out rupture of tunica albuginea Torsion of the testicular appendages is a frequent issue in childhood [20, 21]. They occurs less frequently than

4 642 World J Urol (2011) 29: Fig. 4 Testicular torsion. 18-year-old man who presented with left scrotal pain for 10 h. Longitudinal US shows an unevenly hypoechoic left testis (a) compared to the normal right testis (b). CDU shows normal vascular flow in right testis and absent vascular flow in the left testis testicular torsion does, but it can be as painful. Patients typically present with gradual pain and may manifest with a firm bluish nodule at the superior aspect of the testis referred to as the blue dot sign [19]. Ultrasound shows a circular hyperechoic mass with central hypoechoic area adjacent to the testis or epididymis which may show peripheral increased flow on color Doppler examination; scrotal wall edema, epididymal enlargement, and reactive hydrocele may also been shown. These cases are managed conservatively, with attention to pain management. The role of US examination in torsion of testicular appendages is to exclude testicular torsion and acute epididymoorchitis [22]. Testicular infarction Acute infarction usually presents as acute scrotum, but sometimes sequelae of partial infarction of the testis may atypically present as a testicular mass that may mimic a testicular neoplasm [23]. The pathophysiology of this clinical picture is congestion and thrombosis of the venous and arterial blood supply to the testis. US findings of testicular infarction are similar to torsion, including lack of Doppler flow; and at gray scale, it appears like an ill-defined hypoechoic mass, usually peripheral in location, septal in distribution, and without mass effect (Fig. 5). At times, a wedge-shaped area may be seen [24]. Infarction may also be segmental if due to an embolic phenomenon, manifesting as a well-demarcated region of hypoechogenicity with lack of flow. Conclusion In conclusion, we are firmly convinced that a scrotal ultrasound should always be performed in the presence of Fig. 5 Testicular Infarct. CDU shows an ill-defined hypoechoic mass with increased peritesticular vascularity but absence of intravascularity flow, indicating testicular infarction acute scrotal pain. Moreover, urologist should be able to perform a scrotal ultrasound but, if imaging does not supply a clear diagnosis, surgical exploration is still mandatory. Conflict of interest of interest. References The authors declare that they have no conflict 1. Heller MT, Fargiano A, Rudzinski S, Johnson N (2010) Acute scrotal ultrasound: a practical guide. Crit Ultrasound J 2: Oyen RH (2002) Scrotal ultrasound. Eur Radiol 12: Isidori AM, Lenzi A (2008) Scrotal ultrasound: morphological and functional atlas. Forum Service Editore s.r.l., Genova 4. Siegel MJ (1997) The acute scrotum. Radiol Clin North Am 35(4): Dogra VS, Gottlieb RH, Oka M, Rubens DJ (2003) Sonography of the scrotum. Radiology 227: Carkaci S, Ozkan E, Lane D, Yang WT (2010) Scrotal sonography revisited. J Clin Ultrasound 38:21 37

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