Diagnostic ultrasound ( PDFDrive )

846 PART III Small Parts, Carotid Artery, and Peripheral Vessel Sonography
occur, but venous outlow is oten obstructed, causing diminished
diastolic arterial low on spectral Doppler examination 184,185 (Fig.
22.30E). If spontaneous detorsion occurs, low within the afected
testis may be normal, or it may be increased and mimic orchitis. 186
Spontaneous detorsion can occur with sequelae including a
segmental testicular infarction. 102,103 Segmental testicular infarction
may also occur with Henoch-Schönlein purpura or with orchitis
(see Fig. 22.14). Orchitis may also cause global ischemia of the
testis and mimic torsion. 186
In subacute or chronic torsion, Doppler sonography demonstrates
no low in the testis and increased low in the paratesticular
tissues, including the epididymis-cord complex and dartos fascia
(Fig. 22.30I).
Torsion of the appendix testis or appendix epididymis can
present with acute scrotal pain, potentially mimicking testicular
torsion clinically, although there are no other clinical symptoms
and the cremasteric relex can still be elicited. Patients are rarely
referred for imaging because the pain is usually not severe, and
the twisted appendage may be evident on physical examination
as a small irm nodule palpable at the superior aspect of the
testis, with a bluish discoloration, or the “blue dot” sign. 187 Up
to 95% of twisted appendages involve the appendix testis and
occur most oten in boys aged 7 to 14 years. 65 he sonographic
appearance of the twisted testicular appendage has been described
as an avascular hyperechoic mass with a central hypoechoic focus
adjacent to the head of a normally perfused testis and surrounded
by an area of increased color Doppler perfusion. 162,188 hese cases
are managed conservatively with pain typically resolving in 2 to
3 days with interval atrophy of the torsed appendage. he role
of sonography is to exclude testicular torsion or epididymoorchitis.
Idiopathic scrotal edema typically afects prepubertal
boys, with acute onset of relatively painless scrotal erythema
and subcutaneous edema. Idiopathic scrotal edema typically
resolves spontaneously in 1 to 3 days without sequelae.
Epididymitis and Epididymo-orchitis
Epididymitis is the most common cause of acute scrotal pain in
postpubertal men. It may be acute or chronic, depending on the
inciting organism and the duration of the process. Acute epididymitis
usually results from a lower urinary tract infection
and is less oten hematogenous or traumatic in origin. he
common causative organisms are Escherichia coli, Pseudomonas,
and Klebsiella. Sexually transmitted organisms causing urethritis,
such as Neisseria gonorrhoeae and Chlamydia trachomatis, are
common causes of epididymitis in younger men. Less frequently,
epididymitis may be caused by tuberculosis, mumps, or syphilitic
orchitis. 153,189 he age of peak incidence is 40 to 50 years. Typically,
patients present with the insidious onset of pain which increases
over 1 or 2 days. Fever, dysuria, and urethral discharge may also
be present.
In acute epididymitis, sonography characteristically shows
enlargement of the epididymis, involving the tail initially and
frequently spreading to the entire epididymis 190 (Fig. 22.31A and
B). he echogenicity of the epididymis is usually decreased and
its echotexture is oten coarse and heterogeneous, likely secondary
to edema, hemorrhage, or both. Color low Doppler sonography
usually shows increased blood low in the epididymis or testis,
or both, compared with the asymptomatic side. 191 Reactive
hydrocele formation is common, and associated scrotal wall
thickening may be seen.
Direct extension of epididymal inlammation to the testis,
called epididymo-orchitis, occurs in up to 20% of patients with
acute epididymitis. Isolated orchitis may also occur. In such cases,
increased blood low is localized to the testis (Fig. 22.31D and
E, Video 22.6). Testicular involvement may be focal or difuse.
Characteristically, focal orchitis produces a hypoechoic area
adjacent to an enlarged portion of the epididymis. Color Doppler
shows increased low in the hypoechoic area of the testis; increased
low in the tunica vasculosa may also be visible as lines of color
signal radiating from the mediastinum testis. 192 hese lines of
color correspond to septal accentuation visible as hypoechoic
bands on gray-scale sonography (Fig. 22.31H and I). Spectral
Doppler shows increased diastolic low in uncomplicated orchitis
(Fig. 22.32A). If let untreated, the entire testis may become
involved, appearing hypoechoic and enlarged. As pressure in
the testis increases from edema, venous infarction with hemorrhage
may occur, appearing hyperechoic initially and hypoechoic
later. 192 Ischemia and subsequent infarction may also occur when
the vascularity of the testis is compromised by venous occlusion
or venous thrombosis. 193 When vascular disruption is severe,
resulting in complete testicular infarction, the changes
are indistinguishable from those seen in testicular torsion.
Color Doppler sonography may show focal areas of reactive
hyperemia and increased blood low associated with relatively
avascular areas of infarction in both the testis and the epididymis
in patients with severe epididymo-orchitis. Diastolic low reversal
in the arterial waveforms of the testis is an ominous inding,
associated with testicular infarction in severe epididymo-orchitis 194
(Fig. 22.32B).
In addition to infarction, other complications of acute
epididymo-orchitis include intratesticular abscess formation and
development of a pyocele (see Figs. 22.13 and 22.17F). Chronic
changes may be seen in the epididymis or testis from clinically
resolved epididymo-orchitis. Swelling of the epididymis may
persist and appear as a heterogeneous mass on sonography. he
testis may have a persistent, striated appearance of septal accentuation
from ibrosis (Figs. 22.33 and 22.34). his striated appearance
of the testis is nonspeciic and may also be seen ater ischemia
from torsion or during a hernia repair. 192,195 A similar heterogeneous
appearance in the testis may be seen in older patients
because of seminiferous tubule atrophy and sclerosis. 196 Focal
areas of infarction in the testis may persist as wedge-shaped or
cone-shaped hypoechoic areas or may appear as hyperechoic
scars. 192 If complete infarction of the testis has occurred because
of epididymo-orchitis, the testis may become small, with a
hypoechoic or heterogeneous echotexture.
Fournier Gangrene
Fournier gangrene is a necrotizing fasciitis of the perineum,
external genitalia, and perianal area occurring most frequently
in men aged 50 to 70 years. he origin is usually a disease process
from the overlying skin, urinary tract, or colorectal area, frequently
due to a synergistic polymicrobial infection. 197 Predisposing
factors include systemic immunosuppression, diabetes mellitus,