INFECTION, GANGRENE
The scrotum is subject to infections, similar to skin elsewhere in the
body. However, several anatomic issues predispose the scrotal skin to
infection. Reduced ventilation and lack of sweat evaporation cause the scrotal
skin to be moist. In addition, the proximity of the scrotum to the urethra and
rectum can affect the bacterial type and load. Physical contact with the thighs
favors skin maceration that can delay the healing process. Lastly, the loose,
fat-free and contractile scrotal wall reacts to infection with considerable
edema (see Plate 3-8), which can interfere with vascularity and prolong
healing.
Primary abscess of the
scrotal wall is rare. Abscesses secondary to underlying urethral, testicular,
epididymal, perineal, or rectal pathology are more common. Scrotal boils or
furuncles can occur from infection of hair follicles or sweat glands due to
bacteria such as Staphylococcus aureus. They usually require incision
and drainage along with antibiotics and are prone to recur if the sebaceous
cyst is not entirely excised.
Scrotal erysipelas (Greek
for “red skin”) is a diffuse infection of the scrotal dermis and subcutaneous
tissue. It is most commonly due to Streptococcus pyogenes (also known as
beta-hemolytic group A streptococci), although non–group A streptococci are
also implicated. Erysipelas infections enter the skin through minor trauma,
eczema, surgical incisions, abscesses, fistulae, and ulcers. People with immune
deficiency, diabetes, alcoholism, skin ulceration, fungal infections, and
impaired lymphatic drainage are at increased risk for this infection.
Erysipelas is diagnosed by the appearance of well-demarcated rash and
inflammation. Blood cultures are unreliable. It should be differentiated from
herpes zoster and angioedema and be distinguished from cellulitis by its raised
advancing edges and sharp borders. Erysipelas in the lower abdomen or adjacent
skin areas may progress to the scrotum and can gradually invade the entire
scrotum, with soft, loose tissues becoming markedly swollen, tense, smooth, and
warm. Many blebs or vesicles form on the surface, and in some instances the
infection is so intense that the scrotal skin becomes gangrenous. It is treated
with penicillin, clindamycin, or erythromycin antibiotics.
Scrotal gangrene or
necrotizing fasciitis of the
scrotum is uncommon but
lethal. It can occur after extravasation of infected urine into subcutaneous
tissues secondary to urethral stricture (see Plate 2-20) or seeding from stool
due to rectal fistula or fissure. It may also occur after mechanical, chemical,
or thermal injury to the scrotum and is particularly prone to occur in
individuals with underlying systemic immune disturbances, diabetes, or
alcoholism. Scrotal gangrene has also been encountered as a complication of
rare conditions such as embolism of the hypogastric arteries, Entamoeba
histolytica infestation, and rickettsial diseases when accompanied by
thrombosis of small blood vessels. Spread of the infection is usually limited
by scrotal and pelvic fascial planes (see Plate 2-20).
Fulminating, spontaneous, or
idiopathic gangrene (Fournier gangrene) of the scrotum is known for its
dramatic, sudden onset. A combination of aerobic and anaerobic bacteria and
fungi facilitate the rapid course of this infection. Staphylococcal bacteria
clot the blood, depriving surrounding tissue of oxygen. Within this
oxygen-depleted environment, anaerobic bacteria thrive and produce enzymes that
digest tissue and further spread the infection. Men are 10 times more likely
than women to develop Fournier gangrene and those aged 60 to
80 with a predisposing condition are most susceptible. Alcoholism, diabetes
mellitus, leukemia, morbid obesity, immune system disorders such as HIV and
Crohn disease, and intravenous drug users are at increased risk for developing
gangrene. The condition also can develop as a complication of surgery.
With gangrenous infection,
the scrotum becomes abruptly painful and reddened, usually limited to the
demarcation of the scrotum. It may spread quickly under Scarpa fascia to the
abdomen and even to the
axilla, often within hours.
It can be differentiated from erysipelas, which begins in a localized area and
spreads with a red, raised margin. Gangrene is typically accompanied by a
“spongy” or “cracking” feel to the tissues in the scrotum, groin, and perineum
on examination, which represents tissue crepitus from emphysema due to
gas-producing anaerobic organisms. Treatment is emergent and involves making
multiple incisions in affected tissues, irrigation with antibiotic solution,
systemic broad-spectrum antibiotics, and fluid support.
