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INFECTION, GANGRENE


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.
INFECTION, GANGRENE

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.