Clinical History
A diabetic patient presented to the Emergency Department with intense scrotal pain lasting for 4 days. There was increased white blood count (26.000) but no clinical findings of scrotal necrosis.
Imaging Findings
The patient underwent scrotal ultrasound which revealed an oedematous, thickened scrotal skin (15.3 mm). Mobile high-amplitude echoes with dirty acoustic shadows were detected inside the thickened skin, possibly representing subcutaneous gas. There was also a fluid collection inside the right hemiscrotum. Both testes were normal in size, echotexture and vasculature. (Fig. 1, 2) Pelvic radiography of this patient revealed the presence of hyperlucent areas in the right hemiscrotum which confirmed the presence of intrascrotal gas. (Fig. 3) The patient underwent surgery, which confirmed the presence of intrascrotal gas. (Fig. 4)
Discussion
The term Fournier Gangrene (FG) refers to the necrotic inflammation of the fascia found in the penis, scrotum and in some cases the perineal and perianal regions. [1] It is an uncommon disease characterized by high mortality. [2] The patients are usually men of 50-60 years of age whereas women and children are only rarely affected. [2, 3] The main risk factors include diabetes mellitus, alcoholism, HIV infection, corticosteroids (immunity-compromising conditions), catheters, trauma, surgery, radiotherapy, malignancy etc. FG may also be caused by coexisting inflammatory processes like perianal fistulas, abscesses, urogenital infections, diverticulitis and colonic perforations. [1, 2] FG is usually caused by multiple pathogens, including Streptococci, Staphylococci, E. coli and Clostridia species. [1]
Patients with FG usually complain of perineal pruritus, genital swelling, fever and pain or anesthesia in severe cases. Clinical examination reveals erythema, vesicles, crepitus and possibly a foul-smelling discharge. Symptoms take 2-7 days to present and imaging may be needed in cases with inconclusive clinical findings.[1, 4] Other laboratory findings of FG include leukocytosis, dehydration, tachycardia, thrombocytopenia, anaemia, hypocalcaemia and hyperglycaemia. [2]
Plain radiography demonstrates swelling of the soft tissues and hyperlucent areas which correspond to gas. The latter may extend to the inguinal canal, reaching the abdominal wall and may be visible before the detection of clinical crepitus. Ultrasound will characteristically identify echogenic foci with dirty acoustic shadows and reverberation artefact which represent the gas in the subcutaneous emphysema characterizing FG. Ultrasound will also reveal scrotal wall oedema, intrascrotal reactive fluid and will exclude other causes of pneumoscrotum like inguinoscrotal hernia. The testes and epididymides may be unaffected due to their separate vasculature. CT can evaluate the extent of the disease and detect an underlying cause or retroperitoneal spread of the disease. CT findings include subcutaneous emphysema, fluid collections or abscess formation, fat stranding and thickening of the fascia. [1, 2]
The presence of gas inside the scrotum is termed “pneumoscrotum” and may be caused by FG, endoscopy, pneumothorax, trauma or visceral perforation. There was also a case report of a patient with FG caused by excessive masturbation. [5, 6]
FG is an emergency associated with a mortality ranging from 15% to 50%. Thus, once diagnosed, it should be aggressively treated with complete surgical debridement of the necrotic tissue along with fluid resuscitation and intravenous use of broad-spectrum antibiotics. [1, 2, 7]
Take-home message: the presence of echogenic foci with dirty-shadow artefact within the scrotal wall represents subcutaneous emphysema, possibly caused by FG.
Differential Diagnosis List
Fournier gangrene
Cellulitis
Strangulated hernia
Scrotal abscess
Vascular occlusion syndromes
Polyarteritis nodosa
Gonococcal balanitis and oedema
Herpes simplex
