Fournier’s Gangrene

Introduction

Fournier’s gangrene is a form of necrotising fasciitis that affects the perineum. Whilst rare, it is a urological emergency with a mortality rate of 20-40%*.

Necrotising fasciitis is a group of rapidly spreading necrosis of subcutaneous tissue and fascia, the term also encompassing Fournier’s gangrene. Much of the principles for its management therefore hold true for Fournier’s.

Fournier’s gangrene can be a monomicrobial or a polymicrobial infection, with causative organisms including Group A streptococcus, C. Perfringes,and  E. Coli.

Anatomic barriers to the spread of infection include the dartos fascia of the penis and scrotum, Colles fascia of the perineum, and Scarpa fascia of the anterior abdominal wall. As a result, the testes and epididymis are commonly not affected by the fasciitis.

*The condition was first described by Jean Alfred Fournier, who described 5 cases involving previously healthy young men, all of which survived

Risk factors

Diabetes mellitus, excess alcohol intake, poor nutritional state, excess steroid use, haematological malignancies, and recent trauma to the region (allowing the protective outer layers of the perineum to be breached) are all known risk factors.

Clinical Features

Early stage of the condition may simply present with severe pain, out of proportion to clinical signs, or as pyrexia.

Clinical features are often non-specific until significant deterioration, most commonly seen in those who are “not quite right” for a simple cellulitis.

As the condition progresses, crepitus, skin necrosis, and haemorrhagic bullae may begin to develop, however they may not be present at the time of deterioration. Sensory loss of the overlying skin may also occur.

Patients will rapidly deteriorate and become significantly unwell, with sepsis and often entering septic shock.

By Mohammd Kazem Moslemi, Mohammad Ali Sadighi Gilani, Ali Akbar Moslemi and Ali Arabshahi [CC BY 2.0 (https://creativecommons.org/licenses/by/2.0)], via Wikimedia Commons

Figure 1 – A case of Fournier’s gangrene following extensive debridement

Differential Diagnoses

As with any case of suspected necrotising fasciitis, the main differential in the early stage is a cellulitis. For potential Fournier’s Gangrene cases, further differentials will include epididimyo-orchitis and testicular torsion.

Investigation

Diagnosis is largely clinical, often patients being monitored for evidence of disease progressed being the mainstay of diagnosis. Any suspected cases should be taken for immediate surgical exploration.

Ensure routine bloods (FBC, CRP, U&Es, LFTs, clotting) and blood cultures should be taken. If no obvious risk factors present, consider also sending a HbA1c test if feasible, to assess for any underlying diabetes mellitus.

CT imaging can show fascial swelling and soft tissue gas, however is less specific and should not delay surgical intervention.

Management

The definitive management is urgent surgical debridement and this should not be delayed. Debridement can often be extensive, however ensuring adequate removal of all necrotic tissue is key; debrided tissue should be sent for both tissue histology and culture separately (MC&S) and any pus sent for fluid culture (MC&S) too

Patients should be started on broad-spectrum antibiotics (to cover Gram-positive, Gram-negative, Aerobic and Anaerobic bacteria, and an anti-MRSA agent) and transferred to a high-dependency setting. Antibiotics can be tailored accordingly, depending on culture sensitivities.  Further surgical relooks and debridement are required, until the patient is free of necrotic tissue.

Secondary closure with skin grafts can be a long process, therefore early involvement of plastic surgeons is key. Post-operative outcomes vary, depending on disease extent and tissue involvement.

*The surgical debridement may also encompass partial or total orchiectomy, depending of the size of expansion of the process, with the wound usually left open.