Fournier's gangrene

Question 1

definition

Answer 1

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.

There is a predictable pathway for the spread of Fournier’s Gangrene based on scrotal anatomy. 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.

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

Question 2

Risk factors

Answer 2

Diabetes mellitus, excess alcohol, poor nutritional state, 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.

Question 3

Presentation

Answer 3

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.

Question 4

DDX

Answer 4

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.

Question 5

Invx

Answer 5

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, including blood cultures, are taken. CT imaging can show fascial swelling and soft tissue gas, however is less specific.

Question 6

Risk score

Answer 6

A diagnostic scoring system called the Laboratory Risk Indicator for Necrotising Fasciitis (LRINEC) can be used to aid in the diagnosis of necrotising fasciitis, including Fournier’s Gangrene.

Based on laboratory factors, a LRINEC score ≥6 is a reasonable score to consider the diagnosis based on lab results alone. Whilst the LRINEC can be a useful tool, it is not widely accepted in the everyday practise for many urologists

#	0	+1	+2	+4
C-Reactive Protein (mg/L)	<150	–	–	≥150
White Cell Count (x103/µL)	<15	15-25	>25	–
Haemoglobin (g/dL)	>13.5	11.0-13.5	<11	–
Sodium (mEq/L)	≥135	–	<135	–
Creatinine (µmol/L)	≤141	–	>141	–
Glucose (mmol/L)	≤180	>180	–	–

Question 7

Management

Answer 7

The definitive management is urgent surgical debridement. The earlier this is performed, the better the outcomes.

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

Patients should be started on broad-spectrum antibiotics and transferred to a high-dependency setting. Antibiotics can be tailored accordingly, depending on culture sensitivities. Fluid resuscitation and close monitoring is essential is such cases, due to potential rapid deterioration that can occur.

Often further surgical debridement is required; secondary closure with skin grafts can be a long process, aiming to re-cover the scrotum. Post-operative outcomes vary, depending on disease extent and tissue involvement.

Question 8

Key points

Answer 8

Fournier’s gangrene is a form of necrotising fasciitis that affects the perineum
Risk factors include diabetes mellitus, excess alcohol, or poor nutritional state
Clinical features are often non-specific in the conditions early stages, before rapid deterioration occurs
Definitive management is urgent surgical debridement with broad-spectrum antibiotic cover