Life threatening necrotising fasciitis of the perineum and male genitalia.
Usually polymicrobial and requires urgent debridement with concurrent resuscitation.
Mortality rate has historically been 20 – 40 %
Risk factors:
- Diabetes
- Immunosuppression
- Malnutrition
- Urethral instrumentation or peri-anal surgery
- Perianal abscess or inflammatory bowel disease
- Urethral stricture
- Paraphimosis
- Obesity
- Poor hygiene
- Trauma
Pathophysiology
The source is usually either from the urinary tract, rectum/anus, or the skin.
The infection is typically polymicrobial, with synergistic activity or anaerobic and aerobic bacteria.
Organisms include gram positive cocci (staph, strep), gram negative rods (E.coli), anaerobes (bacteroides, clostridium), and occasionally fungal e.g. candida
The infection spreads along fascial planes (typically via Colles’ fascia, contiguous with dartos fascia of the scrotum and Scarpa’s fascia of the abdominal wall).
Rapidly progressive infection causes obliterative endarteritis and microvascular thrombosis which leads to necrosis.
Release of endotoxins and exotoxins can trigger widespread sepsis with resulting septic shock.
Clinical presentation
Pain in the perineum or genitals, often out of proportion to the clinical findings.
Oedema, erythema and tenderness progresses quickly.
Crepitus of the tissues, with associated skin breakdown.
Systemic toxicity, fevers, hypotension may develop quickly.
Urinary or rectal symptoms may be preceding.
Management
Immediate resuscitation following CCrISP protocols in conjunction with ED and ICU.
Broad spectrum antibiotics – meropenem, vancomycin +/- fluconazole.
Urgent surgical debridement:
- Consider suprapubic catheter or diverting colostomy
- Aggressive debridement and excision of all infected tissue until healthy bleeding tissue
- Swabs and tissue for culture, tissue for histology
- Leave open with re-look in theatre after 24 – 48 hours with further debridement as needed
- Saline soaked packs initially, considering VAC dressing after relook
ICU or HDU support as needed with:
- Aggressive glycaemic control
- ID input for appropriate antimicrobials
- Optimising nutrition
Consider plastic surgeon involvement for reconstruction if primary closure not feasible. If closing wound, ensure drain left.
Long term psychological input.
The testis is usually spared from infection due to its independent vascular supply. It can be placed in a thigh pouch if scrotum is excised.
Hyperbaric oxygen has been described but I have not used it.