Fournier’s gangrene with retroperitoneal extension in an immunocompetent patient

Abstract

A male patient in his 80s presented with the classic signs of Fournier’s gangrene. At his initial debridement, an unusual florid involvement of the right cord was noted requiring a right inguinal orchidectomy in addition to extensive debridement. Although he subsequently stabilised in the intensive care unit, his inflammatory markers were noted to uptrend again requiring a relook procedure which revealed evidence of progressive necrosis in the right inguinal region. After further debridement, a CT scan of the abdomen and pelvis revealed intra-abdominal extension of the disease process with a retroperitoneal collection adjacent to the caecum—a rare complication of Fournier’s gangrene. This required open surgical drainage for adequate disease control. He subsequently underwent split skin grafting prior to discharge to a rehabilitation facility.

Background

Fournier’s gangrene continues to be a challenging acute life-threatening surgical condition. Although it is a relatively infrequent presentation, the availability of a wide array of broad-spectrum antibiotics, good intensive care units (ICUs) coupled with prompt surgical debridement means we are better equipped to deal with it.

Physicians need to be aware of the telltale signs that could be used to identify unusual disease spread as this could lead to a prompter diagnosis and more favourable outcomes for the patient.

In the current case, the rising inflammatory markers despite what was thought to be an adequate relook debridement was the first indicator of persistent disease.

Second, the initial finding of extensive cord involvement and subsequent progressive necrosis in the right inguinal region pointed towards the likely source of persistent disease.

Cross-sectional abdominal imaging enabled good radiological clarification of disease extent, and this was used to guide further debridement.

Case presentation

A male patient in his 80s was transferred to our emergency department with problems of scrotal pain, erythema and swelling over the previous 4 days whereupon he became progressively unwell and presented to a peripheral hospital from where he was referred to our tertiary hospital. The patient’s only background medical history was hypertension. He was neither a smoker nor an alcoholic.

On presentation to the emergency department, he was febrile with a temperature of 38°C, hypotensive with a blood pressure of 81/63 mm Hg and tachycardic with a heart rate of 128 beats/min.

The scrotal exam was notable for a large necrotic appearing area demonstrating features consistent with necrotising fasciitis (figure 1).

Figure 1.

Appearance of scrotum at presentation demonstrating thrombosed superficial vessels (red arrows) with accompanying necrotic skin and devitalised subcutaneous tissues (green arrows).

Investigations

Blood tests showed a white cell count of 17, c-reactive protein of 400 mg/L. The arterial blood gas analysis revealed a pH of 7.30, base excess of −6.2 and a lactate of 2.7 mmol/L. All the above tests were in keeping with the clinical findings consistent with sepsis.

Differential diagnosis

A scrotal abscess was the main differential diagnosis in our patient. However, the examination finding of a profoundly unwell patient coupled with the presence of necrotic scrotal skin patches indicated a more severe diagnosis of Fournier’s gangrene.

Treatment

Our patient was fluid resuscitated in the emergency department, was given vasopressors and broad-spectrum antibiotics with vancomycin, meropenem and clindamycin.

He underwent emergency surgery with excision and debridement of the entire scrotal wall performed. The right testes and cord were macroscopically involved with grossly necrotic-appearing tissue extending to the deep ring whereupon a right inguinal orchidectomy was performed in consultation between the urology and general surgical teams. He was admitted to the ICU for vasopressor support and stabilisation.

On day 2 of admission, a first relook debridement was performed whereupon a left subcutaneous pouch was created for the left testicle since only minimal necrotic tissue was encountered. Although the first relook debridement was deemed adequate, his CRP was noted to subsequently uptrend raising the possibility of residual disease.

At the third relook procedure on day 4 of admission, new areas of tissue necrosis in the right inguinal region were noted requiring further debridement following which a CT scan was performed to delineate disease extent.

This demonstrated disease progression into the retroperitoneum with gas tracking along the cord into a fluid and gas-filled collection adjacent to the caecum (figure 2) There was also extensive gas within the superficial fascia of the anterior abdominal wall bilaterally.

Figure 2.

Sagittal CT of abdomen and pelvis demonstrating gas along the cord (red arrow) and extending into the retroperitoneum adjacent to the caecum (green arrow).

A laparoscopy was first performed to exclude caecal involvement, which demonstrated a healthy caecum. This was then converted to open drainage of the retroperitoneal collection through a right lower quadrant muscle splitting incision. A collection of thick pus was encountered adjacent to the caecum. This was drained and washed out, then packed with gauze. Small-bowel content was noticed in the packing gauze during a subsequent relook. A pinhole perforation of the caecum was discovered, which was closed primarily without a diversion then planned for a relook.

The left thigh subcutaneous pouch was also found to be involved with disease requiring its excision and debridement.

The anterior abdominal wall did not demonstrate evidence of macroscopic disease progression.

A repeat CT scan at day 6 showed nil further disease spread with nil new intraperitoneal collections. Vasopressors were subsequently weaned off and the inflammatory markers down trended.

The abdominal packs were subsequently removed with satisfactory healing of the caecal perforation and no further soiling of the surgical site. Closure of the abdominal wall defect was performed.

The patient underwent a split skin graft procedure under the plastic surgeons when his wounds were deemed suitable for grafting.

Outcome and follow-up

The split skin grafts took well, and the patient was subsequently transferred to a rehabilitation unit. He was predictably severely deconditioned after a prolonged ICU admission and required a few weeks of physical rehabilitation prior to discharge back home. He was doing well and living at home when last contacted about 7 months after his initial admission.

Discussion

Fournier’s gangrene is a form of necrotising fasciitis affecting the scrotum primarily, but not infrequently spreading to the perineum and adjacent structures.

It is a polymicrobial, synergistic infection by gas forming organisms that results in an end arteritis with thrombosis of superficial vessels and resultant necrosis of subcutaneous tissues and eventually the overlying skin.¹

Affected patients are typically profoundly unwell requiring urgent surgical debridement as the mainstay of treatment, in addition to broad spectrum antimicrobial therapy.

The infection typically spreads along superficial fascial layers although it can involve deeper fascial layers and muscle.² Evaluation of the patient using scoring systems such as the Laboratory Risk Indicator for Necrotizing Fasciitis (LRINEC) can be used to identify patients at significant risk of disease lethality. Bonne et al report a score greater than or equal to six as having a 92% positive predictive value and a 96% negative predictive value for predicting severe, high-risk infection.³ Retrospectively calculated, our patient presented with a score of 8, accurately representing the clinical condition of the patient. Bozkurt et al compared other scoring criteria such as the Fournier’s gangrene severity index and the neutrophil-lymphocyte ratio to the LRINEC score and determined that each score showed statistically significant correlation when used for predicting high morbidity risk including ICU and mechanical ventilation requirements.⁴

In our patient, the tissue culture reported florid mixed microbial growth along the entire cord in keeping with CT scan findings of gas tracking along the cord into the retroperitoneum.

As demonstrated in previous cases, cross-sectional imaging to determine the extent of spread followed by open surgical debridement is paramount in controlling retroperitoneal involvement. Open surgical debridement not only provides adequate access to the affected tissues for debridement but also ensures it remains relatively ‘oxygenated’—an approach that has been demonstrated in previous studies to offer significant benefit toward resolution of necrotising soft-tissue infections.⁵

Although a subcutaneous pouch was created for the left testicle during his first relook debridement, it likely contributed to spread of infection into an otherwise unaffected area. This eventually required excision and debridement.

Our patient made a full recovery and was eventually discharged after undergoing a split skin graft and rehabilitation.

Patient’s perspective.

“I was suddenly unwell with severe pain in my testicles. I was not aware of how serious this was until I reached the emergency department where I was told I had the flesh-eating bug and urgent surgery was required to save my life. It was indeed a long stay in hospital with very many operations performed which left me quite weak. I am very grateful to the amazing doctors who did everything that saved my life. I am now back at home albeit with many scars. I am grateful for all the care we have received.”

Learning points.

• A finding of necrotic tissue extending to the deep ring should raise a high suspicion for the rare complication of retroperitoneal extension of Fournier’s gangrene.

• Creation of a subcutaneous thigh pouch for the testicle may be delayed until there is no further macroscopic and biochemical evidence of disease progression.

• In the presence of biochemical but nil macroscopic evidence of disease progression consider cross-sectional imaging as soon as possible to guide further debridement.

Ethics statements

Patient consent for publication

Consent obtained from next of kin.