Necrotizing Fournier's Gangrene From a Perforated Rectal Carcinoma

May 25, 2007
Surgical Rounds®, June 2006, Volume 0, Issue 0

Neil R. McMullin, General Surgery Resident; Scott Gering, Colorectal Surgeon; Thomas Levoyer, Surgical Oncologist, Department of Surgery, Brooke Army Medical Center, Fort Sam Houston, TX

Neil R. McMullin, MD

General Surgery Resident

Scott Gering, MD

Colorectal Surgeon

Thomas Levoyer, MD

Surgical Oncologist

Department of Surgery

Brooke Army Medical Center Fort Sam Houston, TX

Fournier’s gangrene is a life-threatening bacterial infection of the skin that affects the genitals and perineum. It is much more common in men, especially the elderly. The authors report the case of a 70-year-old man who went to the emergency department after falling in the shower. His evaluation and workup re­vealed synchronous sigmoid and rectal cancers, which presented as Fournier’s gangrene. The authors discuss this rare case and provide a review of the literature.

Fournier’s gangrene, a necrotizing fascitis involving the male genitalia, is a life-threatening infection that requires prompt diagnosis and surgical intervention. It was first described in 1764 by Baurienne and has since been widely reported and well documented in the medical literature.1We present a case of synchronous rectal and sigmoid carcinomas that presented as Fournier’s gangrene with nontraumatic subcutaneous emphysema. The patient required extensive debridement of the pelvic floor, rectum, and perineum. This case demonstrates an uncommon presentation of a relatively common disease. When a diagnosis of Fournier’s gangrene is made, the underlying pathology must be evaluated. If perineal subcutaneous emphysema is found, the presence of a perforated hollow viscus must be investigated.

Case report

A 70-year-old man presented to the emergency department after falling in the shower. The initial examination was performed by the internal medicine service and revealed he was normotensive, afebrile, and had an irregular heart rhythm. The patient reported no medical or surgical history and had not seen a physician in 20 years. A review of systems was positive for melena for at least 4 weeks and loose bowel movements for the past 11/2 years, which had increased in intensity and volume over the past 4 weeks. He also had an unintentional weight loss of 40 pounds during the previous year. A physical examination noted that the patient was pale, had a tense, rigid abdomen that was nontender to palpation and tympanitic to percussion, and the presence of significant scrotal edema. His admission history and physical ex­amination write-up recorded no digital rectal examination. Laboratory evaluation showed a hematocrit of 14% and a white blood cell (WBC) count of 33,000/mm3. The patient was admitted to the intensive care unit (ICU) for resuscitation and a blood transfusion. Further workup at this time was directed towards the etiology of his diarrhea and significant anemia. The ICU attending physician’s note described scrotal trauma with suprapubic crepitus, which was attributed to hematoma and the possibility of a perforated hollow viscus.

The following morning, a gastroenterologist examined the patient and observed an increasing amount of scrotal edema. There was surrounding erythema and an area of black and green discoloration, which was not present upon admission to the hospital. An abdominal examination found crepitus and that his abdomen had become tender to palpation. It was recommended that a computed tomography (CT) scan be performed to rule out perforation of a hollow viscus and that a regimen of broad-spectrum antibiotics be initiated. While the CT scan was being performed, a urologist was consulted to evaluate the patient’s increasing scrotal edema. His scrotum and perineum were noted as markedly edematous, with focal areas of necrosis and a generalized rubor extended throughout the perianal region, up the abdomen, and down to his thighs (Figure 1). Marked crepitus was palpated over his inguinal ligaments and scrotum. Moreover, he had become more somnolent. At this point, a presumptive diagnosis of Fournier’s gangrene was made based on the physical examination findings of frank cutaneous necrosis and subcutaneous emphysema.

The CT scan of the patient’s abdomen and pelvis showed a 7-cm, anular, constricting lesion consistent with malignancy in the distal descending colon and a rectal constricting lesion with a transition point seen at the distal sigmoid colon, consistent with synchronous malignancies. The CT scan also showed extensive perineal, scrotal, and anterior abdominal wall subcutaneous emphysema, with fluid and air adjacent to the rectal mass (Figure 2).

Given these findings, the patient was taken to the operating room for emergency debridement of his perineum and colectomy. Laparotomy revealed an extensive infection that tracked from the patient’s perineum to the rectal tumor, completely obliterating the anal canal, distal rectum, and pelvic floor (Figure 3). A digital rectal examination found a fixed rectal mass approximately 3 cm above the anal verge that completely obstructed the rectum. The tissues surrounding the perineum, however, ap­peared viable and healthy with no fascial involvement.

In subsequent surgeries, the patient’s testicles were placed into thigh pouches for preservation and serial topical negative pressure dressings were applied to his perineum to promote wound healing (Figure 4). Cultures from the initial de­bridement showed multiple enteric or­ganisms, including Escherichia coli, Enterococcus, and Bacteroides species.

The sigmoid tumor measured 6 cm, invaded the pericolic adipose tissue, and was metastatic to four of six regional lymph nodes, showing evidence of lymphovascular invasion. The rectal tumor, which was only partially resected, was metastatic to one of three lymph nodes and showed evidence of lymphovascular invasion. The sigmoid tumor was staged as T3 N2 MX (stage IIIC) and the rectal tumor was staged as T4 N1 MX (stage IIIB). The patient was discharged to a rehabilitation center on postoperative day 26 and referred to oncology for palliative neoadjuvant and radiation therapy. Two years after his initial presentation, the patient was receiving hospice care due to his end-stage disease.

Discussion

Our patient had a rare presentation of a common disease. A 1988 case study of 35 patients with colorectal cancer and spontaneous gangrene revealed five cases of rectal cancer and three sigmoid cancers that developed nontraumatic gas gangrene, but none of which presented with Fournier’s gangrene.1 An extensive search of the literature found only four previously reported cases of Fournier’s gangrene that resulted from rectal or sigmoid adenocarcinoma.2-5 Of these four cases, one was a stage II (T3 N0 M0) lesion, the others Dukes’ B and Aston Collier C2, and the fourth case had no staging reported.2-5 Our case was a stage IIIC/IIIB, more advanced than the cases previously reported.

Fournier’s gangrene is typically de­scribed as a polymicrobial disease that allows a synergistic necrotizing infection to invade the tissues of the scrotum, perineum, and perianal region.6 It is frequently caused by perineal injury from instrumentation or trauma and is often associated with comorbid diseases, most notably diabetes, and other immunosuppressed states.6 Fournier’s gangrene can also be caused by perianal infection, perirectal abscess, skin infection, urethral stricture, indwelling catheters, penile intravenous drug use (injection of drugs into the corpus cavernosum), hidradenitis, and balanitis.7

The initiating event in Fournier’s gangrene from an anorectal source is penetration of the anal sphincter muscles by a deep infection. The infection then has two avenues of opportunity: it may track up Colles’ fascia to involve the tunica dartos, or it may spread through the Retzius space and down the spermatic cord.7 Fournier’s gangrene from a penile source occurs when the infection penetrates Buck’s fascia and spreads along the shaft of the penis into the scrotum, up along Scarpa’s fascia and by way of Colles’ fascia into the perineum.7

The bacteria typically associated with Fournier’s gangrene are E coli, Staphylococcus, Streptococcus, and Proteus, with an average of at least three bacteria cultured from each patient.6,8 Even with such extensive infections, one review showed that blood cultures were positive in only one third of cases.1

Fournier’s gangrene usually presents with itching and edema as well as perianal or perineal pain that is disproportionate to findings on physical examination.6 The clinical disease becomes more evident with worsening of the subcutaneous infection and inflammation that culminates in frank necrosis of the skin as the blood vessels thrombose.6

Fournier’s gangrene is diagnosed clinically and should be evident from a prompt and thorough patient history, review of systems, and physical examination. If the diagnosis is questionable, some imaging modalities are useful in evaluating the acute scrotum. Ultrasonography of the scrotum can help visualize subcutaneous emphysema and reportedly has shown subcutaneous gas prior to it being found during physical examination.9 Ultrasound findings consistent with Fournier’s gangrene include normal testes, a thickened scrotal wall, and subcutaneous gas that lies parallel to the transducer head.9 Plain abdominal radiographs and CT scanning can assist in early visualization of subcutaneous emphysema and help identify the source of infection.8

Nontraumatic, nongangrenous, subcutaneous emphysema of the lower extremities is documented as being associated with gastrointestinal (GI) perforations.9,10 A 1995 review reported 36 cases of subcutaneous emphysema originating from GI tract perforations.11 This report suggests that subcutaneous emphysema of GI origin depends on three factors: (1) perforation of the bowel; (2) an adequate pressure gradient between bowel lumen and subcutaneous space; and (3) the anatomic site of the perforation.11 Studies have shown that gas pressures in the intestinal lumen may rise to more than 60 cm H2O, while soft tissue pressures are about 5 cm H2O.12 It is thought that the gas gains access to the lower extremities anteriorly under the inguinal ligament or posteriorly across the sciatic foramen.10 Often, subcutaneous emphysema without gas gangrene will be the manifestation of the perforation and is commonly misdiagnosed as gas gangrene.9 Subcutaneous emphysema as the result of a perforated hollow viscus can occur anywhere from the neck to the lower extremities.10 Whether subcutaneous emphysema is mere­ly the manifestation of a perforated hollow viscus or from spontaneous nontraumatic gas gangrene can be difficult to determine because in either case, the patient may present toxic and in extremis. Spontaneous nontraumatic gas gangrene is usually accompanied by other findings on physical examination, such as erythema, skin necrosis, and progressive deterioration of the patient’s clinical condition. Gas gangrene should always be high in the differential diagnosis and immediately excluded. A tissue biopsy will provide conclusive information if the diagnosis is still in doubt after a careful physical examination is performed and a thorough patient history is obtained.7 The pitfall would be to delay prompt surgical management at the expense of obtaining a definitive diagnosis.

Managing Fournier’s gangrene requires prompt diagnosis, antibiotic therapy, and surgical debridement to limit morbidity and mortality. During exploration, the surgeon may not have the luxury of imaging studies to assist in diagnosis and should be prepared for both urinary and fecal diversion, extensive debridement, and laparotomy.7 Before de­bridement, rigid proctoscopy should be performed to evaluate sphincteric involvement. After debridement and once the patient has been brought through the acute phase, the remaining defects can be allowed to heal by secondary intention.7

Mortality from Fournier’s gangrene is variable and ranges from 0% to 75%.7 A study that examined which factors predicted mortality showed that on admission, advanced age, anemia, elevated blood urea nitrogen (BUN), hypocalce­mia, hypoalbuminemia, increased alkaline phosphatase, and low cholesterol predicted a poor outcome. The same study showed that 1 week after admission, an elevated WBC count, thrombocytopenia, hypokalemia, low bicarbonate, elevated lactate dehydrogenase, and elevated BUN predicted a poor outcome.13

Our case was similar to others in the literature involving patients who presented with advanced colorectal carcinoma and other comorbidities, such as diabetes and alcoholism, which predisposed them to this manifestation of their underlying pathology.1-5 The other cases were managed similarly, with extensive debridement, resection of the cancer, and fecal diversion. Only one case had a positive culture for Clostridium; most had mixed enteric flora.5

It is probable that the large amount of subcutaneous emphysema seen on our patient’s CT scan resulted from the perforated rectal cancer. Of special interest regarding this patient is the failure of several experienced physicians to diagnose the infectious process correctly on presentation and subsequent examinations. The differential diagnosis made by the ICU attending and gastroenterologist addressed the possibility of a perforated hollow viscus as the etiology of the subcutaneous emphysema. Given the overall clinical picture of the patient (scrotal edema, subcutaneous emphysema, cutaneous necrosis, and elevated WBC count), it is unfortunate that the possibility of necrotizing Fournier’s gangrene was never contemplated because an earlier diagnosis of the underlying disease process would have led to prompt intervention, allowing more limited debridement. The finding of subcutaneous emphysema should have automatically triggered a consultation for surgical evaluation. Fortunately, the organisms iso­lated from this infection were not gas-forming Clostridia but were instead less virulent anaerobes. Fournier’s gangrene is a true surgical emergency where life-saving, definitive treatment is provided in the operating room.

Conclusion

We described a rare case of Fournier’s gangrene that was the manifestation of a perforated rectal carcinoma. The patient was successfully treated through the acute episode of his disease with extensive debridement, intravenous antibiotics, and palliative resection of his tumors. The soft tissue defects from the extensive debridement were closed using a vacuum-assisted closure device and skin grafts. Fournier’s gangrene should be included in the differential diagnosis of any patient presenting with scrotal edema, subcutaneous emphysema, cutaneous necrosis, and an elevated WBC count. Prompt diagnosis of the pathology and surgical debridement of the infected tissue are life saving and imperative.

References

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13. Laor E, Palmer LS, Tolia BM, et al. Outcome prediction in patients with Fournier’s gangrene. J Urol. 1995;154(1):89-92.