BY DILEM POLAT & KHALID MALIK, MD
A 50-year-old man with hypertension presented to the emergency department with an exacerbation of his lower back and perianal pain that he had had for two weeks, with a new onset of active fecal draining and difficulty urinating for four hours. He said he had no headache, nausea, vomiting, weakness, fatigue, fever, and chills, and all other reviews of systems were negative.
His temperature was 98.5°F, blood pressure was 108/57 mm Hg, pulse rate was 113 bpm, respiratory rate was 20 bpm, and oxygen saturation was 97% on room air. His abdomen was soft, mildly distended, and not tender to palpation with normal bowel sounds. His rectum was edematous with indurated perianal tissue. Digital rectal exam was deferred due to draining stool.
Contrast-enhanced CT of the abdomen and pelvis was obtained, which revealed the presence of air within the bilateral ischiorectal fossa with air extending anteriorly into the right scrotum. (Photo.) Fluid was also present along the bilateral levator ani. A diagnosis of Fournier's gangrene was made.
Contrast-enhanced CT of the abdomen and pelvis showing air extending into the right scrotum (shown in black).
The patient was promptly started on fluid resuscitation and triple antibiotics—piperacillin-tazobactam 3.375 g, metronidazole 500 mg, and vancomycin 1 g. Morphine 4 mg IV push was given for pain, and the patient was hospitalized for surgical debridement. He became stable and was discharged without any complications after six weeks of inpatient care.
A Fatal Infection
Fournier's gangrene is a polymicrobial infection, mainly anaerobic, that arises in the perianal, genital, or abdominal area, followed by the spread of infection in a matter of hours along the epidermis, dermis, subcutaneous tissues, fascia, and muscles, causing necrotizing fasciitis. (Urol Int 2018;101:91; http://bit.ly/2DyAVbL.) Trauma, impaired immunity as seen in diabetics, the HIV virus, and chemotherapy are possible causes of Fournier's gangrene. (J Emerg Med 2013;44:e247.)
This case is unique because none of the above predisposing factors contributed to the development of Fournier's gangrene. Besides tenderness over the perianal area and new onset of mild fecal drainage, the clinical presentation showed no major evidence of systemic infection, necrotizing tissue, or subcutaneous crepitation. A case series analysis of inpatients with Fournier's gangrene who had a surgical debridement revealed a 20-40 percent mortality rate, with some as high as 88 percent. (Urol Int 2016;97:249; http://bit.ly/2DAyrK0.) The diagnosis would have been missed had a contrast-enhanced CT scan of the abdomen and pelvis not been performed, which would have led to sepsis and a fatal outcome in hours.
The clinical presentation of Fournier's gangrene varies from anorectal or genital pain with little evidence of cutaneous necrosis to a rapidly spreading necrosis and systemic sepsis without any suspicious source of infection.
Methods commonly used to diagnose Fournier's gangrene are radiography, ultrasound, computed tomography, and magnetic resonance imaging. A semi-quantitative way of estimating the risk of developing a necrotic infection (the laboratory risk indicator for necrotizing fasciitis, or LRINEC) is based on the assessment of six laboratory considerations, including the number of leukocytes, value of hemoglobin, sodium, glucose, serum creatinine, and C-reactive protein. A score of 6 was recorded in this patient. A LRINEC score of 5 suggests a favorable outcome, compared with a score of 10 pointing to a lethal outcome. (Scand J Trauma Resusc Emerg Med 2017;25:28; http://bit.ly/2DCHlGE.)
Patients must receive prompt fluid resuscitation, triple antibiotic therapy, and pain control. Cultures should also be obtained to define the causative organism and determination of sensitivity to antibacterial drugs. (Urol Int2018;101:91; http://bit.ly/2DyAVbL.)
Septic shock is the most common cause of death. Prognostic factors of unfavorable outcomes for Fournier's gangrene include tissue damage beyond the perineum, severe sepsis, pulse over 90 bpm, leukocytes more than 20 × 109/L, and urea level equal to 7 mmoL/L. (Changgeng Yi Xue Za Zhi 1999;22:31.) Management of Fournier's gangrene should be aggressive. Detection of gas in deeper soft tissues is considered an absolute indication for surgical intervention. (Surg Today 2007;37:558.)
Ms. Polat is a fourth-year medical student completing her clinical rotations at Weiss Memorial Hospital in Chicago, IL. Dr. Malik is a board-certified emergency and internal medicine physician and the director of the emergency department at Weiss Memorial Hospital and an affiliate of the University of Illinois Hospital.