Discussion:
Due to acute and rapidly progressive course, NF has a high mortality rate estimated at between 25% and 75% [1]. It’s life-threatening surgical emergency. Thus, early diagnosis of necrotizing soft-tissue infections followed by administration of intravenous antibiotics and surgical debridement is the best way of decreasing its mortality [3]. In our case, the delay between our physical examination in the operating room and physical examination in the emergency department highlights the importance of early care in this type of soft-tissue infection.
NF of the abdominal wall due to colorectal cancer is widely reported in the literature. However, NF of the thigh caused by colorectal cancer, as in our case, is extremely rare. In this case, a retroperitoneal abscess formed through the femoral ring and reaching the thigh caused NF to occur [1]. Literature review of atypical presentations of perineal necrotizing fasciitis revealed that perforated gastrointestinal tract malignancy was the etiology in 16% [4].
Clinical features of NF include high fever with chills, tenderness over the affected area along with changes in skin color and palpable crepitus [3]. In this case report, the patient presented with sepsis, swelling of the thigh and abdominal pain. NF was not suspected as no suspicious medical history was present. However, imaging showed the classic findings of fluid and gas tracking along fascial plans. From swelling of the thigh to septic shock, these clinical presentations highlight the clinical polymorphism of NF. It is often initially missed leading to lengthy delays in diagnosis and treatment. Weight loss, transit disorders and abdominal pain, like in our case, are signs that can guide to colon cancer as an etiology of NF.
NF can be difficult to recognize in the early stages, so a low index of suspicion is needed when confronted with rapidly spreading erythema or subcutaneous crepitus. Skin necrosis and blistering are late signs [5]. Patients with unexplained soft tissue infections of the thigh should raise suspicion for abdominal pathology and need urgent CT scan [5] for timely diagnosis to avoid delays in the management of sepsis and to offer a better operative planning and counseling for the patient.
The cornerstone of management of NF is recognized as being aggressive surgical debridement and intensive support [6]. Urgent surgical debridement down to healthy tissue allows to stop the spread of the infection and reduces systemic toxicity. In fact, the NF is lethal without operative debridement. Intravenous antibiotics should be started promptly and modified when sensitivities return. However, it is essential to ensure that adequate necrotic material is removed at the first opportunity to reduce the risk of further progression, regardless of the defect that will remain [6].