Clinical case: Necrotizing fasciitis of the anterior abdominal wall

History and physical examination

A 63-year-old female with no remarkable medical history presented to the ER department complaining of right-sided abdominal pain for three days. The physical examination revealed that she was afebrile with stable vital signs. The right side of her abdomen was characterized by patchy erythema in an area extending from her lower right ribs down to, and including, the vulva (Figure 1). Her right labium major was mildly edematous. Palpation indicated right abdominal tenderness, but no crepitus or subcutaneous emphysema. 

Laboratory tests and imaging

A standing chest radiograph failed to show a pneumoperitoneum. Labs revealed leukocytosis. A contrast CT scan indicated a large gas-containing mass in the right abdominal wall (Figure 2). There was no obvious intra-abdominal organ injury although the aorta had calcifications.

Management

A laparoscopy suggested that a fish bone had perforated through the small bowel and become lodged in the anterior abdominal wall, causing the abscess to form; this fish bone was also visible on the CT (Figure 2). This fish bone was removed via laparoscopic surgery (Figure 3 &4).  

The small bowel perforation associated with the fishbone penetration had apparently sealed without treatment (no pneumoperitoneum), but a subcutaneous infection had developed and spread along Scarpa’s fascia in the anterior abdominal wall to the vulva.

Three separate debridements were done (Figure 5&6). Laparoscopy during each debridement confirmed that the patient did not suffer from peritonitis and that there was no bowel perforation. There was, however, a defect in the transversalis fascia, which was about 2 cm in size and was repaired.

The abdominal wall defect that resulted from the debridements was larger than 50 × 20 cm (Figure 6a).  The debridements removed necrotic sections of the skin, Camper’s and Scarpa’s fascial layers and the external oblique muscle (Figure 6a). 

Complications and evolution

Between the debridements, the patient had persistent sepsis and developed cardiovascular complications presumably as a function of the systemic sepsis: takotsubo’s cardiomyopathy, supraventricular tachycardia, and pulseless ventricular tachycardia (VT) requiring defibrillation. 

Despite the sepsis and cardiovascular complications, the patient recovered remarkably well (Figure 7).  The wound was controlled with lavage and vacuum dressing.  The wound healed without the use of any synthetic mashes, skin grafts or tissue flaps to cover the gap.  The patient was discharged from the hospital on post-op day 32. The wound was almost completely healed after five months.

Scarpa's and Camper's fasciae

Scarpa’s and Camper’s are two relatively distinct layers of the superficial fascia of the lower anterior abdominal wall. Scarpa’s fascia is the deeper denser layer whereas Camper’s is the more superficial fatty layer (Figure 6). Camper’s fascia is continuous into the perineum and the thigh. Scarpa’s fascia continues into the perineum and becomes Colle’s fascia, but it fuses to the deep fascia of the thigh, thus forming a barrier to the spread of fluids and infection into the thigh (of course necrotizing fasciitis could eventually penetrate this fascia boundary but in this patient it may have impeded the spread of the infection into the thigh). 

Vulva

In this case report, the authors use the term “vulva.”  This is a somewhat of an ambiguous term but generally is meant to include the mons pubis, labia major and minor, clitoris, bulb of vestibule, vestibule of the vagina, external urinary meatus and greater and lesser vestibular glands. Here, based on Figure 1, we believe the authors were primarily referring to the labium major.

Anterior abdominal wall muscles

The external and internal oblique muscles, plus the transverse abdominis and rectus abdominis are the muscles of the anterior abdominal wall.  During the debridements necrotic sections of the external oblique muscle and the aponeuroses of the muscles were removed in order to thoroughly clean the wound of all the infectious debris.