**6. Gas gangrene (clostridial myonecrosis)**

#### **6.1 Traumatic gas gangrene**

Gas gangrene caused by infection of *Clostridium perfringens* (formerly called *C. welchii*) is a life-threatening emergency, as a representative and grave form of wet gangrene [22–25]. *C. perfringens* is an obligate anaerobic Gram-positive bacillus forming spores on culture plates. Traumatic skin invasion of the microbe results in

**6.2 Nontraumatic gas gangrene**

*DOI: http://dx.doi.org/10.5772/intechopen.93505*

*Pathology of Gangrene*

spongy/foamy appearance.

**Figure 12.**

**103**

scopic appearance is displayed in **Figure 15**.

*pancreatic parenchyma, giving features of severe acute pancreatitis.*

*C. perfringens* commonly resides in the gut lumen of healthy individuals, so that the nontraumatic gas gangrene is encountered in the internal organs such as the gut, bile duct, and pancreas [26, 27]. Representative autopsy cases are presented below. The pancreas is occasionally assaulted by *C. perfringens* [28–30]. An autopsy case of fulminant pancreatitis (emphysematous pancreatitis) in a 66-year-old diabetic man, presenting just a two-day clinical course, is demonstrated. Diabetes mellitus was poorly controlled. The patient suffered sudden abdominal and back pain, and acute pancreatitis was diagnosed by a markedly elevated serum amylase level. Abdominal computed tomography scan demonstrated gas retention in the pancreatic head, intrahepatic branches of the bile duct, and in the abdominal cavity. At autopsy, features of acute hemorrhagic and necrotizing pancreatitis with infiltration of neutrophils were observed (**Figure 12**). Clusters of rods were identified in necrotic, gas-forming areas, and the bacteria grew also along the pancreatic duct. Neutrophilic reaction was sparse in the hypoxic area showing bacterial growth. Not all of the bacteria were stained blue with Gram stain (some remain unstained), and the formation of spores was abortive within the living body (**Figure 13**). These

microscopic features were consistent with infection of *C. perfringens*.

Another case of pancreatic gas gangrene in a diabetic male patient aged 70's showed numerous Gram-positive rods around the gas-filled space formed in the necrotic pancreas, confirming the diagnosis of *C. perfringens* infection. Gross and microscopic findings of the foamy liver are illustrated in **Figure 14**. The cut surface of the formalin-fixed liver shows numerous gas-filled spaces, giving characteristic

Nontraumatic gas gangrene may be associated with colon cancer [31, 32]. An 81-year-old female patient with rectal cancer became acutely ill with abdominal pain and paralytic ileus. The patient soon died of septic shock. Autopsy clarified nontraumatic gas gangrene of the colorectum caused by clostridial infection in rectal adenocarcinoma. The growth of Gram-positive, gas-forming rods was observed in the cancer tissue, crypts of the noncancerous colorectal mucosa, and also in the liver. Gangrenous inflammation was observed in the entire layer of the colorectal wall. Acute tubular necrosis represented the shock kidney. The micro-

Gastric gas gangrene is infrequently experienced [33]. A 65-year-old diabetic male patient underwent endoscopic mucosal resection of intramucosal gastric

*Clostridial acute hemorrhagic and necrotizing pancreatitis (CT scan and H&E). Computed tomography scan demonstrates gas formation in the pancreatic head (arrowhead). At autopsy, neutrophils infiltrate the*

#### **Figure 10.**

*Immunohistochemical identification of MRSA in formalin-fixed, paraffin-embedded sections (H&E, Gram and immunostain). The Gram-positive coccal colonies in the gangrenous decubital lesion express staphylococcal antigens, protein A (staphylococcal IgG Fc-binding protein) and penicillin-binding protein 2*<sup>0</sup> *(PBP2*<sup>0</sup> *), confirming the nature of MRSA. Streptococcal antigens are negative.*

massive ischemic necrosis (gangrene) of the soft tissue involving the striated muscle. Gas production is quite characteristic, and the involved tissue thus reveals crepitation on touch (**Figure 11**). The gas is composed of 5.9% hydrogen, 3.4% carbon dioxide, 74.5% nitrogen, and 16.1% oxygen. As the bacteria grow under an anaerobic condition, the degree of ischemia in the involved tissues and organs becomes advanced. Tissue necrosis is accelerated by α-toxin production of the microbe. Putrid odor is associated. Intravascular hemolysis is a common event due to bacterial production of hemolysin (α-toxin). The prognosis is very poor. The disease is also called as clostridial histotoxic syndrome. Gram-positive rods are microscopically localized adjacent to gas bubbles (see below).

#### **Figure 11.**

*Traumatic gas gangrene of the right thigh (gross appearance). Gas-forming gangrenous process of the soft tissue results in marked swelling of the thigh. Crepitation was palpable on touch. Surgical debridement has been performed for the treatment purpose.*
