**12. Necrotizing fasciitis**

Necrotizing fasciitis represents clinically severe pyogenic infection (cellulitis) of the skin and underlying soft tissue [113–117]. Deep, painful, and intractable ulceration subacutely progresses predominantly on the extremities (**Figure 40**). Minor trauma may provide the entry for pathogens. The condition uncommonly follows

#### **Figure 39.**

*Lethal Fournier's gangrene of the rectum (gross, H&E and immunostain). Transmural necrotic and gangrenous inflammation is seen in the lower part of the rectum in a female patient aged 60's suffering from myelodysplastic syndrome. Gram-negative rods are immunoreactive for* E. coli*-related lipopolysaccharide.*

#### **Figure 40.**

As illustrated in **Figure 39**, fulminant necrotizing inflammation involved the lower part of the rectum in a female patient suffering from myelodysplastic syndrome. Emergency surgery disclosed transmural gangrenous necrosis of the rectal wall with massive mixed bacterial infection, including *E. coli*. Occasionally, Fournier's gangrene has been complicated with rectal cancer [111, 112].

*Fournier's gangrene (gross, H&E, Gram and immunostain). Debridement specimen discloses massive transmural necrosis of the scrotal tissue. Gas bubbles are scattered in the heavily infected necrotic tissue. Grampositive cocci are immunoreactive for streptococcal antigens. This case represents fulminant streptococcal*

*Fournier's gangrene (gross findings of two male cases). Massive hemorrhagic necrosis started from the scrotum and extended to the left hip and leg (left). Marked black swelling of the scrotum is serious, and necrotizing change extends toward the perianal region (right). The rapidly progressive gangrene caused death in both*

*patients. The penis is spared in the left case, but massively involved in the right case.*

Necrotizing fasciitis represents clinically severe pyogenic infection (cellulitis) of the skin and underlying soft tissue [113–117]. Deep, painful, and intractable ulceration subacutely progresses predominantly on the extremities (**Figure 40**). Minor trauma may provide the entry for pathogens. The condition uncommonly follows

**12. Necrotizing fasciitis**

*infection with gas formation (non-clostridial gas gangrene).*

**Figure 37.**

*Pathogenic Bacteria*

**Figure 38.**

**120**

*Necrotizing fasciitis (gross and H&E). Deep and painful ulceration is caused by local and invasive bacterial infection. This aged male diabetic case had a history of arterial replacement therapy for atherosclerosis obliterans. In order to relieve pain and to avoid septicemic spread of infection, amputation surgery was performed. Necrotizing inflammation extends to the striated muscle layer.*

surgical procedures. Diabetes mellitus, immunosuppression, alcoholism, drug abuse, atherosclerosis-related ischemia, and malnutrition may be prodromal to this troublesome condition. It may be seen in healthy persons [118]. Necrotizing fasciitis is categorized into two types: type I (polymicrobial infection) and type II (monobacterial infection).

In **Figure 41**, necrotizing fasciitis seen in a poorly controlled diabetic male patient is presented. In the wintertime, a fan heater gave the patient a severe burn on his sole, because he did not feel pain sensation due to diabetic peripheral neuropathy. The doctor-shy patient did not visit a hospital for 1 week, and this allowed the lesion far progressed. Severe atherosclerosis had provoked dry gangrene in his

#### **Figure 41.**

*Localized severe burn on the sole of a diabetic male caused by a fan heater, resulting in necrotizing fasciitis (gross appearance). Because of diabetic neuropathy, deep ulcers occurred on the senseless foot. Dry gangrene on the first and second toes (arrowheads) indicates the association of diabetes-related atherosclerosis obliterans. The importance of foot care in diabetic patients should be emphasized.*

toes. Diabetes-related neutrophilic dysfunction provided him with the vulnerability to infection. Polymicrobial (type I) necrotizing fasciitis resulted in septicemia. Emergency amputation saved his life. The importance of foot care for patients with diabetes mellitus should be emphasized.

**13.1 Fulminant streptococcal infection without gangrene of the extremities**

Pseudomonas*-related necrotizing fasciitis in a young lady suffering from anorexia nervosa (gross, H&E and immunostain). Her leg with massive necrotic/gangrenous lesions was amputated (left, after sampling of histological specimens). Massive bacterial growth provoked little inflammatory reaction. The bacteria are immunoreactive for* Pseudomonas aeruginosa *antigen detected by a monoclonal antibody (the courtesy by Dr. Takashi Tsuchida, a pathologist in Hamamatsu Medical University Hospital, Hamamatsu, Japan).*

internal organs may cause the fatal disease.

**Figure 42.**

*Pathology of Gangrene*

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

**123**

carbohydrate antigen specific for group A *Streptococcus* [127].

Fulminant infection of group A β-hemolytic *Streptococcus* (*Streptococcus pyogenes*) is typically featured by progressive gangrene in the soft tissue of the extremities, as described above in the Section 10.1. Streptococcal toxic shock syndrome provokes an aggressive lethal condition without predisposing diseases [123, 124]. It should be of note that fulminant group A streptococcal infection is also encountered in cases without gangrenous lesions of the extremities [125]. Streptococcal infection in the

We experienced five cases of fulminant streptococcal infection without gangrene of the extremities (**Table 1**). Four of five cases were young and immunocompetent, and encountered at forensic autopsy. Infectious foci were seen in internal organs such as the tonsil, bronchus, puerperal endometrium, and urinary bladder. The clinical course was very short ranging from 2 to 4 days. Infective and hemorrhagic cystitis with systemic streptococcal dissemination was encountered in an aged female patient with a history of cerebral infarction and femoral neck fracture (**Figure 43**). Necrotizing endometritis in a puerperal lady was the cause of streptococcal toxic shock-like syndrome, as illustrated in **Figure 44**. It can be categorized in so-called puerperal fever. Pregnancy-associated lethal infection should be of particular notice [126]. Group A *Streptococcus* infection was proven by microbial culture in two cases, and immunoreactivities of streptococcal antigens and Strep A were shown on the Gram-positive cocci in all five cases. Strep A is a

There are two different pathological mechanisms in fulminant streptococcal infection without gangrene of the extremities [125]. One form with overwhelming bacterial growth is characterized by secondary systemic bacterial dissemination accompanying bacterial emboli with poor neutrophilic reaction. Bacterial embolism in the adrenal gland provokes bilateral adrenal hemorrhage (acute adrenocortical insufficiency), being categorized in Waterhouse-Friderichsen syndrome [128] (**Figure 45**). Another form without bacterial embolism was featured by bacterial

Infrequently, necrotizing fasciitis is caused by *Pseudomonas aeruginosa* [119, 120]. Reportedly, the mortality rate of this type II lesion is 30%, and the infection often happens in the immunocompromised patients. Clinicians should consider empiric pseudomonal antibiotic coverage for preventing the progression of necrotizing limb infection.

An 18-year-old female patient had suffered from anorexia nervosa for 6 years. She happened to develop phlegmonous inflammation on her left lower leg, rapidly progressing to multifocal ulceration and gangrene. In 3 days, she underwent surgical amputation. *Pseudomonas aeruginosa* was cultured from blood and the leg lesion of necrotizing fasciitis. Immunohistochemical identification of the pseudomonal microbe was achieved by using a commercial monoclonal antibody. Representative features are illustrated in **Figure 42**.

Classic pathogens of cellulitis represent group A β-hemolytic *Streptococcus* and less frequently *Staphylococcus aureus*, but a diverse range of microorganisms, including *Pseudomonas aeruginosa* (as described above), cause cellulitis. Erythematous nodular lesions formed on the leg of neutropenic or leukemic patients were caused by *Stenotrophomonas maltophilia* [121]. Facial cellulitis may result from *Haemophilus influenzae* infection [122].
