Necrotizing infections:
A. Often present with pain out of proportion to findingsBacteria spread along the fascial layer, resulting in the death of soft tissues, which is in part due to the extensive blood vessel thrombosis that occurs. An inciting event is not always identified. Immunocompromised patients and those who abuse drugs or alcohol are at greater risk, with intravenous drug users having the highest increased risk. The infection can by mono- or polymicrobial, with group A P-hemolytic Streptococcus being the most common pathogen, followed by a-hemolytic Streptococcus, Staphylococcus aureus, and anaerobes. Prompt clinical diagnosis and treatment are the most important factors for salvaging limbs and saving life. Patients will present with pain out of proportion with findings. Appearance of skin may range from normal to erythematous or maroon with edema, induration, and blistering. Crepitus may occur if a gas-forming organism is involved. "Dirty dishwater fluid" may be encountered as a scant grayish fluid, but often there is little to no discharge. There may be no appreciable leukocytosis. The infection can progress rapidly and can lead to septic shock and disseminated intravascular coagulation. Radiographs may reveal gas formation, but they must not delay emergent debridement once the diagnosis is suspected. Intravenous antibiotics should be started immediately to cover gram-positive, gram-negative, and anaerobic bacteria. Patients will require multiple debridements, and the spread of infection is normally wider than expected based on initial assessment. Necrotizing myositis, or myonecrosis, is usually caused by Clostridium perfringens due to heavily contaminated wounds. Unlike necrotizing fasciitis, muscle is universally involved and found to be necrotic. Treatment includes emergent debridement of all necrotic tissue along with empirical intravenous antibiotics.