Soft tissue infections of the chest wall often present in physically debilitated immunocompromised individuals either de novo or after surgical or other trauma. These infections can manifest in various ways, including a discrete mass that may be confused with other chest wall tumors, a diffuse superficial spreading infection, or a draining sinus tract. A number of organisms are involved from common bacterial species such as Staphylococcus aureus to more exotic organisms such as the larvae of the Tumbu fly (Cordylobia anthropophaga), which causes cutaneous myiasis.1 This chapter reviews the various pathogens of chest wall infections and discusses their treatment.
Patients afflicted with chest wall infections typically are immunocompromised. Many have been actively immunosuppressed for organ or bone marrow transplantation, or they are being treated with immunomodulating agents for chronic inflammatory disease such as rheumatoid arthritis. Steroid drugs are the most common anti-inflammatory agents used in this setting. Other individuals are immunocompromised as a result of physical debilitation from chronic illness, alcoholism, or poor nutrition. Still others may start out as healthy but become predisposed to infection or inoculated after trauma or surgery.
Infections can seed the chest wall by one of three mechanisms: (1) direct extension from an underlying pulmonary infection/empyema (empyema necessitans), (2) inoculation of the chest wall, and (3) hematogenous spread, with each organ exhibiting a distinct pathway. Manifestations of chest wall infection vary with the pathogen itself and range from discrete masses to draining sinuses to superficial spreading necrotizing infections. Systemic signs of infection vary with the underlying pathogen. Some are asymptomatic, whereas others cause low-grade temperatures and malaise. Yet others lead to septic shock physiology. Diagnosis can be obvious but often is difficult owing to the unusual presentations and rarity of some pathogenic organisms involved. Clinical suspicion is confirmed and complemented by culture data. Treatment rests on symptomatic support as well as antibiotics alone or combined with surgical debridement.
Bacterial: Necrotizing Infections
Necrotizing infections of the chest wall are characterized by extensive tissue necrosis with the production of gas elsewhere in the body. Typically, these infections are associated with mild trauma or are seen postoperatively. Multiple aerobic and anaerobic organisms have been isolated, including anaerobes such as Bacteroides spp., Peptostreptococcus spp., and Clostridium spp., as well as aerobes such as Streptococcus pyogenes, S. aureus, and members of the Enterobacteriaceae family. Fungal species have been isolated as well and are reviewed in Chap. 109.2–6 These infections violate tissue planes and are not contained by typical host immune defenses. They can develop quickly in both immunocompromised and immunocompetent individuals and lead rapidly to death if not expectantly diagnosed and treated with extensive surgical debridement and systemic antibiotic therapy.
Although necrotizing infections involve a spectrum of disease, they can be loosely classified as follows: (1) crepitant anaerobic cellulitis, (2) necrotizing fasciitis, and (3) nonclostridial and clostridial myonecrosis.
Nonclostridial and clostridial myonecrosis ...