Purpura Fulminans Due to Staphylococcal aureus
Purpura Fulminans Due to Staphylococcal aureus
Abstract and Commentary
Dean L. Winslow, MD, Chief, Division of AIDS Medicine, Santa Clara Valley Medical Center, Clinical Professor, Stanford University School of Medicine, Section Editor, HIV, is Associate Editor for Infectious Disease Alert
Synopsis: Five cases of purpura fulminans related to infection with Staphylococcal aureus were identified in Minnesota during 2000-2004.
Source: Kravitz GR, et al. Purpura fulminans due to Staphylococcus aureus. Clin Infect Dis. 2005;40:941-947.
Kravitz and colleagues identified 5 cases of purpura fulminans associated with Staphylococcus aureus infection in the Minneapolis-St. Paul area during the period 2000-2004. Three of the patients died, and 2 recovered with significant sequelae. Three of the 5 cases had Staphylococcal aureus isolated from blood cultures, and 2 patients had staphylococci isolated from the respiratory tract, with negative blood cultures. This latter finding suggested to Kravitz et al that the pathogenesis of purpura fulminans, in these cases, may be due to exotoxin production by the organisms and/or host factors. Three isolates demonstrated production of Staphylococcal enterotoxin C (SEC), one toxic shock syndrome toxin-1 (TSST-1), and one Staphylococcal enteroxin B (SEB). In addition, all 3 of the SEC-expressing isolates also demonstrated the presence of Panton Valentine leukocidin (PVL).
Commentary by Dean Winslow, MD, FACP
Purpura fulminans is generally considered by most clinicians to be synonymous with meningococcemia. However, it most likely represents a subset of the syndrome of symmetric peripheral gangrene (defined as ischemic necrosis simultaneously involving distal portions of 2 or more extremities, in the absence of proximal arterial obstruction), which can be seen in association with a variety of bacteremic and nonbacteremic infections, as well as cardiogenic shock, other low flow states, vasospasm, Raynaud’s, cold agglutinin disease, primary polycythemia, and venomous snake bites.1 In addition to meningococcemia, symmetric peripheral gangrene has occasionally been seen in association with bacteremic infection due to S. pneumoniae, other streptococcal species, S. aureus, various gram negative organisms, and Aspergillus.2 Purpura fulminans has also been described in association after relatively benign, non-bacteremic infections seen in childhood, including scarlet fever, streptococcal pharyngitis, varicella, and measles.3
The pathogenesis of infection-associated symmetric peripheral gangrene/purpura fulminans is complex. Although often associated with DIC, shock (rather than
DIC) may be the more important factor in symmetric peripheral gangrene. Histologic examination of the skin often shows a Schwartzman-like reaction with hemorrhage, perivascular cuffing, and intravascular thrombosis.3 Acquired or transient deficiencies of protein C and/or protein S have been identified in some patients with purpura fulminans, and the lesions are quite similar grossly and histologically to that seen in patients with congenital deficiencies of these clotting factors who develop warfarin-associated skin necrosis.4
Superantigens are pyrogenic exotoxins that induce massive cytokine release by bypassing the normal specific interaction between T-cell receptor, antigen, and the MHC class II receptor by directly binding to the external portion of the V beta domain of MHC class II.5 Staphylococcal superantigens include TSST-1 and several Staphylococcal enterotoxins. In the 5 cases of purpura fulminans associated with S. aureus described by Kravitz et al, all isolates expressed one or more of these superantigens, raising speculation that they may be playing a pathophysiologic role. Clearly more research will need to be done to define the role of these and other bacterial virulence factors and host factors.
It is also clear that while purpura fulminans due to S. aureus is probably not a new syndrome, the occurrence of these 5 cases during a short period of time in Minnesota should raise awareness of clinicians to this entity. In addition, it will be interesting to see if interventions such as administration of activated protein C or intravenous immunoglobulin (which could potentially neutralize various superantigens) may prove useful in the future.
References
- Goodwin JN. Symmetrical Peripheral Gangrene. Arch Surg. 1974;108:780-784.
- Childer BJ, et al. Acute Infectious Purpura Fulminans: A 15-year Retrospective Review of 28 Consecutive Cases. Am Surg. 2003;69:86-90.
- Robboy SJ, et al. The Skin in Disseminated Intravascular Coagulation. Prospective Analysis of 36 Cases. Br J Dermatol. 1973;88:221-229.
- Faust SN, et al. Dysfunction of Endothelial Protein C Activation in Severe Meningococcal Sepsis. N Engl J Med. 2001;345:408-416.
- Dinges MM, et al. Exotoxins of Staphylococcus aureus. Clin Microbiol Rev. 2000;13:16-34.
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