Treating A Patient With Sepsis And Full Thickness Necrosis
Essential Diagnostic Pointers On Purpura Fulminans
The clinical presentation of purpura fulminans starts as a petechial rash that accompanies a severe infection. This petechial rash progresses to rapidly spreading purpura followed by widespread cutaneous hemorrhage. The affected areas are painful and indurated. The cutaneous changes progress to irregular areas of blue-black hemorrhagic necrosis with a surrounding erythematous border. In some cases, vesicles and hemorrhagic bulla are present.6,8 The distribution is symmetrical and affects the peripheral upper and lower extremities with lower extremity involvement being more common. Necrosis may be confined to the dermal tissues or may extend to muscle and bone. Healing occurs with scarring and frequently auto-amputation of the digits occurs.8 The cutaneous pathology of purpura fulminans is accompanied by fever, shock and frequently disseminated intravascular coagulopathy.
Differential diagnoses of purpura fulminans include thrombotic thrombocytopenic purpura, Henoch-Schönlein purpura and post-infectious thrombocytopenic purpura. These purpuric disorders exhibit significantly less severe skin necrosis than in purpura fulminans.6 Additionally, purpura fulminans shows less of an inflammatory component than these other vasculitic skin disorders.
A Closer Look At The Causes And Pathogenesis Of The Condition
Several bacteria reportedly lead to acute infectious purpura fulminans including Meningococcus, Staphylococcus, Escherichia coli, Streptococcus, Neisseria and Enterobacter. Meningococcus is the most common infectious etiology of purpura fulminans in the pediatric population while Streptococcus is the most common infectious cause in the adult population.2,3,5Meningococcus is the most common cause of acute infectious purpura fulminans due to its predisposition to cause dysfunction of the endothelial protein C activation pathway.9,10 Viral infections, Varicella and measles are reportedly causes of purpura fulminans.6
Factors predisposing patients to purpura fulminans include recent upper respiratory infection, recent surgery, recent childbirth, young age and asplenism or functional hyposplenism.11,12 It remains unclear as to why purpura fulminans develops in some patients while other patients with sepsis of the same severity fail to develop this disorder.
The pathogenesis of purpura fulminans results from the impairment of natural anticoagulant and fibrinolytic pathways, and activation of procoagulant pathways. Authors have identified several coagulation abnormalities in purpura fulminans.1,7,13 These abnormalities include decreased protein C, decreased protein S and decreased antithrombin III. Protein C and protein S deficiency can be due to homozygous or compound heterozygous genetic deficiencies, or acquired deficiency secondary to infection. Acquired deficiencies of protein C, protein S and antithrombin are due to coagulative consumption of these proteins during sepsis.
Key Insights On Effective Treatment
Given the multiple types of purpura fulminans and variable causes, one must tailor treatment of purpura fulminans to individual patients. Management of this disorder includes aggressive resuscitation, immediate volume expansion, ventilatory and inotropic support, antibiotic administration, and replacement of blood products and clotting factors.
Transfusion and plasmapheresis. Improvement in skin necrosis has reportedly occurred after the use of whole blood and plasma supply anticoagulant factors protein C, protein S and antithrombin III.8 Large quantities of blood and plasma are frequently needed to replace losses of clotting factors to the affected skin. Plasmapheresis can help control fluid balance when an excessive volume of blood products is necessary. Additionally, plasmapheresis removes circulating endotoxins and inflammatory cell mediators.6
Heparin. Heparin inhibits thrombus formation, halts the consumption of coagulation factors and can slow or stop the process of skin necrosis.8 I recommend heparin to reverse the disseminated intravascular coagulation component of the disease and promote tissue perfusion.3