Postinfectious purpura fulminans secondary to varicella-induced protein S deficiency

An Atypical Case of Idiopathic Purpura Fulminans

Idiopathic purpura fulminans (PF) is rare but has been reported in pediatric patients, commonly following infections. We present a case of a 5-year-old boy, heterozygous for factor V Leiden, with no history of recent infections, who presented with PF secondary to acquired protein S deficiency. Despite initial supportive treatment, the patient required surgical fasciotomy and extensive skin grafts. The protein S level normalized 4 months following the presentation. In this context, an autoimmune component with transient anti-protein S antibodies was believed to be involved. This case report highlights the course of idiopathic PF due to noninfectious acquired protein S deficiency.

Idiopathic purpura fulminans associated with anti-protein S antibodies in children: a multicenter case series and systematic review

Idiopathic purpura fulminans (IPF) is a rare but severe prothrombotic coagulation disorder that can occur after chickenpox or human herpesvirus 6 (HHV-6) infection. IPF leads to an autoantibody-mediated decrease in the plasma concentration of protein S. We conducted a retrospective multicenter study involving patients with IPF from 13 French pediatric centers and a systematic review of cases in published literature. Eighteen patients were included in our case series, and 34 patients were included as literature review cases. The median age was 4.9 years, and the diagnostic delay after the first signs of viral infection was 7 days. The lower limbs were involved in 49 patients (94%) with typical lesions. In all, 41 patients (78%) had a recent history of varicella-zoster virus infection, and 7 patients (14%) had been infected by HHV-6. Most of the patients received heparin (n = 51; 98%) and fresh frozen plasma transfusions (n = 41; 79%); other treatment options were immunoglobulin infusion, platelet transfusion, corticosteroid therapy, plasmapheresis, and coagulation regulator concentrate infusion. The antithrombin level and platelet count at diagnosis seemed to be associated with severe complications. Given the rarity of this disease, the creation of a prospective international registry is required to consolidate these findings.

Symmetrical peripheral gangrene in critical illness

Symmetrical peripheral gangrene (SPG) is a disabling complication that affects a small proportion of patients who survive critical illness. Its pathogenesis reflects profoundly disturbed procoagulant-anticoagulant balance in susceptible tissue beds secondary to circulatory shock (cardiogenic, septic). There is a characteristic SPG triad: (a) shock (hypotension, lactic acidemia, normoblastemia, multiple organ dysfunction), (b) disseminated intravascular coagulation (DIC), and (c) natural anticoagulant depletion (protein C, antithrombin). In recent years, risk factors for natural anticoagulant depletion have been identified, most notably acute ischemic hepatitis ("shock liver"), which is seen in at least 90% of patients who develop SPG. Moreover, there is a characteristic time interval (2-5 days, median 3 days) between the onset of shock/shock liver and the beginning of ischemic injury secondary to peripheral microthrombosis ("limb ischemia with pulses"), reflecting the time required to develop severe depletion in hepatically-synthesized natural anticoagulants. Other risk factors for natural anticoagulant depletion include chronic liver disease (e.g., cirrhosis) and, possibly, transfusion of colloids (albumin, high-dose immunoglobulin) lacking coagulation factors. A causal role for vasopressor therapy is unproven and is unlikely; this is because critically ill patients who develop SPG do so usually after at least 36-48 hours of vasopressor therapy, implicating a time-dependent pathophysiological mechanism. The most plausible explanation is a progressive time-dependent decline in key natural anticoagulant factors, reflecting ongoing DIC ("consumption"), proximate liver disease whether acute or chronic ("impaired production"), and colloid administration ("hemodilution"). Given these evolving concepts of pathogenesis, a rationale approach to prevention/treatment of SPG can be developed.

Extensive Necrotic Skin Lesions Due to Post-varicella Protein S Deficiency

Postvaricella protein S deficiency is a rare and severe disease. We report a case of extensive necrotic skin lesions of acute onset 7 days after varicella in a 4-year-old girl. Protein S antigen and activity were <10%, and antiprotein S antibodies were detected. She was treated with anticoagulation, plasmapheresis and fresh frozen plasma. She survived but required leg amputation.

Varicella complicated by cellulitis and deep vein thrombosis

We report a 16-month-old girl with varicella complicated by cellulitis, invasive Group A Streptococcus (GAS) infection and deep vein thrombosis. She presented with varicella lesions, fever and a painful firm tumefaction on the right lower leg (RLL). Ultrasound showed a local subcutaneous tissue thickening suggestive of cellulitis and antibiotics were initiated. Further swelling of the RLL motivated a second ultrasound that showed an obstructive thrombus for which she was started on enoxaparin. The blood culture confirmed GAS infection leading to directed antibiotherapy. Additional studies showed positive lupus anticoagulant, decreased protein S and antithrombin. She completed a 2-week course of intravenous antibiotics and anticoagulation therapy with clinical and laboratory markers improvement. However, 3 days later, a recrudescence of symptoms occurred and the ultrasound revealed a local abscess. Further amoxicillin treatment resulted on a complete resolution of symptoms. Doppler ultrasound after 1 month showed markedly increased vein patency.