Varicella and thrombotic complications associated with transient protein C and protein S deficiencies in children

[Post-varicella thrombosis and factor V Leiden mutation]

BACKGROUND

Varicella is a benign infectious disease that is rarely complicated by thrombosis. Factor V Leiden (FVL) mutation is presently recognized as the most common inherited cause of thrombosis. From a case report the link between varicella associated thrombosis and FVL is discussed.

CASE REPORT

An eight year-old boy was admitted on 15th day of a varicella infection for difficulty to walk and painful legs. Doppler ultra sound of the lower limbs venous system showed thrombosis of the left iliac vein and femoral veins. Thrombophilia work-up revealed a FVL heterozygotic status for the patient. Biological screening for molecular abnormalities associated with thrombophilia led to the detection of a heterozygous inherited FVL mutation in the patient. Response to heparine followed by oral anticoagulant treatment was good.

CONCLUSION

Thrombosis associated with varicella in child is a rare event. We recommend to realize a thrombophilia screening in such patients. We also support varicella vaccination of children identified as having constitutional prothrombotic disorders like FVL mutation.

[Exploration of hemostasis disorders in children (excluding the neonatal period)]

There are three different aspects in the etiological diagnosis of hemostasis disorders: (1) primary hemostasis evaluation; (2) coagulation evaluation; and, (3) thrombosis evaluation. In every case, a look at the medical history is an essential step before proceeding to biological investigations. Bleeding time is the first step of the primary hemostasis evaluation; prolonged drug use (particularly salicylates) and thrombocytopenia must be first considered; only then will the Von Willebrand factor and platelet functions be studied. Coagulation evaluation first requires the study of the overall coagulation tests (Quicks test, partial thromboplastin time test and thrombin time test); determination of the different plasma coagulation factors and search for a circulating anticoagulant will be performed secondarily, allowing differentiation between the different acquired or constitutional coagulation disorders. Thrombosis evaluation must first consider a local or general inciting factor before looking for anti-phospholipid antibodies, an acquired protein C or S deficiency or a constitutional hemostasis disorder.

Acquired protein S deficiency with multiple thrombotic complications after orthotopic liver transplant

BACKGROUND

Orthotopic liver transplantation (OLT) is frequently complicated by thrombotic events that may threaten the viability of the allograft and severely compromise the overall outcome in these patients. Although multiple prothrombotic pathogenic mechanisms may be involved, a role for inadequate natural anticoagulant levels in the early postoperative period has been postulated.

METHODS

We describe a case of a woman who suffered multiple thrombotic complications after a second OLT. Prospective assays of procoagulant and natural anticoagulant factor levels, in addition to screening tests for a variety of inherited and acquired hypercoagulable states, were carried out.

RESULTS

Serial studies confirmed an acquired, isolated deficiency of Protein S associated with the second transplanted liver. Protein S levels were normal after the patient's first and third OLTs. There was no laboratory evidence of other underlying prothrombotic conditions.

CONCLUSIONS

This unusual case of acquired Protein S deficiency demonstrates that the hypercoagulable phenotype may develop in the recipient of a liver from a heterozygous deficient donor. Furthermore, isolated low Protein S may be causally associated with hepatic artery thrombosis after OLT.

Spontaneous arterial thrombosis in children

Spontaneous peripheral artery thrombosis in children is rare. We present 2 cases, in both of which the diagnosis was delayed. Acute arterial insufficiency should be considered in children who have clinical symptoms of leg pain, pallor, and reduced pulses. Angiography is the gold standard to confirm or exclude the diagnosis.

Laboratory evaluation of hypercoagulable states

The number of well-characterized hereditary and acquired hypercoagulable conditions is increasing, such that in many thrombophilic patients, the laboratory can now identify a hypercoagulable condition. This review describes the currently known hypercoagulable states that predispose patients to venous, and in some instances, arterial thrombosis. For each condition, the discussion includes the incidence, magnitude of the thrombotic risk in the general population in comparison with symptomatic families, synergistic interactions among the various hypercoagulable conditions, molecular pathogenesis, and interpretation of laboratory test results. In addition, recommendations for laboratory testing are summarized.

[Deep venous thrombosis in an adult with varicella]

INTRODUCTION

Some viral infections are associated with deep venous thrombosis. We report a case of deep venous thrombosis in an adult with varicella. He had neither known predisposing factors for thrombosis nor thrombophilia.

EXEGESIS

Transient significant level of antiphospholipid antibodies and lupus circulating anticoagulant were observed. There was no evidence of thrombophilia. Deep venous thrombosis has been mostly associated with varicella in children. A transient protein S deficiency was present in almost all cases, though it was sometimes related to an anti-protein S antibody. This association is exceptional in adults. Some viruses such as herpesvirus and HIV are responsible for endothelium dysfunction, but this is still unclear in the case of varicella-zoster virus.

CONCLUSION

In our observation, endothelium activation or antiphospholipid antibodies might be responsible for thrombosis.

Purpura in infants and children

Hemorrhage into the skin (purpura) may result from abnormalities in any of the three components of hemostasis: platelets, plasma coagulation factors, and blood vessels. The morphology, size, and distribution of the hemorrhagic lesions are helpful diagnostic features. The main causes of purpura in the newborn and the more common hemorrhagic disorders in children are reviewed.

Septic shock

Although our understanding of molecular events in septic shock is growing exponentially, bedside management has changed only incrementally over the last 20 years. In pediatric and adult patients alike, treatment continues to be largely supportive. Morbidity and mortality, though gradually improving, continue to be high. The major similarities, as well as the minor differences, between pediatric and adult septic shock are reviewed in this article, with an emphasis on current clinical practice and recent clinical investigations of novel therapies.

Mechanisms of ischaemic stroke after chickenpox

Ischaemic stroke is a recognized complication of chickenpox. Seven cases of ischaemic stroke in children after recent varicella infection are discussed in detail to emphasise that there are several mechanisms by which this may arise.

Ischemic cerebrovascular disease in children: retrospective study of 35 patients

A 10-year review of a neuropediatric department experience with childhood ischemic cerebrovascular disease identified 35 patients with arterial ischemic stroke. The ability to diagnose stroke in children has improved with the development of imaging techniques in the past few years. Children have a wide array of risk factors for ischemic strokes, since some are acquired and others are congenital. Twenty-eight associated conditions (80%) were found in our patients and we identified 17 specific causes (48.5%) among them. The cause of stroke in children is important to recognize because stroke is likely to recur depending on the etiology.

Lupus anticoagulant and protein S deficiency in children with postvaricella purpura fulminans or thrombosis

OBJECTIVE

The objective of this study was to determine the cause of purpura fulminans, disseminated intravascular coagulation, or thrombosis in seven children with varicella. All children were found to have a lupus anticoagulant and acquired protein S deficiency. Thrombosis in five children was associated with presumed or documented infection with streptococcus.

STUDY DESIGN

Coagulation tests included determinations of the activated partial thromboplastin time, the prothrombin time, the dilute Russell viper venom time, the prothrombin F 1 + 2 fragment, the C4b-binding protein (C4b), total and free protein S antigen, and clotting activities of factors II, V, VII, and X and of protein C and protein S. Autoantibodies to phospholipids, cardiolipin, and protein S were determined in enzyme-linked immunosorbent assays.

RESULTS

All children had a lupus anticoagulant and acquired protein S deficiency. Thrombosis in five children was associated with presumed or documented infection with streptococcus. All children transiently expressed free protein S deficiency, elevated levels of IgG, IgM, or both binding to protein S, the lupus anticoagulant, and increased concentration of the F 1+2 fragment. Four children also had antiphospholipid or anticardiolipin antibodies. In one child a purified IgG fraction cross-reacted with both protein S and a specific varicella antigen.

CONCLUSIONS

A subset of children with varicella infection, some of whom are coinfected with streptococcus, are prone to development of a lupus anticoagulant and an autoantibody to protein S, which results in acquired free protein S deficiency. Such children are at risk of having life-threatening thrombotic events.

Postinfectious purpura fulminans caused by an autoantibody directed against protein S

OBJECTIVE

To determine the mechanism responsible for idiopathic purpura fulminans, we investigated the procoagulant and anticoagulant pathways in five consecutive patients, four after varicella, and the fifth after a nonspecific infection.

METHODS

Procoagulant and anticoagulant factors, including protein C, protein S, and antithrombin III, were measured by quantitative or functional assays. Anti-protein S autoantibodies were identified by dot blotting and Western blotting, and quantified serially by enzyme-linked immunosorbent assay. Clinical and laboratory data were collated retrospectively.

RESULTS

In each case the disease began 7 to 10 days after the onset of the precipitating infection, with rapidly progressive purpura leading to extensive areas of skin necrosis. The illness was complicated by impaired perfusion of limbs or digits (two patients), peripheral gangrene resulting in an above-knee amputation (one patient), and major organ dysfunction caused by thromboembolic phenomena involving the lungs (two patients), the heart (one patient), or the kidneys (one patient). Protein S levels were virtually undetectable at the time of admission and failed to respond to infusions of fresh frozen plasma, despite correction of other procoagulant and anticoagulant factors. All five children had anti-protein S IgM and IgG autoantibodies, which persisted for less than 3 months after admission. Decline in the anti-protein S IgG antibody concentration was associated with normalization of the plasma protein S levels.

CONCLUSIONS

Autoimmune protein S deficiency may be a common mechanism causing postinfectious idiopathic purpura fulminans. Recognition of the pathophysiologic mechanism may provide a rational basis for treatment. Immediate heparinization, infusions of fresh frozen plasma, and, in cases complicated by major vessel thrombosis, the use of tissue-type plasminogen activator may limit thromboembolic complications.