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

Dysregulation of Protein S in COVID-19

Coronavirus Disease 2019 (COVID-19) has been widely associated with increased thrombotic risk, with many different proposed mechanisms. One such mechanism is acquired deficiency of protein S (PS), a plasma protein that regulates coagulation and inflammatory processes, including complement activation and efferocytosis. Acquired PS deficiency is common in patients with severe viral infections and has been reported in multiple studies of COVID-19. This deficiency may be caused by consumption, degradation, or clearance of the protein, by decreased synthesis, or by binding of PS to other plasma proteins, which block its anticoagulant activity. Here, we review the functions of PS, the evidence of acquired PS deficiency in COVID-19 patients, the potential mechanisms of PS deficiency, and the evidence that those mechanisms may be occurring in COVID-19.

Cerebral sinus venous thrombosis: a rare complication of varicella infection in a 12-year-old girl

Varicella infection can present with a variety of neurological manifestations, the most common of which are cerebellitis and encephalitis. A 12-year-old girl presented with headache, altered sensorium, blurring of vision and status epilepticus 2 weeks after she developed varicella lesions. Imaging demonstrated cerebral venous sinus thrombosis involving the left transverse sinus, sigmoid sinus and internal jugular vein with a haemorrhagic infarct in the left parieto-occipital region. Measures were taken to decrease the intracranial pressure, and she was commenced on anti-convulsants (phenytoin) and heparin infusion, following which she improved and was discharged after 2 weeks. Repeat imaging undertaken 3 months later demonstrated a resolving thrombus, and a pro-coagulant work-up at follow-up did not show any underlying pro-thrombotic state. Neurological complications post varicella are rare, with encephalitis and ataxia being the most common. Cerebral sinus venous thrombosis secondary to varicella is very rare with only one case reported in a child.

Total Plasma Protein S Is a Prothrombotic Marker in People Living With HIV

BACKGROUND

HIV-1 infection is associated with multiple procoagulant changes and increased thrombotic risk. Possible mechanisms for this risk include heigthened expression of procoagulant tissue factor (TF) on circulating monocytes, extracellular vesicles, and viral particles and/or acquired deficiency of protein S (PS), a critical cofactor for the anticoagulant protein C (PC). PS deficiency occurs in up to 76% of people living with HIV-1 (PLWH). As increased ex vivo plasma thrombin generation is a strong predictor of mortality, we investigated whether PS and plasma TF are associated with plasma thrombin generation.

METHODS

We analyzed plasma samples from 9 healthy controls, 17 PLWH on first diagnosis (naive), and 13 PLWH on antiretroviral therapy (ART). Plasma thrombin generation, total and free PS, PC, C4b-binding protein, and TF activity were measured.

RESULTS

We determined that the plasma thrombin generation assay is insensitive to PS, because of a lack of PC activation, and developed a modified PS-sensitive assay. Total plasma PS was reduced in 58% of the naive and 38% of the ART-treated PLWH samples and correlated with increased thrombin generation in the modified assay. Conversely, plasma TF was not increased in our patient population, suggesting that it does not significantly contribute to ex vivo plasma thrombin generation.

CONCLUSION

These data suggest that reduced total plasma PS contributes to the thrombotic risk associated with HIV-1 infection and can serve as a prothrombotic biomarker. In addition, our refined thrombin generation assay offers a more sensitive tool to assess the functional consequences of acquired PS deficiency in PLWH.

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.

Cerebral venous sinus thrombosis as a complication of primary varicella infection in a child, case report

INTRODUCTION AND IMPORTANCE

Chickenpox (Varicella) is a benign illness caused by varicella-zoster virus, predominant in childhood.Chicken pox related neurological complications are seen in less than 1% cases of chickenpox.Cerebral Venous thrombosis due to primary (VZV) infection is very rare, and it may occurs secondary to primary or re-activation the virus.

CASE PRESENTATION

We report a case of 5-year-old female complained of ataxia, vomiting, headache, and drowsiness 7 days after the onset varicella zoster infection. She had vesicular lesions with scab over the trunk and limbs.

CLINICAL DISCUSSION

Neurological examination revealed left hemiparesis.Her blood counts and metabolic parameters were normal.Computed tomography brain showed hemorrhagic infarct in the left temporo-parietal region. Coagulation profile was normal. Magnetic resonance imaging (MRI) brain revealed hemorrhagic infarct in the same region. Magnetic resonance Venogram showed thrombosis of left transverse sinus and sigmoid sinus and internal jugular vein.VZV- IgG antibody was positive but CSF VZV PCR (Polymerase chain reaction) was found to be negative.Intravenous acyclovir for 15 days, and low-molecular-weight heparin for 3 days overlapped with oral Warfarin for 3months,. After 3 months follow up, the patient experienced a complete recovery. MRI repeated after 3 months showed recanalization of the sinuses.

CONCLUSION

The pathogenic link of occurrence of CSVT after VZV infection is unclear, but some articles showed that it is related to direct endothelial damage by the virus.Early recognition of this complication of VZV infection and prompt treatment is essential to prevent catastrophic complications.

Common Features Between Stroke Following Varicella in Children and Stroke Following Herpes Zoster in Adults : Varicella-Zoster Virus in Trigeminal Ganglion

The cerebral arteries are innervated by afferent fibers from the trigeminal ganglia. Varicella-zoster virus (VZV) frequently resides in the trigeminal ganglion. Reports of arterial ischemic stroke due to VZV cerebral vasculopathy in adults after herpes zoster have been described for decades. Reports of arterial ischemic stroke due to post-varicella cerebral arteriopathy in children have also been described for decades. One rationale for this review has been post-licensure studies that have shown an apparent protective effect from stroke in both adults who have received live zoster vaccine and children who have received live varicella vaccine. In this review, we define common features between stroke following varicella in children and stroke following herpes zoster in adults. The trigeminal ganglion and to a lesser extent the superior cervical ganglion are central to the stroke pathogenesis pathway because afferent fibers from these two ganglia provide the circuitry by which the virus can travel to the anterior and posterior circulations of the brain. Based on studies in pseudorabies virus (PRV) models, it is likely that VZV is carried to the cerebral arteries on a kinesin motor via gE, gI and the homolog of PRV US9. The gE product is an essential VZV protein.

Infectious Agents and Stroke: A Systematic Review

Introduction:

A major cause of injury and the second cause of death worldwide is stroke. Among several infectious agents considered as the risk factor of stroke, some pathogens demonstrated stronger robust associations with stroke. Proposing an accurate correlation between infectious microorganisms and stroke provides valuable information for early intervention and control of the infections.

Methods:

In this study, we searched the literature using the Web of Science, PMC/Medline via PubMed, and Scopus databases up to July 2018 without time and language restrictions. After quality assessment, 16 articles were included in the study. The whole data extraction process was independently conducted by two reviewers.

Results:

Based on the results of the studies, viruses, such as Hepatitis C virus (HCV), Hepatitis B virus (HBV), Human Immunodeficiency Virus (HIV), Herpes Simplex Virus Type-1, 2 (HSV-1, 2), Varicella-Zoster Virus (VZV or Chickenpox), and West Nile virus (WNV) seem to be common causes of ischemic stroke. Moreover, the association of other microbial categories, such as Streptococcus mutans (in bacteria), Toxocara spp. and Toxoplasma gondii (in parasites), and Rhizopus sp. (in fungi) with stroke was reported.

Conclusion:

Considering the adverse role of the above-mentioned microorganisms, it is necessary to implement some preventive measures for stroke treatment.

Expanding the clinical and neuroimaging features of post-varicella arteriopathy of childhood

OBJECTIVE

Post-varicella arterial ischemic stroke (AIS) is considered an uncommon cause of pediatric stroke that is considered a self-limiting, monophasic disease. However, in a subset of patients, disease recurs; the prevalence of vasculopathy or AIS recurrence, severity of clinical outcomes, and standardized therapies have not been well characterized. Herein, we determined the clinical-neuroradiological features, long-term evolution, and relationship between acute phase treatment and vasculopathy recurrence in a pediatric population with post-varicella AIS.

METHODS

Clinical, laboratory, and neuroradiological features of 22 children with post-varicella AIS between 2010 and 2019 (16 males, mean age at stroke 4 years, range 1.7-10) were reviewed. Statistical analyses were performed using χ² and Fisher exact tests.

RESULTS

Of the 22 cases, mean time from varicella to stroke was 4.5 months with 3 cases presenting more than 12 months after rash; 21 (95%) were not vaccinated for varicella; 3 (13.6%) had posterior circulation involvement; and 5 (22.7%) had AIS or vasculopathy recurrence, of which 4 recurred 6.1 months to 2.8 years after initial clinical onset. Recurrence was associated with lack of antiviral treatment during the first episode (p = 0.02).

CONCLUSIONS

Post-varicella AIS can occur months after rash making diagnosis challenging. Because recurrent vasculopathy was seen predominantly in cases not treated with antiviral therapy during initial presentation, it is important to rapidly diagnose post-varicella AIS through clinical criteria and/or virological testing then treat with antivirals to prevent recurrence.

Acute Cerebral Venous Sinus Thrombosis: A Rare Complication of Primary Varicella Zoster Virus Infection

Varicella-Zoster is a benign self limiting exanthematous illness in pediatric population which can rarely present with severe neurological manifestations such as cerebral venous thrombosis(CVT).We report the case of a 17-years old adolescent male with left hemiparesis, cranial nerve palsies associated with primary Varicella infection. MRI revealed cerebral venous thrombosis involving right transverse sinus, sigmoid sinus, internal jugular vein and infarct involving right cerebral hemisphere, Midbrain and Pons. The patient responded well to Acyclovir, cerebral decongestants and oral anticoagulant therapy.CVT is a rare but the most life threatening complication following primary Varicella infection and early diagnosis is essential for proper management of the patient.

Cerebral Venous Sinus Thrombosis Following Primary Varicella Infection in a Child

Varicella infection commonly called chicken pox is a benign self-limiting infection in children. Neurological complications following varicella infection are rare. Cerebral venous sinus thrombosis following varicella infection is very rare. Herewith we report a child who developed transverse and sigmoid sinus thrombosis following chicken pox.

Elevated serum substance P during simian varicella virus infection in rhesus macaques: implications for chronic inflammation and adverse cerebrovascular events

Varicella and zoster, produced by varicella-zoster virus (VZV), are associated with an increased risk of stroke that may be due to persistent inflammation and hypercoagulability. Because substance P is associated with inflammation, hypercoagulability, and atherosclerotic plaque rupture that may contribute to increased stroke risk after VZV infection, we measured serum substance P in simian varicella virus-infected rhesus macaques. We found significantly increased and persistent serum substance P concentrations during varicella and zoster compared with pre-inoculation, supporting the hypothesis that VZV-induced increases in serum substance P may contribute to increased stroke risk associated with VZV infection.

Von Willebrand factor (vWF): marker of endothelial damage and thrombotic risk in COVID-19?

BACKGROUND

COVID-19 infection is characterised, among other features, by a prothrombotic state with high rate of venous thromboembolism (VTE), D-dimer, and fibrinogen levels. Clinical observations have also highlighted that these patients have elevated von Willebrand factor (vWF) and factor VIIIc.

METHODS

24 consecutive COVID-19 positive patients were selected from the intensive care unit (ICU) or the high acuity ward of Brighton and Sussex University Hospitals NHS Trust.

RESULTS

The rate of VTE was 25% and mortality rate was 16.7%. Fibrinogen and D-Dimers were elevated, 7.9 (1.6) g/L and 2.4 (2.02) ug/ml respectively. Factor VIIIc and von vWF antigen levels were both extremely elevated at 279 (148) u/dL and 350 (131) % respectively, which are comparable to levels seen in ICU patients with severe sepsis. vWF levels were significantly higher in patients that died (p=0.017) and showed a positive correlation with age. There was a statistically significant association between COVID-19 disease and non-O blood group (p=0.02); 80% (4/5) of COVID-19 patients with VTE were blood group A.

CONCLUSION

Very high levels of vWF and factor VIIIc are common in COVID-19 patients, comparable to levels in severely septic non-COVID ICU patients. This could contribute to the hypercoagulable state and increased VTE rate in COVID-19. Further studies are needed to evaluate the use of vWF for stratifying thrombotic risk in COVID-19 and to determine if elevated vWF is contributing to disease pathogenesis.

Recurrent stroke: the role of thrombophilia in a large international pediatric stroke population

Risk factors for arterial ischemic stroke in children include vasculopathy and prothrombotic risk factors but their relative importance to recurrent stroke is uncertain. Data on recurrent stroke from databases held in Canada (Toronto), Germany (Kiel-Lübeck/Münster), and the UK (London/Southampton) were pooled. Data were available from 894 patients aged 1 month to 18 years at first stroke (median age, 6 years) with a median follow-up of 35 months. Among these 894 patients, 160 (17.9%) had a recurrence between 1 day and 136 months after the first stroke (median, 3.1 months). Among 288 children with vasculopathy, recurrence was significantly more common [hazard ratio (HR) 2.5, 95% confidence interval (95% CI) 1.92-3.5] compared to the rate in children without vasculopathy. Adjusting for vasculopathy, isolated antithrombin deficiency (HR 3.9; 95% CI: 1.4-10.9), isolated elevated lipoprotein (a) (HR 2.3; 95% CI: 1.3-4.1), and the presence of more than one prothrombotic risk factor (HR 1.9; 95% CI: 1.12-3.2) were independently associated with an increased risk of recurrence. Recurrence rates calculated per 100 person-years were 10 (95% CI: 3-24) for antithrombin deficiency, 6 (95% CI: 4-9) for elevated lipoprotein (a), and 13 (95% CI: 7-20) for the presence of more than one prothrombotic risk factor. Identifying children at increased risk of a second stroke is important in order to intensify measures aimed at preventing such recurrences.

Recurrent strokes, central nervous system vasculitis, and acquired protein S deficiency secondary to varicella zoster in a child with AIDS

A child with vertical transmission of human immunodeficiency virus refractory to therapy developed zoster-induced protein S deficiency and recurrent strokes. Extensive carotid arteritis was found postmortem. The carotid tissue was positive for herpes varicella zoster by polymerase chain reaction, as were immunofixation stains of the arterial wall.

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.

A Case of Miller Fisher Syndrome, Thromboembolic Disease, and Angioedema: Association or Coincidence?

BACKGROUND Miller Fisher Syndrome is characterized by the clinical triad of ophthalmoplegia, ataxia, and areflexia, and is considered to be a variant of Guillain-Barre Syndrome. Miller Fisher Syndrome is observed in approximately 1-5% of all Guillain-Barre cases in Western countries. Patients with Miller Fisher Syndrome usually have good recovery without residual deficits. Venous thromboembolism is a common complication of Guillain-Barre Syndrome and has also been reported in Miller Fisher Syndrome, but it has generally been reported in the presence of at least one prothrombotic risk factor such as immobility. A direct correlation between venous thromboembolism and Miller Fisher Syndrome or Guillain-Barre Syndrome has not been previously described. CASE REPORT We report the case of a 32-year-old Hispanic male who presented with acute, severe thromboembolic disease and concurrently demonstrated characteristic clinical features of Miller Fisher Syndrome including ophthalmoplegia, ataxia, and areflexia. Past medical and family history were negative for thromboembolic disease, and subsequent hypercoagulability workup was unremarkable. During the course of hospitalization, the patient also developed angioedema. CONCLUSIONS We describe a possible association between Miller Fisher Syndrome, thromboembolic disease, and angioedema.

Hypercoagulable States

The hypercoagulable states consist of a group of prothrombotic clinical disorders associated with an increased risk for thromboembolic events. The abnormalities lead to inappropriate thrombus formation. After a review of the coagulation process, inherited disorders (including antithrombin-III deficiency, protein CS system deficiencies, disorders of plasmin generation, dysfibrinogenemias, and homocysteinuria) and acquired disorders (including responses to surgery, cancer, drugs, and the antiphospholipid syndrome) are described. Screening and management methods are discussed. Copyright © 1997 by W. B. Saunders Company.

A Prospective Study of the Clinical Profile, Outcome and Evaluation of D-dimer in Cerebral Venous Thrombosis

INTRODUCTION

Cerebral Venous Thrombosis (CVT) is a well known disease with diverse clinical presentation and causes. With advances in neuroimaging and changing lifestyles, the clinical profile and causes of CVT are changing. D-dimer has been studied in early diagnosis of CVT with variable results. This prospective study was carried out to assess the clinical profile of CVT and role of D-dimer in diagnosis of CVT.

AIM

To study various aspects of CVT and role of D-dimer.

MATERIALS AND METHODS

The study period was September 2012 to July 2014 and included 80 imaging proven patients of CVT. We also included 39 controls for assessing D-dimer. Data was collected according to a preformed format. D-dimer was assessed by a rapid semi-quantitative latex agglutination assay. Discharged patients were followed up to six months.

RESULTS

Of the total 44 were women and 36 were men (F: M=1.2:1). The mean age of the patients was 29.5±9.68 years. Most common clinical features were headache 77 (96.25%), papilloedema (67.5%) and seizures 51 (63.75%). Pregnancy was the most common cause of CVT. Superior sagittal and transverse sinuses were the most common sinuses to be affected. The sensitivity and specificity of D-dimer for diagnosing CVT was 84.62% and 80% respectively. The risk factors for poor prognosis were altered sensorium, presence of sepsis, increased sinus involvement and deep sinus thrombosis.

CONCLUSION

CVT affects both sexes equally. Puerperium still contributes to majority of the cases. Iron deficiency anaemia needs to be evaluated as a contributing factor for incidence of CVT. D-dimer is not useful in puerperal female with CVT. Positive D-dimer will strengthen the suspicion of CVT in patients with acute headache followed by a neurological deficit.

Varicella Zoster Virus: A Common Cause of Stroke in Children and Adults

BACKGROUND

Varicella zoster virus (VZV) is a neurotropic, exclusively human herpesvirus. Primary infection causes varicella (chickenpox), after which the virus becomes latent in ganglionic neurons along the entire neuraxis. As cell-mediated immunity to VZV declines with advancing age and immunosuppression, VZV reactivates to produce zoster (shingles). One of the most serious complications of zoster is VZV vasculopathy.

METHODS

We reviewed recent studies of stroke associated with varicella and zoster, how VZV vasculopathy is verified virologically, vaccination to prevent varicella and immunization to prevent zoster, and VZV in giant cell arteritis (GCA).

FINDINGS

We report recent epidemiological studies revealing an increased risk of stroke after zoster; the clinical, laboratory, and imaging features of VZV vasculopathy; that VZV vasculopathy is confirmed by the presence of either VZV DNA or anti-VZV IgG antibody in cerebrospinal fluid; special features of VZV vasculopathy in children; vaccination to prevent varicella and immunization to prevent zoster; and the latest evidence linking VZV to GCA.

CONCLUSION

In children and adults, VZV is a common cause of stroke.

Purpura fulminans secondary to rickettsial infections: A case series

Purpura fulminans (PF) is a descriptive term used to describe a heterogeneous group of disorders characterized by rapidly progressive purpuric lesions that may develop into extensive areas of skin necrosis, and peripheral gangrene. This rare disorder is associated with laboratory evidence of consumptive coagulopathy and is often fatal. PF is usually associated with many infections, most notably with meningococcal, staphylococcal, and streptococcal infections. However, there are very few reports of this entity with spotted fever and scrub typhus from India. Rickettsial infections are an underdiagnosed group of diseases presenting as acute febrile illness, with high mortality in untreated cases. Of the available tests, Weil–Felix is a handy and economical tool for early diagnosis of this fatal disease especially in resource poor settings. We present four infants with PF secondary to rickettsial fever diagnosed by the Weil–Felix test.

Varicella-Zoster Virus Vasculopathy: A Case Report Demonstrating Vasculitis using Black-Blood MRI

Infections are rare but important causes of stroke. Among these, varicella zoster virus has been known to cause ischemic stroke. During an attack of herpes zoster ophthalmicus, it has been hypothesized that the virus replicates in the trigeminal ganglion and travels via the trigeminal nerve centrally to cause cerebral vasculopathy. Here we present a case of a 69 year-old Caucasian immunocompromised woman who suffered recurrent ischemic infarcts within the same vascular distribution following an episode of zoster ophthalmicus three months prior. An imaging technique termed black-blood magnetic resonance imaging was utilized to aid in the diagnosis of cerebral vasculitis. The case is used to provide a literature review of the pathogenesis, diagnosis, and treatment of cerebral varicella zoster vasculopathy. In situations where an isolated unilateral cerebral vasculopathy is identified, neurologists are urged to consider varicella zoster as a treatable etiologic agent, as untreated vasculopathy can lead to further strokes.

Vascular Complications of Varicella: Description of 4 Cases and a Review of Literature

Stroke and deep venous thrombosis are rare complications of varicella zoster infection. We report 3 cases of children with a stroke and 1 case of a boy with a deep venous thrombosis after recent chicken pox.

Cerebral venous sinus thrombosis: association with primary varicella zoster virus infection

Varicella zoster virus (VZV) has been known to cause cerebral arterial vasculopathy and an acquired antibody-mediated coagulopathy associated with purpura fulminans and generalized thromboembolism. There are no published reports of cerebral venous sinus thrombosis (CVST) associated with primary VZV infection. We report 2 cases that highlight an unusual presentation of VZV infection: CVST with primary varicella infection. One patient had extensive CVST with coexistent middle cerebral artery involvement. Primary VZV infection can be associated with thrombosis of cerebral arteries and venous sinuses.

Varicella-related musculoskeletal complications in children

Eight children with post-varicella musculoskeletal complications were treated between 2001 and 2009. The complications that were observed were cellulitis (three children), pyomyositis (three children), osteomyelitis (two children) and gangrene (one child). On average, 8.8 days elapsed between primary varicella infection and complication. The most common presentation was pain. Before we started treating them, all children received antibiotics during interhospital transfers (average: 2.4). Interventions included drainage (eight), fasciatomy (one), arthrotomy (one), bone drilling (one), and amputation (one). Blood cultures were negative in all children. Two children had positive pus cultures for Staphylococcus aureus, one of them had a methicillin-resistant S. aureus infection. One of the four children who developed coagulopathy ended with significant morbidity. Varicella-related methicillin-resistant S. aureus osteomyelitis suggests a widening spectrum of these infections.

Chickenpox is not always benign: postvaricella purpura fulminans requires prompt and aggressive treatment

We present 2 patients, who were admitted owing to rapidly progressing purpuric lesions due to postvaricella purpura fulminans, a coagulopathy leading to life- or limb-threatening thrombosis caused by a severe transient autoimmune protein S deficiency. Laboratory results were being consistent with disseminated intravascular coagulation secondary to protein S deficiency; treatment with fresh frozen plasma, intravenous immunoglobulins, and prednisone was started. In our experience, a prompt therapy may limit the course and the extent of the disease. We present a review of the topic with supporting literature for the therapeutic options. Therefore, we should be reminded that purpura fulminans is a rare but severe complication of chickenpox, which demands quick action.

Postinfectious purpura fulminans secondary to varicella-induced protein S deficiency

Varicella is usually a benign and self-limited disease of infancy and childhood although it has been recognized that it sometimes has severe and life-threatening complications. We report a case of postinfectious purpura fulminans with acquired protein S deficiency following varicella in a 6-year-old child and discuss the underlying mechanism of postinfectious purpura fulminans.

Stroke After varicella-zoster infection: report of a case and review of the literature

Ischemic stroke is a recognized complication of varicella-zoster virus infections. We report on an immunocompetent 5-year-old girl who presented with acute neurologic deficits attributed to cerebral infarction, 3 months after varicella-zoster virus infection. Magnetic resonance imaging of the brain showed subacute ischemic lesions in the territory of the right middle cerebral artery. A literature review of 70 similar cases is reported.

Hereditary and acquired protein S deficiencies are associated with low TFPI levels in plasma

BACKGROUND

Protein S and tissue factor pathway inhibitor (TFPI) act together in down-regulating coagulation.

OBJECTIVE

To investigate the TFPI/protein S system in hereditary and acquired protein S deficiency.

METHODS

Plasma antigen levels of protein S and full-length TFPI were determined in heterozygous type I protein S-deficient individuals (n=35), patients on oral anticoagulant treatment (OAT) (n=29), oral contraceptive (OC) users (n=10) and matched controls. Thrombin generation was determined using calibrated automated thrombography.

RESULTS

Full-length TFPI levels were lower in type I protein S-deficient individuals (76.8+/-33.8%) than in age- and sex-matched controls (128.0+/-59.4%, P<0.001). Among protein S-deficient individuals with thrombosis, those on OAT had not only lower total protein S levels (25.7+/-8.2% vs. 54.7+/-8.2%, P<0.001), but also lower full-length TFPI levels (52.6+/-15.0% vs. 75.4+/-22.9%, P=0.009) than those not on OAT. Similarly, OC users had lower protein S (73.8+/-11.5% vs. 87.9+/-10.8%, P=0.005) and full-length TFPI levels (73.7+/-27.7% vs. 106.4+/-29.2%, P=0.007) than non-users. When triggered with tissue factor, plasma from protein S-deficient individuals generated 3-5-fold more thrombin than control plasma. The difference was only partially corrected by normalization of the protein S level, full correction requiring additional normalization of the TFPI level. Protein S-immunodepletion experiments indicated that free protein S and full-length TFPI form a complex in plasma, and the protein S/TFPI interaction was confirmed by surface plasmon resonance analysis.

CONCLUSIONS

Full-length TFPI binds to protein S in plasma and is reduced in genetic and acquired protein S deficiency. The concomitant TFPI deficiency substantially contributes to the hypercoagulable state associated with protein S deficiency.

Varicella-associated purpura fulminans and multiple deep vein thromboses: a case report

Varicella-associated purpura fulminans is a rare syndrome associated with substantial morbidity and mortality. General supportive care, heparinization, and plasma infusions are the mainstays of treatment. A patient aged 8 years and 8 months with purpura fulminans and multiple deep vein thromboses after varicella infection because of deficiencies of proteins C and S is presented in this case report.

Fulminant sepsis/meningitis due to Haemophilus influenzae in a protein C-deficient heterozygote treated with activated protein C therapy

A 13-month-old Japanese female with Haemophilus influenzae type b meningitis presented with unusually severe septic shock and cerebral infarction in half a day of fever. The initial therapy of plasma-derived activated protein C (Anact C) led to an impressive effect on the aggressive condition. However, purpura fulminans and the consistent decline of plasma protein C activity (<20%) required prolonged activated protein C therapy and gene analysis. The patient carried a novel heterozygous mutation of PROC (exon 4; 335 GAC>TAC, Asp46Tyr). This is the first report of infectious purpura fulminans in a protein C-deficient heterozygote. The clinical onset and treatment course adequately corroborated the aggravated immune/hemostatic reactions and the cytoprotective effects of activated protein C replacement in human heterozygous protein C deficiency. The monitoring of plasma protein C activity and sufficient administration of activated protein C product could improve the outcome of severe sepsis in children.

Basal ganglia and internal capsule stroke in childhood--risk factors, neuroimaging, and outcome in a series of 28 patients: a tertiary hospital experience

We present 28 patients with basal ganglia ischemic stroke and describe the main neurological manifestations, neuroimaging findings, risk factors, and outcome. In 23 cases, at least 1 risk factor was identified. A total of 7 cases (25%) had antecedent of varicella infection and 7 cases (25%) had preceding mild head trauma. Similar antecedents were present only in 2.6% and 5.3% of patients with nonbasal ganglia stroke, respectively (odds ratio: 12.2, 95% confidence interval: 2.04-124.65 and odds ratio: 5.92, 95% confidence interval: 1.32-29.7). The arterial abnormalities identified in 10 patients were narrowing (6) or occlusion (4) of the M1 segment. After a median follow-up of 24 months, 19 patients had a good outcome. Magnetic resonance angiography and catheter cerebral angiography played an important role in the identification of arterial disease. We propose that basal ganglia infarction is a different group of ischemic stroke with prevalent risk factors (varicella infection and mild head trauma) and good outcome.

Nonbacterial purpura fulminans and severe autoimmune acquired protein S deficiency associated with human herpesvirus-6 active replication

Nonbacterial purpura fulminans (PF) is rare, usually follows viral infection in young children, and is characterized by specific coagulation disorders, requiring specific therapy. Following a transient rash, a 2-year-old previously healthy girl developed PF without haemodynamic impairment. Laboratory data revealed disseminated intravascular coagulation and a severe transient protein S deficiency. Antiprotein S autoantibodies and active human herpesvirus-6 (HHV6) replication were demonstrated. Purpuric skin lesions spread very rapidly despite broad-spectrum antibiotics and right leg amputation. Plasmapheresis and intravenous immunoglobulins gave complete clinical recovery and normalization of protein S level within 10 days, with progressive clearance of antiprotein S autoantibodies. Transient severe protein S deficiencies have previously been reported in patients with nonbacterial PF, usually after varicella infection. This is the first documented case of PF after HHV6 infection.

[Post-varicella purpura fulminans: potentially fatal]

Although varicella is usually a benign disease, some of its complications, such as post-varicella purpura fulminans, can be fatal. Its pathophysiological mechanism is caused by the production of antibodies to protein C and protein S in the coagulation cascade. This could have fatal consequences for those patients with partial deficiency of these proteins that develop disseminated intravascular coagulation. Treatment is symptomatic: fresh frozen plasma to treat protein depletion, antithrombin III and heparinization against thrombus formation, and anti-inflammatory drugs (steroids). However, new therapies, such as prostaglandin E1 IV and prostacyclin, are being introduced.

Clinical and radiological features of childhood cerebral infarction following varicella zoster virus infection

The aim of the study was to describe the clinical and radiological features of childhood post-varicella cerebral infarction (PVCI). A retrospective review was undertaken of children with arterial ischaemic stroke (AIS) who had experienced varicella zoster virus (VZV) infection within the preceding year. Twenty-four children (15 males, nine females; age range at time of VZV infection 2mo-6y) were identified, with a median of 4 months between VZV and AIS (range 1wk-12mo). All had infarction in the middle cerebral artery (MCA) territory and abnormalities of the M1 segment; arteriopathy affected other arteries in 10 children. After a median of 27 months, six patients had recurrent transient ischaemic attacks (TIA), with new infarcts in two of 22 children on re-imaging. Arterial disease improved in 11 children, was stable in four, and progressed in seven (of whom four had recurrent TIA and two had re-infarction). PVCI affects young, previously healthy children within a few months of VZV infection and is characterized by MCA territory infarction and proximal MCA disease. One quarter of patients have recurrence, usually, but not inevitably, associated with progressive arteriopathy. Treatable co-existing AIS risk factors should always be excluded. A more comprehensive diagnostic evaluation should be considered in children with AIS who do not fit the clinical and radiological profile outlined, even where there is a history of recent VZV infection.

Decreased protein S activity is related to the disease activity of Behcet's disease

We wanted to see whether the active inflammation in Behcet's disease (BD) can cause a thrombotic disorder by decreasing the protein S (PS) activity, and we evaluated the relationship between the decreased PS activity and the disease activity of BD. We included 122 patients with BD whose PS activity levels were measured. In 51 patients, the PS activity was measured again when there were changes in the number of items of "The Behcet's Disease Current Activity Form (BDCAF)". The thrombosis rate was 2.5% (3/122), and the PS activity was low in all three of the patients with thrombosis. The incidence of low PS activity in the total 122 BD patients was 27% (33/122). The incidence of the low PS activity in the active BD patients was 33.7% (31/92), and this was significantly more frequent than in the inactive BD patients, (6.7%, 2/30) (chi(2)-test, P value = 0.0038). The decrease of PS activity had good correlation with the increase of the number of BDCAF items (r = -0.351, P value = 0.012). The PS activity decrease is related to the BD activity. The low PS activity can be the risk factor for thrombotic disorder and also the activity marker for BD and other inflammatory diseases.

Cerebrovascular disease and varicella in children

Varicella-associated stroke has been reported with increasing frequency in recent years. In many cases, diagnosis is difficult because of the late onset of manifestations after the acute infectious episode. Four cases of cerebrovascular disease after varicella infection were observed. Three children presented hemiparesis and one facial paresis. The neuroradiological findings comprised stenosis/occlusion of middle cerebral artery or nucleo capsular signal alteration. Because, several pathogenetic mechanisms have been proposed as the cause of stroke, the relationship between prothrombotic conditions, antipospholipid antibodies and stroke in these patients is discussed. The difficulty in defining the pathogenesis of the ischemic episode is related to problems in the choice of antithrombotic treatment, which is still not standardized and must be decided on individual basis. In the event of rapid onset of stroke after exanthem high dose antiviral therapy seems to be justified. On the basis of our experience and of literature data on varicella-associated stroke, we recommend that VZV infection be taken into account in every episode of stroke in children.

Prothrombotic abnormalities in childhood ischaemic stroke

Childhood ischaemic stroke, incorporating arterial ischaemic stroke and cerebral sinus venous thrombosis, is associated with significant morbidity and mortality in children. The majority of cases in children present with well-recognised risk factors. The appreciation of the role prothrombotic abnormalities have in disease states is developing rapidly. Prothrombotic abnormalities are abnormalities of the coagulation system, fibrinolytic system, endothelial cells or platelets that lead to a reduced threshold for pathological thrombus formation. Our understanding of the role of prothrombotic abnormalities in childhood ischaemic stroke is increasing and has a direct bearing on the development of effective management and prevention strategies. We provide a brief background of prothrombotic abnormalities and review the available literature on prothrombotic markers in childhood ischaemic stroke. Overall, prothrombotic abnormalities have been identified in 20-50% of children presenting with AIS and 33-99% of children with cerebral sinus venous thrombosis. There appear to be a number of associations emerging including an increased frequency of factor V Leiden mutation, elevated lipoprotein (a), protein C deficiency and antiphospholipid antibodies in children presenting with arterial ischaemic stroke. The pathogenic role of prothrombotic abnormalities as predisposing to initial and recurrent childhood ischaemic stroke is becoming increasingly evident. The impact on treatment, however, will only be clarified with carefully designed, multi-institutional prospective studies.

Deep venous thrombosis and pulmonary embolism following chickenpox

An 11-year-old girl developed proximal deep venous thrombosis and bilateral pulmonary embolism associated with antiphospholipid syndrome following chickenpox. She responded to prolonged anticoagulation therapy.

Coagulation, inflammation, and apoptosis: different roles for protein S and the protein S-C4b binding protein complex

Protein S (PS) has an established role as an important cofactor to activated protein C (APC) in the degradation of coagulation cofactors Va and VIIIa. This anticoagulant role is evident from the consequences of its deficiency, when there is an increased risk of venous thromboembolism. In human plasma, PS circulates approximately 40% as free PS (FPS) and 60% in complex with C4b-binding protein (C4BP). Formation of this complex results in loss of PS cofactor function, and C4BP can then modulate the anticoagulant activity of APC. It had long been predicted that the complex could act as a bridge between coagulation and inflammation due to the involvement of C4BP in regulating complement activation. This prediction was recently supported by the demonstration of binding of the PS-C4BP complex to apoptotic cells. This review aims to summarize recent findings on the structure and functions of PS, the basis and importance of its deficiency, its interaction with C4BP, and the possible physiologic and pathologic importance of the PS-C4BP interaction.

Púrpura fulminante posvaricelosa

Purpura fulminans (PF) is an infrequent complication of varicella characterized by the progressive development of purpuric or painful ecchymotic lesions associated with biochemical alternations typical of consumption coagulopathy. Activation of coagulation is due to a marked and prolonged decrease in protein S, which is probably secondary to the formation of antiprotein S antibodies. The mechanism responsible for the synthesis of these autoantibodies is unknown. We present three cases of postvaricella PF and review the clinical and biochemical characteristics of this entity, as well as current diagnostic and therapeutic recommendations.

Transient cerebral arteriopathy in infancy associated with enteroviral infection

We report the case of an 18-month-old boy who presented aphasia and right hemiplegia of acute onset. The neurological deficit completely resolved after a few hours, but identical transient neurological deficits and seizures occurred during the following days. Imaging showed proximal stenosis of the medial cerebral artery and deep ischaemic lesions in the territory of this artery. Analysis of the cerebrospinal fluid showed pleocytosis and an active enteroviral infection with positive RNA detection. The evolution was consistent with transient cerebral arteriopathy of childhood as magnetic resonance angiography showed normalization of the arterial lesions. This is the first report of an enteroviral infection associated with this entity. We want to stress the importance of performing a cerebrospinal fluid analysis when an ischaemic stroke of unclear aetiology occurs in a child.

Postvaricella purpura fulminans caused by acquired protein s deficiency resulting from antiprotein s antibodies: search for the epitopes

Postvaricella purpura fulminans is a rare disease in children that is probably caused by an acquired protein S deficiency resulting from antiprotein S antibodies. The epitope of these antibodies is unknown. A 5-year-old girl is described with postvaricella purpura fulminans and an acquired protein S deficiency. In this patient and in her 3-year-old sister with uncomplicated varicella, the concentrations of antiprotein S antibodies were measured and followed with enzyme-linked immunosorbent assay techniques. The epitope of the antiprotein S antibodies was studied using miniprotein S, a recombinant variant of protein S that consists of the first 242 amino acids of protein S, lacking the sex hormone binding globulin-like domain. In the patient's plasma, concentrations of free protein S antigen and total protein S antigen reached normal levels in 4 months and 5 weeks, respectively. The concentrations of the antiprotein S antibodies decreased to 25% of the initial level in the course of 5 months. In the sister, antiprotein S antibodies were present as well, but the concentrations were lower than those in the patient. Most of the antiprotein S antibodies were directed against the first 242 amino acids of protein S. After varicella, a heterozygous autoantibody response may develop that may result in severe acquired protein S deficiency leading to purpura fulminans. Epitopes of these antiprotein S antibodies are situated on both the first 242 amino acids of protein S and the sex hormone binding globulin-like domain.

Special situations: pediatric, pregnant, and geriatric patients

Venous thromboembolic disease is not an uncommon problem associated with the geriatric patient. These patients are at significantly increased risk of DVT and PE compared with their younger counterparts. Their associated morbidity and mortality is also higher. Treatment of thrombotic disease in these patients necessitates close monitoring owing to their enhanced sensitivity to the effects of anticoagulants.

The varicella-autoantibody syndrome

This cross-sectional study was conducted to determine the incidence of autoantibodies to phospholipids and coagulation proteins in children with acute varicella zoster virus (VZV) infection. Study groups included children with VZV alone or complicated by purpura fulminans and/or thromboembolism. VZV naïve children and children who had VZV >1 y before sample collection formed a control group. Blood was assayed for the following: free protein S (PS), protein C, antithrombin, and prothrombin; antibody binding to these proteins; lupus anticoagulant; anticardiolipin antibody; antiphospholipid antibodies; and prothrombin fragment 1+2. Data regarding coinfections was collected. Forty-three VZV-infected children showed an increased frequency of lupus anticoagulant, anticardiolipin antibody, antiphospholipid antibodies, and autoantibodies to PS, protein C, prothrombin, and antithrombin in comparison to 52 children without acute VZV (p < 0.0001). Seventeen children with VZV and purpura fulminans and/or thromboembolism showed a statistically significant decrease in free PS, significantly increased PS IgG antibody, and significantly increased prothrombin fragment 1+2 (p < 0.0001) compared with the group without acute VZV and the group with uncomplicated VZV. Twenty-six children with uncomplicated VZV showed increased PS IgG antibody (p < 0.001) compared with the children without acute VZV. For all groups combined, elevated PS IgG antibody showed negative correlation with free PS (p < 0.0001) and positive correlation with prothrombin fragment 1+2 (p = 0.0002). Autoantibodies were transient. Transient antiphospholipid and coagulation protein autoantibodies were common with VZV infection, but were not predictive of thrombotic complications.