Cerebrovascular complications of L-asparaginase in the therapy of acute lymphoblastic leukemia

Nonconvulsive Status Epilepticus: A Review for Emergency Clinicians

BACKGROUND

Status epilepticus is associated with significant morbidity and mortality and is divided into convulsive status epilepticus and nonconvulsive status epilepticus (NCSE).

OBJECTIVE

This review provides a focused evaluation of NCSE for emergency clinicians.

DISCUSSION

NCSE is a form of status epilepticus presenting with prolonged seizure activity. This disease is underdiagnosed, as it presents with nonspecific signs and symptoms, most commonly change in mental status without overt convulsive motor activity. Causes include epilepsy, cerebral pathology or injury, any systemic insult such as infection, and drugs or toxins. Mortality is primarily related to the underlying condition. Patients most commonly present with altered mental status, but other signs and symptoms include abnormal ocular movements and automatisms such as lip smacking or subtle motor twitches in the face or extremities. The diagnosis is divided into electrographic and electroclinical, and although electroencephalogram (EEG) is recommended for definitive diagnosis, emergency clinicians should consider this disease in patients with prolonged postictal state after a seizure with no improvement in mental status, altered mental status with acute cerebral pathology (e.g., stroke, hypoxic brain injury), and unexplained altered mental status. Assessment includes laboratory evaluation and neuroimaging with EEG. Management includes treating life-threatening conditions, including compromise of the airway, hypoglycemia, hyponatremia, and hypo- or hyperthermia, followed by rapid cessation of the seizure activity with benzodiazepines and other antiseizure medications.

CONCLUSIONS

An understanding of the presentation and management of NCSE can assist emergency clinicians in the care of these patients.

Complications of Cancer Therapy in Children: A Comprehensive Review of Neuroimaging Findings

ABSTRACT

Complications of cancer therapy in children can result in a spectrum of neurologic toxicities that may occur at the initiation of therapy or months to years after treatment. Although childhood cancer remains rare, increasing survival rates mean that more children will be living longer after cancer treatment. Therefore, complications of cancer therapy will most likely occur with increasing frequency.At times, it is very difficult to differentiate between therapeutic complications and other entities such as tumor recurrence, development of secondary malignancy, and infection (among other conditions). Radiologists often play a key role in the diagnosis and evaluation of pediatric patients with malignancies, and thus, awareness of imaging findings of cancer complications and alternative diagnoses is essential in guiding management and avoiding misdiagnosis. The aim of this review article is to illustrate the typical neuroimaging findings of cancer therapy-related toxicities, including both early and late treatment effects, highlighting pearls that may aid in making the appropriate diagnosis.

Neurotoxicity Associated with Treatment of Acute Lymphoblastic Leukemia Chemotherapy and Immunotherapy

Immunotherapy is a milestone in the treatment of poor-prognosis pediatric acute lymphoblastic leukemia (ALL) and is expected to improve treatment outcomes and reduce doses of conventional chemotherapy without compromising the effectiveness of the therapy. However, both chemotherapy and immunotherapy cause side effects, including neurological ones. Acute neurological complications occur in 3.6–11% of children treated for ALL. The most neurotoxical chemotherapeutics are L-asparaginase (L-ASP), methotrexate (MTX), vincristine (VCR), and nelarabine (Ara-G). Neurotoxicity associated with methotrexate (MTX-NT) occurs in 3–7% of children treated for ALL and is characterized by seizures, stroke-like symptoms, speech disturbances, and encephalopathy. Recent studies indicate that specific polymorphisms in genes related to neurogenesis may have a predisposition to MTX toxicity. One of the most common complications associated with CAR T-cell therapy is immune effector cell-associated neurotoxicity syndrome (ICANS). Mechanisms of neurotoxicity in CAR T-cell therapy are still unknown and may be due to disruption of the blood–brain barrier and the effects of elevated cytokine levels on the central nervous system (CNS). In this review, we present an analysis of the current knowledge on the mechanisms of neurotoxicity of standard chemotherapy and the targeted therapy in children with ALL.

L-asparaginase mediated therapy in L-asparagine auxotrophic cancers: A review

Microbial L-asparaginase is the most effective first-line therapeutic used in the treatment protocols of paediatric and adult leukemia. Leukemic cell's auxotrophy for L-asparagine is exploited as a therapeutic strategy to mediate cell death through metabolic blockade of L-asparagine using L-asparaginase. Escherichia coli and Erwinia chrysanthemi serve as the major enzyme deriving sources accepted in clinical practise and the enzyme has bestowed improvements in patient outcomes over the last 40 years. However, an array of side effects generated by the native enzymes due to glutamine co-catalysis and short serum stays augmenting frequent dosages, intended a therapeutic switch towards the development of biobetter alternatives for the enzyme including the formulations resulting in sustained local depletion of L-asparagine. In addition, the treatment with L-asparaginase in few cancer types has proven to elicit drug-induced cytoprotective autophagy mechanisms and therefore warrants concern. Although the off-target glutamine hydrolysis has been viewed in contributing the drug-induced secondary responses in cells deficient with asparagine synthetase machinery, the beneficial role of glutaminase-asparaginase in proliferative regulation of asparagine prototrophic cells has been looked forward. The current review provides an overview on the enzyme's clinical applications in leukemia and possible therapeutic implications in other solid tumours, recent advancements in drug formulations, and discusses the aspects of two-sided roles of glutaminase-asparaginases and drug-induced cytoprotective autophagy mechanisms.

Venous thromboembolism incidence and risk factors in adults with acute lymphoblastic leukemia treated with and without pegylated E. coli asparaginase-containing regimens

PURPOSE

Asparaginases, key agents in treatment of acute lymphoblastic leukemia (ALL), are associated with venous thromboembolism (VTE). While risks of short-acting asparaginase-related VTE is well-known, we studied VTE incidence and risk factors in adult ALL patients treated with and without long-acting pegylated asparaginase (PegA).

METHODS

Single-center, retrospective analysis of 89 ALL patients treated with (n = 61) or without (n = 28) PegA at Greenebaum Comprehensive Cancer Center. Reviewed patient and disease characteristics, treatment, and VTE incidence.

RESULTS

VTE during treatment occurred in 31 patients (35%), and was associated with PegA (p = 0.001) and Philadelphia chromosome negativity (p = 0.002). Among PegA recipients, VTE was associated with a significantly higher mean body mass index (BMI) of 31.3 kg/m² (p = 0.037), and was more common with pre-T/T cell compared to pre-B/B cell ALL (68.2% vs. 33.3%, p = 0.009). Antithrombin-III (ATIII) levels were measured for 26 patients; 16 (61.5%) were < 50%. Of those, 8 (50%) experienced VTE, while 3 of 10 (30%) patients with ATIII levels ≥ 50% experienced VTE. VTE occurred in 7 of 13 (54%) of patients who received ATIII repletion. There was a trend toward a higher incidence of VTE in the PegA group among patients with non-O compared to O blood type (55.9% vs. 33.3%, p = 0.079) as well as those with a higher hemoglobin at diagnosis (9.3 vs 8.1 g/dL, p = 0.056).

CONCLUSION

This study confirms PegA as a risk factor for VTE in patients with ALL. Risk factors among those receiving PegA include higher BMI and pre-T/T cell ALL. ATIII repletion was not shown to be protective against VTE. There was a higher incidence of VTE in patients who received PegA with non-O compared to O blood type, but the precise correlation is uncertain.

Etiologies, Cerebral Vasomotion, and Endothelial Dysfunction in the Pathophysiology of Posterior Reversible Encephalopathy Syndrome in Pediatric Patients

The posterior reversible encephalopathy syndrome was characterized by Hinchey and colleagues in the 1990s. The condition frequently afflicts patients suffering from hematologic and solid organ malignancy and individuals undergoing transplantation. Cases are more frequently described in the adult population compared with children. In the pediatric population, malignancy, transplantation, renal disease, and hypertension represent the most common etiologies. Theories on pathogenesis have centered upon cerebrovascular dysautoregulation with increases in blood–brain barrier permeability. This generates vasogenic edema of the cerebral parenchyma and consequent neurologic deficits. The parietal and occipital lobes are affected with greatest prevalence, though frontal and temporal lobe involvement is frequent, and that of the contents of the infratentorial posterior cranial fossa are occasionally described. The clinical presentation involves a characteristic constellation of neurologic signs and symptoms, most typically inclusive of headache, visual-field disturbances, abnormalities of visual acuity, and seizures. Supportive care, withdrawal of the offending agent, antihypertensive therapy, and prophylactic anticonvulsants affect convalescence in majority of cases. The principal challenge lies in identifying the responsible agent precipitating the condition in patients with malignancy and those having undergone transplantation and thus deciding which medication among a multidrug treatment regimen to withhold, the duration of drug cessation required to effect clinical resolution, and the safety of resuming treatment with the compound. We accordingly reviewed and evaluated the literature discussing the posterior reversible encephalopathy syndrome in children.

Suspected adverse reaction to compounded preparations prescribed for weight loss: two cases of cerebral venous thrombosis

We report two cases of cerebral venous thrombosis associated with the use of compounded preparations containing several active substances prescribed for weight loss. In both cases there is suspicion of additive/synergic interaction with oral contraceptives. The adverse drug reactions were considered serious, being life-threatening and causing hospitalisation for days.

Complications and Toxicities Associated with Cancer Therapies in the Intensive Care Unit

Advances in the management of hematologic malignancies and solid tumors have given rise to diverse modalities to treat cancer other than cytotoxic chemotherapy, including targeted therapies, immunotherapies, and cellular therapies. Currently, there are over 175 FDA-approved antineoplastic agents in the United States, many with a diverse and profound toxicity profile. Complications of antineoplastic therapy may result in the need for intensive care unit (ICU) admission to provide acute symptom management. Accordingly, ICU providers caring for cancer patients should have a working knowledge of the toxicities and complications associated with antineoplastic therapy.

Posterior reversible encephalopathy syndrome in pediatric patients: pathophysiology, diagnosis, and management

Posterior reversible encephalopathy syndrome (PRES) is well-described in adults, but has been reported with relative rarity in children, usually occurring in the context of chemotherapy for acute leukemia. Pathogenesis involves perturbed cerebral autoregulation leading to vasogenic edema predominantly affecting the parieto-occipital white matter, though involvement of the frontal and temporal lobes, as well as posterior fossa, is also described. We review the literature on the pathophysiology, diagnosis, and management of PRES in pediatric patients.

A survey on hematology-oncology pediatric AIEOP centres: The challenge of posterior reversible encephalopathy syndrome

OBJECTIVES

Posterior reversible encephalopathy syndrome (PRES) is one of the most common neurological complications in hematology-oncology pediatric patients. Despite an increasingly recognized occurrence, no clear consensus exists regarding how best to manage the syndrome, because most cases of PRES have reported in single-case reports or small series. Aim of this paper is to identify incidence, clinical features, management, and outcome of PRES in a large series of hematology-oncology pediatric patients.

METHODS

The cases of PRES occurred in twelve centers of the Italian Association of Pediatric Hematology and Oncology were reported.

RESULTS

One hundred and twenty-four cases of PRES in 112 pediatric patients were recorded with an incidence of 2.1% and 4.7%, respectively, in acute lymphoblastic leukemia in first complete remission and hematopoietic stem cell transplantation (HSCT). The majority of cases occurred after a cycle of chemotherapy rather than after stem cell transplant. PRES after chemotherapy significantly differs from that after HSCT for diagnosis, time of presentation, risk factors, management, and outcome.

CONCLUSIONS

This study demonstrates that PRES is a common neurological complication and occurring preferentially in course of induction treatment of some hematologic malignancies, as ALL and after HSCT. It also highlights great clinical differences in the management and outcome in patients with PRES occurring after chemotherapy or after HSCT.

The Complex Diagnostic Challenge in Children With Non-Central Nervous System Cancer and Cerebellar Mutism

Multiple etiologies should be considered in the differential diagnosis of immunocompromised patients with non-central nervous system cancer and viral infections who develop mutism. Acute cerebellitis, caused by infections or by neurotoxicity resulting from chemotherapy; paraneoplastic cerebellar degeneration; atypical posterior reversible encephalopathy syndrome; and acute disseminated encephalomyelitis may all cause mutism in such patients. This condition warrants prompt recognition and may require treatment with immunotherapy, as it may be an immune-mediated process. We present 2 patients with leukemia and viral illness who developed cerebellar mutism in the setting of acute cerebellitis and responded to immunotherapy, suggesting that the condition involved a parainfectious immune-mediated response.

Neurological Complications of Childhood Cancer

Though the treatment of pediatric cancers has come a long way, acute and chronic effects of cancer are still affecting the life of many children. These effects may be caused not only by the malignancy itself but also by the interventions used for the purpose of treatment. This article focuses primarily on the indirect effects of pediatric cancers and their treatment on the central and peripheral nervous system. Chemotherapy, radiation, and stem cell transplantation cause an immune-compromised state and place the patient at risk of infection, the leading cause of mortality in pediatric cancer. The underlying cancer and the treatments also cause neurovascular changes that may lead to neurological sequelae immediately or many years in the future. Chemotherapy and radiation have both immediate and long-term neurotoxic effects on the central and peripheral nervous system. Cancers may also trigger an immune response that damages nervous system components, leading to altered mental status, seizures, abnormal movements, and even psychosis. Knowledge of these effects can help the practitioner be more vigilant for the signs and symptoms of potential neurological complications during the management of pediatric cancers.

An antithrombin replacement strategy during asparaginase therapy for acute lymphoblastic leukemia is associated with a reduction in thrombotic events

Thrombosis is a well-recognized complication of asparaginase therapy for acute lymphoblastic leukemia (ALL), associated with the depletion of antithrombin (AT). Following a high incidence of thrombotic episodes during induction therapy for ALL in our tertiary referral center, we prospectively instituted a protocol of AT replacement. Forty-five consecutive adolescents and adults with ALL treated with asparaginase-containing phase I induction protocols were included in this observational study. Fifteen received standard therapy with no replacement; the subsequent 30 were managed with the protocol described. One or more low AT levels (<70 iu/dl) were recorded in 76% of patients in the cohort managed using the protocol, resulting them in receiving an AT replacement. There was a significant reduction in the incidence of thrombosis with this strategy (0/30 vs. 5/15, p < 0.001). We suggest that such a strategy should be studied in a prospective randomized sub-study within the context of a national ALL trial.

Incidence and risk factors for Central Nervous System thrombosis in paediatric acute lymphoblastic leukaemia during intensive asparaginase treatment: a single-centre cohort study

Central Nervous System (CNS) thrombosis is a complication of acute lymphoblastic leukaemia (ALL) treatment that is potentially associated with significant morbidity and neurological sequelae. Its presumably multifactorial aetiology is poorly characterized. We conducted a single-centre, retrospective cohort study on 346 ALL paediatric patients (1-16 years old) treated with asparaginase intensive Dana Farber Cancer Institute (DFCI) protocols from 1998 to 2011. The incidence, risk factors and outcome of CNS thrombosis were evaluated. CNS thrombosis occurred in 3·8% (13/346) of the patients (95% confidence interval 2·0-6·3%). Twelve events were diagnosed during intensification, all of which resolved within 2 weeks without neurological sequelae or significant impact in survival. Obesity (body mass index above 95th percentile) and asparaginase formulation were the only factors associated with CNS thrombosis, with an increase in the odds of event in obese patients [odds ratio (OR) = 3·37; P = 0·064] and a reduction in patients receiving Erwinia asparaginase (OR = 0·12; P = 0·018). No association could be demonstrated for age, gender, DFCI risk-group, ALL phenotype, steroid or doxorubicin use, central venous line use or CNS radiotherapy. CNS thrombosis is a rare but manageable adverse event without significant sequelae or detrimental effects in survival. Increased awareness is recommended in obese patients particularly during intensive asparaginase use.

A critical review on properties and applications of microbial l-asparaginases

l-Asparaginase is one of the main drugs used in the treatment of acute lymphoblastic leukemia (ALL), a commonly diagnosed pediatric cancer. Although several microorganisms are found to produce l-asparaginase, only the purified enzymes from E. coli and Erwinia chrysanthemi are employed in the clinical and therapeutic applications in humans. However, their therapeutic response seldom occurs without some evidence of hypersensitivity and other toxic side effects. l-Asparaginase is also of prospective use in food industry to reduce the formation of acrylamide in fried, roasted or baked food products. This review is an attempt to compile information on the properties of l-asparaginases obtained from different microorganisms. The complications involved with the therapeutic use of the currently available l-asparaginases, and the enzyme's potential application as a food processing aid to mitigate acrylamide formation have also been reviewed. Further, avenues for searching alternate sources of l-asparaginase have been discussed, highlighting the prospects of endophytic microorganisms as a possible source of l-asparaginases with varied biochemical and pharmacological properties.

Stroke patients with a past history of cancer are at increased risk of recurrent stroke and cardiovascular mortality

BACKGROUND AND PURPOSE

Cancer patients are at increased risk of cardiovascular and cerebrovascular events. It is unclear whether cancer confers any additional risk for recurrent stroke or cardiovascular mortality after stroke.

METHODS

This was a single center, observational study of 1,105 consecutive Chinese ischemic stroke patients recruited from a large stroke rehabilitation unit based in Hong Kong. We sought to determine whether patients with cancer are at higher risk of recurrent stroke and cardiovascular mortality.

RESULTS

Amongst 1,105 patients, 58 patients (5.2%) had cancer, of whom 74% were in remission. After a mean follow-up of 76 ± 18 months, 241 patients developed a recurrent stroke: 22 in patients with cancer (38%, annual incidence 13.94%/year), substantially more than those without cancer (21%, 4.65%/year) (p<0.01). In a Cox regression model, cancer, age and atrial fibrillation were the 3 independent predictors of recurrent stroke with a hazard ratio (HR) of 2.42 (95% confidence interval (CI): 1.54-3.80), 1.01 (1.00-1.03) and 1.35 (1.01-1.82) respectively. Likewise, patients with cancer had a higher cardiovascular mortality compared with those without cancer (4.30%/year vs. 2.35%/year, p = 0.08). In Cox regression analysis, cancer (HR: 2.08, 95% CI: 1.08-4.02), age (HR: 1.04, 95% CI 1.02-1.06), heart failure (HR: 3.06, 95% CI 1.72-5.47) and significant carotid atherosclerosis (HR: 1.55, 95% CI 1.02-2.36) were independent predictors for cardiovascular mortality.

CONCLUSIONS

Stroke patients with a past history of cancer are at increased risk of recurrent stroke and cardiovascular mortality.

The eukaryotic initiation factor 2 kinase GCN2 protects against hepatotoxicity during asparaginase treatment

Asparaginase is an important drug in the treatment regimen for acute lymphoblastic leukemia. Asparaginase depletes circulating asparagine and glutamine, activating an amino acid stress response (AAR) involving phosphorylation of eukaryotic initiation factor 2 (eIF2) by general control nonderepressible kinase 2 (GCN2). We hypothesized that GCN2 functions to mitigate hepatic stress during asparaginase therapy by activating the AAR. To test this idea, C57BL/6J wild-type mice (Gcn2(+/+)) and those deleted for Gcn2 (Gcn2(-/-)) were injected with asparaginase or saline excipient one time daily for 1 or 6 days. In liver, increased phosphorylation of eIF2 and mRNA expression of AAR target genes activating transcription factor 4, asparagine synthetase, eIF4E-binding protein 1, and CAAT enhancer-binding protein homologous protein were significantly blunted or blocked in the liver of Gcn2(-/-) mice. Loss of AAR during asparaginase coincided with increases in mammalian target of rapamycin signaling, hepatic triglyceride accumulation, and DNA damage in association with genetic markers of oxidative stress (glutathione peroxidase) and inflammation (tumor necrosis factor alpha-α). Although asparaginase depleted circulating asparagine in both Gcn2(+/+) and Gcn2(-/-) mice, all other amino acids, including plasma glutamine, were elevated in the plasma of Gcn2(-/-) mice. This study shows that loss of GCN2 promotes oxidative stress and inflammatory-mediated DNA damage during asparaginase therapy, suggesting that patients with reduced or dysfunctional AAR may be at risk of developing hepatic complications during asparaginase treatment.

Hemorrhagic and ischemic stroke in children with cancer

BACKGROUND

Adult survivors of childhood cancer have an increased risk of cerebrovascular disease; little is known about early stroke risk in childhood cancer. Our objectives were to assess stroke prevalence in children with cancer, to establish cancer and stroke type, and to determine if modifiable risk factors for stroke were present.

METHODS

Children with stroke and cancer were compared with all children seen for cancer at a single institution between 2000 and 2009. An International Classification of Disease, 9th version, code search and search of existing pediatric oncology and stroke databases identified children <18 years with ischemic stroke, intracerebral hemorrhage, and cerebral sinovenous thrombosis.

RESULTS

Of 1411 children with cancer, 15 had a stroke (1.1%, 95% CI: 0.6-1.7%). Stroke classifications were seven intracerebral hemorrhages, five ischemic strokes (one of which was followed by intracerebral hemorrhage), and three sinovenous thromboses. Stroke occurred at a median of 5 months after cancer diagnosis. Ten children with strokes had hematologic malignancies and five had brain tumors. Thirteen patients died poststroke, eight because of withdrawal of care. White blood cell count ≥48,000/mm3 was found in four children, all with intracerebral hemorrhage. Five of seven children with intracerebral hemorrhage had platelets <50,000/mm3.

CONCLUSIONS

Stroke has a prevalence of approximately 1% in children with cancer. Hemorrhagic stroke and ischemic stroke occur with approximately equal frequency; children with leukemia and brain tumors are at greatest risk.

L-asparaginase fatal toxic encephalopathy during consolidation treatment in an adult with acute lymphoblastic leukemia

Patient: Male, 51

Final Diagnosis: Encephalopaty toxic

Symptoms: Confusion • disorientation • drowsiness • fever

Medication: L-asparaginase

Clinical Procedure: —

Specialty: Oncology

Cerebral venous sinus thrombosis in pediatric cancer patients: long-term neurological outcomes

Cerebral venous sinus thrombosis (CVST) is an uncommon but recognized complication of treatment for leukemia. Our goal was to determine the long-term neurocognitive outcomes in childhood cancer survivors who had CVST during therapy. Nine patients were identified from an institutional database. All had experienced CVST in the setting of L-asparaginase therapy in combination with other chemotherapeutic agents. Four patients completed neuropsychological evaluation. Their neurological examinations were normal. Neuropsychological testing showed that the participants performed well, with average to above-average scores on cognitive and behavioral testing. Three exhibited difficulties on a visual-motor integration task and 1 had difficulty with fine-motor dexterity, nonverbal memory, emotional control, shifting attention, and anxiety. Overall, by patient and parent report, the survivors had few problems. CVST is a known complication associated with treatment for leukemia and non-Hodgkin lymphoma, most commonly observed if asparaginase is used in combination with other chemotherapeutic agents. Although subtle difficulties were noted in survivors on neuropsychological testing, survivors themselves were not aware of the deficits. Further evaluation of leukemia survivors with a history of CVST is needed to assess for deficits and to understand whether further intervention is necessary.

Surgical treatment of refractory epilepsy after chemotherapy in two children with leukemia

Refractory epilepsy is a rare, long-term complication in children with acute leukemia who are receiving chemotherapy. A few studies have reported cases of several patients who developed recurrent complex partial seizures after the initiation of chemotherapy. In these cases, the cause of the refractory seizures was identified as mesial temporal lobe sclerosis. Here, we report on two patients with extratemporal lesions accompanied by refractory seizures, a long-term complication of acute lymphocytic leukemia. Using presurgical evaluations and measures of the surgical outcomes, the lesions were identified as epileptogenic and were located in the mesial temporal lobe. The underlying pathophysiological background is discussed to aid in understanding this uncommon long-term complication.

Nonconvulsive status epilepticus due to drug induced neurotoxicity in chronically ill children

Nonconvulsive status epilepticus (NCSE) is a specific form of status epilepticus and is defined as epileptic activity on an EEG without seizures and as an alteration in mental status lasting more than 30 min. NCSE may be caused by drugs, cerebrovascular events, metabolic disorders or toxins. Herein, we present four cases of patients with drug-induced NCSE who were chronically ill due to renal failure or childhood leukemia. NCSE should be suspected in patients with an altered mental status without clinical seizures who are being treated with multiple drugs.

[Cerebral sinovenous thrombosis in a girl with acute lymphoblastic leukaemia carrying the prothrombin G20210A variant]

Although cerebral venous thrombosis is rare, it is more commonly associated with children suffering from acute lymphoblastic leukaemia. We report the case of a 7-year-old girl who developed massive cerebral sinovenous thrombosis on day 22 of induction therapy for high-risk acute lymphoblastic leukaemia. Clinical symptoms were gradual onset of headache, decreasing consciousness, and ensuing left hemiplegia. A subsequent prothrombotic study revealed a heterozygous prothrombin G20210A variant in the child and mother. We analysed the prothrombotic factors found in the case before and after thrombosis. We confirm the importance of early exploration of patients for clinical predisposing risk factors of thrombosis and primary prothrombotic states in children with acute lymphoblastic leukaemia. This might help identify patients at particular risk from thrombosis and so administer thromboprophylaxis.

Central nervous system chemotoxicity during treatment of pediatric acute lymphoblastic leukemia/lymphoma

In the last decades, increasing success rates are being obtained in the chemotherapy of pediatric leukemia and lymphoma. However, the cornerstone of this treatment is still formed by a reduced number of drugs with a highly toxic profile. In particular, central nervous system complications remain a challenging clinical problem, requiring rapid detection and prompt treatment to limit permanent damage. Furthermore, clinicians are often challenged to discriminate between CNS involvement by the disease, toxicity of drugs or infections. This clinically oriented review will help recognize and handle the main neurologic adverse effects induced by chemotherapy in pediatric patients with lymphoblastic leukemia/lymphoma. Different clinical entities and putative drugs involved are discussed in each chapter, with clinical cases illustrating the most relevant and challenging events. In addition, specific clinical-radiological patterns of some of these neurologic events are detailed. Finally, the role of pharmacogenetics, with special focus on those polymorphisms that could help explain the occurrence of neurotoxicity, is also discussed.

Side effects of oncologic therapies in the pediatric central nervous system: update on neuroimaging findings

The need for early, accurate diagnosis of central nervous system (CNS) complications occurring during and after pediatric cancer treatment is growing because of the improvement in overall survival rates related to innovative and aggressive oncologic therapies. An elevated degree of suspicion is needed to recognize the radiologic features of these CNS complications. Radiologists need familiarity with the early and late side effects of cancer therapy in the pediatric CNS (eg, toxic effects, infection, endocrine or sensory dysfunction, neuropsychologic impairment, second malignancies), in order to accelerate the imaging diagnosis and minimize as much as possible the associated morbidity. Acquisition of knowledge about these complications will enable the development of more appropriate therapeutic trials and more effective patient surveillance and will lead to an improved quality of life by decreasing the long-term sequelae in survivors.

Prevention and management of asparaginase/pegasparaginase-associated toxicities in adults and older adolescents: recommendations of an expert panel

The rapidly increasing use of pegasparaginase (pegASNase) in adults, after a half century of use of asparaginase (ASNase) in children, has prompted a need for guidelines in the management and prevention of toxicities of asparagine depletion in adults. Accordingly, an initial set of recommendations are provided herein. Major advantages of pegASNase are its 2-3-week duration of action, in contrast to less than 3 days with native ASNase, and the flexibility of intravenous or intramuscular administration of pegASNase and associated patient and physician convenience. The most frequent toxicities of both types of ASNase are hepatic and pancreatic, with pancreatitis being the most serious. Other toxicities are hypersensitivity reactions, thrombosis, nausea/vomiting, and fatigue. Whether or not the replacement of one dose of pegASNase for 6-9 doses of native ASNase can be achieved in adults with similar efficacy and acceptable toxicities to those achieved in children remains to be established.

Thromboembolic and bleeding complications in acute leukemia

The risk of both thromboembolic and bleeding complications is high in acute leukemia. This double hazard has a significant negative impact on the morbidity and mortality of patients with this disease. The clinical manifestations of both complications show special features specific to the form of acute leukemia. Recognition of these characteristics is important in the diagnosis and management of acute leukemia. In this article, several additional issues are addressed, including the features of bleeding and thrombosis in acute promyelocytic leukemia, the current understanding of the leukostasis syndrome and the iatrogenic complications including catheter-associated thrombosis, and the adverse effects of therapeutic agents used in acute leukemia. As regards the bleeding complications, thrombocytopenia is a major cause. Corrective measures, including recent guidelines on platelet transfusions, are provided.

Management of uncommon chemotherapy-induced emergencies

Chemotherapy can induce various clinical emergencies. Prompt recognition and management of these adverse events are important for avoiding further morbidity and mortality. Some events such as hypersensitivity and extravasation are quite common, whereas emergencies such as neutropenic typhlitis, pancreatitis, and acute haemolysis are very rare. Little information exists on the management of rare chemotherapy-induced emergencies that affect fewer than 1% of patients. We review these uncommon chemotherapy-induced life-threatening emergencies, their pathogenesis and management, and recommendations for rechallenge with the offending chemotherapy.

Posterior reversible encephalopathy syndrome in paediatric leukaemia

This report describes four patients with acute lymphoblastic leukaemia, suffering from posterior reversible encephalopathy syndrome during the induction period of treatment. A review of the literature on posterior reversible encephalopathy syndrome in paediatric leukaemia is given. The exact mechanism of posterior reversible encephalopathy syndrome is not clear and seems to be multifactorial. Hypertension is likely to play a major role in the development but could be also secondary. All patients in this case series presented after introduction of the new induction protocol for acute lymphoblastic leukaemia. Treatment of hypertension is likely to have a favourable role and posterior reversible encephalopathy syndrome is most often reversible. It is important to consider this diagnosis during the induction phase of leukaemia treatment in the presence of neurological symptoms. The incidence of PRES in the induction scheme should be investigated, in order to optimize the ALL treatment.

Tolerability and efficacy of L-asparaginase therapy in pediatric patients with acute lymphoblastic leukemia

L-asparaginase (L-ASNase) has been an essential component of multiagent chemotherapy for acute lymphoblastic leukemia in childhood for over 3 decades. There are currently 2 Food and Drug Administration (FDA)-approved formulations of L-ASNase derived from Escherichia coli and 1 non-FDA approved formulation derived from Erwinia chrysanthemi. Modifications in L-ASNase have included pegylation, which decreases drug immunogenicity and increases the half-life, allowing less frequent administration. Although L-ASNase is well-tolerated in most patients and causes little myelosuppression, significant toxicities occur in up to 30% of patients. Hypersensitivity is the most common toxicity of L-ASNase therapy and limits the further use of the drug. Other significant toxicities relate to a reduction in protein synthesis and include pancreatitis, thrombosis, central nervous system complications, and liver dysfunction. The spectrum of common toxicities and the efficacy of different formulations of L-ASNase are presented in this review.

Anesthetic considerations for the pediatric oncology patient--part 2: systems-based approach to anesthesia

One of the prices paid for chemo- and radiotherapy of cancer in children is damage to the vulnerable and developing healthy tissues of the body. Such damage can exist clinically or subclinically and can become apparent during active antineoplastic treatment or during remission decades later. Furthermore, effects of the tumor itself can significantly impact the physiologic state of the child. The anesthesiologist who cares for children with cancer or for survivors of childhood cancer should understand what effects cancer and its therapy can have on various organ systems. In part two of this three-part review, we review the anesthetic issues associated with childhood cancer. Specifically, this review presents a systems-based approach to the impact from both tumor and its treatment in children, followed by a discussion of the relevant anesthetic considerations.

Successful surgical treatment of medically refractory epilepsy after chemotherapy in a child with leukemia: a case report

INTRODUCTION

Mesial temporal sclerosis associated with acute lymphoblastic leukemia has been rarely reported.

CASE REPORT

We report a case of a 15-year-old boy with acute lymphoblastic leukemia who developed medically refractory temporal lobe epilepsy in a long time period after chemotherapy, and successfully treated with surgical resection.

CONCLUSIONS

To our knowledge, this is the first description of a leukemic child with medically refractory temporal lobe epilepsy who achieved seizure-freedom postoperatively during the long-term follow-up. The clinical history and details of the underlying pathophysiological background and treatment of this complication are discussed in this case report.

Thrombosis in childhood acute lymphoblastic leukaemia: epidemiology, aetiology, diagnosis, prevention and treatment

Acute lymphoblastic leukaemia (ALL) is the most common malignancy associated with venous thromboembolism (VTE) in children. The prevalence of symptomatic VTE ranges from 0% to 36%, and the variation can be explained, at least in part, by differences in chemotherapeutic protocols. The mechanism for increased risk of VTE is associated with alterations in the haemostatic system by use of L-asparaginase (ASP) alone or in combination with vincristine or prednisone, presence of central venous lines (CVLs) and/or inherited thrombophilia. The children at greatest risk are generally those receiving Escherichia coli ASP concomitant with prednisone. The majority of symptomatic VTEs occur in the central nervous system or in the upper venous system. In the majority of cases, asymptomatic VTEs are associated with CVLs. External CVLs are affected more often than internal CVLs. Evidence-based guidelines on prevention and treatment guidelines for ALL-related VTE are lacking, and carefully designed clinical trials are needed urgently.

Mesial temporal sclerosis associated with methotrexate-induced leukoencephalopathy

Mesial temporal sclerosis is a common form of symptomatic, localization-related epilepsy in children and adolescents, but its occurrence with acute lymphoblastic leukemia is rare. We present clinical records and neuroimaging results of a 13-year-old patient with acute lymphoblastic leukemia who developed recurrent partial seizures after an episode of leukoencephalopathy thought to be caused by methotrexate. Neuroradiologic images revealed hippocampal abnormalities consistent with the findings of mesial temporal sclerosis. Mesial temporal sclerosis was not previously reported in acute lymphoblastic leukemia patients with methotrexate-induced leukoencephalopathy. However, our case suggests that the pathogenesis of mesial temporal sclerosis may be associated with methotrexate-induced neurotoxicity.

Intracranial hypertension in pediatric patients with acute lymphoblastic leukemia

Acute lymphoblastic leukemia (ALL) remains one of the most common malignancies of childhood. Between April 1999 and August 2004, 9 of 207 patients treated at a Tertiary Oncology Service for ALL presented with Intracranial Hypertension (IH). Seven of the patients met the diagnostic criteria for Idiopathic Intracranial Hypertension (IIH). Four of the patients were treated with cerebrospinal fluid (CSF) drainage alone and four required Acetazolamide. Two of the four patients who were treated with Acetazolamide required subsequently a lumbar-peritoneal (LP) shunt. One patient succumbed to his disease before receiving any specific treatment.

Stroke and cancer: a review

Stroke is a disabling disease and can add to the burden of patients already suffering from cancer. Several major mechanisms of stroke exist in cancer patients, which can be directly tumour related, because of coagulation disorders, infections, and therapy related. Stroke can also occur as the first sign of cancer, or lead to its detection. The classical literature suggests that stroke occurs more frequently in cancer patients than in the average population. More recent studies report a very similar incidence between cancer and non-cancer patients. However, there are several cancer-specific types and causes of stroke in cancer patients, which need to be considered in each patient. This review classifies stroke into ischaemic, haemorrhagic, cerebral venous thrombosis and other rarer types of cerebrovascular disease. Its aim is to identify the types of stroke most frequently associated with cancer, and give a practical view on the most common and most specific types of stroke. The diagnosis of the cause of stroke in cancer patients is crucial for treatment and prevention. Management of different stroke types will be briefly discussed.

Management of stroke in cancer

Cerebrovascular disorders, including brain infarction, brain hemorrhage, and cerebral venous thrombosis, can occur as an early sign of cancer, but typically occur late in the clinical course. These disorders are due to a variety of pathogenic mechanisms, including coagulation disorders associated with the cancer, invasion or compression of vessels from tumor in or adjacent to the brain, and the adverse effects of cancer therapy. The appropriate therapy for these cerebrovascular disorders is empiric in most instances, because as yet there are no prospective treatment trials for them. A review of the existing literature reveals that improvement in patient quality of life and prevention of further cerebrovascular events can be obtained in some clinical situations.

Outcomes of a modified CALGB 19802 regimen in adult acute lymphoblastic leukemia

We analyzed the efficacy and toxicity of a modified Cancer and Leukemia Group B (CALGB) 19802 regimen in adult acute lymphoblastic leukemia (ALL). From February 2002 to August 2005, 25 adults with untreated ALL were enrolled in the study. Compared to the original regimen, the modified CALGB 19802 regimen consisted of a 4-drug induction (cyclophosphamide, daunorubicin, vincristine, and prednisone) instead of a 5-drug induction (L-asparaginase was added to the previous regimen). This was followed by high-dose methotrexate (1,000 mg/m(2) x 3 days) and cytarabine (2,000 mg/m(2) x 4 days) for the consolidation cycles. High-dose systemic and intrathecal methotrexate was given for central nervous system prophylaxis. Twenty-three patients (92%) achieved a complete remission (CR), and two patients (8%) had refractory disease. With a median follow-up of 21.5 months, 10 patients (40%) were alive and continued to be in CR. The 3-yr probability of an event-free survival and the overall survival were 39.0% and 47.4%, respectively. Treatment related mortality and major grade 3 to 4 neurotoxicity occurred in 1 patient and 3 patients, respectively. The modified CALGB 19802 regimen demonstrated a high remission rate and a favorable survival rate.

Cerebral sinovenous thrombosis in children

Cerebral sinovenous thrombosis (CSVT) is a rare but increasingly recognized disease process in children. In the pediatric population, the etiologies of CSVT are multiple and the outcomes are variable. The current therapies for CSVT include anticoagulation, thrombolysis, hydration, surgery, and supportive care. Adult studies, pediatric case studies, and expert opinion form the basis for these treatment strategies. International cooperative efforts are currently being undertaken to collect data on pediatric stroke patients, including CSVT. These multicenter collaborations are needed to increase our understanding of the incidence, risk factors, treatment modalities, and outcomes of CSVT in pediatric populations.

Central nervous system toxicity from cancer therapies

The central nervous system (CNS) is an organ with a unique profile of vulnerability to antineoplastic treatments. In many cases, CNS neurotoxicity is the dose-limiting side effect of treatment for systemic and CNS neoplasms. Novel methods of delivering radiation and chemotherapy agents have led to recognition of new forms of CNS neurotoxicity. In this article, the authors review the most important CNS toxicities of cancer treatment.

Double Hazard of Thrombophilia and Bleeding in Leukemia

The association between thrombosis and cancer has been extensively studied since first pointed out by Trousseau in 1895. It is, however, not commonly appreciated that the incidence of thrombosis in malignant hematologic disorders is as high or even higher than in solid tumors. Thrombotic complications in acute leukemia are often overlooked because bleeding complications generally dominate the clinical picture. Yet, the patient is at risk for both. While there are many thrombogenic factors shared by both solid tumors and leukemia, many additional prothrombotic features are present in leukemia. The prothrombotic factors include hyperleukocytosis, increased expression of tissue factor and its activation in leukemic cells, and the prothrombotic adverse effects of therapeutic agents and vascular access catheters. In addition, comorbid conditions including hereditary thrombophilia, infection, endothelial cell activation by cytokines, antiphospholipid syndrome and acquired activated protein C resistance are major contributory factors. Factors that increase the bleeding risk include thrombocytopenia, disseminated intravascular coagulation, and excessive fibrinolysis, which is enhanced by increased expression of Annexin II by leukemic cells. Therapeutic approaches to both bleeding and thrombotic conditions require special considerations of these factors.