Multiple causes of cerebrovascular events in children with tumors of the parasellar region

The Genetic Landscape of Ischemic Stroke in Children - Current Knowledge and Future Perspectives

Stroke in childhood has multiple etiologies, which are mostly distinct from those in adults. Genetic discoveries over the last decade pointed to monogenic disorders as a rare but significant cause of ischemic stroke in children and young adults, including small vessel and arterial ischemic stroke. These discoveries contributed to the understanding that stroke in children may be a sign of an underlying genetic disease. The identification of these diseases requires a detailed medical and family history collection, a careful clinical evaluation for the detection of systemic symptoms and signs, and neuroimaging assessment. Establishing an accurate etiological diagnosis and understanding the genetic risk factors for stroke are essential steps to decipher the underlying mechanisms, optimize the design of tailored prevention strategies, and facilitate the identification of novel therapeutic targets in some cases. Despite the increasing recognition of monogenic causes of stroke, genetic disorders remain understudied and therefore under-recognized in children with stroke. Increased awareness among healthcare providers is essential to facilitate accurate diagnosis in a timely manner. In this review, we provide a summary of the main single-gene disorders which may present as ischemic stroke in childhood and describe their clinical manifestations. We provide a set of practical suggestions for the diagnostic work up of these uncommon causes of stroke, based upon the stroke subtype and imaging characteristics that may suggest a monogenic diagnosis of ischemic stroke in children. Current hurdles in the genetic analyses of children with ischemic stroke as well as future prospectives are discussed.

When and why is surgical revascularization indicated for the treatment of moyamoya syndrome in patients with RASopathies? A systematic review of the literature and a single institute experience

BACKGROUND

Moyamoya disease (MMD) is a cerebrovascular disorder characterized by the progressive occlusion of the supraclinoid internal carotid artery (ICA), resulting in the formation of an abnormal cerebral vascular network. When MMD occurs in association with an underlying medical condition, including some distinctive genetic disorders, it is named moyamoya syndrome (MMS). The discrimination between MMD and MMS has been validated by recent genetic researches and international reviews. Similarly to patients suffering from MMD, patients with MMS generally become symptomatic because of ischemic complications, which lead to hemiparesis, transient ischemic events, seizures, and sensory symptoms. RASopathies are a group of neurodevelopmental disorders that can be associated with MMS.

RESULTS

We retrospectively reviewed 18 RASopathy patients with MMS treated at our institution from 2000 to 2015 (16 neurofibromatosis type 1, 1 Costello syndrome, and 1 Schimmelpenning syndrome). Here, we report clinical data, performed surgical procedures, and clinic-radiological outcome of these patients. Most of them received both indirect revascularization and medical therapy.

CONCLUSIONS

At the moment, there are no univocal recommendations on which of these two treatment strategies is the treatment of choice in patients with RASopathies and MMS. We suggest that patients with a good overall prognosis (primarily depending on the distinctive underlying genetic disorder) and initial cerebrovascular disease could benefit from a prophylactic surgical revascularization, in order to prevent the cognitive impairment due to the progression of the vasculopathy.

Review of cranial radiotherapy-induced vasculopathy

Cranial radiation can impact the cerebral vasculature in many ways, with a wide range of clinical manifestations. The incidence of these late effects including cerebrovascular accidents (CVAs), lacunar lesions, vascular occlusive disease including moyamoya syndrome, vascular malformations, and hemorrhage is not well known. This article reviews the preclinical findings regarding the pathophysiology of late radiation-induced vascular damage, and discusses the clinical incidence and risk factors for each type of vasculopathy. The pathophysiology is complex and dependent on the targeted blood vessels, and upregulation of pro-inflammatory and hypoxia-related genes. The risk factors for adult CVAs are similar to those for patients not exposed to cranial radiotherapy. For children, risks for late vascular complications include young age at radiotherapy, radiotherapy dose, NF1, tumor location, chemotherapy, and endocrine abnormalities. The incidence of late vascular complications of radiotherapy may be impacted by improved technology, therapeutic interventions, and appropriate follow up.

Moyamoya syndrome precipitated by cranial irradiation for craniopharyngioma in children

Recently, combination of surgery and radiation therapy (RT) has been recommended in the treatment of craniopharyngioma. RT could be associated with late complications, including vasculopathy. We report two cases of the moyamoya syndrome seen in children with craniopharyngioma who received RT after surgical resection. Thirty-five patients in pediatric age with craniopharyngioma were surgically treated. Fifteen out of 35 patients underwent surgical resection followed by RT or gamma knife surgery. Two of the 15 were found to have symptoms of transient ischemic attack and were diagnosed as moyamoya syndrome through the cerebral angiography. Age at RT was 4 and 13 years, respectively. The latent period for development of the moyamoya syndrome was 27 months and 3 years, respectively, after RT. The RT dose of both patients was 54 Gy. These two patients received bilateral encephaloduroarteriosynangiosis procedures. We report here these two cases of radiation-induced moyamoya syndrome in pediatric craniopharyngioma. Pediatric patients with craniopharyngioma who received RT should be reminded, during follow-up, about the risk of development of the moyamoya syndrome.

Incidence of vasculopathy in children with hypothalamic/chiasmatic gliomas treated with brachytherapy

INTRODUCTION

External brain irradiation in children can cause cognitive decline, endocrine dysfunctions and second malignancies. A rare complication is cerebral vasculopathy, which occurs most often in patients with neurofibromatosis type 1. Interstitial radiotherapy using transient Iodine-125 implants is a radiotherapy option, called brachytherapy, offering excellent survival rates, but little is known on treatment-related morbidity, especially long time vascular changes.

PATIENTS AND METHODS

Thirteen children with low-grade hypothalamic gliomas, four of them with neurofibromatosis type 1, were diagnosed and treated at the University Hospital Freiburg, Germany. They belong to a larger group of 44 children with suprasellar low-grade gliomas, treated with transient Iodine-125 seeds and include those who attended all routine follow-up examinations in Freiburg. After written informed consent from the parents or caregivers all patients underwent magnetic resonance imaging with angiographic techniques in 2001, 3 to 13 years after treatment.

RESULTS AND DISCUSSION

Six out of 13 revealed cerebral vasculopathies, only one of them revealed symptoms of intermittent cerebral ischemia. Neurofibromatosis type 1 was present in one affected patient. The aetiology of the cerebral vascular changes is not fully understood so far. Tumour encasement, surgical damage and brachytherapy may contribute as a single risk factor or in combination. To get more information, we recommend MRA for artery vasculopathy at follow-up in all patients with suprasellar brain tumours irrespectively to their former treatment or presence of cerebrovascular symptoms.

Radiation-induced moyamoya syndrome

PURPOSE

The moyamoya syndrome is an uncommon late complication after radiotherapy (RT).

METHODS AND MATERIALS

A PubMed search of English-language articles, with radiation, radiotherapy, and moyamoya syndrome used as search key words, yielded 33 articles from 1967 to 2002.

RESULTS

The series included 54 patients with a median age at initial RT of 3.8 years (range, 0.4 to 47). Age at RT was less than 5 years in 56.3%, 5 to 10 years in 22.9%, 11 to 20 years in 8.3%, 21 to 30 years in 6.3%, 31 to 40 years in 2.1%, and 41 to 50 years in 4.2%. Fourteen of 54 patients (25.9%) were diagnosed with neurofibromatosis type 1 (NF-1). The most common tumor treated with RT was low-grade glioma in 37 tumors (68.5%) of which 29 were optic-pathway glioma. The average RT dose was 46.5 Gy (range, 22-120 Gy). For NF-1-positive patients, the average RT dose was 46.5 Gy, and for NF-1-negative patients, it was 58.1 Gy. The median latent period for development of moyamoya syndrome was 40 months after RT (range, 4-240). Radiation-induced moyamoya syndrome occurred in 27.7% of patients by 2 years, 53.2% of patients by 4 years, 74.5% of patients by 6 years, and 95.7% of patients by 12 years after RT.

CONCLUSIONS

Patients who received RT to the parasellar region at a young age (<5 years) are the most susceptible to moyamoya syndrome. The incidence for moyamoya syndrome continues to increase with time, with half of cases occurring within 4 years of RT and 95% of cases occurring within 12 years. Patients with NF-1 have a lower radiation-dose threshold for development of moyamoya syndrome.

Vascular complications of cranial radiation

OBJECTIVES

Cerebral vascular disease has been reported as a long-term complication of cranial radiotherapy. The purpose of this study was to examine the frequency and risk factors associated with development of cerebral vascular disease in children after cranial radiation.

MATERIALS AND METHODS

A retrospective chart review of all cancer patients treated between 1985 and 2003 who were under the age of 18 years at the time of initial radiotherapy was performed. Variables examined include diagnosis and site of malignancy, age at the time of radiotherapy, sex, total radiation dosage, number of fractions, duration, and whether the patient had proven cerebral vascular event.

RESULTS

Two hundred and forty-four patients met the study criteria. One hundred and 13 cases involved tumors of the central nervous system. The remaining patients had systemic neoplastic disease. Post radiation cerebral vascular disease occurred in 11 (5%) patients, and all but one patient had a tumor involving the central nervous system (mainly in the posterior fossa and supratentorial midline).

CONCLUSION

There is an increased risk of cerebral vascular disease after radiation therapy in childhood, especially in children who received high dose radiation at the posterior fossa and supratentorial axial region.

Cerebrovascular complications in cancer patients

Coagulation disorders are common in cancer patients. In patients with solid tumors, a low-grade activated coagulation can result in systemic and cerebral arterial or venous thrombosis. Cancer treatments may also contribute to this coagulopathy, which usually, but not exclusively, occurs in the setting of advanced malignant disease. There may be TIAs or cerebral infarctions. Because of the widespread distribution of cerebral thromboses, there may be a superimposed encephalopathy; sometimes this is the only sign. Concurrent systemic thrombosis is present in many patients and is a useful clue to the diagnosis. In cerebral venous occlusion, the initial symptom is usually a headache. Except for cerebral intravascular coagulation that is unassociated with NBTE, neuriomaging studies usually demonstrate one or more parenchymal infarctions. MRI or MRV may demonstrate venous thrombosis. The laboratory evidence of coagulopathy is difficult to distinguish from the asymptomatic coagulopathy that often accompanies advanced cancer, and the test results must be interpreted cautiously. NBTE can be diagnosed by transesophageal echocardiography. There is no established treatment for the thrombotic coagulopathy associated with cancer, but anticoagulation should be considered. In leukemia and lymphoma, the coagulopathy is typically acute DIC that can lead to systemic and brain hemorrhages. It is especially common in acute myelogenous leukemias. The clinical signs of cerebral hemorrhage are fulminant and may be fatal. The bleeding usually occurs in the brain or subdural compartment, and rarely in the subarachnoid space. The diagnosis can be suspected by the clinical setting and by systemic thrombosis or hemorrhage. It can be established by examination of the peripheral smear, the platelet count, and tests of coagulation function. Therapy of acute DIC is controversial and should be individualized for the clinical setting. Cerebrovascular disorders can complicate metastatic or primary tumor in the brain, skull, dura, or leptomeninges. The clinical signs of infarction are indistinguishable from other causes of stroke, except that tumor-related venous occlusion will usually first produce signs of increased intracranial pressure. The diagnosis of tumor-related infarction can usually be established by neuroimaging studies that show infarction and may show extracerebral sites of tumor. CSF examination is useful in diagnosing leptomeningeal metastasis. A search for lung or cardiac tumor should be performed when embolic tumor infarction is suspected. Primary or metastatic tumors in the brain or dura may hemorrhage, producing the initial clinical signs of the brain tumor or a change in chronic signs induced by the tumor. There are helpful clues to a neoplastic hemorrhage on brain CT or MRI scans. The brain hemorrhage may require evacuation and the underlying tumor will usually require additional antineoplastic treatment. Hyperleukocytosis (extreme elevation of the cell count) in acute myelogenous leukemia is a less common cause of brain hemorrhage in recent years because of improved methods to lower the cell count. Cerebral arterial or venous thrombosis is sometimes the result of cancer therapy. The attribution of thrombosis to chemotherapy in many published cases is only speculative, because carefully conducted prospective studies that include investigation for other thrombotic causes are not available. The best-known associations with thrombosis are L-asparaginase, which is typically used in the induction therapy of acute lymphocytic leukemia, and combination hormonal therapy and chemotherapy for breast cancer. Radiation to the head and neck, typically administered for head and neck epithelial cancers or lymphoma, may result in delayed carotid atherosclerosis. The distribution of stenosis or occlusion is within the radiation portal and is typically more extensive than is atherosclerosis that develops in the absence of radiation. Small clinical series suggest that surgical treatment is equally effective as in nonirradiated carotid atherosclerosis. In children, the cerebral vessels can be affected by brain radiation resulting in stenosis or occlusion. Brain hemorrhages can result from chemotherapy effects on the hemostatic system or a microangiopathic anemia. Hemorrhages from radiation-induced vascular abnormalities are rare. Opportunistic infections, especially fungal infections, can complicate cancer or its treatment. Septic cerebral emboli may result in focal cerebral signs, seizures, or encephalopathy. Sometimes there is an associated hemorrhagic vasculitis or cerebritis. Rarely, mycotic aneurysms may bleed. A high index of suspicion is needed to diagnose fungal infection because of the difficulty in culturing the organism from the blood or CSF. A clinician can usually establish the cause of stroke in the cancer patient by performing a careful review of the clinical setting--including the type and extent of cancer and the type of antineoplastic therapy--in which the stroke occurred. Systemic thrombosis, embolism, or hemorrhage can be a clue to the cause, and appropriate neuroimaging and coagulation studies to aid in the diagnosis are available. Therapy may ameliorate symptoms or prevent further episodes. The identification of one of these unusual stroke syndromes that leads to the diagnosis of an occult and treatable cancer can be particularly rewarding.

Preirradiation endocrinopathies in pediatric brain tumor patients determined by dynamic tests of endocrine function

PURPOSE

To prospectively evaluate pediatric patients with localized primary brain tumors for evidence of endocrinopathy before radiotherapy (RT).

METHODS AND MATERIALS

Seventy-five pediatric patients were evaluated with the arginine tolerance test and L-dopa test for growth hormone secretory capacity and activity; thyroid-stimulating hormone surge and thyrotropin-releasing hormone stimulation test for the hypothalamic-thyroid axis; the 1-microg adrenocorticotropin hormone (ACTH) and metyrapone test for ACTH reserve; and, depending on age, a gonadotropin-releasing hormone stimulation test to determine gonadotropin response. The study included 38 male and 37 female patients, age 1-21 years with ependymoma (n = 35), World Health Organization (WHO) Grade I-II astrocytoma (n = 18), WHO Grade III-IV astrocytoma (n = 10), craniopharyngioma (n = 7), optic pathway tumor (n = 4), and germinoma (n = 1). Seven patients receiving dexamethasone at the time of the evaluation were excluded from the final analysis.

RESULTS

Of 68 assessable patient, 45 (66%) had evidence of endocrinopathy before RT, including 15 of 32 patients (47%) with posterior fossa tumors. Of the 45 patients, 38% had growth hormone deficiency, 43% had thyroid-stimulating hormone secretion abnormality, 22% had an abnormality in ACTH reserve, and 13% had an abnormality in age-dependent gonadotropin secretion.

CONCLUSION

The incidence of pre-RT endocrinopathy in pediatric brain tumor patients is high, including patients with tumors not adjacent to the hypothalamic-pituitary unit. These data suggest an overestimation in the incidence of radiation-induced endocrinopathy. Baseline endocrine function should be determined for brain tumor patients before therapy. The potential for radiation-induced endocrinopathy alone cannot be used as an argument for alternatives to RT for most patients. Pre-RT endocrinopathy may be an early indicator of central nervous system damage that will influence the functional outcome unrelated to RT.

Growth hormone therapy for hypopituitary adults: time for re-appraisal

The advent of the production of large quantities of recombinant growth hormone (GH) has made it possible to have sufficient material to assess its efficacy in adult growth hormone deficiency (GHD). Although some studies have shown that patients who are severely deficient benefit from GH therapy, the spectrum of GHD is broad, and the degree of deficiency at times is very difficult to define. In some cases, benefit is not easily quantified, and some studies have claimed benefits that, although statistically significant, are either not clinically important or are so marginal as to be questionable in terms of cost, difficulty of administration and potential risks. The purpose here is to identify the current problems in the diagnosis of GHD, to discuss the rationale for GH therapy and to assess the potential effects of GHD as well as the benefits of GH therapy in GHD adults. We will include a commentary as to which effects appear more robust than others and which are likely to result in the greatest patient benefit. Finally, some attention will be paid to long-term safety issues that should be monitored to ensure that this medication is safe even for the patients with the greatest need.