Robert Listernick

Natural history of optic pathway tumors in children with neurofibromatosis type 1: A longitudinal study

To assess the natural history of optic pathway tumors (OPT) in children with neurofibromatosis type 1 (NF-1), from January 1985 through May 1993 we performed a prospective, longitudinal study of OPT in an unselected population of children with NF-1. Of 227 children with NF-1 seen in a specialty clinic, 176 (77%) underwent neuroimaging. Children in whom tumors were identified were followed closely by both repeated neuroimaging and ophthalmologic examinations to detect tumor growth or visual deterioration. Thirty-three children (19%) were found to have OPT at a median age of 4.2 years. The median age of children who had ophthalmologic complaints was significantly lower than that of children who had no such complaints (1.9 vs 5.3 years; p < 0.001). Although eight tumors were discovered because of ophthalmologic complaints or evidence of precocious puberty, 25 children (76%) were free of symptoms at the time of diagnosis. Twenty-one children (64%) had normal ophthalmologic findings at diagnosis; six children, all with chiasmal tumors, had previously unrecognized decreased visual acuity. Only three children (9%) had evidence of either tumor growth or deteriorating vision after diagnosis; the median duration of neuroimaging follow-up was 2.4 years (range, 0.2 to 7.2 years) and of ophthalmologic examinations 3.4 years (range, 0.2 to 8.1 years). All symptomatic OPT were diagnosed before 6 years of age. We conclude that OPT rarely progress during the next few years in children with NF-1 once the OPT have been discovered. The utility of screening neuroimaging for OPT in symptom-free children with NF-1 appears very limited.

Optic pathway gliomas in neurofibromatosis-1: controversies and recommendations.

Optic pathway glioma (OPG), seen in 15% to 20% of individuals with neurofibromatosis type 1 (NF1), account for significant morbidity in young children with NF1. Overwhelmingly a tumor of children younger than 7 years, OPG may present in individuals with NF1 at any age. Although many OPG may remain indolent and never cause signs or symptoms, others lead to vision loss, proptosis, or precocious puberty. Because the natural history and treatment of NF1‐associated OPG is different from that of sporadic OPG in individuals without NF1, a task force composed of basic scientists and clinical researchers was assembled in 1997 to propose a set of guidelines for the diagnosis and management of NF1‐associated OPG. This new review highlights advances in our understanding of the pathophysiology and clinical behavior of these tumors made over the last 10 years. Controversies in both the diagnosis and management of these tumors are examined. Finally, specific evidence‐based recommendations are proposed for clinicians caring for children with NF1. Ann Neurol 2007;61:189–198

Optic gliomas in children with neurofibromatosis type 1

To determine the frequency and natural history of tumors of the optic nerves and chiasm in patients with neurofibromatosis type 1, we obtained computed tomographic scans of 65 children who had no known visual or ocular abnormalities before their initial evaluation. Optic gliomas were detected in 10 children (15%). The median age of children with gliomas was 4.3 years (mean 5.8 years, range 9 months to 21 years). Three children (30%) had isolated, unilateral tumors, three (30%) had bilateral tumors, and four (40%) had involvement of the optic chiasm and of one or both nerves. Definite abnormalities of vision were found in only two children (20%). Five additional children were referred to the clinic after evaluation of ophthalmologic complaints led to the diagnosis of neurofibromatosis type 1: three had unilateral exophthalmos and two had plexiform neurofibromas of the eyelid with associated glaucoma. Ipsilateral optic gliomas were found in all five children; one child also had a contralateral tumor. Optic gliomas are commonly identified in young children with neurofibromatosis type 1 who have no ocular or visual abnormalities. Optic nerve gliomas may be associated with plexiform neurofibromas of the eyelid and glaucoma.

Dexamethasone in bronchiolitis: a randomised controlled trial

BACKGROUND Although corticosteroids are commonly prescribed in the treatment of bronchiolitis, there is no evidence on the efficacy of these drugs in this disorder. We designed a randomised, double-blind, prospective study to assess the efficacy of dexamethasone in infants with bronchiolitis who require hospital management. METHODS Infants younger than 12 months who had been admitted to hospital for an initial episode of wheezing, were randomly allocated intramuscular dexamethasone (1 mg/kg daily) or placebo, every 24 h for three doses. We excluded infants who were younger than 4 weeks, who required admission to the intensive care unit, or who had a history of congenital heart disease, mechanical ventilation, or supplemental oxygen use. We assessed infants on admission and every 12 h thereafter--vital signs were taken, severity of accessory muscle use and wheezing were measured by a clinical severity score, and pulse oximetry in room air was done. Our primary endpoints were the time to resolution of symptoms--defined as the number of assessments needed to reach oxygen saturation of more than 95% while receiving no supplemental oxygen, an accessory muscle score of 0, a wheeze score of 0 or 1, and resumption of normal feeding--and duration of oxygen therapy. Follow-up assessments were made 10-14 days after discharge by telephone. We used a proportional-hazards model for our survival analysis. FINDINGS 197 infants presented with bronchiolitis that required inpatient management. 75 were not enrolled (31 no consent, 28 no approach made, 16 transferred elsewhere). Of the 122 enrolled, four were excluded (clinical deterioration, diagnosis of cystic fibrosis, previous intubation, did not receive all study treatment). There were no differences between the dexamethasone (n = 65) and placebo-treated infants in demographic factors, exposure to tobacco smoke, duration of illness, presence of respiratory syncytial virus (RSV) antigen, respiratory rate, or severity score. More dexamethasone-treated patients had an initial oxygen saturation of 95% or less (51 [79%] dexamethasone vs 31 [59%] placebo, p = 0.02). There were no differences in duration of oxygen therapy (p = 0.74) or time to resolution of symptoms (p = 0.22). Stratification for presence of RSV antigen or family history of atopy did not affect the results. INTERPRETATION Our findings do not support the use of dexamethasone in the treatment of bronchiolitis in infants.

Optic pathway tumors in children: The effect of neurofibromatosis type 1 on clinical manifestations and natural history

OBJECTIVE To distinguish the clinical manifestations and natural history of optic pathway tumors (OPT) associated with neurofibromatosis type 1 (NF-1 OPT) from that of OPT not associated with NF-1 (non-NF-1 OPT). METHODS Two groups of children with OPT were compared: (1) 17 children with NF-1 OPT who were followed prospectively, and (2) 19 children with non-NF-1 OPT who were identified retrospectively by a review of medical records. RESULTS Precocious puberty was a common initial sign in the children with NF-1 OPT (5/17), and was not found in any patients without NF-1. In contrast, children with non-NF-1 OPT had symptoms attributable to increased intracranial pressure (12/19 and nystagmus (5/19); these symptoms were not found in any patient with NF-1. Decreased visual acuity at the time of diagnosis was common in both groups. There was no significant difference between the children with NF-1 OPT and those with non-NF-1 OPT as to age at diagnosis or sex distribution. Optic nerve involvement was more common in NF-1 (p < 0.001). Both isolated and bilateral optic nerve tumors were found exclusively in children with NF-1, whereas chiasmal (p = 0.016) and optic tract involvement (p = 0.001) were more common in those with non-NF-1 OPT. Radiographic evidence of hydrocephalus was found in none of the children with NF-1 OPT compared with 79% of the non-NF-1 OPT group. Progressive disease was seen in 12% of patients with NF-1 OPT compared with 63% of those with non-NF-1 OPT. CONCLUSIONS Differences exist between NF-1 OPT and non-NF-1 OPT both at the time of diagnosis and during follow-up. Optic pathway tumors caused by NF-1 and non-NF-1 OPT have different biologic properties that distinguish both their initial clinical manifestations and their natural history.

Intracranial gliomas in neurofibromatosis type 1

Optic pathway gliomas and brainstem gliomas are the predominant intracranial neoplasms associated with neurofibromatosis type 1 (NF1). Before the past 15 years, studies of optic pathway gliomas in NF1 were hampered by the inaccurate diagnosis of NF1, the unavailability of noninvasive neuroimaging techniques, and the frequent rendering of what would now be considered unnecessary, overly aggressive therapy. When studied systematically, these tumors behave in a much more benign fashion than their counterparts in children who do not have NF1. While they may cause symptoms in as many of 50% of cases, progression to the point where specific intervention is deemed necessary is unusual. Consequently, screening neuroimaging of asymptomatic patients is unwarranted. Because optic pathway tumors universally arise in children younger than 7 years of age, all such children should undergo yearly ophthalmologic evaluations and annual assessments of growth to monitor for signs of precocious puberty. Am. J. Med. Genet. (Semin. Med. Genet.) 89:38-44, 1999.

Visual outcomes in children with neurofibromatosis type 1-associated optic pathway glioma following chemotherapy: a multicenter retrospective analysis

Optic pathway gliomas (OPGs) occur in 15%-20% of children with neurofibromatosis type 1 (NF1); up to half become symptomatic. There is little information regarding ophthalmologic outcomes after chemotherapy. A retrospective multicenter study was undertaken to evaluate visual outcomes following chemotherapy for NF1-associated OPG, to identify risks for visual loss, and to ascertain indications for treatment. Subjects included children undergoing initial treatment for OPGs with chemotherapy between January 1997 and December 2007. Of 115 subjects, visual acuity (VA) decline and tumor progression were the primary reasons to initiate treatment, although there were significant differences in the pattern of indications cited among the institutions. Eighty-eight subjects and 168 eyes were evaluable for VA outcome. At completion of chemotherapy, VA improved (32% of subjects), remained stable (40%), or declined (28%). Tumor location was the most consistent prognostic factor for poor VA outcome. There was poor correlation between radiographic and VA outcomes. Although visual outcomes for NF1-associated OPG are not optimal, approximately one-third of children regain some vision with treatment. Since radiographic outcomes do not predict visual outcomes, their use as the primary measure of treatment success is in question. The lack of consensus regarding the indications for treatment underlines the need for better standardization of care. Future clinical trials for OPG require standardized visual assessment methods and clear definitions of visual outcomes.

Precocious puberty in children with neurofibromatosis type 1

We undertook a comprehensive study of children with neurofibromatosis type 1 (NF-1) cared for in a large multidisciplinary clinic to determine the prevalence of precocious puberty and its relationship to optic pathway tumors (OPTs). Precocious puberty was diagnosed in 7 of 219 children with NF-1 (5 boys and 2 girls) examined between Jan. 1, 1985, and April 20, 1993. All seven children had OPTs involving the optic chiasm; they represented 39% of children with NF-1 and chiasmal tumors (95% confidence interval, 17% to 64%). Eleven prepubertal children (aged 2 to 10 years) with NF-1 and OPTs, and age- and sex-matched NF-1 control subjects without OPTs, underwent luteinizing hormone-releasing hormone (LH-RH) stimulation tests. Two boys with OPTs had pubertal luteinizing hormone (LH) responses, and testosterone levels > 10 ng/dl. Basal LH levels were also elevated in these two boys when tested with a very sensitive immunochemiluminometric assay. None of the children without an OPT had either a pubertal response to LH-RH or an elevated basal LH level. We conclude that precocious puberty in children with NF-1 is found exclusively in those who have OPTs involving the optic chiasm; it is a common complication in those children. With the use of a highly sensitive LH assay, biochemical evidence of hypothalamic-pituitary-gonadal axis activation may be demonstrated, even without provocative testing.

Optic pathway gliomas in neurofibromatosis type 1: The effect of presenting symptoms on outcome

Children with neurofibromatosis type 1 (NF1) may present with optic pathway gliomas (OPG) that can progress to visual loss or other neurologic symptoms. These tumors may become evident either as a result of patient signs or symptoms or as an incidental finding on “baseline” neuroimaging studies. In an attempt to determine if there were differences between symptomatic and asymptomatic children with OPG, a retrospective cohort study of ninety children with NF1 and OPG was performed using data from two large NF1 referral centers. Age at diagnosis, presenting symptoms, tumor location, associated features, and clinical response were assessed for children who were initially symptomatic from their OPG (n = 51) and compared to similar data of asymptomatic children whose tumors were incidentally discovered by MRI (n = 39). There were no differences in age at presentation, tumor location, NF1‐associated symptoms, or clinical response between the groups. Initially symptomatic children were much more likely to require treatment (OR: 14.8, 95% CI [1.9–116.7]) than those with incidentally discovered, asymptomatic OPG. Although 36% of OPG were diagnosed in children over the age of 6 years, none received prior neuroimaging and only two children had previously normal eye examinations, suggesting that the vast majority of OPG in this group were longstanding, undiagnosed tumors. Based on these findings, we do not advocate “baseline” MRI in children with NF1, but strongly recommend that all children of the age 10 years and younger with NF1 have complete annual ophthalmologic evaluations.

Late-onset optic pathway tumors in children with neurofibromatosis 1

Identification of new optic pathway tumors (OPTs) and progression of pre-existing OPTs in children with neurofibromatosis 1 (NF1) have been reported infrequently after age 6. The authors present eight children with NF1 (mean age 12.2 years) seen in three NF1 centers who had either late-onset (four of eight) or late-progressive (seven of eight) OPT. Continued monitoring of individuals with NF1 into adulthood for the development of OPTs and for progression of known OPTs is warranted.