Grant T. Liu

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

Revised diagnostic criteria for the pseudotumor cerebri syndrome in adults and children

The pseudotumor cerebri syndrome (PTCS) may be primary (idiopathic intracranial hypertension) or arise from an identifiable secondary cause. Characterization of typical neuroimaging abnormalities, clarification of normal opening pressure in children, and features distinguishing the syndrome of intracranial hypertension without papilledema from intracranial hypertension with papilledema have furthered our understanding of this disorder. We propose updated diagnostic criteria for PTCS to incorporate advances and insights into the disorder realized over the past 10 years.

EARLY COMMITMENT OF NEURAL SUBSTRATES FOR FACE RECOGNITION

We present evidence of a striking failure of plasticity in the neural substrates of face recognition, which suggests that the distinction between faces and other objects, and the localisation of faces relative to other objects, is fully determined prior to any postnatal experience. A boy who sustained brain damage at 1 day of age has the classic lesions and behavioural profile of adult-acquired prosopagnosia. He has profoundly impaired face recognition, whereas his recognition of objects is much less impaired. This implies that the human genome contains sufficiently explicit information about faces and nonface objects, or visual features by which they can be distinguished, that experience with these categories is not necessary for their functional delineation and differential brain localisation.

Reference Range for Cerebrospinal Fluid Opening Pressure in Children

To the Editor: A reference range for cerebrospinal fluid (CSF) opening pressure in children undergoing diagnostic lumbar puncture has not been established.1 The influence of age, body-mass index (B...

Visual loss in children with neurofibromatosis type 1 and optic pathway gliomas: relation to tumor location by magnetic resonance imaging.

PURPOSE To examine the potential for visual acuity loss, and its relation to extent and location of optic pathway gliomas in a cohort of children with neurofibromatosis type 1 studied with magnetic resonance imaging. METHODS We reviewed the neuro-ophthalmologic records and brain/orbital magnetic resonance imaging scans for 43 consecutive pediatric patients with neurofibromatosis type 1 and optic pathway gliomas who were followed at the Childrens Hospital of Philadelphia. The presence of visual loss, defined as abnormal visual acuity for age in one or both eyes, was determined. Optic pathway gliomas were classified by tumor extent and location according to involvement of the optic nerves, chiasm, and postchiasmal structures by magnetic resonance imaging. RESULTS Involvement of the optic tracts and other postchiasmal structures at tumor diagnosis was associated with a significantly higher probability of visual acuity loss (P =.048, chi-square test). Visual loss was noted in 20 of 43 patients (47%) at a median age of 4 years; however, three patients developed visual acuity loss for the first time during adolescence. CONCLUSIONS In pediatric patients with neurofibromatosis type 1 and optic pathway gliomas, the likelihood of visual loss is dependent on the extent and location of the tumor by magnetic resonance imaging and is particularly associated with involvement of postchiasmal structures. Furthermore, older age during childhood (adolescence) does not preclude the occurrence of visual loss. Close follow-up beyond the early childhood years, particularly for those with postchiasmal tumor, is recommended.

Idiopathic intracranial hypertension: Relation of age and obesity in children

Article abstract The relation between obesity and age in children with idiopathic intracranial hypertension (pseudotumor cerebri) has remained uncertain. The authors reviewed the records of 45 consecutive children with newly diagnosed idiopathic intracranial hypertension seen at two medical centers. Forty-three percent of patients aged 3 to 11 years were obese, whereas 81% of those in the 12- to 14-year age group and 91% of those in the 15- to 17-year age group met criteria for obesity (p = 0.01). Younger children with idiopathic intracranial hypertension are less likely to be obese than are older children or adults.

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.

High-dose Methylprednisolone and Acetazolamide for Visual Loss in Pseudotumor Cerebri

We treated four patients who had acute, severe visual loss associated with pseudotumor cerebri with intravenous methylprednisolone (250 mg four times per day) for five days followed by an oral taper, in combination with acetazolamide and ranitidine. In addition to high-grade disk edema, one patient had serous detachment of both maculas and lipid deposition, one had a unilateral macular star, and one had a monocular branch retinal artery occlusion. These three patients experienced rapid and lasting improvement in visual acuity, visual field, papilledema, and symptoms. Vision of the fourth patient did not improve, requiring optic nerve sheath fenestration for chronic papilledema. Transient acne developed in one patient. This regimen is a safe, effective treatment of acute, severe visual loss associated with florid papilledema of pseudotumor cerebri. Lack of immediate improvement is an indication for optic nerve sheath decompression.

Persistent positive visual phenomena in migraine

Article abstract-Ten patients with migraine developed persistent positive visual phenomena lasting months to years. The complaints were similar in their simplicity and involvement of the entire visual field and usually consisted of diffuse small particles such as TV static, snow, lines of ants, dots, and rain. Neurologic and ophthalmologic examinations were normal, and EEGs were normal in eight of eight patients tested. MRI was normal in all patients except one who had nonspecific biparietal white matter lesions and another with a small venous angioma. Treatment of this unusual complication of migraine was unsuccessful. NEUROLOGY 1995;45: 664-668

Sixth nerve palsies in children

The causes of sixth nerve palsies in 75 children, all of whom had undergone modern neuroimaging, were reviewed. Neoplasms or their neurosurgical removal was the most common cause (n = 34 [45%]); elevated intracranial pressure (nontumor) (15%), traumatic (12%), congenital (11%), inflammatory (7%), miscellaneous (5%), and idiopathic (5%) causes represented other categories but were less commonly present. Isolated sixth nerve palsies were relatively uncommon (9%). On the basis of the relatively high risk of neoplasm, the authors suggest neuroimaging early in the clinical course of children with sixth nerve palsies, even if the palsy is isolated.