Role of gadolinium-based contrast agents in neurological disorders

Managing Headache Disorders Associated with Tuberous Sclerosis and Neurofibromatosis

PURPOSE OF REVIEW

Tuberous sclerosis complex (TSC) and neurofibromatosis (NF) are neurocutaneous disorders often encountered by neurologists in clinical practice. This article aims to familiarize adult and pediatric neurologists with common features of these disorders and headache specific evaluation and management.

RECENT FINDINGS

Non-malignant intracranial tumors in TSC include cortical tubers (glioneuronal hamartomas), subependymal nodules or subependymal giant-cell astrocytomas (SEGA). Headache disorders in TSC are largely secondary and can cause headaches due to increased intracranial pressure, mass effect, obstructive hydrocephalus, or hemorrhage. Neurosurgical intervention is typically required for management of large SEGAs; however, in patients with increased surgical risk, newer treatment modalities may be offered such as neoadjuvant therapy with an mTOR inhibitor (mTORi). Newer studies indicate headache disorders are more prevalent in neurofibromatosis type 1 (NF1). Primary headache disorders can include migraine and tension-type headache, while secondary headache disorders can be due to associated neoplasms such as optic pathway gliomas or brainstem gliomas, or less commonly vasculopathies such as moyamoya syndrome. Selumetinib is an oral, small molecule mitogen-activated protein kinase (MEK) agent with antineoplastic activity which is in ongoing trials for treatment of NF1-associated pediatric low-grade gliomas. NF1 stands out as having a higher association with primary headache disorders such as migraine. This association may be related to effects of mutation of the neurofibromin gene on pathways involved in pain and migraine genesis, however, warrants future study. Care should be taken when formulating a headache treatment plan to address comorbidities and avoid medications that may be contraindicated.

Updated International Tuberous Sclerosis Complex Diagnostic Criteria and Surveillance and Management Recommendations

BACKGROUND

Tuberous sclerosis complex (TSC) is an autosomal dominant genetic disease affecting multiple body systems with wide variability in presentation. In 2013, Pediatric Neurology published articles outlining updated diagnostic criteria and recommendations for surveillance and management of disease manifestations. Advances in knowledge and approvals of new therapies necessitated a revision of those criteria and recommendations.

METHODS

Chairs and working group cochairs from the 2012 International TSC Consensus Group were invited to meet face-to-face over two days at the 2018 World TSC Conference on July 25 and 26 in Dallas, TX, USA. Before the meeting, working group cochairs worked with group members via e-mail and telephone to (1) review TSC literature since the 2013 publication, (2) confirm or amend prior recommendations, and (3) provide new recommendations as required.

RESULTS

Only two changes were made to clinical diagnostic criteria reported in 2013: "multiple cortical tubers and/or radial migration lines" replaced the more general term "cortical dysplasias," and sclerotic bone lesions were reinstated as a minor criterion. Genetic diagnostic criteria were reaffirmed, including highlighting recent findings that some individuals with TSC are genetically mosaic for variants in TSC1 or TSC2. Changes to surveillance and management criteria largely reflected increased emphasis on early screening for electroencephalographic abnormalities, enhanced surveillance and management of TSC-associated neuropsychiatric disorders, and new medication approvals.

CONCLUSIONS

Updated TSC diagnostic criteria and surveillance and management recommendations presented here should provide an improved framework for optimal care of those living with TSC and their families.

Investigation of suspected gadolinium neurotoxicity in a dog

Gadolinium-based contrast agents are used across species to better visualize abnormalities during MRI and are considered generally safe in clinical practice. The aim of this study was to investigate central nervous system (CNS) gadolinium deposition in 11 dogs that had an MRI performed, received 0.22 mL/kg (0.1 mmol/kg) of gadopentetate dimeglumine, and were necropsied on the same hospital admission. The index case was a 5-year-old castrated male Australian Shepherd that presented for ataxia and following MRI developed seizure-like activity that became refractory to anticonvulsant therapy. Gadolinium concentration was quantified in CNS tissues by inductively-coupled plasma mass spectrometry and was 43-fold higher in the index case. These findings suggest the possibility of gadolinium toxicity in select patients.