Consensus recommendations for the assessment and management of idiopathic intracranial hypertension in children and young people.

BACKGROUND: Idiopathic intracranial hypertension (IIH) is a potentially disabling condition. There is a lack of evidence and national guidance on how to diagnose and treat paediatric IIH, leading to variation in clinical practice. We conducted a national Delphi consensus via the Children's Headache Network to propose a best-practice diagnostic and therapeutic pathway. METHODS: The Delphi process was selected as the most appropriate methodology for examining current opinion among experts in the UK. 104 questions were considered by 66 healthcare professionals, addressing important aspects of IIH care: assessment, diagnosis, treatment, follow-up and surveillance. General paediatricians, paediatric neurologists, ophthalmologists, opticians, neuroradiologists and neurosurgeons with a clinical interest or experience in IIH, were invited to take part. RESULTS: The Delphi process consisted of three rounds comprising 104 questions (round 1, 67; round 2, 24; round 3 (ophthalmological), 13) and was completed between March 2019 and August 2021. There were 54 and 65 responders in the first and second rounds, respectively. The Delphi was endorsed by the Royal College of Ophthalmologists, which engaged 59 ophthalmologists for round 3. CONCLUSIONS: This UK-based Delphi consensus process reached agreement for the management of paediatric IIH and has been endorsed by the Children's Headache Network and more broadly, the British Paediatric Neurology Association. It provides a basis for a pragmatic clinical approach. The recommendations will help to improve clinical care while minimising under and over diagnosis.

RYR1-related malignant hyperthermia with marked cerebellar involvement - a paradigm of heat-induced CNS injury?

Heat-induced CNS injury has been recognized for more than 50 years but the biological basis for the marked selectivity of CNS damage is currently uncertain. We present clinical, imaging, autopsy and genetic findings of a 14-year-old male who developed fatal cerebellar swelling in the course of a malignant hyperthermia (MH) episode caused by triggering anaesthetics. Unaccustomed intense exercise in the days prior to general anaesthesia was a probable confounding factor for the MH reaction. Autopsy findings demonstrated pronounced degeneration of cerebellar Purkinje cells. Post mortem genetic analysis revealed a mutation (c.6502G>A; p.Val2168Met) in the skeletal muscle ryanodine receptor (RYR1) gene previously associated with the MH trait. RYR1 mutations appear to be associated with heat-induced CNS injury in a distribution compatible with known expression pattern of the RyR1 isoform in cerebellar Purkinje cells. Recent exercise in genetically predisposed individuals may prime abnormal muscle prior to general anaesthesia and contribute to the severity of MH reactions.

SURF1 deficiency: a multi-centre natural history study.

BACKGROUND: SURF1 deficiency, a monogenic mitochondrial disorder, is the most frequent cause of cytochrome c oxidase (COX) deficient Leigh syndrome (LS). We report the first natural history study of SURF1 deficiency. METHODS: We conducted a multi-centre case notes review of 44 SURF1-deficient patients from ten different UK centres and two Australian centres. Survival data for LRPPRC-deficient LS and nuclear-encoded complex I-deficient LS patients were obtained from previous publications. The survival of SURF1-deficient patients was compared with these two groups using Kaplan-Meier survival analysis and logrank test. RESULTS: The majority of patients (32/44, 73%) presented in infancy (median 9.5 months). Frequent symptoms were poor weight gain (95%, median age 10 months), hypotonia (93%, median age 14 months), poor feeding/vomiting (89%, median age 10 months), developmental delay (88%, median age 14 months), developmental regression (71%, median age 19 months), movement disorder (52%, median age 24 months), oculomotor involvement (52%, median age 29 months) and central respiratory failure (78%, median age 31 months). Hypertrichosis (41%), optic atrophy (23%), encephalopathy (20%), seizures (14%) and cardiomyopathy (2%) were observed less frequently. CONCLUSIONS: SURF1-deficient patients have a homogeneous clinical and biochemical phenotype. Early recognition is essential to expedite diagnosis and enable prenatal diagnosis.

Narcolepsy with cataplexy as presenting symptom of occult neuroblastoma.

Neuroblastoma associated with the paraneoplastic syndrome of opsoclonus-myoclonus is well-described. However, presentation with narcolepsy-cataplexy is not well-documented in the literature. Narcolepsy with cataplexy is also rare in children younger than 5 years of age. Here we describe three patients, each presenting in early childhood with complex neurological symptoms including narcolepsy with cataplexy that were subsequently found to have paraspinal neuroblastoma. In two of the cases, neurological symptoms resolved with treatment of the tumor and/or immunosuppression, but in one case, the child persistently had a devastating course despite complete resection of the tumor and aggressive immunosuppression.

Basilar artery dolichoectasia in childhood: evidence of vascular compromise.

INTRODUCTION: Dolichoectasia describes the elongation, dilatation and tortuosity of an arterial vessel. In adults, clinical presentation of basilar dolichoectasia (BD) is most often with ischaemic stroke. True BD has been very rarely reported in childhood, but the implication is of a congenital susceptibility. CASE REPORT: We describe two cases of infants with BD complicated by brainstem ischaemia. DISCUSSION: This first description of childhood BD associated with ischaemic infarction adds to the understanding of this rarely reported arteriopathy.

Infantile onset myofibrillar myopathy due to recessive CRYAB mutations.

Mutations in the αB-crystallin (CRYAB) gene, encoding a small heat shock protein with chaperone function, are a rare cause of myofibrillar myopathy with autosomal-dominant inheritance, late-onset and moderate severity. We report a female infant presenting from 4 months with profound muscle stiffness, persistent creatine kinase elevation and electromyography characterized by spontaneous electrical activity and pseudomyotonic discharges. Muscle biopsy suggested a myofibrillar myopathy and genetic testing revealed homozygosity for the CRYAB mutation c.343delT (p.Ser115ProfsX14). These findings suggest a severe, recessively inherited form of CRYAB-related myofibrillar myopathy. Profound muscle stiffness as the main presenting feature indicates αB-crystallin as a potent modifier of muscle contractility.

Congenital muscular dystrophy, myasthenic symptoms and epidermolysis bullosa simplex (EBS) associated with mutations in the PLEC1 gene encoding plectin.

Mutations in the PLEC1 gene encoding plectin have been reported in neonatal epidermolysis bullosa simplex with muscular dystrophy of later-onset (EBS-MD). A neuromuscular transmission defect has been reported in one previous patient. We report a boy presenting from birth with features of a congenital muscular dystrophy and late-onset myasthenic symptoms. Repetitive nerve stimulation showed significant decrement, and strength improved with pyridostigmine. Subtle blistering noticed only retrospectively prompted further genetic testing, revealing recessive PLEC1 mutations. We conclude that PLEC1 should be considered in the differential diagnosis of congenital muscular dystrophies and myasthenic syndromes, even in the absence of prominent skin involvement.

Benefit of corticosteroid therapy in Angelman syndrome.

Angelman syndrome is often associated with an intractable seizure disorder. We describe 4 children who demonstrated an excellent response to corticosteroid therapy. The benefits included not only reduction in clinical seizures but also modification of the "typical'' Angelman electroencephalogram. In addition, there was improvement in the myoclonic jerks, sleep pattern, and developmental progress. Corticosteroids appeared to have a broad benefit on the epileptic encephalopathy. We believe that these cases pose a challenge to the conventional management of intractable epilepsy in Angelman syndrome.

High-dose riboflavin for migraine prophylaxis in children: a double-blind, randomized, placebo-controlled trial.

This is the first study to evaluate the efficacy of riboflavin for migraine prophylaxis in children. This was a randomized, double-blind study of riboflavin (200 mg daily) versus placebo in 48 children. The primary efficacy measure was the number of patients achieving a 50% or greater reduction in the number of migraine attacks per 4 weeks. Other outcome measures were the mean severity of migraine per day, mean duration of migraine, days with nausea or vomiting, analgesic use, and adverse effects. A 50% or greater reduction in headaches was seen in 14/21 patients in the placebo group and 12/27 patients in the riboflavin group (not significant P = .125). There were no differences between riboflavin and placebo for primary or secondary outcome variables. These results suggest that riboflavin is not an effective therapy for preventing migraine in children. A high placebo responder rate was seen, with implications for other studies of migraine in children.