Acquired neuromyotonia in children with CASPR2 and LGI1 antibodies

Acquired neuromyotonia is a form of peripheral nerve hyperexcitability. In adults, pathogenic antibodies that target the extracellular domains of leucine-rich glioma-inactivated protein 1 (LGI1) and contactin-associated protein-like 2 (CASPR2) have been reported. We describe three paediatric patients with acquired neuromyotonia and CASPR2 and LGI1 serum antibodies. They all presented with acute-onset myokymia and pain in the lower limbs; one patient also had muscle weakness. Electromyography was suggestive of peripheral nerve hyperexcitability. Two patients improved without immunotherapy; one treated patient remained immunotherapy-dependent. Although not fatal, acquired paediatric neuromyotonia can be disabling. It is amenable to symptomatic treatment or may undergo spontaneous recovery. More severe cases may require rational immunotherapy. What this paper adds: The symptoms of neuromyotonia may resolve spontaneously or may require sodium channel blockers. Patients with debilitating symptoms who are refractory to symptomatic therapy may require immunotherapy

Ophthalmoplegic "Migraine" or Recurrent Ophthalmoplegic Cranial Neuropathy:New Cases and a Systematic Review

Ophthalmoplegic migraine is a poorly understood neurologic syndrome characterized by recurrent bouts of head pain and ophthalmoplegia. By reviewing cases presenting to our centers in whom the phenotype has been carefully dissected, and systematically reviewing all published cases of ophthalmoplegic migraine in the magnetic resonance imaging (MRI) era, this review sets out to clearly define the syndrome and discuss possible etiologies. We found that in up to one-third of patients, the headache was not migrainous or associated with migrainous symptoms. In three-quarters of the cases involving the third nerve, there was focal nerve thickening and contrast enhancement on MRI. Observational data suggest systemic corticosteroids may be beneficial acutely. The etiology remains unclear, but may involve recurrent bouts of demyelination of the oculomotor nerve. “Ophthalmoplegic migraine” is a misnomer in that it is probably not a variant of migraine but rather a recurrent cranial neuralgia. A more appropriate name might be “ophthalmoplegic cranial neuropathy.