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Purpose/Aim: Acquired neuromyotonia or Isaacs syndrome is a type of peripheral nerve hyperexcitability of autoimmune origin. It may occur as an isolated, paraneoplastic or accompanied with some autoimmune diseases. This report describes acquired neuromyotonia in a child with a new reported association with vitamin D deficiency. Case report: A 9-year-old child, in whom the diagnosis of acquired neuromyotonia was made by clinical and typical electromyographic findings. All paraneoplastic and autoimmune workup was normal, except for a vitamin D deficiency state. A dramatic improvement was recorded on both clinical and electrophysiological base after vitamin D replacement. Conclusion: An in-depth future analysis of vitamin D status in patients with neuromyotonia will help to establish whether the association of neuromyotonia with vitamin D deficiency is casual or whether these two conditions may be causally related.

Ocular neuromyotonia (ONM) is a rare eye movement disorder, presenting as a paroxysmal involuntary spasm of one or more extra-ocular muscles, that can persist for a few seconds up to several minutes. The phenomenon is caused by the contraction of an extra-ocular muscle, excited by a damaged nerve, which leads to delayed muscle relaxation. We present eight patients with this rare condition together with an overview of the literature on all published ONM cases. One of the presented cases is possibly secondary to hypovitaminosis D. This association has not been reported previously in the literature. A possible underlying mechanism is given.

Ocular neuromyotonia is an uncommon disorder resulting from episodic involuntary discharge of ocular motor nerves producing sustained contraction of their respective ocular muscles. Ocular neuromyotonia manifests in brief spells of diplopia occurring spontaneously or after eccentric gaze holding. In most cases, ocular neuromyotonia follows months or years after radiotherapy to the sellar and parasellar region and involves the oculomotor nerve. We report two unusual cases of abducens nerve ocular neuromyotonia that followed radiation therapy of tumors in areas other than the sellar or parasellar region.

Ocular neuromyotonia is a rare motility disorder occurring after tumor irradiation near the skull base or as a consequence of vascular abnormalities. Ocular myasthenia, convergence spasm and a cyclic third nerve palsy must be considered as differential diagnoses. The case of a 32-year-old woman suffering from intermittent diplopia six months after radiation therapy of a recurrent pituary gland adenoma is presented.