SHM Converge Scientific Abstract ePoster Gallery-Pins and Needles: A Case of Neuromyotonia Presenting as Subacute Pain

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This case describes a 39-year-old woman with 2 months of severe generalized pain, muscle spasms, diffuse twitching, weight loss, restlessness, hyperreflexia, diaphoresis, and myokymia. Her symptoms were initially treated with gabapentin and analgesics with minimal benefit. Laboratory testing showed mildly elevated creatine kinase, positive voltage-gated potassium channel (VGKC) antibodies, and negative inflammatory myositis studies. EMG demonstrated myokymic and repetitive discharges, supporting the diagnosis of Isaac’s syndrome (acquired neuromyotonia).<br /><br />Neuromyotonia is a rare peripheral nerve hyperexcitability disorder characterized by muscle cramps, fasciculations, delayed relaxation, and sometimes autonomic symptoms such as sweating, orthostatic hypotension, or constipation. It can be associated with autoimmune disease, malignancy, toxin exposure, or may be idiopathic. VGKC-complex antibodies, especially against CASPR2 and related proteins, are found in many cases and are thought to cause abnormal nerve excitability and excessive acetylcholine release.<br /><br />Because neuromyotonia may be paraneoplastic or autoimmune, the patient underwent extensive evaluation including CT scans of the chest, abdomen, and pelvis, PET imaging, lumbar puncture, and MRI of the brain and cervical spine. These studies did not reveal malignancy or infection.<br /><br />She was treated with 5 days of IV methylprednisolone followed by a 3-week taper, with improvement in symptoms. Psychiatry and psychology were also involved in care. She was discharged with outpatient follow-up in pain management, neurology, and a neuromuscular clinic.<br /><br />The key lesson is that Isaac’s syndrome can present as chronic or subacute pain with muscle twitching and spasms. In patients with neuromuscular symptoms and elevated CK, neuromyotonia should be considered and evaluated with antibody testing and EMG. Treatment may include immunotherapy such as corticosteroids, IVIG, or plasmapheresis, along with symptomatic agents like carbamazepine, phenytoin, diazepam, or gabapentin.

Asset Subtitle

Lora Greene Sowunmi

Meta Tag

Author List Lora Greene Sowunmi

Category Clinical Vignettes

Concept Neuromyotonia

Concept Peripheral Nerve Hyperexcitability

Concept Muscle Spasm

Concept Myokymia

Concept Electromyography

Distinguished Non-Finalist

Presenter Organization Cleveland Clinic

Presenting Author Lora Greene Sowunmi

Track Adult

Keywords

Isaac's syndrome

acquired neuromyotonia

VGKC antibodies

myokymia

muscle spasms

neuromuscular hyperexcitability

EMG

corticosteroid therapy

autoimmune disorder

peripheral nerve hyperexcitability

Neuromyotonia

Peripheral Nerve Hyperexcitability

Muscle Spasm

Myokymia

Electromyography