Neuromyotonia

INTRODUCTION: Recessive mutations in the gene encoding the histidine triad nucleotide-binding protein 1 (HINT1) are associated with axonal motor-predominant Charcot-Marie-Tooth (CMT) disease with neuromyotonia. A total of 24 HINT1 gene mutations have been reported so far. Some of these cases had mild to moderate elevations of creatinine kinase with no earlier reports of muscle biopsy findings in these cases. In this study, we describe a patient with axonal motor-predominant neuropathy and myopathy with rimmed vacuoles, likely due to a novel HINT1 gene mutation...

We illustrate the case of a 71-year-old male who initially presented with sudden onset muscle weakness and ambulation difficulty. Following medication discontinuation and additional clinical studies, he failed to improve and was admitted to the hospital 11 weeks later. He had an associated 20-pound weight loss, sudorrhea, and muscle stiffness only when weight-bearing. A complete connective tissue cascade and a paraneoplastic panel were obtained. Clinical diagnosis of acquired neuromyotonia, or Isaacs syndrome (IS), was made, and he began experiencing significant improvement after intravenous steroid infusion...

BACKGROUND: Apart from myasthenia gravis (MG), thymoma is associated with a wide spectrum of autoimmune paraneoplastic syndromes (PNSs). Here, we report on a rare case presenting with four different PNSs, namely, MG, membranous nephropathy, cutaneous amyloidosis, and Morvan's syndrome associated with thymoma. CASE PRESENTATION: A middle-aged man was frequently hospitalized because of nephrotic syndrome (stage I membranous nephropathy), cutaneous amyloidosis, and MG with acetylcholine receptor (AChR) antibody and titin antibody positivity...

We presented a 23-year-old patient who had experienced neuromyotonia in his left leg. Although he tested negative for anti-LGI1 and anti-CASPR2 antibodies, we diagnosed him with Isaacs syndrome due to myokymic discharges on electromyography and symptoms being relieved by intravenous methylprednisolone (IVMP) and intravenous immunoglobulin (IVIg). IVMP, IVIg, plasma exchange, or cyclosporine treatment did not provide a long-term response; however, rituximab showed long-term improvement. Rituximab should be considered early in the treatment of patients with antibody-negative Isaacs syndrome who are responsive to immunotherapy, including IVMP, IVIg, and plasma exchange, and have long-term symptoms that are hard to control...

BACKGROUND: Recessive loss-of-function variations in HINT1 cause a peculiar subtype of Charcot-Marie-Tooth disease: neuromyotonia and axonal neuropathy (NMAN; OMIM[#137200]). With 25 causal variants identified worldwide, HINT1 mutations are among the most common causes of recessive neuropathy. The majority of patients are compound heterozygous or homozygous for a Slavic founder variant (c.110G>C, p.Arg37Pro) that has spread throughout Eurasia and America. RESULTS: In a cohort of 46 genetically unresolved Lithuanian patients with suspected inherited neuropathy, we identified eight families with HINT1 biallelic variations...

PURPOSE OF REVIEW: Autoimmune neuromyotonia encompasses a group of rare immune-mediated neurological disorders frequently associated with anti-contactin-associated protein-like 2 (CASPR2) antibodies and featuring clinical and electrical signs of peripheral nerve hyperexcitability (PNH). We aim to summarize the current knowledge on immune-mediated neuromyotonia, focusing on clinical presentations, pathophysiology, and management. RECENT FINDINGS: Neuromyotonia is a major feature of several autoimmune neurological syndromes characterized by PNH with or without central neurological system involvement...

Morvan's syndrome (MoS) is a rare, complex neurological disorder characterized by neuromyotonia, neuropsychiatric features, dysautonomia, and neuropathic pain. The majority of MoS cases have a paraneoplastic etiology, most commonly thymoma, usually occurring before the diagnosis of the underlying tumor and showing improvement following surgery. We present a case of 60-year-old patient presenting with suspicious of MoS and autoimmune encephalitis (AE), F-18 fluorodeoxyglucose positron emission tomography/computed tomography as single imaging modality detected and confirmed both AE and thymoma...

PURPOSE OF REVIEW: The current review will cover the clinical presentation, causes, epidemiology, differential diagnoses, workup, and treatment of ocular neuromyotonia (ONM) in detail. RECENT FINDINGS: While ONM largely remains a unilateral eye movement disease affecting adults with a history of sellar radiation, recent case reports highlight an expansion of this presentation to include bilateral, pediatric, and congenital cases. SUMMARY: ONM is a rare but recognizable ocular motility disorder involving sustained contraction of the extraocular muscle, commonly resulting in intermittent diplopia...

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We describe a patient who presented with fatigue and pulling sensation in his lower limbs. He had continuous muscle contractions over his trunk (myokymia) which pointed towards the diagnosis of Isaacs syndrome which was confirmed by strongly positive CASPR2 antibodies in blood.

Neuromyotonia is a rare peripheral nerve hyperexcitability syndrome often associated with antibodies directed against contactin-associated protein-like 2 and leucine-rich, glioma inactivated 1. The quadrivalent human papilloma virus vaccine Gardasil® , first approved in 2006, is known to be a highly effective prophylaxis against papillomavirus types 6, 11, 16, and 18. Molecularly, this non-infectious recombinant vaccine is based on purified L1 proteins from the human papilloma virus capsid. Since the approval of this vaccine, several studies have investigated its safety regarding the occurrence of autoimmune conditions following application...

Inherited peripheral neuropathy (IPN) is a heterogeneous group of disorders due to pathogenic variation in more than 100 genes. In 2012, the first cases of IPN associated with HINT1 pathogenic variations were described in 33 families sharing the same phenotype characterized by an axonal neuropathy with neuromyotonia and autosomal recessive inheritance (NMAN: OMIM #137200). Histidine Triad Nucleotide Binding Protein 1 regulates transcription, cell-cycle control, and is possibly involved in neuropsychiatric pathophysiology...

The term "la chorιe fibrillare" was used by the French physician Augustine Marie Morvan to describe a syndrome showing hyperactivity features involving the central, autonomic, and peripheral nervous system. The central hyperactivity symptoms are confusion, behavioral problems, hallucinations, myoclonus, and insomnia; the autonomic hyperactivity symptoms are hyperhidrosis and variations in blood pressure; and peripheral hyperexcitability is characterized by painful cramps, myokymia, and neuromyotonia. Here, we present a case that has typical features of Morvan's syndrome and provides a brief description based on available literature...

Autoantibody encephalitis causes distinct clinical syndromes involving alterations in mentation, abnormal movements, seizures, psychiatric symptoms, sleep disruption, spasms, and neuromyotonia. The diagnoses can be confirmed by specific antibody tests, although some antibodies may be better detected in spinal fluid and others in serum. Each disorder conveys a risk of certain tumors which may inform diagnosis and be important for treatment. Autoantibodies to receptors and other neuronal membrane proteins are generally thought to be pathogenic and result in loss of function of the targets, so understanding the pharmacology of the receptors may inform our understanding of the syndromes...

INTRODUCTION: The first report of oculomotor neuromyotonia (ONM) in a child induced by thyroid peroxidase antibodies (anti-TPO) in the absence of thyroid eye disease (TED). CASE: 14-year-old girl complained of left eye (LE) paroxysmal upper lid fluttering and ptosis precipitated by hyperventilation or sustained left gaze. On sustained left gaze, right eye (RE) upper lid retraction and LE upper lid fluttering with ptosis ensued. RESULTS: Diagnostic work-up revealed markedly elevated anti-TPO (> 600 IU/ml) and no TED...

INTRODUCTION: Autosomal recessive axonal neuropathy with neuromyotonia (ARAN-NM) is a rare disease entity linked to mutations in the histidine triad nucleotide binding protein 1 (HINT1) gene. The diagnosis and treatment of ARAN-NM are challenging. There have been few reports of ARAN-NM in East Asia. METHODS: A 15-year-old Chinese ARAN-NM patient developed muscle weakness, cramps and atrophy in the lower limbs at the age of 12. Electromyography (EMG) showed motor axonal degeneration and neuromyotonic discharges...

Neurovascular syndrome is a dysfunction of an individual cranial nerve which is compressed by vessels. Several neurovascular compression syndromes are well known such as trigeminal neuralgia, hemifacial spasm, and glossopharyngeal neuralgia. Having neurovascular conflicts at oculomotor nerves and abducens nerve cause ocular neuromyotonia and abducens nerve palsy. Site of compression is still controversial because of unclear definition. The term root entry/ exit zone (REZ) is defined variously and used interchangeably with transitional zone making it hard to compare between studies...

BACKGROUND: HINT1 mutations cause an autosomal recessive axonal neuropathy with neuromyotonia. This is a first case report of coexistence of myasthenia gravis (MG) and HINT1-related motor axonal neuropathy without neuromyotonia. CASE PRESENTATION: A 32-year-old woman presented with recurrent ptosis for 8 years, diplopia for 2 years and limb weakness for 1 year and a half. Neostigmine test, elevated AChR antibody level and positive repetitive nerve stimulation supported the diagnosis of MG...

Objectives: The clinical data of patients with double-positive for leucine-rich glioma-inactivated protein 1 (LGI1) and contactin-associated protein-like 2 (CASPR2) antibodies is limited, particularly for children. This study aimed to investigate and summarize the clinical features and long-term prognosis of children's LGI1 and CASPR2 antibodies related to neurological disorders. Methods: We collected the clinical data and prognosis of patients with dual positive antibodies of CASPR2 and LGI1, hospitalized in the Department of Neurology, Children's Hospital of Chongqing Medical University...