Therapeutic and Diagnostic Challenges in Myasthenia Gravis

Case Report: Treatment of Myasthenic Ptosis with Topical Ocular Oxymetazoline

SIGNIFICANCE

Ptosis is often the hallmark finding in ocular and general myasthenia gravis. Reduction of ptosis has been achieved with oral and topical ocular medications. However, these medications can result in systemic and ocular adverse effects. A novel eye drop seems to be effective in reducing ptosis while minimizing adverse effects.

PURPOSE

This case report aimed to demonstrate the efficacy of topical oxymetazoline hydrochloride 0.1%, an α-adrenergic agonist, in temporary elimination of ptosis associated with myasthenia gravis.

CASE REPORT

A 68-year-old woman with a history of myasthenia gravis and long-standing ptosis in the right eye presented to improve the asymmetrical appearance of her eyelids. One drop of oxymetazoline hydrochloride 0.1% was instilled in the right eye of the patient. Within 2 hours, the ptosis was eliminated, the margin-reflex distance 1 increased by 2.0 mm, and the superior visual field measured by a superior 36-point screening test increased by 15 points. The effect lasted for at least 7 hours. Of note, there was a decrease in elevation of the contralateral nonptotic eyelid that did not receive a drop of oxymetazoline, which might occur only in myasthenia gravis. Further evaluation is warranted.

CONCLUSIONS

Oxymetazoline 0.1% is effective in reducing and potentially eliminating ptosis related to ocular myasthenia gravis for up to 7 hours.

Gastrointestinal dysfunction in neuroinflammatory diseases: Multiple sclerosis, neuromyelitis optica, acute autonomic ganglionopathy and related conditions

Disorders of the nervous system can produce a variety of gastrointestinal (GI) dysfunctions. Among these, lesions in various brain structures can cause appetite loss (hypothalamus), decreased peristalsis (presumably the basal ganglia, pontine defecation center/Barrington's nucleus), decreased abdominal strain (presumably parabrachial nucleus/Kolliker-Fuse nucleus) and hiccupping and vomiting (area postrema/dorsal vagal complex). In addition, decreased peristalsis with/without loss of bowel sensation can be caused by lesions of the spinal long tracts and the intermediolateral nucleus or of the peripheral nerves and myenteric plexus. Recently, neural diseases of inflammatory etiology, particularly those affecting the PNS, are being recognized to contribute to GI dysfunction. Here, we review neuroinflammatory diseases that potentially cause GI dysfunction. Among such CNS diseases are multiple sclerosis, neuromyelitis optica spectrum disorder, myelin oligodendrocyte glycoprotein associated disorder, and autoimmune encephalitis. Peripheral nervous system diseases impacting the gut include Guillain-Barre syndrome, chronic inflammatory demyelinating polyneuropathy, acute sensory-autonomic neuropathy/acute motor-sensory-autonomic neuropathy, acute autonomic ganglionopathy, myasthenia gravis and acute autonomic neuropathy with paraneoplastic syndrome. Finally, collagen diseases, such as Sjogren syndrome and systemic sclerosis, and celiac disease affect both CNS and PNS. These neuro-associated GI dysfunctions may predate or present concurrently with brain, spinal cord or peripheral nerve dysfunction. Such patients may visit gastroenterologists or physicians first, before the neurological diagnosis is made. Therefore, awareness of these phenomena among general practitioners and collaboration between gastroenterologists and neurologists are highly recommended in order for their early diagnosis and optimal management, as well as for systematic documentation of their presentations and treatment.

Immunopathology of Autoimmune Myasthenia Gravis: Implications for Improved Testing Algorithms and Treatment Strategies

Myasthenia gravis (MG) is a heterogeneous condition, characterized by autoantibodies (Abs) that target functionally important structures within neuromuscular junctions (NMJ), thus affecting nerve-to-muscle transmission. MG patients are more often now subgrouped based on the profile of serum autoantibodies, which segregate with clinical presentation, immunopathology, and their response to therapies. The serological testing plays an essential role in confirming MG diagnosis and guiding disease management, although a small percentage of MG patients remain negative for antibodies. With the advancements in new highly effective pathophysiologically-specific immunotherapeutic options, it has become increasingly important to identify the specific Abs responsible for the pathogenicity in individual MG patients. There are several new assays and protocols being developed for the improved detection of Abs in MG patients. This review focuses on the divergent immunopathological mechanisms in MG, and discusses their relevance to improved diagnostic and treatment. We propose a comprehensive "reflex testing," algorithm for the presence of MG autoantibodies, and foresee that in the near future, the convenience and specificity of novel assays will permit the clinicians to consider them into routine systematic testing, thus stimulating laboratories to make these tests available. Moreover, adopting treatment driven testing algorithms will be crucial to identify subgroups of patients potentially benefiting from novel immunotherapies for MG.