The complement system is a tightly controlled signaling network that plays a role in innate immune surveillance. However, abnormal signaling through this pathway contributes to tissue damage in several inflammatory, autoimmune, and degenerative diseases. Myasthenia gravis (MG) and neuromyelitis optica spectrum disorders (NMOSD) have complement dysfunction at the core of pathogenesis, providing a strong rationale for therapeutic targeting of complement components. The purpose of this paper is to briefly review the role of complement activation in the pathogenesis of MG and NMOSD, to discuss the rationale and evidence for complement inhibition as a method to manage these diseases, and to provide a Canadian perspective on the use of complement inhibition therapy through real-world cases of MG and NMOSD.

To explore whether higher degrees of electrophysiological abnormalities are associated with a more frequent exposure to a more aggressive treatment regimen, we performed a retrospective chart review of patients attending the neuromuscular clinic from June 2012 to December 2015 and included 87 patients. We compared treatment regimens during the follow-up period between patients with high and low jitter and decrement. Myasthenia gravis patients with high jitter or decrement at baseline were more frequently treated with intravenous immunoglobulins (IVIG) and/or plasma exchange (PLEX) during the follow-up period. In patients with mild disease, IVIG or PLEX treatment was associated with high decrement.

Background: Myasthenia gravis (MG) is an autoimmune disorder of the neuromuscular junction in which a clinical diagnosis may be confirmed with serological testing. The most common autoantibodies used to support a diagnosis of MG are anti-acetylcholine receptor antibodies and anti-muscle-specific tyrosine kinase antibodies. In cases in which both of these autoantibodies are negative (termed double-seronegative [dSNMG]), other autoantibodies such as low-density lipoprotein receptor-related protein 4 (LRP4) may be used to aid in diagnosis. Methods: We have undertaken a systematic literature review to identify studies that have assessed the frequency of anti-LRP4 antibodies in dSNMG patients and the characteristics of anti-LRP4+ dSNMG patients (epidemiology, clinical features, electromyographic findings, or management). PubMed, EMBASE, Medline, and Scopus were searched on January 14, 2017, using the medical subject headings “myasthenia gravis” and “low-density lipoprotein receptor-related protein 4” or “LRP4.” Results: The initial search identified 367 articles. Fourteen publications met the inclusion criteria. There were ten cross-sectional research studies, three were case series, and one was a case report. The majority of studies were limited by small sample sizes of LRP4+ dSNMG. There has been a wide range of frequencies of anti-LRP4 antibodies detected in different MG patient populations, some involving different laboratory techniques. Conclusions: LRP4+ dSNMG is more likely than LRP4– dSNMG to have a younger onset of disease and occur in females. LRP4+ dSNMG most often is mild in severity and often involves isolated ocular weakness. It typically responds well to pyridostigmine or prednisone.

Lambert–Eaton syndrome (LES) is a rare immune-mediated disorder characterized by proximal leg weakness, autonomic symptoms and hypoactive tendon reflexes. The paraneoplastic form is associated with small-cell lung cancer in 50-60% of cases, whereas the remaining cases are found in younger adults with a higher likelihood of coexisting autoimmune disease. The early recognition of LES is crucial for improving clinical outcomes but remains a major challenge. In this review, we analyze the clinical characteristics and diagnostic considerations in treating LES through a series of three case studies, one of which showed definitive response to pyridostigmine and corticosteroid combination therapy, followed by spontaneous remission. Patients were assessed by image-based screening, serological testing and electrophysiological evaluations, which included respiratory and autonomic testing. A better understanding of the common pitfalls in the clinical, serological and neurophysiologic diagnosis of LES through assessment of typical LES dysfunction throughout the nervous system should enable improved recognition and treatment of this syndrome.

The assessment of facial expression is an important aspect of a clinical neurological examination, both as an indicator of a mood disorder and as a sign of neurological damage. To date, although studies have been conducted on certain psychosocial aspects of myasthenia, such as quality of life and anxiety, and on neuropsychological aspects such as memory, no studies have directly assessed facial emotion recognition accuracy. The aim of this study was to assess the facial emotion recognition accuracy (fear, surprise, sadness, happiness, anger, and disgust), empathy, and reaction time of patients with myasthenia. Thirty-five patients with myasthenia and 36 healthy controls were tested for their ability to differentiate emotional facial expressions. Participants were matched with respect to age, gender, and education level. Their ability to differentiate emotional facial expressions was evaluated using the computer-based program Feel Test. The data showed that myasthenic patients scored significantly lower (p < 0.05) than healthy controls in the total Feel score, fear, surprise, and higher reaction time. The findings suggest that the ability to recognize facial affect may be reduced in individuals with myasthenia.

Objectives: To demonstrate the importance of detailed clinical analysis in the differential diagnosis of unilateral vocal fold paralysis, and to provide an update on current knowledge and treatment of myasthenia gravis.

Case report: A female patient presented with left unilateral vocal fold immobility. Diagnostic investigation revealed a 10 mm thyroid adenoma, but no other abnormality likely to cause unilateral vocal fold paralysis. Follow-up flexible endoscopy at three months showed laryngeal remobilisation with persistent left vocal fold bowing and vertical asymmetry of the vocal folds on phonation. Over the following months, voice quality varied between normal and breathy, with the breathy periods lasting from three days to one month. Laryngeal electromyography (EMG) showed a slight bilateral paradoxical activation of both posterior crico-arytenoid muscles on phonation. Magnetic resonance imaging of the brain and brainstem was normal. A diagnostic test for myasthenia gravis with intravenous edrophonium bromide (Tensilon®) lead to an immediate improvement in voice quality. The patient was subsequently treated with pyridostigmine bromide, with complete resolution of dysphonia.

Conclusions: Myasthenia gravis affecting the larynx may mimic unilateral vocal fold paresis or paralysis. A personal or family history of auto-immune disease, fluctuating symptoms, motor deficits in cranial nerve territories, and normal or subnormal laryngeal EMG results should lead the physician to reconsider a diagnosis of idiopathic unilateral vocal fold paralysis and to perform specific testing.