A Case of MuSK Myasthenia Gravis Presenting With Persistent Respiratory Insufficiency

Peripheral nervous system and neuromuscular disorders in the emergency department: A review

INTRODUCTION

Acute presentations and emergencies in neuromuscular disorders (NMDs) often challenge clinical acumen. The objective of this review is to refine the reader's approach to history taking, clinical localization and early diagnosis, as well as emergency management of neuromuscular emergencies.

METHODS

An extensive literature search was performed to identify relevant studies. We prioritized meta-analysis, systematic reviews, and position statements where possible to inform any recommendations.

SUMMARY

The spectrum of clinical presentations and etiologies ranges from neurotoxic envenomation or infection to autoimmune disease such as Guillain-Barré Syndrome (GBS) and myasthenia gravis (MG). Delayed diagnosis is not uncommon when presentations occur "de novo," respiratory failure is dominant or isolated, or in the case of atypical scenarios such as GBS variants, severe autonomic dysfunction, or rhabdomyolysis. Diseases of the central nervous system, systemic and musculoskeletal disorders can mimic presentations in neuromuscular disorders.

CONCLUSIONS

Fortunately, early diagnosis and management can improve prognosis. This article provides a comprehensive review of acute presentations in neuromuscular disorders relevant for the emergency physician.

"De Novo" Hypercapnic Respiratory Failure Unmasking Neuromuscular Disorders: Experiences From a Tertiary Care Center and Review of Literature

OBJECTIVES

Neuromuscular disorders could have respiratory involvement early or late into illness. Rarely, patients may present with a hypercapnic respiratory failure (with minimal motor signs) unmasking an underlying disease. There are hardly any studies which have addressed the spectrum and challenges involved in management of this subset, especially in the real-world scenario.

METHODS

A retrospective study comprising consecutive patients hospitalized with hypercapnic respiratory failure as the sole/dominant manifestation. The clinical-electrophysiological spectrum, phrenic conductions, diaphragm thickness, and outcomes were analyzed.

RESULTS

Twenty-seven patients were included, the mean age was 47.29 (SD 15.22) years, and the median duration of respiratory symptoms was 2 months (interquartile range [IQR] 1-4). Orthopnea was present in 23 patients (85.2%) and encephalopathy in 8 patients (29.6%). Phrenic nerve latencies and amplitudes were abnormal in 83.3% and 95.6%, respectively. Abnormal diaphragm thickness was noted in 78.5%. Based on a comprehensive electrophysiological strategy and paraclinical tests, an etiology was established in all. Reversible etiologies were identified in 17 patients (62.9%). These included myasthenia gravis (anti-AChR and MuSK), inflammatory myopathy, riboflavin transporter deficiency neuronopathy, Pompe disease, bilateral phrenic neuritis, and thyrotoxicosis. Respiratory onset motor neuron disease was diagnosed in 8 patients (29.6%). Despite diaphragmatic involvement, a functional respiratory recovery was noted at discharge (45%) and last follow-up (60%). Predictors for good outcomes included female sex, normal nerve conductions, and recent-onset respiratory symptoms.

DISCUSSION

A good functional recovery was noted in most of the patients including respiratory onset motor neuron disease. A systematic algorithmic approach helps in proper triaging, early diagnosis, and treatment. Clinical and electrodiagnostic challenges and observations from a tertiary care referral center are discussed.

Respiratory failure as first presentation of myasthenia gravis: a case report

Myasthenia gravis (MG) is often complicated by respiratory failure, an exacerbation known as myasthenic crisis. However, most patients with MG develop respiratory symptoms during the late course of the disease. Respiratory failure as an exclusive initial and primary complaint in patients with MG is rare and seldom reported. We herein describe a woman in her late 50s who presented with respiratory failure and was diagnosed with obesity hypoventilation syndrome at a local hospital. Her condition gradually worsened during the next 4 months and became accompanied by dysphagia. After 1 year of medical investigation, she was diagnosed in our hospital. A high level of anti-muscle-specific receptor tyrosine kinase antibody was found in her serum, and stimulation and electromyography results suggested MG. The patient's symptoms were improved by intravenous immunoglobulin and hormone therapy. This case reminds physicians to consider MG when encountering a patient who initially presents with respiratory failure.

A rare association: Obesity hypoventilation syndrome with myasthenia gravis and systemic lupus erythematosus, case report

Background

Shrinking lung syndrome (SLS) is an uncommon complication of systemic lupus erythematosus (SLE) that has also been seen in other autoimmune diseases and is linked with a high risk of acute or chronic respiratory failure. Alveolar hypoventilation in the presence of obesity-hypoventilation syndrome, systemic lupus erythematosus (SLE), and myasthenia gravis (MG) is uncommon and poses a diagnostic and therapeutic challenge.

Case report

We reported a 33-year-old female patient from Saudi Arabia who suffered from obesity, bronchial asthma, newly diagnosed essential hypertension, type 2 diabetes mellitus, with recurrent acute alveolar hypoventilation, secondary to obesity hypoventilation syndrome and mixed autoimmune disease (systemic lupus erythematosus and myasthenia gravis), based on the correct constellation of clinical findings and laboratory evidence.

Conclusion

The interesting aspect of this case report: is the presentation of the overlap of obesity hypoventilation syndrome and shrinking lung syndrome due to systemic lupus erythematosus with generalized and respiratory muscle dysfunction due to myasthenia gravis with good outcomes after therapy.

A late diagnosis of myasthenia gravis at the respiratory practice: back to basics

Myasthenia gravis may affect respiratory muscles. To differentiate between other neuromuscular diseases, evaluation for muscle fatigability can be demonstrated by cardiopulmonary exercise testing and the maximal voluntary ventilation test.https://bit.ly/3qMeWFd