Isolated laryngeal myasthenia gravis for 26 years

Hypophonia as only presenting symptom in myasthenia gravis - a diagnostic dilemma in poor countries: a case report

INTRODUCTION

The autoimmune disease myasthenia gravis can mimic a variety of neurological disorders leading to a delay in diagnosis and treatment. In the older population, due to confusion with signs of the ageing process or comorbidities due to ageing, there are many underdiagnosed or misdiagnosed cases of myasthenia gravis. A majority of myasthenia gravis symptoms appear as ocular or motor symptoms and there are very few cases of bulbar symptoms. We present a case of myasthenia gravis with only hypophonia as a clinical feature.

CASE PRESENTATION

We present a case of a 51-year-old Madheshi woman whose only complaint was sudden onset of hypophonia which later showed a fluctuating nature throughout the daytime. There was only reduced pitch in her voice with no nasal tone or dysarthria (so-called dysphonia), which created a diagnostic dilemma. Later, a neurological examination and other relevant investigations suggested myasthenia gravis.

CONCLUSIONS

Sudden onset and focal neurological deficit can raise the diagnostic dilemma of myasthenia gravis. Relevant laboratory tests and clinical examinations are important to diagnose this disease properly. In resources-deprived nations like Nepal, where several investigations are expensive and access to them is difficult, it becomes very difficult to achieve a solid diagnosis for rare presentations of diseases.

Clinical features of laryngeal myasthenia gravis: A case series

BACKGROUND

Myasthenia gravis (MG) is an autoimmune disease. Dysarthria, dysphagia, and difficulty swallowing as exclusive initial and primary complaints in MG (laryngeal MG) are rare and seldom reported.

METHODS

Here we review and analyze the largest series of laryngeal MG patients.

RESULTS

A total of 30 patients with laryngeal MG as primary manifestation were found in 20 case reports/series. Dysarthria was the most frequent primary symptom (14/30), followed by dysphagia (11/30), slurred speech (4/30) and dysphonia (1/30). Sixty-three percent visited the otolaryngology department first. Only 23.33% of patients were diagnosed with MG at the first clinic visit. Forty-five percent laryngeal MG patients were acetylcholine receptor (AChR) antibody positive, 52.9% showed decremental response in the repetitive nerve stimulation (RNS) test, and 92.6% were positive in the neostigmine/edrophonium test. Fluctuating weakness was examined in 16 of 30 patients and observed in 14/16 patients.

CONCLUSION

Laryngeal MG is a rare and possibly under-diagnosed condition. The patients can present with dysarthria, dysphagia, or difficulty swallowing. Fluctuation in severity of disease by neostigmine/edrophonium test is a typical feature for MG patients. AChR antibody and RNS tests should be included to evaluate the pathologic changes in the neuromuscular junction.