SESSION TITLE: Miscellaneous Student/Resident Case Report Posters I
SESSION TYPE: Medical Student/Resident Case Report
PRESENTED ON: Tuesday, October 28, 2014 at 01:30 PM - 02:30 PM
INTRODUCTION: Co-existing neuromuscular disorders are rare, debilitating and challenging to treat.
CASE PRESENTATION: A 25-year-old woman with episodic slurred speech and dysconjugate gaze presented with exertional dyspnea and 50-pound weight loss over 1-year. She was hypoxic and improved with supplemental oxygen but was subsequently intubated for hypercapnic respiratory failure. Failed weaning trials led to tracheostomy 1 week later and prompted investigation for underlying pathology, such as neuromuscular disorders. Electromyography findings were consistent with peripheral nervous system disease with the neuromuscular junction being the most likely location. Voltage-gated calcium channel and muscle-specific (MuSK) anitbodies were positive. She was diagnosed with anti-MuSK myasthenia gravis (anti-MuSK MG) and Lambert Eaton myasthenic syndome (LEMS). No underlying malignancy was found. Despite receiving 5 days IVIG, 4 weeks of rituximab, 5 cycles of plasmapharesis and mycophenylate mofetil, she continues to require mechanical ventilation.
DISCUSSION: It is quite unusual to find two rare neuromuscular disorders co-existing in the same patient (1). Anti-MuSK MG is often a severe and debilitating disease that requires aggressive immunosuppressive therapy (2,3). Patients with anti-MuSK MG tend to have lower remission rates as compared to those with Acetylcholine (Ach) receptor positive disease as 30% of patients with anti-MuSK MG develop permanent cranial and bulbar weakness(3). LEMS occurs much less frequently than MG. Treatment of LEMS can also include immunosuppressive therapy. However, it is still challenging to effectively treat both diseases presenting in the same patient.
CONCLUSIONS: Although neuromuscular diseases are rare, there should be a high index of suspicion for these disorders in young patients with respiratory failure of uncertain etiology.
Reference #1: Basta I, Nikolic A, Losen M, Martinez-Martinez P, Stojanovic V, Lavrnic S, de Baets M, Lavrnic D. MuSK myasthenia gravis and Lambert-Eaton myasthenic syndrome in the same patient. Clin Neurol Neurosurg. 2012; 114(6):795-7
Reference #2: Lebrun C, Bourg V, Tieulie N, Thomas P. Successful treatment of refractory generalized myasthenia gravis with rituximab. European Journal of Neurology 2009; 16: 246-250
Reference #3: Evoli A, Bianchi MR, Riso R, Minicuci GM, Batocchi AP, et al. Response to therapy in myasthenia gravis with anti-MuSK antibodies. Ann N.Y. Acad. Sci. 2008; 1132:76-83
DISCLOSURE: The following authors have nothing to disclose: Stephanie Chong, Anita Laloo, Heather Kurtis
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