Case Presentation: An 88-year-old Japanese female with a history of treated breast cancer, palate squamous cell carcinoma and meningioma presented with acute on subacute worsening of left-sided facial droop, dysarthria, and dysphagia. Two weeks prior to admission, she developed these neurological symptoms followed by a brain magnetic resonance imaging (MRI) that revealed no acute intracranial mortalities. She was seen in the emergency department for dehydration and urinary tract infection, but was noted to have an acute exacerbation of her slurred speech and asymmetrical facial expression. On physical examination, vital signs were significant for a blood pressure of 191/105 mmHg. She was alert and conscious. Neurological examination demonstrated a slurred but intelligible speech, left-sided ptosis and facial weakness sparing the forehead. Otherwise, no focal deficits were noted and the remainder of the examination was unremarkable. Labs were within normal range. Head computed tomography (CT) and brain MRI showed no change from previous studies with no acute pathology. The patient was hospitalized for close monitoring of her neurological findings. A cerebral spinal fluid analysis showed normal results including negative cytology. Following her lumbar puncture, the patient suddenly developed hypercapnic respiratory failure requiring mechanical ventilation. During endotracheal intubation, she had inadequate paralysis with succinylcholine, raising suspicion for myasthenic crisis. Subsequently, pyridostigmine was administered with improved ptosis, indicating a therapeutic diagnosis of myasthenia gravis (MG). The patient received intravascular immunoglobulin (IVIG) therapy and was successfully extubated on hospital day 8. The anti-acetylcholine receptor antibody result returned positive. There was no thymoma identified on chest CT.
Discussion: MG is caused by antibody-mediated postsynaptic acetylcholine receptor destruction in the neuromuscular junction. The clinical features are fluctuating weakness and fatigability affecting ocular, bulbar, respiratory and proximal limb muscles. Our patient demonstrated asymmetrical cranial nerve abnormalities, which were initially considered atypical for autoimmune neuromuscular junction diseases. In fact, over half of all MG patients initially present with ptosis alone, which can be unilateral, asymmetrical or with alternating laterality. In our case, the approach to the final diagnosis was directed by the patient’s resistance to succinylcholine, a depolarizing muscle relaxant that is known to have variable and unpredictable paralytic effect in MG. Myasthenic crisis may be precipitated by stress events, such as infection and procedure in our patient. Careful observation of the patient’s signs and symptoms served as an important key to the right clinical diagnosis.
Conclusions: Unilateral facial weakness with acute onset tends to yield a kneejerk diagnosis of a cerebral vascular accident in the clinical setting. With atypical course, however, cautious attention to subtle yet paramount clinical signs and symptoms may lead to the correct diagnosis.
To cite this abstract:Zhang, ZS; Lee, D; Awakuni, SK; Satomi, F. MYASTHENIA GRAVIS THAT MIMICS PRESENTATION OF CEREBRAL VASCULAR ACCIDENT. Abstract published at Hospital Medicine 2018; April 8-11; Orlando, Fla. Abstract 930. https://www.shmabstracts.com/abstract/myasthenia-gravis-that-mimics-presentation-of-cerebral-vascular-accident/. Accessed July 23, 2019.