Hi, everyone, thank you for checking out my poster today that discusses double seronegative myasthenia gravis and a patient presenting with chronic dysphagia. I'm Andrea and I'm a resident at Ohio State. So, the patient we're discussing is a 71 year old female with a history of cold gluten and hemolytic anemia. Autoimmune hepatitis, hypothyroidism, GERD, Sjogren's disease, chronic dysphagia, and osteoporosis. She presented to our inpatient rehab after a fall, which resulted in a T12 burst fracture that was managed nonoperatively. She was diagnosed with dysphagia, secondary to esophageal dysmotility, and this required a gastrostomy, too. Modified barium swallow revealed penetration with thin and nectar consistencies and aspiration of thin and possible aspiration of nectar thick barium with varying maneuvers. Inpatient myasthenia panel was negative. She worked with speech therapy who helped her out with right side lying and masecho exercises without improvement in her dysphagia. Follow-up esophageal and pharyngeal manometry revealed esophageal dysmotility and pharyngeal weakness. Myopathic panel, acetylcholine receptor antibodies and muscle specific kinase antibodies were negative. She underwent EMG and nerve conduction study of the lower limb, including repetitive nerve stimulation of the face and needle exam of proximal arm muscles and the tongue, and this was normal. She represented to neurology clinic several months later with new onset hypophonia. Single fiber EMG was performed and it was diagnostic of myasthenia gravis. She started IVIG with improvement in dysphagia. Single fiber EMG is the most sensitive test for diagnosing myasthenia gravis in adults. It is abnormal if the mean jitter value exceeds the upper limit of normal, or more than 10% of the pairs have increased jitter, or if there is any blocking present. Definition of jitter is variation of the interpotential interval between the triggered potential and the time locked second single muscle fiber potential. And blocking occurs if a muscle fibers end plate potential never reaches a threshold and depolarization does not occur. Figure 1 reveals our patient's single fiber EMG results, which revealed blocking in 1 out of 9 potentials and increased jitter in 6 out of 9 potentials. So, in conclusion, myasthenia gravis presenting as dysphagia is more common in elderly patients and is the only symptom in 15% of patients. There is a bimodal onset with the 1st peak occurring in the 2nd and 3rd decades, which affects more women. And the 2nd peak occurs in the 6th and 7th decades, which tends to affect more men. So, myasthenia gravis must remain on the differential for patients presenting with dysphagia as 15% of patients with generalized and 50% with ocular forms of myasthenia gravis or negative for acetylcholine receptor antibodies and muscle specific kinase antibodies. Early diagnosis of this condition results in improved outcomes.

chronic dysphagia

esophageal dysmotility

myasthenia gravis

elderly patients

early diagnosis