A 58-year-old woman presents to the physician for a 3-month history of difficulty swallowing and changes in her vision. She has experienced a 10-lb (4.5-kg) weight loss over this time. She has an 80-pack-year history of smoking. A CT of the chest is shown. Her pathology is outlined in red.
Laboratory screening is positive for anti-muscle-specific kinase antibodies. Which of the following is most likely to be seen in this patient?
Minimal response to edrophonium; Anti-postsynaptic acetylcholine receptor antibodies
Minimal response to edrophonium; Anti-postsynaptic ligand-gated calcium channel antibodies
Minimal response to edrophonium; Anti-postsynaptic voltage-gated calcium channel antibodies
Minimal response to edrophonium; Anti-presynaptic acetylcholine receptor antibodies
Minimal response to edrophonium; Anti-presynaptic ligand-gated calcium channel antibodies
Minimal response to edrophonium; Anti-presynaptic voltage-gated calcium channel antibodies
Significant response to edrophonium; Anti-postsynaptic acetylcholine receptor antibodies
Significant response to edrophonium; Anti-postsynaptic ligand-gated calcium channel antibodies
Significant response to edrophonium; Anti-postsynaptic voltage-gated calcium channel antibodies
Significant response to edrophonium; Anti-presynaptic acetylcholine receptor antibodies
Significant response to edrophonium; Anti-presynaptic ligand-gated calcium channel antibodies
Significant response to edrophonium; Anti-presynaptic voltage-gated calcium channel antibodies
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Cut-to-the-chase Answer (0:28):
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HY USMLE Answer (5:59):
