Neuromuscular Junction

A 52-year-old woman presents with progressive ptosis, diplopia, and proximal muscle weakness worsening towards the end of the day. Clinical examination reveals fatigable weakness. Which investigation is most appropriate to confirm the diagnosis of myasthenia gravis?

A 35-year-old man with a history of small-cell lung cancer presents with progressive proximal muscle weakness and autonomic dysfunction. Clinical examination reveals reduced tendon reflexes. Which investigation would best demonstrate the presynaptic defect characteristic of Lambert-Eaton myasthenic syndrome (LEMS)?

A 58-year-old woman presents with progressive ptosis, diplopia, and proximal muscle weakness that worsens with activity and improves with rest. Serology is positive for anti-acetylcholine receptor (AChR) antibodies. What is the most common site of involvement in myasthenia gravis?

Which single feature best distinguishes myasthenia gravis (MG) from Lambert-Eaton myasthenic syndrome (LEMS)?

Which of the following neurotransmitters is released at the neuromuscular junction and binds to nicotinic receptors on the motor end plate?