Myasthenia Gravis

A 38-year-old woman presents with progressive ptosis and diplopia over 3 weeks. On examination, she has bilateral ptosis that worsens with sustained upward gaze and improves after rest. Antibody testing for anti-acetylcholine receptor (AChR) is negative. Which is the most appropriate next investigation to confirm the diagnosis of seronegative myasthenia gravis?

A 52-year-old man with known myasthenia gravis presents with acute worsening of generalized weakness, difficulty swallowing, and respiratory distress. He has been on pyridostigmine monotherapy for 2 years. Before initiating immunosuppression, the clinician needs to exclude a thymoma, which is present in 30–50% of generalized MG cases. Which is the most appropriate investigation of choice for detecting thymoma in this patient?

A 48-year-old man from Mumbai with known generalized myasthenia gravis (seropositive for AChR antibodies) on pyridostigmine 60 mg four times daily presents with acute worsening of muscle weakness, respiratory distress, and increased salivation. His wife reports he took an extra dose of pyridostigmine 2 hours ago after feeling weak. Vital signs: BP 110/70 mmHg, HR 88/min, RR 24/min. Which of the following is the most appropriate next step?

A 28-year-old man with ocular myasthenia gravis (OMG) presents with persistent ptosis and diplopia despite 3 months of prednisolone therapy. He wishes to avoid long-term corticosteroids due to side effects. What is the preferred second-line agent to add for steroid-sparing effect?

A 32-year-old woman from Delhi presents with a 3-month history of progressive ptosis and diplopia. Symptoms worsen towards evening and improve after rest. On examination, she has bilateral ptosis that worsens with sustained upward gaze. Edrophonium test is positive. Serum anti-acetylcholine receptor (AChR) antibodies are negative. CT chest is normal. What is the most likely diagnosis?