A 45-year-old woman presents with ptosis, diplopia, and fatigable proximal muscle weakness worse in the evening. Edrophonium (Tensilon) test is positive. Anti-AChR antibodies are positive. CT chest reveals a 3.5 cm anterior mediastinal mass. Management includes:

• A Pyridostigmine alone (symptomatic) — surgery not indicated
• B Thymectomy plus pyridostigmine and immunosuppression (steroids ± azathioprine) ✓
• C Plasma exchange only, avoid immunosuppression
• D Neostigmine IV and observation

Explanation

A mediastinal mass in the context of myasthenia gravis is thymoma until proven otherwise, and thymectomy is indicated for all thymoma-associated MG regardless of age. The MGTX trial confirmed thymectomy plus prednisone improves outcomes in generalized anti-AChR positive MG versus prednisone alone. Pyridostigmine provides symptomatic relief; immunosuppression (steroids ± azathioprine/mycophenolate) is required for disease modification. Plasma exchange is reserved for myasthenic crisis or pre-thymectomy preparation.

Reference: Harrison's Principles of Internal Medicine, 21st ed.

High-yield for: NEET PGINI-CETNExTFMGEUSMLEPLABMRCP

Written and medically reviewed by the StethoPrep medical team.