A 42-year-old woman presents with fatigable ptosis, dysphagia, and proximal limb weakness. Repetitive nerve stimulation shows a decrement at 3 Hz. AChR antibodies are negative, but MuSK antibodies are positive. Which feature is more likely compared to AChR-antibody positive myasthenia gravis?

• A Prominent ocular involvement with minimal bulbar symptoms
• B Excellent response to pyridostigmine
• C Thymic hyperplasia on imaging
• D Predominant bulbar and respiratory weakness with relative sparing of ocular muscles ✓

Explanation

MuSK antibody-positive myasthenia gravis typically presents with predominant bulbar, neck, and respiratory weakness, often with prominent facial and tongue atrophy, and relatively less isolated ocular involvement. Response to pyridostigmine is often poor. Thymic pathology is usually absent or atrophic, unlike AChR-positive MG where thymic hyperplasia is common.

Reference: Adams and Victor's Principles of Neurology, 11th ed.

High-yield for: NEET PGINI-CETNExTFMGEUSMLEPLABMRCP

Written and medically reviewed by the StethoPrep medical team.