A 32-year-old woman presents with a 3-month history of progressive ptosis, diplopia, and fatigable weakness of limb muscles. Examination reveals ocular and generalized myasthenic features. Serology is positive for anti-acetylcholine receptor (AChR) antibodies. Chest imaging shows no thymoma. What is the next step in management?

Explanation

## Management Strategy in Seropositive Myasthenia Gravis **Key Point:** In a seronegative or seropositive patient with confirmed MG (positive AChR antibodies), the next step is to initiate symptomatic treatment with an acetylcholinesterase inhibitor AND refer for thymectomy evaluation, as thymectomy is indicated in generalized MG regardless of thymoma presence. ### Rationale for Correct Answer **High-Yield:** Pyridostigmine is the first-line symptomatic agent in MG—it provides rapid relief of fatigable weakness by inhibiting acetylcholinesterase, prolonging acetylcholine action at the neuromuscular junction. Thymectomy is indicated in generalized MG (especially in seropositive patients aged 15–50 years) because: - 30–50% of generalized MG patients have thymoma - Even without thymoma, thymectomy induces remission in ~30% and significant improvement in ~50% of generalized MG - Early referral (within 1 year of diagnosis) yields better outcomes **Clinical Pearl:** The combination of pyridostigmine (symptomatic relief) + thymectomy (disease-modifying) is the standard initial approach in generalized seropositive MG without acute crisis. ### Why Diagnosis is Already Confirmed The patient has: - Clinical features consistent with MG (ptosis, diplopia, fatigable weakness) - Positive AChR antibodies (diagnostic) - Negative thymoma imaging Diagnosis is established; further confirmatory testing (RNS) is unnecessary at this stage. ## Comparison: When Each Alternative Is Used | Intervention | Indication | Timing | |---|---|---| | **Pyridostigmine + Thymectomy** | Generalized MG, seropositive, no thymoma | First-line; refer early | | **IVIG** | Myasthenic crisis, acute exacerbation, pre-operative | Acute/emergency setting | | **RNS** | Diagnostic confirmation in seronegative cases | Before serology available | | **Azathioprine monotherapy** | Steroid-sparing agent, chronic maintenance | After initial stabilization | **Mnemonic: PITA** — **P**yridostigmine (first-line symptomatic), **I**mmunotherapy (azathioprine/prednisolone for chronic control), **T**hymectomy (early referral), **A**cute crisis management (IVIG/plasmapheresis). **Warning:** Do not delay thymectomy referral in a young patient with generalized MG—early surgery (within 1 year) has superior outcomes compared to delayed intervention.