What myasthenia gravis is
Myasthenia gravis (MG) is an autoimmune disorder in which antibodies — most commonly against the acetylcholine receptor (AChR) — block or destroy the neuromuscular junction, the communication point between nerve and muscle. This results in fluctuating, fatigable weakness that characteristically worsens with sustained activity and improves after rest. The condition can affect any voluntary muscle but commonly involves the eyes (ptosis, double vision), face, jaw, throat (difficulty chewing, swallowing or speaking) and limbs.
MG is not a single disease — seronegative MG (negative AChR antibodies), anti-MuSK MG and anti-LRP4 MG represent distinct subtypes with different clinical features and management implications. Thymic abnormalities (thymoma or thymic hyperplasia) occur in approximately 10–15% of AChR-positive patients and thymectomy is considered in specific circumstances. Accurate serological and clinical phenotyping guides treatment strategy.
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Symptoms and diagnosis
The hallmark of MG is fluctuating weakness that worsens throughout the day and improves with rest. Ocular symptoms (ptosis, diplopia) are the most common presenting feature in approximately 85% of patients; generalised weakness involving limbs, bulbar muscles (chewing, swallowing, speech) and respiratory muscles develops in a subset over months to years. Symptoms may be exacerbated by heat, infection, stress and certain medications.
Diagnosis relies on clinical history supported by serological testing (AChR, MuSK or LRP4 antibodies), repetitive nerve stimulation (showing decrement) and single-fibre EMG (showing increased jitter). Ice pack testing (improvement of ptosis with cooling) and edrophonium testing may be used adjunctively. Chest imaging (CT thorax) evaluates for thymoma. These tests confirm the diagnosis and subtype, which directly influences treatment decisions.
Management approach
Symptomatic treatment with acetylcholinesterase inhibitors (pyridostigmine) provides temporary improvement in neuromuscular transmission. Immunosuppressive therapy (prednisolone, azathioprine, mycophenolate, cyclosporine) targets the underlying autoimmune process. Thymectomy is considered for generalised AChR-positive MG, especially with thymoma. Acute exacerbations (myasthenic crisis) may require intravenous immunoglobulin (IVIg) or plasma exchange (PLEX).
Management requires regular monitoring for medication side effects, assessment of functional status, and adjustment of therapy based on response. Patients are educated about medication interactions (certain antibiotics, anaesthetics and magnesium can worsen MG), sick-day management, and when to seek emergency care for respiratory difficulty. Dr. Jitendra Prasad Yadav (NMC 8029) provides structured follow-up at Kathmandu Neurology Clinic & Cognitive Center, Durbar Marg, Opposite of Yak & Yeti Hotel, coordinating with other specialists as needed.