An uncommon neurological disorder caused by autoantibodies against the acetylcholine receptor (AChR), against a receptor-associated protein, muscle-specific tyrosine kinase (MuSK-Ab), or occasionally to the low-density lipoprotein receptor-related protein 4 (LPR4)
The autoimmune attack at the muscle endplate leads to failure of neuromuscular transmission and eventually muscle weakness
Signs and Symptoms
Fatigability and weakness of voluntary muscles
Weakness tends to increase during repeated use
May improve with rest or sleep
Diplopia and ptosis
Common initial complaints
Generally asymmetrical
Cogan’s lid twitch or excessive lid elevation
Facial weakness which results in snarl-like expression when smiling
Nasal or slurred speech
Difficulty in swallowing
If generalized, there will be weakness in the limb muscles
Often asymmetric and proximal
Deep tendon reflexes and sensation are preserved
If severe, there will be shortness of breath
Clinical Features
Acetylcholine Receptor Myasthenia Gravis (ACh-MG)
Muscle weakness predominant in the limb than bulbar, neck extensor than neck flexor, prominent ptosis, and external ocular muscle weakness
Wasting of proximal limb and ocular muscles in long-standing disease (myasthenic myopathy)
