neurologic disorders
Myasthenia Gravis
Key Points
Consider myasthenia gravis in patients with ptosis, diplopia, and muscle weakness after use of the affected muscle. To confirm the diagnosis, measure serum levels of AChR antibody (usually present in myasthenia gravis), do electromyography (EMG), or both. After the diagnosis is confirmed, test for thymic hyperplasia, thymomas, hyperthyroidism, and autoimmune disorders, which commonly accompany myasthenia gravis. For most patients, use anticholinesterase drugs to relieve symptoms and immunomodulating treatment to slow disease progression and help relieve symptoms; do not use these treatments in patients with congenital myasthenia. If patients have a myasthenic crisis, treat with IVIG or plasma exchange. If patients suddenly deteriorate after responding well to treatment, provide respiratory support and stop anticholinesterase drugs for several days because they may have cholinergic crisis. 