This is a disease of motor weakness that is often characterized by proximal weakness, especially of the lower extremities. It is caused by autoantibodies to the voltage gated calcium channels of the presynaptic membrane. Calcium is not able to enter the nerve ending and to allow acetylcholine release.
Weakness typically improves with repetitive use as these allow to build up calcium.
Patients are sensitive to both the depolarizing and nondepolarizing muscle relaxants and patient may need postoperative ventilatory support.
It is often seen as a paraneoplastic syndrome related to a small cell cancer of the lung. It may also be seen with sarcoidosis, other malignancies, thyroiditis, and collagen vascular disease
