(Multifocal Acquired Demyelinating Sensory And Motor Neuropathy, MADSAM)

Extremely rare. Acquired demyelinating polyneuropathy, characterized by distal asymmetric upper or lower limb weakness and motor dysfunction, appearing in adulthood. It is considered a variant of chronic inflammatory demyelinating polyneuropathy. Its cause is unknown: inflammation of the myelin has been suggested.

It is characterized by asymmetric involvement of the upper limbs, with focal abolition of reflexes, and, in the case of associated sensory involvement, epicritic and proprioceptive sensitivities are impaired. The electromyogram is pathognomonic, with conduction blocks.

Treatment: IV administration of gamma globulin appears to be effective.

Anesthetic implications: 

preoperative neurological assessment, as there is a risk of postoperative deterioration; avoid succinylcholine: risk of hyperkalemia in the event of significant muscle denervation. Difficult to monitor curarization in the affected limb; one case of increased sensitivity to rocuronium has been described.

References : 

-         Sales F, Cruz A S, Maldonado F, Cunha M.
Perioperative management of Lewis-Sumner syndrome.
Cureus 2023 ; 15(3): e36297. DOI 10.7759/cureus.36297

Updated: July 2024