Abstract
Stiff-person syndrome (SPS) is manifested by increased tone of the trunk muscles that gradually spreads to the limbs. The mechanism underlying this muscle hypertonia involves derangement of the inhibitory action of gamma-aminobutyric acid (GABA) at cortical and spinal levels with subsequent continuous motor unit activity.
A co-contraction mechanism with a board-like abdomen and painful lumbar hyperlordosis plays an important role. Symptomatic treatment involves drugs that enhance inhibition (baclofen and benzodiazepines).
Causal treatment focuses on immunosuppression (corticosteroids, intravenously administered immunoglobulins, and plasmapheresis). A combination of SPS and another genetic disease has not yet been described.
We describe a case study of a 46-year-old man with gradual development of severe SPS whose electromyography (EMG) showed continuous motor unit activity as well as several myotonic discharges. Genetic testing was indicative of myotonic dystrophy type 2 (DM2).