Stiff-person syndrome (SPS) is an autoimmune disorder causing progressive muscle stiffness and spasms due to GABAergic dysfunction.
SPS is:
- Anti-amphiphysin or anti-GAD related
- Female predominance
- Often associated with cancer
- GABAergic dysfunction
- Renshaw cells
- Ia inhibitory neurons
- Loss of inhibition
- Reticulospinal pathways
- Motor tone regulation
- Startle response
- Purkinje cells
- Deep nuclei
- Motor coordination
¶ Antibody Targets
- Amphiphysin (paraneoplastic)
- GAD65 (non-paraneoplastic)
- Gephyrin (rare)
- Reduced inhibition
- Motor neuron hyperexcitability
- Stiffness/spasms
- Axial muscles first
- Progressive
- Rigid abdomen, spine
- Triggered by stimuli
- Painful
- Can cause falls
- Falls
- Deformity
- Respiratory compromise
- Corticosteroids
- IVIG
- Rituximab
- Benzodiazepines
- Baclofen
- Valproate
- Stiff-person syndrome (2022)
- GABAergic autoimmunity (2021)