Stiff Person Syndrome (SPS) - Diagnosis and Management Summary Epidemiology: • Prevalence: 1-2 cases per million - rare • Age 20-50, Females 2-3 times than men • Commonly associated with DM-1, thyroiditis, vitiligo, and pernicious anemia Stiff Person Syndrome Pathophysiology: • Associated with autoimmunity • Research indicates that it is the result of an autoimmune response gone awry in the brain and spinal cord. Clinical Manifestations of Stiff Person Syndrome: • Progressive muscle stiffness, rigidity, spasm - axial muscles • Severely impaired ambulation • Excessive muscle rigidity - lumbar, trunk, proximal muscles - sustained muscle contractions (agonist and antagonist muscles) • Wide based gait with tendency to fall • Triggers - sudden movement, noise, emotional upset • Spasms - visualized-tight, rock-hard, board-like feel • Autonomic dysfunction - hyperpyrexia, diaphoresis, high HR • Sudden death - diaphragm spasm - apnea Stiff Person Syndrome - Diagnosis: • High index of suspicion • Presence of: - Stiffness in axial and limb muscles resulting in impairment of ambulation - Presence of superimposed spasms triggered by noise, movement or emotions - A positive therapeutic response to diazepam or findings of continuous motor unit activity on EMG - Absence of other neurological disorders • Testing anti-GAD (positive in 2/3 of pts) • Therapeutic trial of diazepam • EMG testing Lab Findings in Stiff Person Syndrome: • Anti-GAD Ab (>1000u/ml) - People with SPS have elevated levels of GAD, an antibody that works against an enzyme involved in the synthesis of an important neurotransmitter in the brain. • CSF: Oligoclonal bands • Normal ESR, CRP • Other autoantibodies - TPO, TTG, etc EMG Studies: • Continuous motor-unit activity, typically decreased by diazepam, sleep DDx: • Neuromyotonia, Tetanus, Strychnine poisoning, Parkinson's disease, Multiple sclerosis, Ankylosing spondylitis, Axial dystonia, Focal limb or joint disorders, Fibromyalgia, Psychosomatic illness, Anxiety, Phobia Stiff Person Syndrome Treatment: • Initial/Symptomatic Therapy: - BDZ: Diazepam or clonazepam • Resistant to Initial Symptomatic Therapy: - Baclofen • Severe Disease/Resistant: - IVIG - If Resistant to IVIG: Rituximab (anti-CD20), plasma exchange, or others (botox, sodium valproate, vigabatrin, propofol) #Stiff #Person #Syndrome #SPS #Diagnosis #Management #treatment #neurology
