We report a 61-year-old man presenting with rapidly progressive stiffness and painful muscle spasms in the lower extremity muscles. The patient was diagnosed with chronic lymphocytic leukaemia (CLL) approximately a year before symptom onset. Electromyography displayed continuous motor unit activity and immunocytochemistry showed a positive staining for antiglycine receptor (anti-GlyR) antibodies. The clinical course was complicated by autonomic instability and cardiac arrest, but stabilised under continuous therapy with plasma exchange and symptomatic treatment with baclofen and clonazepam. Anti-GlyR antibodies induce rare, but severe, variants of stiff person syndrome that can be of paraneoplastic origin and life threatening due to autonomic dysfunction.
