Creutzfeldt-Jakob disease presenting with encephalopathy, rigidity, and hyperekplexia

Creutzfeldt-Jakob disease (CJD) is a prion disease occurring at an estimated rate of 1-1.5 per million per year(1) and accounting for up to 30.6% of patients with rapidly progressive dementia.(2) The clinical presentation of CJD is heterogeneous.(3,4) A wide spectrum of atypical early manifestations have been reported, which include seizures, psychiatric or sensory disturbances, atypical parkinsonism, dystonia, myoclonus, chorea, blepharospasm, stroke symptoms, aphasia, and neuropathy.(3) Diagnosis can be facilitated by CSF End-point quaking-induced conversion (EP-QuIC) with reported sensitivity and specificity of 98% and 91%, respectively.(5) By comparison, progressive encephalomyelitis with rigidity and myoclonus (PERM) occurs at an estimated rate of 10 per million per year(6) and presents with subacute (over weeks) axial muscle stiffness, rigidity, and painful spasms, sometimes associated with diaphoresis or other autonomic signs, sensory symptoms, or brainstem signs.(6) A minority (similar to 11%) present with encephalopathy.(7) Supportive findings include anti-GAD65 and anti-glycine receptor antibodies present in 43.0% and 18.2% of cases, respectively.(8)