Improving Early Recognition of Potentially Treatable Causes of Rapidly Progressive Dementia

Abstract

AbstractBackgroundRapidly progressive dementia (RPD) includes patients with less than two years from the onset of cognitive impairment to incapacitation due to dementia. Although RPD is often associated with fatal neurodegenerative diseases, including early‐onset Alzheimer disease or Creutzfeldt‐Jakob disease, treatable forms of RPD are increasingly recognized. Early recognition of patients with potentially treatable causes of RPD is key to the timely provision of therapies required to achieve the best possible long‐term outcomes.Method155 patients with RPD were prospectively enrolled from February 2016 to August 2022 via two tertiary care centers. Etiologic diagnoses were independently assigned by two neurologists with good agreement (>90%). Causes of RPD were further classified as treatment‐responsive or nonresponsive, referencing the extant literature. Demographic, clinical, and paraclinical features associated with treatable causes of RPD were identified using stepwise multivariate logistic regression and validated with 5‐fold cross validation.Result87/155 patients (56.1%) had a potentially treatable cause of RPD, including autoimmune/inflammatory disease (n = 52, 59.8%), vasculitis (n = 13, 14.9%), primary psychiatric disease (n = 4, 4.6%), or nutritional deficiency (n = 4, 4.6%). Multivariable analyses identified seven features that were independently associated with treatment‐responsiveness: age‐at‐symptom onset (OR: 0.62 per decade, 95%CI: 0.42‐0.93), seizures (OR: 9.81, 95%CI: 2.84‐33.89), MRI suggestive of autoimmune encephalitis (OR: 23.08, 95%CI: 2.28‐233.40), CSF white blood cell count ≥10 cells/mm3 (OR: 32.24, 95%CI:5.80‐179.21), movement abnormalities (OR: 4.99, 95%CI: 1.76‐14.10), presence of disease‐associated tumor (OR: 13.82, 95%CI: 2.25‐85.11), and mania (OR: 18.47, 95%CI: 1.76‐193.61). Model performance was excellent (c‐statistic = 0.88, 95%CI: 0.82‐0.94; p<0.001): 71 patients (81.6%) with potentially treatable causes of RPD and 56 patients (82.4%) with non‐treatable causes of RPD were correctly classified (PPV = 85.5%; NPV = 77.8%).ConclusionTreatment‐responsive causes of RPD were common in our series. Younger age, seizures, movement abnormalities, or mania at presentation, and paraclinical tests suggesting inflammation (MRI or CSF) or tumor in patients with RPD should prompt consideration of treatable causes of RPD and initiation of treatment when indicated.