Prevalence of potentially reversible conditions in dementia and mild cognitive impairment in a geriatric clinic

Abstract

To examine the prevalence of potentially reversible conditions in dementia and mild cognitive impairment (MCI) patients in a geriatric clinic. We retrospectively reviewed the medical records of patients who attended the outpatient geriatric clinic at Siriraj Hospital, Bangkok between January 2005 and December 2010. We collected the data regarding potentially reversible conditions of cognitive impairment. There were 233 patients newly diagnosed with dementia and 60 patients diagnosed with MCI. We found potentially reversible causes of dementia in 17 patients (7.3%). The causes were hypothyroidism (2.6%), B12 deficiency (1.7%), normal pressure hydrocephalus (NPH) (0.9%), depression (0.9%), folate deficiency (0.4%), reactive Venereal Disease Research Laboratory (VDRL; 0.4%) and chronic subdural hematoma (CSH; 0.4%). The patients with NPH and CSH were clinically suspicious for having such conditions before the investigations, while patients with low B12 level, low folate level, hypothyroidism and VDRL+ were not. In the MCI group, we found potentially reversible causes in two patients (3.3%), these were B12 deficiency (1.7%) and hypothyroidism (1.7%). Clinical improvement after treatment of the potentially reversible conditions was seen in four patients (one NPH, one subdural hematoma and two with depression) in dementia group (1.7%) and none in the MCI group. All were partially reversed. Routine investigations might be more warranted for metabolic conditions (B12 level and hypothyroidism) as clinical presentations are not suggestive of the conditions. However, reversibility of dementia might not occur in these cases. Neuroimaging should be performed selectively as clinically indicated. Truly reversible conditions are rare and occur in surgical and depressive patients.