[Reversible dementias and treatable dementias]

When studying patients with dementia the search of reversible or treatable entities has a primordial role. Many patients do not recover the previous cognitive level; however, that does not signify that the disease is not treatable with partial recovery or prevention of secondary progression.

The prevalence of reversible dementias is around 15% in most series. Rutine studies include complete blood cell count, erythrocyte sedimentation rate, electrolytes and chemistry panel, liver function tests, vitamin B12 and folate serum levels, urianalysis and syphilis serology. Special tests such as thyroid function tests, protein electrophoresis, human immunodeficiency virus serology, heavy metals serum levels, electrocardiography, cerebrospinal fluid analysis, and chest roentnography should be performed according to the patient clinical profile. Neuroimaging should be done in all cases. Non-contrasted computed tomography must be performed first. Magnetic resonance imaging is most useful for searching for more subtle structure abnormalities. Electroencephalogram, positron emission tomography and single photon emission computed tomography are not recommended as routine studies. Brain biopsy is indicated in few cases.

Most common causes of reversible and treatable dementias include: medications, obstructive hydrocephalus, infectious, vascular, immunological, psychiatric, toxic and metabolic disorders, among others.