<prompt> Reversible cause of dementia is -Alzheimers diseaseParkinsonismHypothyroidismVascular dementia  <response>: Ans. is c i.e., Hypothyroidism Causes of dementiaReversible causesSurgically treatableMedically treatableo Normal pressure hydrocephaluso Brain tumors frontal lobe tumoro Meningiomao Subdural hematoma Head injuryo Hydrocephaluso Hypothyroidismo Depressiono HIV infectiono Alcohol abuseo Vitamin B12, Folate, Niacin deficiencyo Any metabolic or endocrine disturbanceo Neurosyphiliso Hashimotos encephalopathy o Wilsons diseaseo Celiac disease or Whipples diseaseo Chronic meningoencephalitiso Drugs and toxin toxic dementiaIrreversible causeso Alzheimers diseaseo Huntingtons choreao Lewy body dementiao Vascular Multi-infarct dementiao Parkinsons diseaseo Creutzfeld Jakob diseaseo Picks diseaseo Overall Alzheimers disease is the most common cause. Vascular dementia is the 2nd most common cause. 