This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Degenerative Disorders, Subject name: Psychiatry
All are reversible causes of dementia except - 
Select and explain. 
A. Hypothyroidism, B. Hydrocephalus, C. Meningoencephalitis, D. Alzheimer's disease
D: Alzheimer's disease
Answer: D: Alzheimer's disease 
Explanation: Ans. is 'd' i.e., Alzhimer's disease Reversible causes of dementia1) Surgically treatable :- Normal pressure hydrocephalus, brain tumors (frontal lobe tumor), meningioma, subdural hematoma due to head injury, hydrocephalus.2) Medically treatable :- Depression, hypothyroidism, alcohol abuse, vitamin B Jfolate/Niacin deficiency, any metabolic or endocrine disturbance, neurosyphilis, Hashimoto's encephalopathy, Wilson's disease, celiac disease, whipple's disease, chronic meningoencephalitis, drugs and toxin (toxic dementia).Irreversible causes of dementia :- Alzheimer's disease, vascular (multi-infarct) dementia, Parkinsonism, Huntington 9s chorea, Lewy body dementia, Pick's disease.