Treatable dementias

• Reactions to medications. Some medications have side effects that mimic the symptoms of dementia. Even a single dose of a medicine may trigger such a reaction in an older person or in someone whose liver fails to eliminate the drug normally. Interactions among two or more drugs may lead to reversible symptoms of dementia as well.
• Metabolic abnormalities. Decreased thyroid function (hypothyroidism) can result in apathy or depression that mimics dementia. Hypoglycemia, a condition in which there isn't enough sugar in the bloodstream, can cause confusion or personality changes. Pernicious anemia caused by an inability to absorb vitamin B-12 also can cause cognitive changes. Similarly, changes in blood sodium, calcium, heavy metals, or other compounds can cause a reversible dementia.
• Nutritional deficiencies. Chronic alcoholism can be associated with deficiencies of thiamin (vitamin B-1), which can seriously impair mental abilities. Severe deficiency of niacin (vitamin B-3) may cause pellagra, a neurological illness with features of dementia. Dehydration also can cause confusion that may resemble dementia.
• Emotional problems. The confusion, apathy and forgetfulness associated with depression are sometimes mistaken for dementia, particularly in older individuals. Similarly, bipolar disease, schizophrenia, and obsessive-compulsive disorder can be misdiagnosed as FTD
• Infections. Meningitis and encephalitis, which are infections of the brain or the membrane that covers it, can cause confusion, memory loss or sudden dementia. Untreated syphilis or Lyme disease can damage the brain and cause dementia.
• Normal-pressure hydrocephalus. If cerebrospinal fluid builds up in the ventricles of the brain, the brain tissue is compressed even though the fluid pressure remains normal. This may cause dementia. If this condition is identified in time, it may be treated by draining the excess fluid via a tube (shunt).