Dementia refers to a syndrome (a group of symptoms) which  affects a person's intellectual and social abilities severely enough to interfere with daily functioning. Different types of dementia exist, depending on the cause. Alzheimer's disease is the most common type. It is NOT a  a normal part of aging.

Medication and other treatments can improve many symptoms of dementia and the quality of life of the patient and family.

Tips for caring for a person with Dementia

Tips for handing persons with Dementia

Tips for managing problem behaviour in Dementia

Causes

Dementia has many causes. It's not always caused by the same disease.

Progressive dementia: These are dementias that get worse with time. There are several types of progressive dementia.

• Alzheimer's disease. This is the most common among the progressive dementias and usually occurs in in people aged 65 and older. However early-onset forms of the disease can occur, usually as the result of a defective gene. It is caused by destruction of brain cells through formation of plaques (clumps of a normally harmless protein called beta-amyloid) and tangles (fibrous tangles made up of an abnormal protein called tau protein). Alzheimer's disease usually progresses slowly, over seven to 10 years, causing a gradual decline in cognitive abilities including  memory, and  language, judgment, behavior and abstract thinking and ultimately leading to sever disability including movement disorders.
• Lewy body dementia. In this disorder the brain cells are destroyed by abnormal clumps of protein called Lewy bodies. The symptoms are predominantly fluctuations between confusion and clear thinking (lucidity), visual hallucinations and tremor and rigidity. Other symptoms may be similar to Alzheimer's disease. People with this disorder will often have acting out dreams, including thrashing or kicking during sleep.

• Vascular dementia. In general, vascular dementia is more common with age.  It is a result of damage to the brain caused by  "mini stokes" (lacunar infarcts)  that destroy small parts of the brain. It occurs due to  interference with blood supply to the brain. The symptoms may be similar to Alzheimer or Lewy body dementia but occur suddenly and progress in a "step ladder" pattern, with sudden onset of a group of symptoms, a period (sometimes months) with no worsening, and then sudden onset of another group of symptoms with worsening of the condition. People with high blood pressure, diabetes, high cholesterol, or previous strokes or heart attacks are at risk of developing this disorder. 

• Frontotemporal dementia. This disorder is caused by damage to the brain cells  in the frontal and temporal lobes of the brain associated with personality, behavior and language. Symptoms of frontotemporal dementia —  include socially inappropriate behaviors, loss of mental flexibility, language problems and difficulty with thinking and concentration It usually occurs between the ages of 40 and 65.

Reversible Dementias:

Dementia can occur due to various disorders or deficiencies that can be treated. In such cases the symptoms of dementia disappear with treatment of thy underlying cause.or dementia-like symptoms can be reversed. 

• Infections: Dementia can result from infections of the brain (meningitis and encephalitis etc).
• Metabolic problems and endocrine abnormalities. Dementia can be caused by thyroid problems, hypoglycemia, too little or too much sodium or calcium, and an impaired ability to absorb vitamin B-12.
• Immune system disorders. A  side effect of your body's attempt to fight off an infection (auto immune disorder) can result in dementia e.g. multiple sclerosis. Conditions that cause a completely compromised immune system, such as leukemia can also cause dementia.
• Nutritional deficiencies. Symptoms of dementia can  occur as a result of damage to brain cells by dehydration, and deficiencies in vitamins B-1, B-6 and B-12.
• Insufficient oxygen. Brain cells can be damaged when not enough oxygen gets to organ tissue due to heart attack, severe asthma, chronic lung problems or a heart condition that deprives the brain of the oxygen it needs, carbon monoxide poisoning, strangulation, high-altitude exposure or an overdose of anesthesia.
• Reactions to medications. Dementia may occur as a reaction to a single medication or because of an interaction of several drugs.
• Subdural hematomas. These are caused by bleeding between the brain's surface and its outer covering.
• Exposure to poisons. Exposure to heavy metals, such as lead or manganese, and other poisons, such as pesticides can damage brain cells as can excessive use of alcohol and recreational drugs also sometimes display symptoms.
• Brain tumors. Dementia can be the result of damage caused by a brain tumor.

Treatment:

Six drugs have been approved  for treating the cognitive symptoms of Alzheimer's disease / Dementia. Four act in different ways to delay the breakdown of acetylcholine, a chemical in the brain that facilitates communication among nerve cells and is important for memory. Alzheimer's disease is associated with inadequate levels of this important neurotransmitter. One acts by a different mechanism. It shields brain cells from overexposure to another neurotransmitter called glutamate, excess levels of which contribute to the death of brain cells in people with Alzheimer's. The sixth is an improves acetylcholine production boosting brain metabolism. They all improve mental function memory.

In general, medication is most effective when treatment is begun in the early stages. All medication slows the progression of cognitive symptoms and reduce problematic behaviors in some people. While the overall "treatment effect" of these medications is modest, studies show that when they do work, they can make a significant difference in a person's quality of life and day-to-day functioning ("activities of daily living"). 

Symptoms 

Signs and symptoms of Alzheimer's disease include

• Memory loss
• Difficulty communicating
• Inability to learn or remember new information
• Difficulty with planning and organizing
• Difficulty with coordination and motor functions
• Personality changes
• Inability to reason
• Inappropriate behavior
• Paranoia
• Agitation
• Hallucinations

Signs and symptoms of fronto-temporal dementiainvolve extreme changes in behavior and personality, including:

• Increasingly inappropriate actions
• Euphoria
• Lack of judgment and inhibition
• Apathy
• Repetitive compulsive behavior
• A decline in personal hygiene
• Lack of awareness of thinking or behavioral changes
• impairment or loss of speech and linguistic abilities
• primary progressive aphasia (an increasing difficulty in using and understanding written and spoken language)
• semantic dysphasia (uttering grammatically correct speech that has no relevance to the conversation at hand
  

Signs and symptoms of Lewy body dementiamay include:

• Visual hallucinations (Seeing colors, shapes, animals or people that don't exist)
• Movement disorders including slowed movement, rigid muscles, tremors or a shuffling walk.
• Delusions (false ideas about another person or situation).
• Cognitive problems including confusion, memory loss and reduced attention spans.
• Sleep difficulties.

Movement-related signs and symptoms may include:

• Tremor
• Rigidity
• Muscle spasms
• Poor coordination
• Difficulty swallowing
• Muscle weakness
  

Risk factors that can't be changed

• Age. The risk of Alzheimer's disease, vascular dementia and several other dementias increases significantly with age.
  
• Family history. People with a family history of dementia are at greater risk of developing it.

Risk factors that can be changed:

• Blood pressure. Very high or very low blood pressure can increase the  risk of developing Alzheimer's disease and vascular dementia.

• Cholesterol. High levels of low-density lipoprotein (LDL) cholesterol, the "bad" cholesterol, can significantly increase your risk of developing vascular dementia. Plaques (Buildup of fatty substances) in and  on the lining of the arteries  interferes with blood flow to your brain and causes vascular dementia because it .
• Smoking. Smoking increases the risk of developing dementia by increasing the risk of vascular disease resulting in dementia.
• Alcohol abuse. Consuming large amounts of alcohol  increases the risk of dementia. Although  moderate amounts of alcohol — 2 units per day -   have a protective effect, abuse of alcohol increases risk of developing dementia.
• Homocysteine blood levels. Elevated blood levels of homocysteine — a type of amino acid produced by your body — due to inability to metabolize  vitamins B-6, B-12 and folic acid, or a deficiency of these vitamins, increases the risk of developing Alzheimer's disease and vascular dementia.
• Depression. Although not yet well understood, late-life depression, especially in men, may be an indication for the development of Alzheimer's-related dementia.
• Diabetes. If you have type 2 diabetes, you're at increased risk of developing both Alzheimer's disease and vascular dementia.
• High estrogen levels. High levels of total estrogen in women have been associated with greater risk of developing dementia.

How can you find out that there is damage to brain cells?

Dementias change brain structure over time which can be seen with a brain scan. Several types of scans are used.

• CT and MRI scans. Computerized tomography (CT) and magnetic resonance imaging (MRI) scans help identify brain-size changes, strokes and other problems such as excess fluid in the brain (hydrocephalus) or bleeding on the surface of the brain (subdural hematoma).
• Electroencephalogram (EEG). Using electrodes placed on your scalp, patterns of electrical activity can be recorded and show abnormalities which can indicate cognitive dysfunction.

Laboratory tests
A variety of lab tests can help rule out  conditions that can cause dementia.