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”).