“Dr Irena’s” Health Tips – No.19

Dementia (Part 1)

 

Irena Hulson is continuing with her series of health Dr Irena phototips, which have been very well received by our readers, especially those who can relate to certain of the topics covered and we hope to receive and publish more in the future for your information.  If there is a particular topic you would like to see published please let us know and we will ask Irena to see what she can find on the subject.

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By Irena Hulson

What is Dementia?

Dementia is not a specific disease. It is a descriptive term for a collection of symptoms that can be caused by a number of disorders What is dementiathat affect the brain. People with dementia have significantly impaired intellectual functioning that interferes with normal activities and relationships. They also lose their ability to solve problems and maintain emotional control, and they may experience personality changes and behavioural problems such as agitation, delusions, and hallucinations. While memory loss is a common symptom of dementia, memory loss by itself does not mean that a person has dementia.  Doctors diagnose dementia only if two or more brain functions – such as memory, language skills, perception, or cognitive skills including reasoning and judgment – are significantly impaired without loss of consciousness.

A woman in her early 50s was admitted to a hospital because of increasingly odd behaviour. Her family reported that she had been showing memory problems and strong feelings of jealousy. She also had become disorientated at home and was hiding objects. During a doctor’s examination, the woman was unable to remember her husband’s name, the year, or how long she had been at the hospital.

What Are the Different Kinds of Dementia?

Dementing disorders can be classified many different ways. These classification schemes attempt to group disorders that Dementiahave particular features in common, such as whether they are progressive or what parts of the brain are affected.  Some frequently used classifications are shown in this chart.

Some types of dementia fit into more than one of these classifications. For example, Alzheimer’s disease is considered both a progressive and a cortical dementia. There are many disorders that can cause dementia.

Alzheimer’s Disease

Alzheimer’s disease is the most common cause of dementia in people aged 65 and older. Experts believe that up to 4 million people in the United States are currently living with the disease: one in ten people Handsover the age of 65 and nearly half of those over 85 have Alzheimer’s disease. At least 360,000 Americans are diagnosed with Alzheimer’s disease each year and about 50,000 are reported to die from it. In most people, symptoms of Alzheimer’s disease appear after age 60. However, there are some early-onset forms of the disease, usually linked to a specific gene defect, which may appear as early as age 30. Alzheimer’s disease usually causes a gradual decline in thinking abilities, usually during a span of 7 to 10 years. Nearly all brain functions, including memory, movement, language, judgment, behaviour, and abstract thinking, are eventually affected.

In the early stages of Alzheimer’s disease, patients may experience memory impairment, lapses of judgment, and subtle changes in personality. As the disorder progresses, memory and language problems worsen and patients begin to have difficulty performing Losing memoryactivities of daily living, such as dealing with a cheque book or remembering to take medications. They may become disorientated about places and times, may suffer delusions (such as the idea that someone is stealing from them or that their spouse is being unfaithful), and may become short-tempered and hostile. During the late stages of the disease, patients begin to lose the ability to control motor functions such as swallowing, or lose bowel and bladder control. They eventually lose the ability to recognize family members and to speak. As the disease progresses it begins to affect the person’s emotions and behaviour and they develop symptoms such as aggression, agitation, depression, sleeplessness, or delusions. On average, patients with Alzheimer’s disease live for 8 to 10 years after they are diagnosed. However, some people live as long as 20 years. Patients with Alzheimer’s disease often die of aspiration pneumonia because they lose the ability to swallow late in the course of the disease.

Vascular (Multi-Infarct) Dementia

Vascular dementia is the second most common cause of dementia, after Alzheimer’s disease. It accounts for up to 20% of all dementias and is caused by brain damage from cerebrovascular or cardiovascular problems – usually strokes. It also may result from genetic diseases, endocarditis (infection of a heart valve), or amyloid angiopathy (a process in which amyloid protein builds up in the brain’s blood vessels, sometimes causing hemorrhagic or “bleeding” strokes). In many cases, it may coexist with Alzheimer’s disease. Unlike people with Alzheimer’s Roadsdisease, people with vascular dementia often maintain their personality and normal levels of emotional responsiveness until the later stages of the disease. People with vascular dementia frequently wander at night and often have other problems commonly found in people who have had a stroke, including depression and incontinence.

There are several types of vascular dementia, which vary slightly in their causes and symptoms. One type, called multi-infarct dementia (MID), is caused by numerous small strokes in the brain. Multi-infarct dementia typically includes multiple damaged areas, called infarcts, along with extensive lesions in the white matter, or nerve fibers, of the brain. Although not all strokes cause dementia, in some cases a single stroke can damage the brain enough to cause dementia. This condition is called single-infarct dementia. Dementia is more common when the stroke takes place on the left side (hemisphere) of the brain and/or when it involves the hippocampus, a brain structure important for memory.

Other types of vascular dementia include Binswanger’s disease and CADASIL (cerebral autosomal dominant arteriopathy with subcortical infarct and leukoencephalopathy).

Lewy Body Dementia (LBD)

Lewy body dementia (LBD) is one of the most common types of progressive dementia. Lewy body dementia usually occurs sporadically, in people with no known family history of the disease. However, rare familial cases have occasionally been reported. In Lwey BodyLewy body dementia, cells die in the brain’s cortex (outer layer), and in a part of the mid-brain called the substantia nigra. Many of the remaining nerve cells in the substantia nigra contain abnormal structures called Lewy bodies that are the hallmark of the disease.

The symptoms of Lewy body dementia overlap with Alzheimer’s disease in many ways, and may include memory impairment, poor judgment, and confusion. However, Lewy body dementia typically also includes visual hallucinations, parkinsonian symptoms such as a shuffling gait (walk) and flexed posture, and day-to-day fluctuations in the severity of symptoms. Patients with Lewy body dementia live an average of 7 years after symptoms begin. There is no cure for Lewy body dementia, and treatments are aimed at controlling the parkinsonian and psychiatric symptoms of the disorder.

Front temporal Dementia (FTD)

Front temporal dementia, sometimes called frontal lobe dementia, describes a group of diseases characterized by degeneration of nerve cells – especially those in the frontal and temporal lobes of the brain. Unlike Alzheimer’s disease, front temporal dementia usually does not include formation of amyloid plaques. In many people with front temporal dementia, there is an abnormal form of tau protein in the brain, Leaveswhich accumulates into neurofibrillary tangles. This disrupts normal cell activities and may cause the cells to die.

Experts believe front temporal dementia accounts for 2% to 10% of all cases of dementia. Symptoms of front temporal dementia usually appear between the ages of 40 and 65. In many cases, people with front temporal dementia have a family history of dementia, suggesting that there is a strong genetic factor in the disease. The duration of front temporal dementia varies, with some patients declining rapidly over 2 to 3 years and others showing only minimal changes for many years. People with front temporal dementia live with the disease for an average of 5 to 10 years after diagnosis.

Because structures found in the frontal and temporal lobes of the brain control judgment and social behaviour, people with front temporal dementia often have problems maintaining normal interactions and following social conventions. They may steal or exhibit impolite and socially inappropriate behaviour, and they may neglect their normal responsibilities. Other common symptoms include loss of speech and language, compulsive or repetitive behaviour, increased appetite, and motor problems such as stiffness and balance problems. Memory loss also may occur, although it typically appears late in the disease.

(HIV) that causes AIDS. HIV-associated dementia can cause widespread destruction of the brain’s white matter. This leads to a type of dementia that generally includes impaired memory, apathy, social withdrawal, and difficulty concentrating. People with HIV-associated dementia often develop movement problems as well. There is no specific treatment for HIV-associated dementia, but AIDS drugs can delay onset Huntington’s disease usually begin when patients are in their thirties or forties, and the average life expectancy after diagnosis is about 15 years. Cognitive symptoms of Huntington’s disease typically begin with mild personality changes, such as irritability, anxiety, and depression, and progress to severe dementia. Many patients also show psychotic behavior. Huntington’s disease causes chorea – involuntary jerky, arrhythmic movements of the body – as well as muscle weakness, clumsiness, and gait disturbances.

Dementia Pugilistica

Dementia pugilistica, also called chronic traumatic encephalopathy or Boxer’s syndrome, is caused by head trauma, such as Boxingthat experienced by people who have been punched many times in the head during boxing. The most common symptoms of the condition are dementia and parkinsonism, which can appear many years after the trauma ends. Affected individuals may also develop poor coordination and slurred speech. A single traumatic brain injury may also lead to a disorder called post-traumatic dementia (PTD). Post-traumatic dementia is much like dementia pugilistica but usually also includes long-term memory problems. Other symptoms vary depending on which part of the brain was damaged by the injury.

Corticobasal degeneration (CBD)

Corticobasal degeneration (CBD) is a progressive disorder characterized by nerve cell loss and atrophy of multiple areas of the brain. Brain cells from people with corticobasal degeneration often have abnormal accumulations of the protein tau. Corticobasal degeneration usually progresses gradually over the course of 6 to 8 years. Initial symptoms, which typically begin at or around age 60, may first appear on one side of the body but eventually will affect both sides. Some of the symptoms, such as poor coordination and rigidity, are similar to those found in Parkinson’s disease. Other symptoms may include memory loss, dementia, visual-spatial problems, apraxia (loss of the ability to make familiar, purposeful movements), hesitant and halting speech, myoclonus (involuntary muscular jerks), and dysphagia (difficulty swallowing). Death is often caused by pneumonia or other secondary problems such as sepsis (severe bacterial infection of the blood) or pulmonary embolism (a blood clot in the lungs).

Creutzfeldt-Jakob Disease (CJD)

Creutzfeldt-Jakob disease (CJD) is a rare, degenerative, fatal brain Mad Cow Diseasedisorder that affects about one in every million people per year worldwide. Creutzfeldt-Jakob disease belongs to a family of human and animal diseases known as the transmissible spongiform encephalopathies (TSEs). This includes bovine spongiform encephalopathy (BSE), which is found in cows and often referred to as “mad cow” disease. Symptoms usually begin after age 60 and most patients die within 1 year. Many researchers believe Creutzfeldt-Jakob disease results from an abnormal form of a protein called a prion. Most cases of Creutzfeldt-Jakob disease occur sporadically – that is, in people who have no known risk factors for the disease. However, about 5% to 10% of cases of Creutzfeldt-Jakob disease in the United States are hereditary, caused by a mutation in the gene for the prion protein. Patients with Creutzfeldt-Jakob disease may initially experience problems with muscular coordination; personality changes, including impaired memory, judgment, and thinking; and impaired vision. Other symptoms may include insomnia and depression. As the illness progresses, mental impairment becomes severe. Patients often develop myoclonus and they may go blind. They eventually lose the ability to move and speak, and go into a coma. Pneumonia and other infections often occur in these patients and can lead to death.

Dementias in Children

While it is usually found in adults, dementia can also occur in children. For example, infections and poisoning can lead to dementia in people of any age. In addition, some disorders unique to children can cause dementia. These include Niemann-Pick disease, Batten disease and Lafora body disease.

What Other Conditions Can Cause Dementia?

Doctors have identified many other conditions that can cause dementia or dementia-like symptoms. Examples of these include:

  • Reactions or side effects to medications;
  • Metabolic problems and endocrine abnormalities such as thyroid disease, hypoglycemia, too little (hypernatremia) or too much sodium or calcium (hypercalcemia), or the inability to absorb vitamin B12 (pernicious anemia);
  • Nutritional deficiencies such as thiamine (vitamin B1), B6, or B12 and severe dehydration;
  • Infections such as meningitis, encephalitis, untreated syphilis, and Lyme disease;
  • Subdural hematomas where there is bleeding between the brain’s surface and its outer covering (the dura);
  • Poisoning such as exposure to lead, other heavy metals, alcohol, recreational drugs or other poisonous substances;
  • Brain tumors;
  • Anoxia/hypoxia in which there is a diminished supply of oxygen to an organ’s tissues, for example heart attack, severe asthma, heart surgery, smoke or carbon monoxide inhalation, or an overdose of anesthesia; and
  • Heart and chronic lung problems disease that prevents the brain from receiving adequate oxygen, which can starve brain cells.

What Conditions Are Not Dementia?

  • Age-related cognitive decline. As people age, they usually experience slower information processing and mild memory impairment. In addition, their brains frequently decrease in volume and some nerve cells, or neurons, are lost.
  • Mild cognitive impairment. Some people develop cognitive and memory problems that are not severe enough to be diagnosed as dementia but are more pronounced than the cognitive changes associated with normal aging. Although many patients with this condition later develop dementia, some do not.
  • Depression. People with depression are frequently passive or unresponsive, and they may appear slow, confused, or forgetful.
  • Delirium. Delirium is characterized by confusion and rapidly altering mental states. The person may also be disorientated, drowsy, or incoherent, and may exhibit personality changes. Delirium is usually caused by a treatable physical or psychiatric illness, such as poisoning or infections. Patients with delirium often, though not always, make a full recovery after their underlying illness is treated.

What Causes Dementia?

All forms of dementia result from the death of nerve cells and/or the loss of communication among these cells. The Altzheimershuman brain is a very complex and intricate machine and many factors can interfere with its functioning. Researchers have uncovered many of these factors, but they have not yet been able to fit these puzzle pieces together in order to form a complete picture of how dementias develop.

Many types of dementia, including Alzheimer’s disease, Lewy body dementia, Parkinson’s dementia, and Pick’s disease, are characterized by abnormal structures called inclusions in the brain. Because these inclusions, which contain abnormal proteins, are so common in people with dementia, researchers suspect that they play a role in the development of symptoms. However, that role is unknown, and in some cases the inclusions may simply be a side effect of the disease process that leads to the dementia.

Genes clearly play a role in the development of some kinds of dementia. However, in Alzheimer’s disease and many other disorders, the dementia usually cannot be tied to a single abnormal gene. Instead, these forms of dementia appear to result from a complex interaction of genes, lifestyle factors, and other environmental influences.

What Are the Risk Factors for Dementia?

Researchers have identified several risk factors that affect the likelihood of developing one or more kinds of dementia. Some of these factors are modifiable, while others are not.

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Editor’s Note

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