print this pageDementia and its causes
Dementia is the loss of mental function in two or more areas such as language, memory, visual and spatial abilities, or judgment severe enough to interfere with daily life. Dementia itself is not a disease but a broader set of symptoms that accompanies certain diseases or physical conditions. Well-known disease that cause dementia include Alzheimer's disease, multi-infarct dementia, Parkinson's disease, Huntington's disease, Creutzfeldt-Jakob disease, Pick's disease, and Lewy body dementia. Other physical conditions may cause or mimic dementia, such as depression, brain tumors, head injuries, nutritional deficiencies, hydrocephalus, infections (AIDS, meningitis, syphilis), drug reactions, and thyroid problems. Individuals experiencing dementia-like symptoms should undergo diagnostic testing as soon as possible. An early and accurate diagnosis helps to identify reversible conditions gives patients a greater chance of benefiting from exiting treatments, and allows them and their families more time to plan for the future.
ALZHEIMER'S DISEASE
Alzheimer's disease is the most common cause of dementia, affecting as many as 4 million
Americans. AD is a degenerative disease that attacks the brain, begins gradually, and
progresses at a variable rate. AD results in impaired memory, thinking, and behavior and
can last from 3 to 20 years from the time of onset of symptoms. Warning signs of AD are
memory loss that affects job/home skills, difficulty performing familiar tasks, problems
finding the right words, disorientation as to time and place, poor or decreased judgment,
difficulty with learning and abstract thinking, placing things in inappropriate places,
changes in mood and personality, and marked loss of initiative. In the last stage of AD,
patients are unable to take care of themselves. Recent research has shown links between
particular genes and Alzheimer's disease, but in about 90% of AD cases, there is no clear
genetic link. With the help of standardized diagnostic criteria, physicians can now
diagnose AD with an accuracy of 85-90% once symptoms occur. However, a definitive
diagnosis of Alzheimer's disease is possible only through the examination of brain tissue
at autopsy.
MULTI-INFARCT DEMENTIA
Multi-infarct dementia (MID), or vascular dementia, is a deterioration of mental capacity
caused by multiple strokes (infarcts) in the brain. These events may be described as
mini-strokes, where small blood vessels in the brain become blocked by blood clots, causing
the destruction of brain tissue. The onset of MID may seem relatively sudden, as it may
take several strokes for symptoms to appear, These strokes may damage areas of the brain
responsible for a specific function as well as produce general symptoms of dementia. As a
result, MID is sometimes misdiagnosed as Alzheimer's disease. MID is not reversible or
curable, but detection of high blood pressure and other vascular risk factors can lead to
a specific treatment that may modify MID's progression. MID is usually diagnosed through
neurological examination and brain scanning techniques, such as a computerized tomography
(CT) scan or magnetic resonance imaging (MRI).
PARKINSON'S DISEASE
Parkinson's disease (PD) is a progressive disorder of the central nervous system that
affects over one million Americans. In PD certain brain cells deteriorate for reasons not
yet known. These cells produce a substance called dopamine, which helps control muscle
activity. PD is often characterized by tremors, stiffness in limbs and joints, speech
difficulties, and difficulty initiating physical movement. Late in the course of the
disease, some patients develop dementia and eventually Alzheimer's disease. Conversely,
some Alzheimer's patients develop symptoms of Parkinson's. Medications such as levodopa,
which converts to dopamine inside the brain, and deprenyl, which prevents degeneration of
dopamine-containing brain cells, are used to improve diminished or reduced motor symptoms
in PD patients but do not correct the mental changes that occur.
HUNTINGTON'S DISEASE
Huntington's disease (HD) is an inherited, degenerative brain disease that causes both
physical and mental disabilities and usually begins in mid-life. Early symptoms can vary
from person to person but include involuntary movement of the limbs or facial muscles.
Difficulty concentrating, and depression. Other symptoms include personality change,
memory disturbance, slurred speech, and impaired judgment. Children born to a person with
HD have a 50% chance of inheriting the gene that causes HD. Today a genetic test is
available to confirm a diagnosis of HD and to identify carriers of the HD gene. It is
recommended that anyone considering genetic testing talk first with family and/or
appropriate medical and counseling professionals. There is no treatment to stop the
progression of HD, but the movement disturbances and psychiatric symptoms can be treated
with medication.
CREUTZFELDT-JAKOB DISEASE
Creutzfeldt-Jakob Disease (CJD) is a rare, fatal brain disorder that causes rapid,
progressive dementia and other neuromuscular disturbances. CJD is caused by a
transmissible agent. Research suggests that the agent differs significantly from viruses
and other conventional agents. This newly discovered pathogen is called a
"prion," short for "proteinaceous infectious particle," because it
consists of protein and transforms normal protein molecules into infectious ones. The
disease can be inherited, but the majority of cases are not. Early symptoms of CJD include
filing memory, changes in behavior, and lack of coordination. As the disease advances,
usually very rapidly, mental deterioration becomes pronounced, involuntary movements
(especially muscle jerks) appear, and the patient experiences severe difficulty with
sight, muscular energy, and coordination. Like Alzheimer's disease, a definitive diagnosis
of CJD can be obtained only through examination of brain tissue at autopsy.
PICK'S DISEASE
Pick's disease is also a rare brain disorder characterized by shrinkage of the tissues of
the frontal and temporal lobes of the brain and by the presence of abnormal bodies (Pick's
bodies) in the nerve cells of the affected areas of the brain. Pick's disease usually
begins between ages of 40 and 60. The symptoms are similar to Alzheimer's disease, with a
loss of language abilities, skilled movement, and the ability to recognize objects or
people. Initial diagnosis is based on family history (Pick's disease may be inherited),
symptoms, tests, and ruling out other causes of dementia. A definitive diagnosis of Pick's
disease is usually obtained at autopsy.
LEWY BODY DEMENTIA
Lewy body dementia (LBD) is an irreversible form of dementia associated with abnormal
protein deposits in the brain called Lewy bodies. Symptoms of LBD are similar to Alzheimer
symptoms and include memory loss, confusion, and difficulty communicating. Hallucinations
and paranoia also may become apparent in the earlier stages of the disease and often last
throughout the disease process. Although initial symptoms of LBD may be mild, affected
individuals eventually develop severe cognitive impairment. At this time, there is no
treatment available for Lewy body dementia.
NORMAL PRESSURE HYDROCEPHALUS
Normal pressure hydrocephalus is an uncommon disorder, which involves an obstruction in
the normal flow of cerebrospinal fluid. This blockage causes a buildup of cerebrospinal
fluid on the brain. Symptoms of normal pressure hydrocephalus include dementia, urinary
incontinence and difficulty in walking. Presently, the most useful diagnostic tools are
the neuroimaging techniques (ie., MRI). Normal pressure hydrocephalus may be caused by any
of several factors including meningitis, encephalitis and head injuries. In addition to
treatment of the underlying cause, the condition may be corrected by a neurosurgical
procedure (insertion of a shunt) to divert the fluid away from the brain.
DEPRESSION
Depression is a psychiatric disorder marked by sadness, inactivity, difficulty in thinking
and concentration, feelings of hopelessness, and sometimes suicidal tendencies. Many
severely depressed patients will have some mental deficits including poor concentration
and attention. When dementia and depression are present together, intellectual
deterioration may be exaggerated. Depression, whether present alone or in combination with
dementia, can be reversed with proper treatment.
This information is from the Alzheimer's Association of Los Angeles