Dementia: Causes and Treatments

Dementia is not a specific disease. It is a term which describes a group of symptoms that causes a significant decline in intellectual functioning, impairing normal activities and changing relationships. While memory loss is a common symptom of dementia, by itself it does not mean that a person has dementia. Doctors diagnose dementia only if two or more brain functions - such as memory, orientation, learning or language skills, reasoning or judgment - are significantly impaired.  Such impairments eventually decrease one’s ability to perform everyday activities like driving, paying bills, housekeeping, preparing meals and even personal care skills like bathing and dressing. A person with dementia also may exhibit personality changes, loss of emotional control and behavioral problems such as agitation, paranoia and hallucinations.

Dementia is most common in older adults, but is not a normal part of aging. It is caused by a number of medical conditions. In come cases, dementia can be reversed or stopped from getting worse. In others, it is permanent and usually gets worse over time. As with any other medical condition, it is essential that a proper evaluation be made when the symptoms of dementia first appear, so that appropriate treatments can be offered. Common forms and causes of dementia include:

Alzheimer's Disease is the most common cause of dementia in older persons. It is marked by the abnormally rapid death of brain cells. The precise cause of Alzheimer’s Disease is unknown, but this is being aggressively studied worldwide by researchers. Alzheimer’s is characterized by a progressive loss of intellectual and functional abilities. On average, persons with Alzheimer’s Disease live for 8-10 years after they are diagnosed, with death often resulting from pneumonia and other infections that arise late in the disease. Current treatments focus on medications to prolong the functioning of still-living brain cells. These medications slow, but do not halt the progression of Alzheimer’s Disease.

Vascular Dementia is caused either by a severe narrowing or blockage of arteries that carry blood to the brain, or from strokes caused by an interruption of blood flow to the brain. The first symptoms of vascular dementia usually start suddenly, and progression is often marked by abrupt “step downs” of cognitive abilities. But vascular dementia may also slowly and progressively worsen over time. Treatment involves preventing additional strokes by addressing underlying diseases, such as high blood pressure and high cholesterol, and by use of blood-thinning medications. There is some evidence that use of medications commonly prescribed to treat Alzheimer’s Disease may also slow the progression of vascular dementia.

Parkinson's Dementia. Persons with late-stage Parkinson’s Disease or “Parkinson’s Plus” Diseases (such as Progressive Supranuclear Palsy) may develop a dementia with symptoms and a progressive course similar to those of Alzheimer’s Disease.

Lewy Body Dementia is marked by small protein deposits found in deteriorating nerve cells in the brain. These often appear in areas of the brain that are associated with the tremor and rigidity of Parkinson’s Disease. When these lewy bodies are spread through out the brain, they may produce symptoms similar to those of Alzheimer’s Disease as well as hallucinations and major fluctuations in alertness.
 
Fronto-Temporal Dementia is marked by a deterioration of nerve cells in the frontal and temporal lobes of the brain. Initial symptoms include behavioral and personality changes, such as poor judgment and impulsiveness. It then progresses to impairments of language and cognitive skills. Fronto-Temporal Dementia is not curable, and usually does not respond to the medications used to treat Alzheimer’s Disease. Mood and behavioral problems can be treated using standard anti-psychotic and anti-depressant medications.

Head Trauma Dementia may result from a single, significant head injury, or from a series of head blows, such as those suffered by professional boxers. A single traumatic brain injury may produce an immediate dementia, but symptoms vary depending on which part of the brain was damaged. Dementia from repeated head blows may appear many years after the trauma ends, and is often marked by symptoms of Parkinsonism.

Doctors have identified other conditions that can cause dementia or dementia-like symptoms. In the following conditions, cognitive problems may sometimes be reversed with appropriate treatment.

Hypoxia occurs when there has been a significant disruption in the flow of oxygen to the brain. This can cause serious impairments of physical, cognitive and psychological skills. The rate and extent of recovery are unpredictable and largely depend on which parts of the brain have been affected, and how severe the injury is.

Brain Tumor  A tumor may press on and damage brain cells, and other structures in the brain. Medical or surgical treatment of the tumor can sometimes reverse the symptoms of dementia however, depending upon the degree of brain injury sustained because of pressure on brain cells and structures, a person may be left with some degree of permanent cognitive disability.

Subdural Hematoma is a collection of blood, a hematoma, that forms on the surface of the brain. It often results from head injury but can occur spontaneously in older persons, especially those who take blood thinning medications. Symptoms may include numbness and weakness, slurred speech, drowsiness and mental confusion. Cognitive changes occur and progress quickly or slowly depending upon the size and location of the hematoma. This condition requires emergency treatment that may include medications and/or surgery to drill a small hole in the skull to allow the blood to drain and relieve pressure on the brain. Depending upon the degree of brain injury caused by pressure from the hematoma, a person may be left with some degree of permanent cognitive disability.

Normal Pressure Hydrocephalus (NPH) is a condition that arises when the flow of spinal fluid in and out of the brain is obstructed, causing it to backup into areas of the brain and creating increased pressure that can damage brain tissue. NPH often results from a prior brain injury or infection, and also produces symptoms of walking difficulties and loss of bladder control. NPH may often be corrected with surgery to install a small tube (a “shunt”) into the brain to drain off the excess fluid. The degree of cognitive improvement after such treatment, however, varies among patients.

Alcohol Dependence can lead to symptoms of dementia. Long term and/or heavy use of alcohol can damage brain cells, causing them to deteriorate and die off more rapidly than they otherwise would. Alcohol abuse also contributes to nutritional and vitamin deficiencies and liver diseases which can cause dementia symptoms. Abstaining from alcohol can often improve all of these problems.

Infections of the brain and central nervous system, from disorders such as meningitis, encephalitis Lyme Disease or late-stage syphilis, will cause inflammation that damages brain cells if not properly treated

Hormone Disorders involve body glands that secrete and/or regulate hormones. These include the thyroid, parathyroid, pituitary and adrenal glands. Severe and/or prolonged imbalances in such hormones can lead to dementia if not corrected.

Metabolic Disorders such as kidney, liver and pancreas diseases, can cause symptoms of dementia, and may be progressive and irreversible if left untreated.  
            
What conditions are not dementia?

Depression can make an older person appear to be demented because it can cause inattention, apathy and impair one’s ability to learn and remember new things. Persons with a significant depression, but without any underlying dementia, should regain cognitive skills if their mood is successfully treated. However, depression can also be a symptom of dementia. In such cases, treating depression is still important but does not fully restore cognition.

Delirium causes confusion and rapidly fluctuating mental states. The person may also be disoriented, drowsy or incoherent, and may have personality changes. Delirium is usually caused by a treatable physical illness, such as a poisoning or an infection, and persons will often, though not always, make a complete recovery after the underlying illness is treated.

Medication Effects  Misuse or abuse of some prescription and over-the-counter medications can produce a delirium that mimics symptoms of dementia. Medications which can produce such side effects include sleeping pills, tranquilizers and anti-anxiety drugs, antihistamines and other cold medications. When such medications are stopped or decreased, the delirium and symptoms of dementia usually lessen or stop.

Age-Related Cognitive Decline is marked by very mild memory impairment and a slowing in the rate in which the brain processes new information. These changes are considered normal and are not considered signs of dementia. 

Mild Cognitive Impairment is a condition in which cognitive and memory problems are more pronounced than the cognitive changes associated with normal aging, but are not severe enough to be diagnosed as dementia. Many persons with Mild Cognitive Impairment, however, eventually go on to develop a dementia. 

Sources:

“What is Alzheimer’s Disease?”      

“Dementia: It’s Not Always Alzheimer’s”   

“Dementia Overview”  

“Dementia”   

“The Dementias: Hope Through Research” The National Institute of Neurological Disorders and Stroke" 

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