Читать книгу The Small Guide to Alzheimer's Disease - Gary Small - Страница 9

One of the most frequent questions patients and families ask me involves the difference between Alzheimer’s disease and dementia. Briefly, dementia is a cognitive loss that makes a patient dependent on others for care, and Alzheimer’s disease is simply the most common type of dementia, accounting for about two-thirds of all dementia cases. Memory is just one aspect of cognition, which refers to several mental skills in addition to memory. These include attention, language ability, reasoning, and visual-spatial functioning.

In part because of the extensive media coverage about Alzheimer’s disease, the public has tremendous anxiety about that diagnosis. However, because early interventions can slow down the neurodegeneration of Alzheimer’s disease, a diagnosis of dementia from other causes can sometimes have a worse prognosis. For example, a patient who has a severe vascular dementia caused by multiple small strokes may have greater functional impairment than a patient experiencing mild cognitive losses from early-stage Alzheimer’s. Also, Alzheimer’s disease usually progresses very slowly.

Many different diseases and conditions can cause a dementia syndrome. Dementia from Lewy bodies in the brain has symptoms similar to Alzheimer’s disease as well as rigidity and other motor symptoms typical of Parkinson’s disease. Frontotemporal dementia primarily affects the frontal and temporal lobes of the brain, causing difficulties in thinking, language, and personality but fewer symptoms of memory loss than in Alzheimer’s. In addition to these progressive neurodegenerative diseases, there are some cases where a reversible cause of the dementia is discovered. Anything from drug toxicity to urinary tract infections to depression can lead to cognitive impairments that disrupt a patient’s daily functioning.

Symptoms of Dementia

 • Memory loss

 • Difficulties in reasoning

 • Disorientation, getting lost

 • Language difficulties such as word-finding

 • Misplacing things

 • Mood or personality changes

 • Showing less interest or initiative

 • Trouble completing familiar tasks like cooking or cleaning

Completely reversible dementias are relatively rare, but I’ve certainly seen them during the course of my practice. In fact, one of the first patients I saw while training as a geriatric psychiatrist was admitted to the hospital with a working diagnosis of Alzheimer’s dementia. During my assessment, I discovered that he had been taking 10 milligrams of Valium (diazepam) every evening for several years. I gradually tapered down his Valium dose, and within a few weeks I had “cured” his dementia.

Possible Causes of Dementia

Although most dementias are chronic and progressive, sometimes a treatable medical cause is uncovered, which reverses some or occasionally all of the symptoms. There are hundreds of different causes of dementia. Below are some of the more common ones and examples.

Possible Cause	Examples
Medical illness	Pneumonia, heart failure, cardiac arrhythmia, thyroid abnormalities, anemia, cancer, liver disease, lung disease, kidney failure, infections, metabolic disturbances, vitamin B12 or folate deficiency, autoimmune disease
Medications	Sedatives, antidepressants, over-the-counter sleep medicines, antihistamines, steroids, pain medicines
Neurodegenerative disorders	Lewy bodies (abnormal brain protein deposits), frontotemporal dementia, Parkinson’s disease, normal pressure hydrocephalus (excess brain fluid), vascular disease, Down syndrome
Psychiatric disorders	Depression, anxiety
Other conditions	Head injury, toxic exposures

Because there are so many medical conditions that can cause a dementia, it is important for families and patients to see their doctor if they are concerned about a memory issue. A simple blood test, brain scan, or physical examination can uncover a treatable illness. Early treatment of such illnesses usually yields the best outcome.

Many times, tests reveal that a combination of both a medical illness and progressive neurodegeneration is causing the patient’s dementia. However, even in those cases, correcting treatable illnesses like anemias, thyroid abnormalities, or medication side effects can improve the patient’s cognitive symptoms to some extent.