Reversible Dementia
By William K. Summers, MD
© William K. Summers, MD
When this section was last written, there was a hopeful but pessimistic view of the demented patient. Much has changed. A dementia is a chronic (greater than 3 months) impairment of intellectual function manifest by memory, language, visual spatial skills, emotion or personality, and cognition. Here, cognition is abstraction, calculation, judgment, and decision-making. A brief list of common causes of dementia is given in Table 26-A. Note that the frequency of findings adds up to more than one hundred percent. Careful evaluation of the demented patient will often show overlapping causes of dementia. For example, a 70-year-old alcoholic hypertensive patient with a slowly progressive dementia, AD7C positive, who is on haloperidol 10 mg per day will have five interacting causes for his confusion. These are 1) alcoholism 2) possible hepatic encephalopathy 3) multi-infarct dementia 4) Alzheimer's disease and 5) drug intoxication with haloperidol.
Accurate diagnoses are possible at about a 90% range, making the concept of accurate diagnosis only by brain biopsy or autopsy obsolete. The clinical evaluation of the patient with dementia is given in Table 26-B.
Previously, it was felt hopeful that 20% of dementias were "reversible" and only 80% were irreversible. Today, in addition to the 20% reversible dementias, over 60% of the irreversible can be improved or the natural history positively altered. Table 26-C gives the five available drugs that are of benefit to Alzheimer's dementia patients. Notice that only Tacrine has the positive effects of CNS microvasculature dilatation and blockade of ß-amyloid deposition. Pure anticholinesterase inhibitors tend to cause vasospasm and increase ß-amyloid deposition, which means that the long-term outcomes may be less favorable. Additionally, Tacrine has beneficial effects on norepinephrine and serotonin levels. Donepezil, Rivastigmine, and Metrifonate are specific anticholinesterase inhibitors, which are more convenient to administer. They are said to be safer than Tacrine; however in the five years since release, there have been no deaths credited to Tacrine in over 300,000 patients.
Alternative agents for Alzheimer's include nonsteroidal anti-inflammatories (NSAIDs), estrogens, steroids, vitamin E, selegiline (Eldepryl), phosphatidylcholine and anti-oxidants. As in other areas of medicine (AIDS and Cancer protocols), it may be proven that a combination of these agents with the ethical drugs will become the standard of Alzheimer's care.
TABLE 26-A COMMON CAUSES OF DEMENTIA
CORTICAL DEMENTIA
Alzheimer’s disease [50%]
Pick’s disease [<1%]
SUBCORTICAL DEMENTIA
Extrapyramidal syndromes
Parkinson’s disease [~1%]
Huntington disease [<1%]
Progressive supranuclear palsy [<1%]
Wilson’s disease [<<1%]
Spinocerebellar degeneration [<<1%]
Normal pressure hydrocephalus [<5%]
Toxic and metabolic encephalopathies
Drug abuse (alcohol, etc) [~8%]
Systemic illness [<5%]
Endocrinopathies (thyroid, diabetic, etc) [<5%]
Anoxic encephalopathy [~1%]
Deficiency states (B12, Folate, iron, etc) [~1%]
Drug intoxications (numerous) [`20 %]
Heavy metal exposure (lead, bismuth, mercury, arsenic) [`1%]
Pseudo dementia (Depression of the elderly) [~7%]
MIXED CORTICAL /SUBCORTICAL DEMENTIAS
Multi-infarct dementia [~12 %]
Infectious dementias (AIDS, slow virus, Kuru, Jakob-Creutzfeldt disease, etc) [<1 %]
Post traumatic (pugilistic dementia) [<1%]
Brain tumor (primary, metastatic) [<5%]
Table 26-B Clinical evaluation of the patient with Dementia
A real history and physical examination by a physician
CBC
T4, T3, and TSH
FTA
AIDS screen
Serum glucose, BUN, creatinine, sodium, potassium, bicarbonate, calcium, phosphate, magnesium, alkaline phosphatase, lactate dehydrogenase, AST (SGOT) aspartate aminotransferase, GGT , ALT (SGPT) alanine aminotransferase
B12, Folic Acid
EKG
Holter Monitor
Cranial MRI
APOE genotyping
Urine AD7C
The "full court press"
Carotid duplex scan
Lumbar Puncture
MRI SPECT scan
Digital EEG
RISA cisternogram
Ceruloplasmin without Kayser-Fleischner rings
Drug and heavy metal screen.
Table 26-C Available Treatments for Alzheimer’s Disease
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