Evaluating Dementia: Assessment for Treatable Causes

"Dementia" means an acquired, persisting decrease incancerous, but because space inside the skull is
mental functioning. Dementia is not a disease or alimited, they cause trouble by crowding the brain.
final diagnosis; instead, it refers to a category ofSubdural hematomas and epidural hematomas are
symptoms that can be the result of a diverse grouptwo other space-occupying abnormalities that crowd
of conditions and diseases.the brain. These are masses of clotted blood usually
Everyone with eyes and a brain of their own knowscaused by traumatic blows to the head. The injuries
that dementia is a very common and seriousproducing the bleeding are not always remembered
problem, robbing some people of their memories,or, if remembered, might have been dismissed as
ability to function independently and even theirtrivial at the time they occurred. These, too, can be
personalities. As a community-based neurologist, I seetotally removed by a neurosurgeon.
all too many cases of dementia, but the part thatNormal pressure hydrocephalus is another cause of
worries me the most is when patients, familydementia responding to neurosurgery, but in this
members and even medical personnel assume thatcondition the surgeon doesn't remove a mass-lesion.
nothing can be done and don't even bother toInstead, the surgeon places a tube inside one of the
evaluate for underlying causes.brain's swollen fluid-chambers known as ventricles,
Although it is certainly true that modern medicineallowing the excessive fluid-accumulation to drain
lacks effective treatments for many causes ofaway through the tube and into another body-space
dementia, it's also true that still others can be curedwhere it causes no harm. Normal pressure
or favorably modified. It would be a shame tohydrocephalus can be identified not only by its
assume that a case was untreatable and therebydementia and enlarged ventricles, but by the
miss something that could have been cured or betterconcurrent presence of a prominent walking
managed.impairment as well as urinary incontinence.
So how do dementia specialists or other doctorsNon-surgical treatments can be helpful for other
investigate cases of dementia? The medicalcauses of dementia. Two conditions involving a
detective-work begins with a thorough history anddeficiency or shortage of a biochemical are
physical examination.hypothyroidism and vitamin B12 deficiency. Finding
Clues might come from the history of the patient'sone of these is a blessing in disguise because they
other medical problems, the medication list, use ofare easily fixed. In hypothyroidism, the thyroid gland
alcohol or other drugs, or from other physicalin the neck secretes too little thyroid hormone. This is
problems that developed concurrently with themanaged by making up for the shortfall in pill form. In
dementia. Apart from the general physical exam, thevitamin B12 deficiency, the problem is that this
doctor also explores the patient's ability to payessential vitamin is not properly absorbed into the
attention, remember, calculate, draw pictures, reason,bloodstream via the gastrointestinal tract, so the
comprehend words and express himself or herself.deficiency is treated by periodic injections of vitamin
Further neurological examination assesses otherB12.
aspects of brain function like vision, hearing, strength,As people get older and acquire more medical
coordination, sensation, walking and reflexes.problems, their list of medications often grows longer.
After compiling the results of the history andOne or more of the medications they take might
examination, the physician can usually judge theinterfere with mental functioning. Common offenders
relative likelihoods of different underlying causes forare medications for urinary incontinence, anxiety or
the dementia, but follows up these clinical judgmentsinsomnia. If a problem-medication is eliminated or
with additional medical tests to nail down the mostreplaced with another drug, the patient's mental
likely cause. The irreducible minimum of additionalprowess can improve.
testing includes a brain scan--either a CT or anDepression is a common cause of dementia in which
MRI--plus a panel of blood tests.the mood disorder itself interferes with
The brain scan might detect a brain tumor, previouslyconcentration, memory and other mental
unsuspected strokes, clotted blood compressing theperformance. In many cases the mental impairments
brain or hydrocephalus (water on the brain) all ofare more prominent than the mood disturbance,
which can cause dementia and which can also becausing it to be overlooked. Depression is treated
treated. The blood tests look for salt-and-waterwith medication, psychotherapy, or both.
imbalances, abnormal blood-sugar levels, kidneyChronic infections with the Lyme and syphilis bacteria
impairment, liver impairment, excessive calcium levels,can be resolved with appropriate antibiotics.
thyroid disease, and deficiencies of vitamin B12 andOccasionally a fungal infection is to blame, and can
folic acid. Each of these problems, if found, wouldalso be treated with specific medication. Treatments
warrant specific treatment.for HIV are less good, but this disease still needs to
Other tests can be applied depending on thebe identified in order to obtain the best possible
physician's judgment of their usefulness in individualoutcome.
cases. These might include an electroencephalogramChronic alcohol abuse can damage the brain and
(brain-wave test), lumbar puncture (spinal tap) or acause dementia. In most cases the previously caused
PET (positron emission tomographic) scan, which is adamage cannot be undone, but further damage can
newer technique that shows the relative activity ofbe prevented through treatment of the alcoholism.
brain cells in different parts of the brain. AdditionalWernicke's encephalopathy is an alcohol-associated
blood-tests can screen for infections with humancause of confusion for which injections of thiamine
immunodeficiency virus (HIV) or the bacteria(vitamin B1) are urgently needed.
associated with Lyme disease or syphilis.Strokes can also produce dementia. Strokes are
After all is said and done, what turns up?caused by disrupted circulation which damages parts
Unfortunately, about half the dementia casesof the brain. In most cases, the patient and family
evaluated in this way lead to a diagnosis ofwere aware of strokes when they occurred, but in
Alzheimer's disease or similar degenerative brainother cases one or more strokes might have gone
disease for which there is no cure. Althoughundetected at the time they occurred. Prior strokes
treatments exist for these degenerative dementias,cannot be undone, but recognition of the presence
their benefits are modest.of strokes can lead to preventive measures to
It's the other half of the cases which reveal andecrease the likelihood of future strokes.
interesting grab-bag of different underlying causesApart from the conditions and diseases already
and, for that matter, treatments.mentioned, the list of potential causes of dementia is
Neurosurgery can be indicated for dementias causedlonger still. In brief, not every cause of dementia can
by brain tumors, especially meningiomas which arebe cured or significantly improved, but without a
slow-growing tumors that respond poorly tothoughtful, thorough, medical evaluation the ones that
chemotherapy or radiation therapy, but can be totallycan be treated could easily go undetected.
removed in surgical operations. Meningiomas are not