Evaluating Dementia: Assessment for Treatable Causes

"Dementia" means an acquired, persistinghematomas and epidural hematomas are two
decrease in mental functioning. Dementia is not aother space-occupying abnormalities that crowd
disease or a final diagnosis; instead, it refers to athe brain. These are masses of clotted blood
category of symptoms that can be the result ofusually caused by traumatic blows to the head.
a diverse group of conditions andThe injuries producing the bleeding are not always
diseases.Everyone with eyes and a brain of theirremembered or, if remembered, might have been
own knows that dementia is a very common anddismissed as trivial at the time they occurred.
serious problem, robbing some people of theirThese, too, can be totally removed by a
memories, ability to function independently andneurosurgeon.Normal pressure hydrocephalus is
even their personalities. As a community-basedanother cause of dementia responding to
neurologist, I see all too many cases of dementia,neurosurgery, but in this condition the surgeon
but the part that worries me the most is whendoesn't remove a mass-lesion. Instead, the
patients, family members and even medicalsurgeon places a tube inside one of the brain's
personnel assume that nothing can be done andswollen fluid-chambers known as ventricles,
don't even bother to evaluate for underlyingallowing the excessive fluid-accumulation to drain
causes.Although it is certainly true that modernaway through the tube and into another
medicine lacks effective treatments for manybody-space where it causes no harm. Normal
causes of dementia, it's also true that still otherspressure hydrocephalus can be identified not only
can be cured or favorably modified. It would be aby its dementia and enlarged ventricles, but by
shame to assume that a case was untreatablethe concurrent presence of a prominent walking
and thereby miss something that could have beenimpairment as well as urinary
cured or better managed.So how do dementiaincontinence.Non-surgical treatments can be helpful
specialists or other doctors investigate cases offor other causes of dementia. Two conditions
dementia? The medical detective-work beginsinvolving a deficiency or shortage of a biochemical
with a thorough history and physicalare hypothyroidism and vitamin B12 deficiency.
examination.Clues might come from the history ofFinding one of these is a blessing in disguise
the patient's other medical problems, thebecause they are easily fixed. In hypothyroidism,
medication list, use of alcohol or other drugs, orthe thyroid gland in the neck secretes too little
from other physical problems that developedthyroid hormone. This is managed by making up
concurrently with the dementia. Apart from thefor the shortfall in pill form. In vitamin B12
general physical exam, the doctor also exploresdeficiency, the problem is that this essential
the patient's ability to pay attention, remember,vitamin is not properly absorbed into the
calculate, draw pictures, reason, comprehendbloodstream via the gastrointestinal tract, so the
words and express himself or herself. Furtherdeficiency is treated by periodic injections of
neurological examination assesses other aspectsvitamin B12.As people get older and acquire more
of brain function like vision, hearing, strength,medical problems, their list of medications often
coordination, sensation, walking and reflexes.Aftergrows longer. One or more of the medications
compiling the results of the history andthey take might interfere with mental functioning.
examination, the physician can usually judge theCommon offenders are medications for urinary
relative likelihoods of different underlying causesincontinence, anxiety or insomnia. If a
for the dementia, but follows up these clinicalproblem-medication is eliminated or replaced with
judgments with additional medical tests to nailanother drug, the patient's mental prowess can
down the most likely cause. The irreducibleimprove.Depression is a common cause of
minimum of additional testing includes a braindementia in which the mood disorder itself
scan--either a CT or an MRI--plus a panel of bloodinterferes with concentration, memory and other
tests.The brain scan might detect a brain tumor,mental performance. In many cases the mental
previously unsuspected strokes, clotted bloodimpairments are more prominent than the mood
compressing the brain or hydrocephalus (water ondisturbance, causing it to be overlooked.
the brain) all of which can cause dementia andDepression is treated with medication,
which can also be treated. The blood tests lookpsychotherapy, or both.Chronic infections with the
for salt-and-water imbalances, abnormalLyme and syphilis bacteria can be resolved with
blood-sugar levels, kidney impairment, liverappropriate antibiotics. Occasionally a fungal
impairment, excessive calcium levels, thyroidinfection is to blame, and can also be treated with
disease, and deficiencies of vitamin B12 and folicspecific medication. Treatments for HIV are less
acid. Each of these problems, if found, wouldgood, but this disease still needs to be identified in
warrant specific treatment.Other tests can beorder to obtain the best possible outcome.Chronic
applied depending on the physician's judgment ofalcohol abuse can damage the brain and cause
their usefulness in individual cases. These mightdementia. In most cases the previously caused
include an electroencephalogram (brain-wave test),damage cannot be undone, but further damage
lumbar puncture (spinal tap) or a PET (positroncan be prevented through treatment of the
emission tomographic) scan, which is a neweralcoholism. Wernicke's encephalopathy is an
technique that shows the relative activity of brainalcohol-associated cause of confusion for which
cells in different parts of the brain. Additionalinjections of thiamine (vitamin B1) are urgently
blood-tests can screen for infections with humanneeded.Strokes can also produce dementia.
immunodeficiency virus (HIV) or the bacteriaStrokes are caused by disrupted circulation which
associated with Lyme disease or syphilis.After alldamages parts of the brain. In most cases, the
is said and done, what turns up? Unfortunately,patient and family were aware of strokes when
about half the dementia cases evaluated in thisthey occurred, but in other cases one or more
way lead to a diagnosis of Alzheimer's disease orstrokes might have gone undetected at the time
similar degenerative brain disease for which therethey occurred. Prior strokes cannot be undone,
is no cure. Although treatments exist for thesebut recognition of the presence of strokes can
degenerative dementias, their benefits arelead to preventive measures to decrease the
modest.It's the other half of the cases whichlikelihood of future strokes.Apart from the
reveal an interesting grab-bag of differentconditions and diseases already mentioned, the list
underlying causes and, for that matter,of potential causes of dementia is longer still. In
treatments.Neurosurgery can be indicated forbrief, not every cause of dementia can be cured
dementias caused by brain tumors, especiallyor significantly improved, but without a thoughtful,
meningiomas which are slow-growing tumors thatthorough, medical evaluation the ones that can be
respond poorly to chemotherapy or radiationtreated could easily go undetected.(C) 2005 by
therapy, but can be totally removed in surgicalGary CordingleyGary Cordingley, MD, PhD, is a
operations. Meningiomas are not cancerous, butclinical neurologist, teacher and researcher who
because space inside the skull is limited, theyworks in Athens, Ohio.
cause trouble by crowding the brain. Subdural