Alzheimer’s Disease- Presentation, Symptoms, Diagnosis/Workup Flashcards
To stay healthy, neurons must do what 3 things?
Communicate with each other
Carry out metabolism
Repair themselves
In AD, what happens to these 3 processes?
They’re all disrupted!
Alzheimer’s disease definition
brain atrophy with ventricular enlargement with degeneration of cholinergic and other neurons, absent or minimal vascular disease, neuronal loss
Cardinal signs of AD
Neurofibrillary tangles, senile plaques, accumulation of beta-amyloid
Beta-amyloid plaque definition
dense deposits of protein and cellular material that accumulates outside and around nerve cells
Precursor to beta-amyloid plaque
Amyloid precursor protein (APP)
How are beta-amyloid fragments made?
Enzymes cut the APP into fragments of protein (beta-secretase and gamma-secretase) –> beta-amyloid fragments come together in clumps to form plaques –> the plaques disrupt the work of neurons –> affects the hippocampus and other areas of the cerebral cortex
Neurofibrillary tangle defintion
Twisted fibers that build up inside the nerve cell
How are neurofibrillary tangles made?
Stabilizing tau molecules become abnormally hyperphosphorylated –> unstable –> fall apart –> tangled clumps of tau proteins form neurofibrillary tangles
Preclinical AD presentation
Affected regions will shrink as nerve cells die; changes can begin 10-20 years before symptoms appear
First sign of AD
Memory loss!
How does memory loss progress in AD?
“The clock ticks backwards,” you lose your most recent memories first and lose the earliest ones last
Mild-moderate AD presentation
Cerebral cortex begins to shrink as more neurons stop working and die
Mild signs of AD
memory loss, confusion, trouble handling money, poor judgement, mood changes, increased anxiety
Moderate signs of AD
increased memory loss and confusion, problems recognizing people, difficulty with language and thoughts, restlessness, agitation, wandering, repetitive statements
Severe AD presentation
Extreme shrinkage occurs in the brain, and patients are completely dependent on others for care
Signs of severe AD
weight loss, seizures, skin infections, groaning/moaning/grunting, increased sleeping, loss of bladder and bowel control
How does death from AD usually occur?
Aspiration pneumonia or other infections
10 warning signs of AD
Problems with words in speaking or writing
Misplacing things and losing the ability to retrace their steps
Decreased or poor judgment
Withdrawal from work or social activities
Changes in mood or personality
Memory loss that disrupts daily life
Challenges in planning or solving problems
Difficulty completing difficult tasks
Confusion with time or place
Problems with visual images and spatial relationships
Workup of AD- History
Most important component of the initial evaluation is adequate history with help from a family member
The history should include…
Descriptions of: cognitive, memory, behavioral problems and effects on daily life: difficulty with driving, work, family relationships
Details on temporal course of illness: chronic, progressive (Alzheimer’s or other neurodegenerative diseases), step-wise (multi-infarct dementia that happens after a patient has multiple strokes that can leave the patient with impaired cognition and produce a true dementia), static (after a traumatic injury, episode of severe hypotension)
Workup of AD- PE
Check for focal evidence of neovascular risk factors and specific neurologic abnormalities
Workup of AD- labs
CBC with sedimentation rate (to look for infections, anemia)
Chemistry panel (electrolytes, calcium, albumin, BUN, creatinine, transaminase)
TSH (hypothyroidism can cause cognitive impairment)
VDRL test for syphilis
Urinalysis for UTI (UTI in elderly patients can cause cognitive changes)
Serum B12 and folate levels
Chest x-ray
ECG (if there are concerns about something CV-related)
CT scan
When is a CT scan most appropriate in AD workup?
If there’s history suggestive of a mass lesion, focal neurologic signs or symptoms, dementia of abrupt onset, history of seizures or stroke
CT scan vs. MRI in AD workup
MRI with gadolinium contrast is superior to CT scan for diagnosis of multi-infarct dementia diagnosis and problems deferrable to the posterior fossa
Is neuroimaging diagnostic for AD?
No, it’s more used to rule out other sources of cognitive impairment
