Setting: office
CC: “My memory is getting bad.”
HPI: A 77-year-old former chairman of medicine at your medical school comes to see you for initial testing for memory loss. He wants to get an initial evaluation by you privately before his wife and children find out he may have serious memory loss.
PMHX:
Localized prostate cancer surgically resected 10 years ago
Sober alcoholic; last drink 2 years ago
Medications: none
PE:
General: charming older gentleman; no abnormalities noted
Neurological: no focal deficits, able to remember only two of three objects at 5 minutes. No cogwheel rigidity. No myoclonus. No movement disorder.
Initial Orders:
Head MRI
Vitamin B12 and methylmalonic acid level
Thyroid function tests (thyroid-stimulating hormone [TSH], thyroxine [T4])
Rapid plasma reagin (RPR) Venereal Disease Research Laboratory (VDRL) test
Alzheimer disease: neurofibrillary tangles, amyloid plaques
Vivid hallucinations with exquisite detail are characteristic of
a. Alzheimer disease
b. Lewy body dementia
c. Creutzfeldt-Jakob disease (CJD)
d. Multiinfarct (vascular) dementia
Answer b. Lewy body dementia
Lewy body dementia is characterized by parkinsonism and extremely vivid hallucinations with great detail. There is no specific test and no treatment beyond the dopamine agonists and dopamine replacement that you would use for Parkinson disease.
The patient returns a week later to discuss the laboratory test results. He feels the same. He loves what he is doing, but just gets forgetful.
Reports:
Head MRI: normal
Vitamin B12 and methylmalonic acid levels: normal
TSH and T4: normal
VDRL: normal
Which of these is characterized by rapid progression and myoclonus?
a. Alzheimer disease
b. Frontotemporal dementia (Pick disease)
c. CJD
d. Multiinfarct (vascular) dementia
Answer c. CJD
CJD can take a person from normal function to death in 3 to 6 months. There is no effective therapy for CJD. CSF shows the 14-3-3 protein, which spares the patient a need for brain biopsy for definitive diagnosis.
CJD is associated with prions. They are
• Transmissible
• Cause spongiform encephalopathy
• Do not grow or replicate in the laboratory
You explain to the patient he might have early Alzheimer-type dementia or mild cognitive impairment. He wants to start therapy. You order donepezil.
Donepezil, rivastigmine, and galantamine increase CNS ACh level.
Which of these is characterized by choreiform movement and emotional lability?
a. Huntington disease
b. Frontotemporal dementia (Pick disease)
c. CJD
d. Normal pressure hydrocephalus
Answer a. Huntington disease (HD)
HD is characterized by
• Dementia at an early age
• Emotional lability
• Movement disorder or chorea
HD has CAG trinucleotide repeat genetic sequences.
HD Treatment
• Tetrabenazine
• Increases dopamine
• Improves movement disorder
Over the next 6 to 12 months, the patient’s memory loss continues to progress. You add memantine to his donepezil. Get a neurology consultation, but do not expect them to tell you anything.
Memantine Mechanism
• N-methyl-D-aspartate (NMDA) receptor antagonist
• Neuroprotective
Combine
Acetylcholinesterase inhibitor (donepezil)
and
Memantine
The patient’s memory stabilizes over the next 6 months.