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142 Cards in this Set
- Front
- Back
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what is amnesia?
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Memory loss with otherwise preserved intellectual function.
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what are the types of amnesia?
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retrograde: cannot recall recently presented info, up to onset of injury
anterograde: cannot recall newly presented info, after onset of injury global: both retrograde and anterograde |
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where does dysfunction of amnesia occur in the brain?
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hippocampus and/or other parts of limbic system, based in temporal/frontal lobes
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what is transient amnesia?
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suddenly occurring memory loss lasting several minutes to hours.
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what distinguishes non-neurological amnesia (amnesia from psychiatric illness or malingering) ?
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pt loses memory for personal identity or emotionally laden events rather than recently presented info
inconsistent results on formal memory testing Amytal infusion temporarily restores memory (would not with amnesia from brain damage) |
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What are the complications of electroconvulsive therapy (ECT)?
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acute confusional state: disorientation/general confusion lasting approx 10-30 minutes (UpToDate) to 1-2 days (Kaufmann)
anterograde amnesia: lasting for several weeks retrograde amnesia, especially for autobiographical information, is most persistent complication of ECT |
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what are the domains of cognitive function?
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memory
calculation judgment visual-spatial conceptualization performance skills learned motor actions (praxis) (not mood, affect or emotions) |
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what is confabulation?
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neuropsychological condition where patient offers implausible explanations in sincere, forthcoming, often jovial manner.
Pts disregard truth, but do not intend to deceive. Seen in Wernicke-Korsakoff syndrome, Anton syndrome, anosognosia |
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what is difference between subcortical and cortical dementia?
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cortical = dementia occurring with neuropsychologic signs of cortical injury: aphasia, anosognosia and/or apraxia
patients remain alert, attentive & ambulatory e.g. Alzheimer's, cerebral cortical anoxia subcortical = typified by apathy, affective change, slowed mental processing/cognitive impairment, gait abnormalities e.g. Parkinson disease, Huntington disease, NPH, HIV-associated dementia, VCI, DLB |
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At what age do neurological ages from normal aging occur?
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Beginning about age 50 years.
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What changes in memory and other neurological functions occur from normal aging? What stays intact or near intact?
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impaired recall of newly learned lists (can recall with time)
shortened attention span slowed learning decreased ability to perform complex tasks (vocabulary, language comprehension, fund of knowledge intact) (per WAIS-R, general intelligence declines slightly) |
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What changes in sleep occur from normal aging?
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times of falling asleep/awakening occur earlier
slow-wave sleep declines sleep fragments restless leg syndrome/ REM behavior disorder commonly disrupt sleep |
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What changes in motor and gait occur from normal aging?
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loss of muscle mass/strength
loss of DTR in ankles loss of vibration sense in legs impaired postural reflexes/sense of balance (cannot stand on one foot with eyes closed) senile gait: increased trunk/limb flexion, diminished arm swing, shorter steps Increased risk of falling, with significant morbidity/mortality |
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What changes in special senses occur from normal aging?
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smaller, less reactive pupils
some retinal degeneration require greater light, more contrast, sharper focusing to read/drive poorer hearing/taste/smell |
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What EEG and imaging changes occur from normal aging?
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EEG slows to lower end of normal (8-12 Hz alpha range)
decreased frontal/parietal lobe volume cerebral cortex atrophy Sylvian fissure expansion increased volume of lateral/3rd ventricles white matter hyperintensities (white dots) on MRI |
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What macroscopic/microscopic changes occur from normal aging?
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Brain weight decreases to about 85%
accumulation of granulovacuolar degeneration, amyloid containing senile plaques, neurofibrillary tangles in frontal/temporal lobes > parietal lobes loss of neurons in locus ceruleus, suprachiasmatic nucleus, substantia nigra, nucleus basalis of Meynert (mamillary bodies unaffected) |
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What is the prevalence of different types of dementia?
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Alzheimer's: 70%
dementia with Lewy bodies (DLB): 15% vascular cognitive impairment (VCI) / vascular cognitive impairment: 10% frontotemporal dementia: 5-10% all others: 5-10% |
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what is the genetics of typical forms of dementia?
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autosomal dominant: Huntington, frontotemporal, familial Creutzfeldt-Jakob, familial Alzheimer's
autosomal recessive: Wilson |
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What forms of dementia are rapid vs. gradual in onset?
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develops over years to a decade: Alzheimer's
develops in 6-12 months: frontotemporal, HAD, DLB, paraneoplatic limbic encephalitis, Creutzfeldt-Jakob disease & variant CJD |
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what forms of dementia are reversible?
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depression
over-medication hypothyroidism B12 deficiency other metabolic abnormalities subdural hematomas NPH |
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what score is concerning on the MMSE and what might this indicate?
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Scores of 20 or less on MMSE indicate dementia, delirium, schizophrenia and/or affective disorders
(these scores not found with normal elderly or those with neuroses/personality disorders) |
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What is the MoCA and what can it be used for?
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Montreal Cognitive Assessment readily detects mild impairment
useful for pts with possible cognitive impairment who score 25 or better on MMSE or who only have memory impairment can be used with pts with neurodegenerative disease, e.g.: Parkinson, DLB, frontotemporal, Alzheimer's |
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what is the ADAS and what can it be used for?
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Alzheimer Disease Assessment Scale
cognitive (-Cog) and noncognitive sections more sensitive, reliable and less influenced by educational level than MMSE more complex and subjective requires special training to give test takes 45-60 mins higher score with worsening performance (0-70) used routinely by researchers to monitor course of disease/medication effects during trials |
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When are neuropsychologic tests used?
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for very intelligent/educated/high functioning pts with symptoms of dementia whose screening tests fail to show cognitive impairment
to evaluate ability to execute critical decisions to assess patients with confounding deficits to distinguish dementia from depression/malingering/other psych d/o to distinguish Alzheimer's from frontotemporal dementia |
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How does DSM-V define Alzheimer's disease?
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Mild and Major subtypes of Neurocognitive Disorder due to Alzheimer's Disease.
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What are the three stages of Alzheimer's disease recognized by neurologists?
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Preclinical (presymptomatic)
Mild cognitive impairment (MCI) Dementia |
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What is preclinical Alzheimer's disease?
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asymptomatic patients with lab evidence indicating they are in preclinical/presymptomatic stage of disease
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What tests evaluate for preclinical Alzheimer's? What results indicate this stage of the disease?
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amyloid imaging, using Pittsburgh Compound B (binding ligand) on PET to quantify cerebral amyloid burden
accumulation of amyloid in cortex, esp frontal/parietal lobes, is marker for Alzheimer's CSF analysis for amyloid concentration & tau proteins low amyloid (Aβ)& elevated tau protein: marker for Alzheimer's |
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What is MCI?
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Mild Cognitive Impairment
impairment either memory (amnestic) or non-memory (non-amnestic) function, such as executive ability or language function. precursor to Alzheimer's in many individuals |
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what is difference between MCI and dementia?
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Pts with MCI continue to work, socialize, maintain hobbies and function independently.
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How often does MCI progress to dementia?
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10% yearly (vs. 1-2% of unaffected peers)
(but as many as 30% revert to normal, though due to tx of psychiatric illnesses or toxic-metabolic disturbances) |
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How do cholinesterase inhibitors affect MCI?
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cholinesterase inhibitors do not slow cognitive decline or reduce rate of progression of MCI to dementia.
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what is cognitive reserve and what does it represent?
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education, occupation and leisure-time activities that insulate the brain.
How Alzheimer's disease produces dementia at different rates/trajectories in different patients despite similar laboratory evidence/studies. |
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what remains intact in the dementia stage of Alzheimer's disease?
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Pts are superficially conversant
sociable able to perform routine tasks physically intact |
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what signs/symptoms will patients in dementia stages demonstrate
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incapacitating memory impairment
inability to cope with new situations language impairment, including: anomia (Inability to find words) paraphasic errors (use of incorrect words) tendency to circumvent forgotten words deterioration in visuospatial ablities: pts lose way in familiar surroundings |
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what is constructional apraxia?
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inability either to translate an idea into use of a physical object or to integrate visual and motor functions
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what are the neuropsychiatric manifestations of Alzheimer's disease?
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disruptive behavior (almost 50%)
apathy, agitation, dysphoria, abnormal behavior: delusions (20-40%), often paranoid hallucinations (10-20%), usually visual (could indicate toxic-metabolic disturbance or DLB) wandering sleep fragmentation, greater than normal greater MVA rate (not as high as 16-24 yo men!) |
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What are the physical signs of Alzheimer's disease?
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anosmia
frontal release signs (snout, grasp reflexes), increased jaw jerk reflex, Babinski signs in advanced disease eventually become mute, unresponsive, confined to bed, assume decorticate (fetal) posture frequently slip into persistent vegetative state |
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what is seen on EEG in Alzheimer's disease?
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first: slowing of background activity (may be age-related)
advanced: disorganized, slow background activity |
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what is seen on imaging studies in Alzheimer's disease?
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CT: cerebral atrophy, widened 3rd & lateral ventricle
MRI: progressive atrophy: hippocampus temporal/parietal lobes frontal lobes also widening of ventricles PET: (50%) areas of decreased metabolism in b/l parietal/temporal association cortex spreads to frontal lobe |
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What areas of the brain are affected in Alzheimer's disease?
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cerebral cortical association areas:
parietal-temporal junction limbic system: hippocampus locus ceruleus and olfactory nerve (results in apathy) |
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what happens to the ventricles in Huntington's disease, unlike in Alzheimer's?
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anterior horns of lateral ventricles become convex (bow outward)
due to loss of caudate nucleus (in Alzheimer's, CN preserved & lateral ventricles maintain concave (bowed inward) shape |
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Is cerebral cortex biopsy necessary for diagnosis of Alzheimer's disease?
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No.
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what histological features are found in Alzheimer's disease? Which correlates most closely with Alzheimer's dementia?
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Accumulation in cortex association areas, limbic system and hippocampus (greatest concentration) of:
1) neuritic plaques (form of senile plaques) made up of amyloid beta-peptide (Aβ) 2) neurofibrillary tangles made up of tau proteins Loss of neuron synapses in frontal/temporal lobes, esp in Nucleus basalis of Meynert (AKA substantia innominata) depleting cerebral ACh loss of neuronal synapses correlates most closely with Alzheimer's dementia |
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how are amyloid plaques formed?
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enzymes encoded on chromosome 21 cleave amyloid precursor protein (APP) into Aβ, which forms up to 50% of core of plaques
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what is the amyloid hypothesis?
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enzymatic degradationof APP results in accumulation of Aβ
Aβ causes inflammatory/oxidative cerebral damage possible critical mechanism in Alzheimer's disease |
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what biochemical features are found in Alzheimer's disease?
What is the result of this? How is this related to the cholinergic hypothesis? |
loss of neurons in basal nucleus of Meynert
marked reduction of choline acetyltransferase activity results in marked reduction in cerebral cholinergic activity cholinergic hypothesis: reduced cholinergic activity causes Alzheimer's disease dementia. |
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what does cholinesterase do?
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cholinesterase metabolizes ACh
enzyme degradation terminates ACh activity (vs. reuptake terminates most 5HT & DA activity) |
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what do atropine and scopolamine do? Name two other similar acting medications.
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Block ACh from interacting with receptors (ACh antagonists), decreasing ACh activity
scopolamine does so in CNS (readily crosses blood-brain barrier) atropine does so primarily in autonomic NS (doesn't cross blood-brain barrier unless concentration is great) benztropine (Cogentin) & trihexyphenidyl (Artane) |
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What do cholinesterase inhibitors do?
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AKA anticholinesterases
stops cholinesterase & prolongs/increases ACh concentrations/activity |
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Name five key anticholinesterases and their functions.
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Donezepil (Aricept): preserves ACh activity in Alzheimer's disease
Physostigmine: reverses action of atropine/scopolamine/TCA overdoses, short halflife, readily crosses BBB Edrophonium (Tensilon): restores ACh activity at NMJ in MG temporarily Pyridostigmine (Mestinon): restores ACh activity at NMJ in MG as treatment Insecticides (organophosphates): create excessive ACh activity at NMJ & ANS |
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How does scopolamine support the cholinergic hypothesis?
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Scopolamine, which readily crosses BBB, induces transient episodes of Alzheimer's-like cognitive impairment (reversible with physostigmine)
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what are anticholinergic side-effects/syndrome? What causes this? How do you treat it?
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side-effects:
drowsiness dry mouth constipation urinary hesitancy/retention accommodation paresis syndrome: dilated pupils (mydriasis) elevated HR/BP/temp dry skin progression to delirium/coma ACh antagonists (blocks muscarinic ACh receptors) Physostigmine (anticholinesterase that crosses BBB) |
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what are the effects of excessive ACh activity/toxicity? What causes this?
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excessive muscarinic parasympathetic activity:
constricted pupils (miosis) bradycardia/hypotension/lightheadedness outpouring of bodily fluids: sweating lacrimation salivation bronchial secretions nausea/vomiting diarrhea anticholinesterases, organophosphates Atropine (ACh antagonist) & pralidoxime (reactivates cholinesterase) |
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what is the greatest risk factor for Alzheimer's disease? How does it relate to incidence of the disease?
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Living longer than 65 years (
incidence doubles for every 5 years over 65: 10% at 65 to almost 40% over 85 |
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what are other risk factors for Alzheimer's disease?
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family history (20% of offspring, 10% of 2nd degree relatives)
trisomy 21 Apo-E 3/4 or 4/4 allele pairs |
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How does Chromosome 19 relate to risk of Alzheimer's disease?
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Chromosome 19 encodes for Apolipoprotein-E (Apo-E)
Apo-E binds to Aβ which accumulates in neuritic plaques you get 1 of 3 allele (E2, E3, E4) from each parent no E4: 20% develop Alzheimer's one E4: 50% develop Alzheimer's, 5-10 years earlier E4/4: 90% develop Alzheimer's 10-20 years earlier |
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Do neurologists order Apo testing? What is effect of this testing on patients?
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No.
Chromosome 19 is risk factor, no causal relationship considered "susceptibility" gene Pts learning they carry Apo E4 alleles show no significant short-term psychological risks. |
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Which genes cause Alzheimer's disease? What percentage & type of cases do they cause?
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Chromosome 1 (presenilin 2): <1%
Chromosome 14 (presenilin 1): 1-5% Chromosome 21 (APP): <1% account for most of early-onset Alzheimer's disease (30-60 years) |
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How is Alzheimer's disease treated? Name two methods and four medications used, and their effects.
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1) prolong/increase ACh activity with cholinesterase inhibitors:
donezepil (Aricept) rivastigmine galantamine modest (9-12 m) improvement in cognition reduction of depression/anxiety/psychosis alone or with psychotropics 2) block toxic glutamine excitatory neurotransmission with NMDA receptor antagonists memantine (Namenda) modest memory/learning improvement for several months transient suppression of agitation/aggression |
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How is neuropsychiatric symptoms of Alzheimer's disease treated?
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Avoid anticholinergic meds (SSRIs/SNRIs vs. TCAs)
antipsychotics for disruptive behavior/agitation daytime exercise, sunlight exposure, restricted naps vs. hypnotics/anxiolytics to combat sleep disruptions behavioral management techniques: non-pharmological alternatives (removing doorknobs, "safe zones", frequent snacks/toilet trips) |
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What is CATIE-AD? What did it show?
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Clinical Antipsychotic Trials of Intervention Effectiveness-Alzheimer's Disease
no significant difference between antipsychotics & placebo on cognition, functioning, care needs or quality of life olanzapine & especially risperidone improved hostile suspicious factor of BPRS & NPI total score (may reduce aggression & improve psychosis) |
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What is the relation between Trisomy 21 and Alzheimer's disease?
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Almost all Trisomy 21 pts living to 50 years develop Alzheimer's-like dementia
Women who give birth to Trisomy 21 child have 5x increase in Alzheimer's disease |
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What is DLB?
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Dementia with Lewy Bodies
previously called Lewy body disease or diffuse Lewy Body disease |
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what are the histological features of DLB?
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Lewy bodies: eosinophilic cortical spherical intracytoplasmic inclusions
containing aggregates of α-synuclein & ubiquitin greater loss of ACh/ChAT than in Alzheimer's |
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what are the features of DLB?
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3 Core features:
Parkinsonism (little/no tremor, cognitive impairment at onset unlike Parkinson's disease) Visual Hallucinations (see Capgras below) Fluctuating cognition 2 Suggestive features: REM behavior disorder (movement during sleep) Antipsychotic hypersensitivity 1 Classic feature: "impostor" replaces close friend/relative (Capgras syndrome) |
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What are characteristics of frontal lobe injury?
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various combinations of:
apathy/indifference to surroundings/ongoing events/injuries cognitive slowing: difficulty with transitions/alternatives bradyphrenia (slowed thinking) paucity of speech: reticience to abulia (loss of spontaneous speech/expression) impaired verbal output/aphasia if dominant frontal lobe language center injured movements: bradykinetic (slowed) to perseverative (repetitive) to reduced to akinetic (absent) akinetic mutism (absence of speaking/expression following absence of movement) impaired inhibitions resulting in flighty ideas, inappropriate comments, unrestrained expression of sexual urges, possible incontinence, easily distracted by stimuli (stimulus-bound), superficial odd jocularity with uncontrollable facetious laughter (witzelsucht) anosmia (olfactory nerves located under frontal lobes) intact calculation/memory/visuospatial perception (based in parietal/temporal lobes or throughout cortex) MoCA or Frontal Assessment Battery better than MMSE |
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what is frontotemporal dementia? What is its age of onset, sex distribution and course?
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insidious onset of dementia completely overshadowed by personality and behavioral disturbances following fatal course in <4 years.
twice as frequent in men average age of onset of 53 (vs. over 65 in Alzheimer's accounts for 50% of dementia in pts younger than 60 |
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what are the neurologic criteria for frontotemporal dementia? What is required for diagnosis?
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3 of following 6 disturbances:
Hyperorality (excessive/compulsive talking/eating/cigarette smoking) Impaired executive ability Perseverative or compulsive behaviors) Loss of sympathy Apathy Disinhibition probable diagnosis: disturbances + imaging definitie diagnosis: includes histologic evidence stinky mnemonic: HIP LAD |
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What is seen on imaging studies in frontotemporal dementia?
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frontal/anterior temporal lobe atrophy
parietal lobes intact (as is visuospatial ability) PET: hypometabolism in frontal lobes |
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what histological features are found in frontotemporal dementia?
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tau deposits
minority of cases show Pick bodies: argentophilic inclusions, referred to as Pick disease |
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what genetic features are found in frontotemporal dementia?
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linked to mutant gene on chromosome 17 (codes for tau)
autosomal dominant (40% of patients have family history) |
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What are tauopathies? Give three examples.
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diseases with aggregations of tau: intraneuronal protein
Alzheimer's disease, frontotemporal dementia, progressive supranuclear palsy (PSP) |
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what are synucleinopathies? Give two examples.
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diseases with aggregations of α-synuclein: intraneuronal protein
Parkinson's disease, DLB |
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what is PSP? What is its age of onset and sex distribution?
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progressive supranuclear palsy
hybrid of dementia-producing illness and conjugate eye movement disorder slight male predominance onset between 60-70 progressive deterioration over approx 7 years |
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what are the characteristics of PSP?
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apathy
aberrant behavior disinhibition executive disability reduced verbal output pseudobulbar palsy parkinsonism: axial rigidity forcing overly straight/upright posture, bradykinesia scowl from contraction of facial muscles pathogonomic feature: inability to look vertically, then laterally |
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what is seen in imaging studies in PSP?
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frontal cortex, basal ganglia and upper brainstem degeneration
PET: predominant frontal lobe hypometabolism (not as marked as frontotemporal dementia) |
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what are histologic features seen in PSP?
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accumulation of tau proteins
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what is VCI?
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Vascular Cognitive Impairment
AKA multi-infarct dementia AKA vascular dementia AKA Vascular Neurocognitive Disorders (DSM V) dementia from strokes or other cerebral vascular disease |
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what are the characteristics of VCI?
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physical signs overshadow cognitive impairment (unlike Alzheimer's, DLB & frontotemporal dementia)
depending on location of stroke: aphasia anosognosia dyscalculia hemiparesis hemianopsia dysarthria ataxia pseudobulbar palsy gait impairment cognitive impairment step-wise deterioration reflecting accumulation of strokes |
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what is seen in imaging studies of VCI?
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MRI (more than CT): periventricular 0.5-1.5 cm white matter changes (lacune) & large strokes
PET (rarely needed): multiple almost random hypometabolic regions |
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How do strokes cause VCI?
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obliteration of at least 50 grams of brain tissue
small strokes striking strategic regions, especially limbic system |
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What is Binswanger's disease
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AKA etat lacunaire
hypertension-induced multiple lacunes predominantly in subcortical white matter |
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what are histologic features seen in VCI?
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tau protein accumulation and neurofibrillary tangles as seen in Alzheimer's disease
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what is the greatest risk factor for VCI?
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pre-existing cognitive impairment
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What is Wernicke-Korsakoff syndrome?
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alcoholism-induced amnesia (Korsakoff's syndrome)
combined with cognitive impairment & signs of CNS/PNS damage (Wernicke's encephalopathy) AKA Substance-Induced Neurocognitive Disorder (DSM V) thiamine (Vitamin B1) deficiency |
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what are characteristics of Wernicke-Korsakoff syndrome?
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mostly impairs short-term memory, abstract reasoning & visual/psychomotor dexterity
hallmark: anterograde amnesia combination of ataxia & ocular motility abnormalities: conjugate gaze paresis abducens nerve paresis nystagmus ataxic gait from cerebellar atrophy peripheral neuropathy |
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what is seen on imaging studies in Wernicke-Korsakoff syndrome?
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petechial hemorrhages in mamillary bodies & periaqueductal gray matter (causes amnesia & adjacent to 3rd/6th CN nuclei causing ocular motility abnormalities)
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How is CSF produced and secreted?
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CSF secreted by choroid plexus in lateral ventricles
CSF circulates through ventricles around brain & SC arachnoid villi absorb CSF sending it into venous circulation |
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What's the difference between communicating hydrocephalus vs. obstructive hydrocephalus?
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inflammatory material from meningitis or
blood from SAH block arachnoid villi -> obstructive hydrocephalus stenosis of aqueduct of sylvius prevents CSF passage from 3rd to 4th ventricle -> obstructive hydrocephalus |
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what are the characteristics of normal pressure hydrocephalus? What causes this?
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gait apraxia: ventricular expansion disrupts corticospinal tracts supplying legs
urinary incontinence (urgency/frequency): ventricular expansion disrupts corticospinal tracts supplying voluntary muscles of bladder dementia: pressure on frontal lobes causes cognitive impairment & psychomotor retardation (subcortical dementia: slowing thought/gait, spares language skills) |
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What test can confirm diagnosis of NPH?
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removal of large volumes (30-60 ml) of CSF
or series of 3 LPs resultant improvement of urinary incontinence & gait apraxia indicates NPH (negative test does not preclude diagnosis!) |
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what is gait apraxia?
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failure to alternate leg movements
do not shift weight to forward foot attempting to lift weight-bearing foot results in foot with tremor appearing "magnetized" to floor require multiple steps to turn 180 stepping reflex intact: can still step over stick |
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what is treatment for NPH?
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placement of shunt from lateral ventricle to chest or abdomen
(though inconsistent benefits & neurosurgical complications in up to 30%) |
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when evaluating a patient for neurosyphilis, what test do you order?
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FTA-ABS or MHA-TP
more sensitive and specific than RPR |
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what test do you use on CSF for neurosyphilis?
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VDRL
CSF VDRL provides generally accepted confirmation of neurosyphilis |
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What are the CSF findings in neurosyphilis?
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elevated protein (45-100 mg/dl)
lymphocytic pleocytosis (5-200 cells/ml) |
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what is SSPE? What age does it occur?
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Subacute Sclerosing Panencephalitis
rare predominately childhood-onset illness likely due to latent/mutant measles (rubeola) virus infection of neurons mean of 12 years (85%) or adulthood (15%) |
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What are the features of SSPE?
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early: poor school work, behavior disturbances, restlessness, personality changes
weeks: cognition deteroriates into dementia one limb weakness evolves into total body paralysis hallmark: myoclonus (may have seizures) then: akinetic mutism most die in 1-2 years (95% in 5 years) survivors in vegetative state |
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What are laboratory findings in SSPE?
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elevated CSF measles antibody titer
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What are EEG findings in SSPE?
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periodic sharp-wave complexes
or burst suppression pattern |
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What are histologic findings in SSPE?
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intranuclear eosinophilic inclusions (Cowdry bodies)
note: Lewy bodies are intracytoplasmic eosinophilic inclusions |
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what are prions? What are they resistant to, and what are they susceptible to?
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proteinaceous infective agents
made up of Prion protein (PrP), amyloid protein coded on chromosome 20 composed (almost) entiredly out of protein lacking DNA/RNA resistant to sterilization, heat, formaldehyde & nucleic acid hydrolyzation susceptible to denaturation, i.e. proteases |
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what is spongiform encephalopathy? What does it look like on cerebral cortex biopsies?
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distinctive microscopic vacuoles (sponge-like
appearance) results from PrP.c isoform transformed to PrP.Sc which aggregates in cortex |
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What is Creutzfeldt-Jakob disease?
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prion infection causing transmissible spongiform encephalopathy
AKA Neurogenerative Disorder due to Prion Disease (DSM V) |
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What are features of Creutzfeldt-Jakob disease?
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cognitive deterioration/dementia
myoclonus ataxia periodic sharp-wave complexes or burst suppression pattern on EEG appears at younger age (50-64) death in about 6 months |
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How is Creutzfeldt-Jakob disease transmitted?
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Interspecies, i.e. to lab animals
also rarely intraspecies, i.e. corneal transplantation or grown hormone harvested from cadavers |
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What is Gerstmann-Straussler-Scheinker (GSS) disease?
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familial form of Creutzfeldt-Jakob disease
autosomal dominant genetic suspectibility from mutation on chromosome 20. |
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what lab findings occur in Creutzfeldt-Jakob disease?
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CSF:
14-3-3 protein in 90% elevated tau proteins |
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Name six other spongiform encephalopathies and their features.
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scrapie (sheep & goats scrape off coats)
transmissible mink encephalopathy (vicious minks loose motor ability) fatal familial insomnia Kuru (New Guinea: dementia, tremulousness, dysarthria, ataxia) Bovine spongiform encephalopathy (BSS) aka mad-cow disease (belligerence, apprehension, tremulousness, ataxia in cattle) chronic wasting disease of deer and elk |
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What is variant Creutzfeldt-Jakob disease (vCJD)? What are two notable characteristics?
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human counterpart of BSE
cause of dementia in adolescents/young adults initial symptoms psychiatric without physical neurological correlates |
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What are the features of variant Creutzfeldt-Jakob disease (vCJD)?
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mean age 27 years
memory impairment, inattention, aggression, withdrawal anxiety (1st 4 months) painful paresthesias dementia, myoclonus, decorticate posture death in approx 14 months |
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what EEG finds occur with variant Creutzfeldt-Jakob disease (vCJD)?
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nonspecific slowing
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what are CSF findings of Lyme disease?
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lymphocytic pleocytosis
elevated protein reduced glucose Lyme antibodies |
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What is HAD and HAND?
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HIV-associated Dementia
HIV-associated neurocognitive disorder (less severe than HAD) AKA Neurocognitive Disorder due to HIV infection (DSM V) |
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What does HIV primarily infect?
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macrophages and microglia
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what are risk factors for HAD?
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low CD4 (usually <200 cells/mm3)
high viral load advanced age Apo E4 alleles anemia weight loss substance abuse TBI depression coinfection with Hepatitis C |
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What are features of HAD?
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rapidly progressing (several weeks to few months)
slowness, clumsiness psychomotor retardation, gait impairment memory impairment, apathy, withdrawal decline into persistent vegetative state with possible myoclonus, EPS, ocular saccades/pursuits (basal ganglia/brainstem involvement) |
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What is treatment for HAD?
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ART
stimulants antidepressants |
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What do imaging studies show in HAD?
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CT/MRI:
cerebral atrophy enlarge ventricles basal ganglia abnormalities MRI: nonspecific scattered white-matter abnormalities |
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What does CSF show in HAD?
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mild lymphocytic pleocytosis
normal or slightly elevated protein oligoclonal bands HIV |
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What is the most common AIDS-related CNS infection (other than HIV)? What causes it?
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cerebral toxoplasmosis
Toxoplasma gondii |
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what is seen on imaging studies of cerebral toxoplasmosis?
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CT/MRI: multiple ring-shaped enchancing lesions
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what are features of progressive multifocal leukoencephalopathy (PML)?
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combinations of:
cognitive impairment hemiparesis spasticity blindness |
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what causes PML?
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JC virus
infects oligodendroglia (generates/maintians CNS myelin) causing white matter demyelination in brain/SC |
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what is seen on imaging studies in PML?
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mutiple areas of demyelination without mass effect
that slowly become confluent |
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What are CSF findings in PML?
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PCR: JC virus DNA
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what is the most common cerebal neoplasm in AIDS patients?
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primary cerebral lymphoma
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what is pseudodementia?
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psychiatric disturbance mimicking/producing cognitive impairment
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what causes pseudodementia?
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Most often depression
also caused by anxiety, schizophrenia & other psychiatric conditions |
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what is toxic-metabolic encephalopathy?
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AKA delirium
disturbance in level of awareness & ability to focus, sustain & direct attention |
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what is the most commonly occurring risk factor for toxic-metabolic encephalopathy?
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pre-existing dementia
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what are EEG findings in toxic-metabolic encephalopathy?
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background slowing
disorganization triphasic waves in hepatic/uremic encephalopathy |
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what are features of delirium in children and adolescents?
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sleep disturbances
disorientation inattention short-term amnesia agitation |
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what region of the brain is most affected by toxic-metabolic encephalopathy?
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reticular activating system
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what causes cerebral edema?
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vigorous dialysis or insulin adminstration clears solute more rapidly from serum than brain
concentration gradient causes free water to move into brain -> cerebral edema |
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what is osmotic demyelination syndrome? What are its features?
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AKA central pontine myelinolysis
correction of hyponatremia too rapidly lose myelin in pons permanent nystagmus quadriparesis ataxia occurs with: alcoholics with malnutrition pregnant women with hyperemesis liver transplant recipients |
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what is best imaging study for osmotic demyelination syndrome?
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MRI
(visualizes myelin-containing/small structures) |
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what is post-injection delirium/sedation syndrome?
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IM olanzapine causes:
confusion agitation anxiety sedation depressed LOC (delirium, coma) (thought from medication seeping into vasculature) |
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what are features of hepatic encephalopathy?
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mild confusion with lethargy/agitation
progresses to coma overtly abnormal LFTs asterixis: waving hands on arm extension triphasic waves on EEG |
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what causes hepatic encephalopathy?
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NH3 from protein (high-protein meals) or blood (GI bleeds)
shunted by cirrhosis-induced portal HTN into systemic circulation NH3 readily penetrates BBB alternate theory: toxins bind to GABA receptors & increase GABA activity |
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what are nine "red flags" warnings against Alzheimer's disease diagnosis?
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1)age <65
2) fluctuating LOC 3) behavioral/emotional/personality disturbances overshadowing cognitive impairment 4) rapid (6-12 m) progression 5) gait impairment 6) lateral signs (i.e. corticospinal tract signs) 7) movement disorders 8) myoclonus 9) parkinsonism |
