What disorders of cognitive function can be due to a result of concussion or a mild brain injury?
When evaluating for new altered mental status, prior medical history on what body systems should always be asked about/examined?
What is included in a general mental status exam?
general behavior & appearance
stream of talk
mood & affective response
content of thought
mini mental status exam (<24/30 needs more testing)
What is the included in a formal mental status exam?
attention & concentration
language & speech
mood & behavior
content of thought
integrative sensory & motor function
Ability to focus on a particular sensory stimulus (sustained=concentration), is typically grossly impaired in delirium but not so much with dementia, and is tested by serial 7s or identifying a letter in a series w/o error.
attention (mental status exam)
What are the essential elements of language & speech tested for with the mental status exam?
Type of aphasia in which fluency & comprehension is preserved, and repetition is impaired caused by a lesion in the arcuate fasciculis.
Type of aphasia in which fluency is impaired, repetition & comprehension is preserved, pt may have an associated right hemiparesis, is caused by a lesion near Broca's area.
transcoritcal motor aphasia
Type of aphasia in which fluency and repetition is preserved, comprehension is impaired, is caused by a lesion in Wernicke's area.
transcortical sensory aphasia
Type of aphasia in which fluency, repetition, and comprehension is impaired, pt may have associated severe right hemiparesis, is caused by a large lesion in the left hemisphere.
Type of aphasia in which fluency and comprehension are variable, pt may have associated hypophonia, is caused by a lesion in the left basal ganglia or thalamus.
Disturbed memory in which pt can't remember emotionally charged events but can remember objective facts and events.
Disturbed memory in which pt can't remember objective facts.
Disturbed memory in which pt loses memory for event immediately prior to the disorder (head trauma).
How is memory tested?
immediate, recent, and remote recall
What things are tested for when checking integrative sensory function?
2 point discrimination
What are the historical red flags for acutely confused patients?
Type of memory that lasts <30 seconds, can recall 7 bits of info (+/-2), vulnerable to distraction, anatomically related to the RAS, prefrontal cortex, and parietal lobe, and is tested with recalling digits backwards.
Type of memory that lasts minutes to months, "lays down" significant memories throughout the day, is anatomically related to the hippocampus and dorsomedial nucleus of the thalamus. Is tests with word recall @ 3-5 mins or by asking about trivial events during the day (what they had for breakfast, etc).
Type of memory that is lifelong (related to new protein synthesis and creation of new synapses), is anatomically related to the left anterior temporal lobe and frontal lobe.
This can occur as a feature of an acute confusional state, dementia, or isolated abnormality.
What are the acute causes of amnestic syndromes?
bilateral cerebral artery occlusion
transient global amnesia
dissociative (psychogenic) amnesia
What are the chronic causes of amnestic syndromes?
alcoholic Korsakoff amnestic syndrome
paraneoplastic limbic encephalitis
Generalized loss of memory (psychogenic/organic). Acutely confused pt my have impaired attention & inability to learn new material. Demented pts have normal attention span with problems with recent memory (remote memory intact).
Mental activities involved in planning, initiating, and regulating behavior. Is considered the central organizing function of the brain and is highly dependent on working memory, primarily involves the frontal lobe, and is diminished/lost in many types of dementia.
Condition typically ACUTE in onset, responds to at least some stimuli appropriately, pt can appear sleepy/disoriented/inattentive (LOC may be impaired), can occur at any age and is typically reversible.
Condition typically CHRONIC in onset with worsening over time, pt usually appears "normal" but confused, normal LOC with impairment in the content of consciousness, is typically more common in elderly (associated with age) and is irreversible.
Acute change in mental status (hours to days) with a disturbance of consciousness that results from an underlying medical cause. Hallmark is waxing and waning levels of consciousness.
How is delirium mainly differentiated from dementia?
by the history
Note: short onset within hours to a few weeks favors delirium, chronic disturbance/gradual onset favors dementia
what is the hallmark description for delirium?
waxing and waning levels of consciousness
What are the key features of delirium?
memory impairment & disorientation
Progressive decline in cognitive function beyond what might be expected from normal aging. Symptoms vary and slowly progress but all do involve loss of cognitive skills, especially learned tasks (apraxia). Recent memory is what is usually markedly affected (long term is affected last). Pts have normal level of consciousness.
What are degenerative causes for dementia?
What are vascular causes for dementia?
What are the CNS conditions that can cause dementia?
What are the conditions occurring in the chest that can cause dementia?
congestive heart failure
What conditions other than degenerative, chest, or CNS conditions can cause dementia?
What treatment can precipitate or worsen Wernicke's encephalopathy?
administration of glucose without thiamine
Nutritional disorder that presents with mild confusion to dementia to psychosis. Occurs in patients who have had gastric bypass, alcoholics, chronic users of acid blockers but is usually due to poor intake.
vitamin B12 deficiency
Note: tx with IM injections monthly due to poor GI absorption (aka pernicious anemia)
For practical purposes, all patients with undiagnosed altered mental status, oculomotor disorders or ataxia should receive what treatment?
thiamine 100mg IV (may consider glucose bolus first since ONE dose isn't likely to worsen the problem)
Note: ataxia may not be fully reversible, deficits in learning and memory may follow
Infection of the brain's subarachnoid space.
Infection of the brain tissue itself.
What three criteria in CSF are helpful in the diagnosis of bacterial meningitis?
WBC >/= 500/uL
glucose to blood glucose ratio of </= 0.4 (low CSF glucose)
lactate level of >/= 31.35 mg/dL
What are infectious disorders that can cause encephalitis?
west nile virus
What are infection disorders that can cause meningitis?
acute: bacterial, fungal
chronic: fungal, TB
What are the two major pathways in which meningitis can be contracted and what are examples for each?
invasion of the bloodstream: bacteremia, viremia "aseptic meningitis", fungemia, parasitemia
direct contiguous spread: sinusitis, otitis media
What are the general signs and symptoms of meningitis?
fever to 104
other sources of infection (middle ear, sinuses, lungs, UTI, wounds)
What is the classic triad found in 2/3 of patients with meningitis?
mental status changes
What is a positive Kernig's test?
pt does not allow knee extension when hip is flexed
What is a positive Brudzinski's test?
pt resists passive flexing of the chin onto the chest, brings knees up in response
What can a lumbar puncture reveal in a patient with meningitis?
What may an MRI show in a patient with meningitis?
What are the rules of thumb for meningitis patients?
1) empiric therapy should be initiated whenever bacterial meningitis is suspected
2) LP everyone you suspect that COULD have meningitis (don't delay abx!)
3) viral meningitis seldom presents with depressed mental status, seizures, or focal neurologic deficit
When do you need to CT or MRI a pt before performing a lumbar puncture in a suspected case of meningitis?
recent head trauma
known metastatic lesions or CNS tumor
anyone with focal neuro findings (papilledema, decreased level of consciousness)
What clinical signs may be observed with meningitis?
What were the most common pathologic agents that caused bacterial meningitis before vaccines (HIB) were available?
Now due to the HIB meningitis vaccine cases of bacterial meningitis have decreased by 90%, however it is still an issue for some namely adults. What is the organism most responsible for adult bacterial meningitis?
penicillin resistant S pneumoniae
What is the bacterial empiric therapy for meningitis by predisposing features?
<3 months old: ampicillin plus (cefotaxime/ceftriaxone) vancomycin
3 months to 50 years old: (ceftriaxone/cefotaxime) plus vancomycin
>50 years old: ampicillin plus ceftriaxone or ceftriaxone plus vancomycin
impaired cellular immunity: ampicillin plus ceftazidime plus vancomycin
neurosurgery, head trauma, or CSF shunt: vancomycin plus ceftazidime plus ampicillin
What are the steps in treatment and procedures performed for meningitis?
1) begin abx ASAP if bacterial meningitis is suspected (empiric=penicillin 24 million units/day in 6 divided doses, ceftriaxone 6 gm/day in 3 divided doses, vancomycin 2gm/day in 2 divided doses)
2) evacuate immediately
3) airway support and O2 (intubate as needed)
4) fluid hydration with IV NS or LR
5) control fever with Tylenol
6) if viral meningitis is suspected give acyclovir 12.5 mg/kg/day IV divided TID for 10 days
7) consider steroids (decadron 0.4 mg/kg q12 hr for 4 doses) with first dose prior to starting abx
What clinical sign is characteristic of Neisseria meningitidis?
What is the goal in treating bacterial meningitis?
to begin ABX therapy within 60 minutes of arrival to ER!
What is the basic empiric therapy for bacterial meningitis?
What factors are part of a poor prognosis for patients with meningitis?
extremes of age
delay in diagnosis and/or treatment
focal neurologic signs
What is the most common type of encephalitis?
What are common viruses that cause encephalitis and how are they transmitted?
enterovirus: fecal-oral transmission
HSV, VZV: human to human transmission
arboviruses: mosquitoes, ticks (ie west nile)
Type of encephalitis caused by a virus that directly invades the brain and spinal cord.
Type of encephalitis caused by a virus that first infects another part of the body.
secondary (post infectious) encephalitis
What is the most common cause of fatal encephalitis in the US? How is it contracted/developed?
herpes viruses (HSV, VZV)
human to human transmission/reactivation of latent virus
What is the antiviral treatment for encephalitis?
acyclovir 10-15 mg/kg IV q8 hours for 14-21 days (start ASAP!!)
What are the signs and symptoms of encephalitis?
altered mental status
What are the labs and tests that should be performed to diagnose encephalitis?
head CT: with AND without contrast, before LP to search for elevated ICP, obstructive hydrocephalus, and mass effect
MRI: more likely to show abnormalities
EEG: diffuse slowing
CSF: nl or slightly increased protein, lymphocytes present, normal glucose
What labs should be run on an acutely confused patient?
WBC (r/o infection)
chem 7 (Na, BUN, creatinine, glucose)
thyroid function tests
serum & urine drug screen (including ETOH level)
head CT (or MRI if pt is "stable")
What are the historical red flags for the acutely confused patient?
progressively declining level of consciousness/neuro exam
disorientation (can't recognize people/places)
confused, irritable, strange behavior
unsteady on feet
weakness/numbness in arms or legs
A disorder involving impairment of learning & memory and one or more of the following: impaired ability to perform complex tasks, impaired reasoning ability, spacial orientation or language.
Note: simple definition is deterioration in cognitive abilities that impairs previously successful performance of activities of daily living
Prevalence of dementia types depends on the population. What types are most prevalent in western society?
parkinson's (often with lewy bodies)
What are the three most common reversible causes of dementia?
What is the biggest risk factor for developing dementia?
Note: prevalence increases over age 50, microscopic changes consistent with alzheimer's is the most common autopsy finding
What is the course of cognitive impairment with normal aging?
subtle decline in episodic memory
no affect on daily life
age is the single greatest risk factor for cognitive decline
What are the signs/symptoms of mild cognitive impairment?
typically mild cognitive deficits
interferes with daily lifemajor risk factor for frank dementia
What are the risk factors of mild cognitive impairment turning into frank dementia (usually alzheimer's type)?
memory deficit >1.5 SD from normal
presence of apolipoprotein e4 allele
small hippocampal volume
What are the four major classes of dementia to aware of that are each associated with aggregation of an abnormal protein?
frontotemporal dementia: tau
lewy body dementia (DLB): a-synuclein
prion disorders: PrP
Most common cause of dementia in the US, characterized macro and microscopically.
What are the macroscopic characteristics of alzheimer's disease?
diffuse cortical atrophy
What are the microscopic characteristics of alzheimer's disease?
neuritic plaques of AB42 amyloid
silver staining neurofibrillary tangles in neural cytoplasm
accumulation of AB42 amyloid in arterial walls of cerebral blood vessels
A progressive neurological disorder that results in memory loss (typically first finding), language and visual spacial deficits, and anosognosia (lack of awareness of cognitive deficits) in most patients. Symptoms begin gradually but progress to involve daily life.
What are the factors for increased risk of developing alzheimer's disease?
female (female to male ratio is 2:1)
positive family hx
more common in lower educated populations
head trauma (minor risk)
Where is the pathology of alzheimer's disease localized to?
lateral septum (nucleus of Meynert)
What are the key findings in the brain for people with alzheimer's disease?
What are "senile plaques"?
collections of degenerative presynaptic endings (cannot see this on MRI!)
Cortical atrophy leads to ________ of the ventricles.
What is the general course of alzheimer's disease symptoms?
gradual development of forgetfulness (major symptom) often first noticed by family
halting speech (can't recall word), eventually speech becomes restricted
progresses to disorientation to time then place
motility, behavior, temperament, and conduct begin to decline (pt gets restless, agitated, depressed)
symptoms progress over 7-15 years
What are the early signs/manifestations of alzheimer's disease?
non-focal neuro exam
abnl short term memory
score of 24-27 on MMSE
What are the later signs/manifestations of alzheimer's disease?
language, cognition decline
paranoia, hallucinations, delusions
primitive reflexes emerge
pt becomes mute, bed bound, incontinent
What are the diagnostic studies used to identify alzheimer's disease?
MRI, CT: no difference than mentally intact elderly early on, later shows enlarged ventricles (lateral and 3rd), widened cerebral sulci and hippocampal atrophy
neuropsychiatric testing: deterioration in memory and verbal skills; decreased "executive functioning"
apo e testing: useful to confirm dx
What are the cholinesterase inhibitor medications used to treat alzheimer's disease?
What are the NMDA receptor antagonist medications used to treat alzheimer's disease?
What is the MOA for the medications that treat alzheimer's disease and what effect do they have?
they increase CNS levels of ACh
slows progression of cognitive decline (avg pt maintains MMSE at 1 yr compared with placebo)
Which medication has been approved for use in moderate to severe alzheimer's disease? What are the main side effects?
nausea, other GI effects
Condition also known as multi-infarct dementia, meaning dementia arising from vascular insult, that lacks a uniform set of criteria.
Note: cerebrovascular disease may play a role in the presence and severity of AD symptoms, silent infarcts may also increase the likelihood of dementia
What are the findings that suggest vascular dementia as a diagnosis?
cognitive deficit onset associated with a stroke
abrupt onset with stepwise deterioration
focal findings on neuro exam consistent with CVA
infarcts seen on imaging
White matter infarcts that cause patients to present with apathy, agitation, and bilateral corticospinal or bulbar signs.
Class of dementia that comes on between 50-70 years of age that is characterized by early behavioral symptoms, and is associated with marked atrophy of temporal and frontal lobes.
frontotemporal dementia (FTD)
Note: microscopically associated with tau protein accumulation within neurons
Dementia syndrome characterized by visual hallucinations, parkinsonism (symptoms often begin before dementia, and respond with delirium to L-dopa), fluctuating alertness, and falling.
dementia with lewy bodies
Note: microscopically reveal lewy bodies throughout the cerebral cortex
What are general causes for reversible dementia?
depression (most common)
normal pressure hydrocephalus
chronic subdural hematomas
Condition most commonly mistaken for dementia. Both conditions tend to show mental slowness, apathy, self-neglect, irritability, difficulty with memory, etc.
Note: all patients with suspected dementia must be screened for depression
What are the features of dementia that distinguish it from depression?
pt is unaware of deficit extent
no complaints of memory loss
few vegetative symptoms
worse at night
abnormal neuro exam
possibly abnormal labs
What are the features of depression that distinguish it from dementia?
pt is aware of deficits
complains of memory loss
prominent vegetative symptoms
not worse at night
normal neuro exam
How and when is pseudodementia (depression) treated?
Note: anticipate relatively rapid improvement in function
What is the classic triad that patients with normal pressure hydrocephalus present with?
How is normal pressure hydrocephalus managed?
Syndrome that shows damage mostly in the thalamus and other midline structures occurring in the presence of a LONG STANDING thiamine deficiency.
What is the classic presentation for thiamine deficiency?
What cancers can cause reversible dementia, and where would it be located to cause the dementia?
primary or secondary
frontal cortex of the temporal lobe
What is the term used to describe reversible dementia caused by recurrent head trauma?
What is the general symptomatic treatment for reversible dementia?
identify and tx reversible cause
remove sedating meds/cognitive impairing drugs
tx depression aggresively
tx behavioral problems by addressing environmental cues (reorienting, exercise, memory aides) or using antipsychotics