Cohen: Coma, Dementias, Seizures, Syncope Flashcards
steps to take when found in coma?
- Stabilize: patent airway, adequate breathing, circulation
- Blood pressure and perfusion check: there may be circulatory collapse from hemorrhage or dehydration
- Peripheral or central intravenous line; draw blood for labs first, if possible; if any chance of hypoglycemia, give dextrose and thiamine
- Intubation/ventilation in many cases, sometimes just a cannula or a face mask for oxygen delivery; arterial blood gases can be followed
- Look for evidence of trauma, especially head and cervical spine
- Complete history from witnesses or neighbors or family; keep them available or get telephone numbers for later inquiries
- Comprehensive laboratories: chemistry, blood count, toxicology
- If any chance of opiate overdose, give naloxone (Narcan)
decerebrate vs. decorticate
decerebrate: (arm and leg extensions) is usually the top of the brainstem or the thalamus
decorticate: arms are flexed, legs extended - is usually widespread damage to both hemispheres
corneal reaction
blink reflex, is an involuntary blinking of the eyelids elicited by stimulation of the cornea (such as by touching or by a foreign body), or bright light, though could result from any peripheral stimulus.
tests CNs V and VII
oculocephalic reflex
normally vestibulo-ocular reflex results in eye moves in opposite way that head moves - if brainstem is in tact then eyes will do this
negative “doll’s eyes” are the result of eyes staying fixed midorbit = brainstem not intact
“Doll’s eyes” with eyes going opposite direction of head turn if there is NO inhibition by the cerebral hemispheres; rarely seen, because most coma patients have damage to brain AND both hemispheres, involving the pons and medulla oblongata
oculovestibular reflex
“cold calorics,”eyes deviate conjugately toward ear given ice water, involving the pons and medulla oblongata
hot water - eyes drift away from warm water
damage to CN III
see dilated, unreactive pupil and inability to move eye any dx except laterally (CN VI)
The nuclei for CN III are at the top of the brain stem, in the midbrain
The nuclei and its oculomotor fibers can be compressed by uncal herniation of the ipsilateral, and occasionally contralateral hemisphere
Brain damage without herniation also tends to hit CN III hard, causing weakly reactive pupils and both eyes tend to deviate laterally (again, if preservation of CN VI)
prognostic indicators for coma?
Probably the two most important signs:
- Pupillary reactions to light
- Spontaneous movements
Any patient with coma for 72 hours, excluding those with reversible swelling from trauma or sedation from drug overdose, or hypothermia, with multiple missing brain stem reflexes, has less than a 5% chance of a meaningful recovery
brain death
loss of brain stem and cerebral system
The patient who is brain dead IS LEGALLY DEAD
requirements:
- Exclude patients who may have a reversible condition: swelling from trauma, hypothermia, known drug overdose
- No evidence of cerebral function: no response to stimulation, no movements, no vocalization
- No evidence of brain stem function: all of the brain stem reflexes are absent, and no spontaneous respiration from centers in the medulla and pons
confirmation: APNEA TEST - – ventilator is turned off, but 100% oxygen is still delivered, until the PC02 rises to approximately 60 mmHg; if brain dead, no respiratory effort is seen at a high PCO2
other confirmatory tests: EEG, lack of cerebral blood flow on cerebral arteriography
Vegetative State
It suggests loss of both cerebral hemispheres, but maintenance of part or all of the brainstem
The brain stem can maintain sleep-wake cycles, respiration, heart beat, swallowing, some eye movements and facial contractions
Patients do not truly speak words but make some simple vocal sounds, such as grunts or event laughter
The arms and legs move but not in a directed manner
Gross vision is maintained, but no specific responses to what these patients seem to “see”
PVS = persistent vegetative state
definition: one month or more of vegetative state
- No awareness of self or surroundings, although eye opening and eye movements occur
- No meaningful communication between patient and others, including no comprehensible speech and no accurate mimicry
- Facial expressions not accurately related to stimulation, although patients may laugh or cry (CN VII in tact)
- Sleep-wake cycles may be intact
- Arm or leg movements, but not under voluntary control or with a directed purpose
- Adequate control of cardiovascular functions
- Incontinent of bowel and bladder
dementia def.
= loss of the “higher functions,” including memory, awareness, insight, judgement, executive function, abstract reasoning, visuospatial and construction skills, reasoning ability, social skills, use of meaningful language
- AD - 60-70%
- LBD/Parkinsons: 10-15%
- Multi-infarct/Vascular Dementia 5 - 10%
- Fronto-temporal Dementia : 5- 10%
- Alcoholism/Vitamin B12 deficiency: 5 %
AD
Pathogenesis:
- accumulation of beta-amyloid plaques
- accumulation of phosphylated tau protein in MT’s
- cell death, apoptosis - esp. in temporal and parietal lobes
** tau more effective in tx, thus maybe the more important accumulation.
seen in 10-25% of people 80+ y/o
Clinical Course;
- begins with a LOSS OF MEMORY for recent information or events - objects misplaced, trouble w/ names, repeating questions, speech restricted, trouble w/ daily affairs
- visuospatial decline, gait disorders
- depression, boredom, paranoia, anxiety
- apraxia - loss of simple actions
Levels:
- mild: ok at home, can be left alone
- moderate: pt. is kept at home w/ full-time caregiver
- Severe: pt. must go to nursing home
ddx:
- primarily clinical
- CSF shows tau increase and beta amyloid decrease
- brain MRIs show atrophy of medial and temporal lobe (but not specific)
tx of AD?
Option 1: AChE inhibitors: relieve memory impairement, agitated behavior by raising ACH levels - have a slower decline
- Donepezil (Aricept) Most widely used, well-tolerated, fewest systemic adverse effects, once daily
- Rivastigmine (Exelon) Strongly cholinergic effects, including vomiting and diarrhea, as a capsule, but now available as a skin patch to limit adverse effects
- Galantamine (Razadyne) Similar to rivastigmine, extended release form is available
Option 2: Memantine (Namenda)
- Antagonizes glutamate at the N-methyl-D-aspartate receptor
- May prevent cell death from glutamate activity
- Used alone or with an AChE for moderate or severe AD, but memantine is seldom very effective
Option 3:
Antidepressants are often needed, especially early in disease
There is often the use of antipsychotics to control agitation, anxiety; but studies show increased falls and earlier death
** keep pt. physically active and prevent from seeking isolation!
lewy body dementia
1/5 as common as AD
sx:
- dementia, agitated behavior along with decreased facial expression slowness and imbalance (but mild or no tremor) suggesting a case of early Parkinson’s Disease, except for the EARLY dementia and agitation, which are usually LATE problems in Parkinson’s Disease
- more common in men
- “crazy person” more psychiatric w/ parkinsonian mvmts - more angry/fear
common features:
- dementia, progressive but FLUCTUATING
- visual hallucinations
- parkinsonism - rigidity and slowness
tx:
* * BAD RESPONSE TO ANTIPSYCHOTIC DRUGS!!!
- may improve with AChE drugs
- levodopa sometimes given if parkinson sx increase
pathology:
- Lewy Bodies (alpha-synuclein seen in parkinsons) distributed throughout the brain NOT just substantia nigra.
- also have senile plaques and tangles
clinical course:
- more rapid decline than AD
- psychotic behavior fluctuates - may be injured or killed d/t hallucinations
multi-infarct dementia
- dementia d/t strokes causing ischemic changes –> rapid step-like downhill course
- “focal” findings on exam, including aphasia, dysarthria, hemiparesis, spasticity, visual field cuts
- Seizures more common than in other dementias
- Likely concurrent coronary artery disease, peripheral vascular disease and carotid stenosis, which may be seen with ultrasound
Common risk factors: HTN, DM, hyperlipidemia, obesity, smokers, alcoholics, CAD, A fib
tx: aspirin, anti-cogulants sometimes (warfarin)