Neurological Flashcards
(17 cards)
What are the 4 manifestations of psychosis?
Psychiatric illnesses are considered after D.I.M.S. ruled out!
- Delusions - false beliefs that can be plausible or bizzare
- Hallucinations - wakeful sensory experiences, can be in any of the senses but auditory is most common
- Thought disorganization - unlinked thinking as opposed to ‘word salad’
- Agitation - acute anxiety
What is the Hunt & Hess score?
Classifies severeity of subarachnoid hemmorhage to predict mortality.
- Asymptomatic or mild headache/nuchal rigidity 30%
- Moderate/severe headache, nuchal rigidity, no neuro deficit except cranial nerve palsy 40%
- Drowsiness, confusion or mild focal deficit 50%
- Stupor, hemiparesis, possible early decerebrate posturing, rigidity and vegetative disturbances 80%
- Deep coma, decerebrate, moribund 90%
Describe neurogenic pulmonary edema
Increase in interstitial and alveolar fluid due to acute CNS injury, sometimes classified as a form of ARDS.
Likely caused by SNS activation and increased pulmonary HTN, inflammatory cascades and neural changes.
s/s appear usually within minutes to hours: hemoptysis, dyspnea, tachypnea, tachycardia, crackles.
Most resove within 24-48 hours with supportive care and mech vent as needed.
What is the NIHSS?
Objectively rates ischemic stroke severity, assigning scores based on:
- LOC
- Gaze/visual
- Facial palsy
- Arm and leg motor fx
- Best language/speech
- Inattention or neglect
What is the Fisher scale?
Rates risk of vasospasm in acute aneurysmal SAH based on amount and type of blood on initial CT.
Evaluates size of aneurysm - thin <1mm, thick >1mm - and whether there is intraventricular hemorrhage.
RASS Evaluation
- +4 violent, imminent danger to self or staff
- +3 pulls at tube or cath, agressive
- +2 frequent, non-purposeful movements, fights the ventilator
- +1 anxious, but movements are not agressive
0 alert and calm
- -1 sustained eye contact to voice >10 seconds
- -2 eye contact to voice <10 seconds
- -3 movement or eye opening to voice (no eye contact)
- -4 movement or eye opening to physical stimulation
- -5 no response
D.I.M.S
Pnemonic for potential causes of ALOC/status epilepticus or delirium.
- Drugs: intoxication, withdrawal, sedatives, anticholinergics & psychotropics
- Infections: pneumonia, UTI’s, sepsis, meningitis
- Metabolic: electrolytes, hypo/hyperglyceia, hypothyroidism, Wernicke’s encephalopathy
- Structural: CVA, cardiac events, seizures, hepatic encephalopathy
What is mass effect on CT?
Compression or displacement of brain tissue and structures due to a space occupying lesion or mass within the skull. Signs are:
- Effacement of sulci/gyri, blurring of the grey/white matter
- **Midline shift **of falx cerebri. Significant if >5mm
- Hydrocephalus marked by compression of the ventricles, which continue to produce CSF at a rate of 20-30mL/hr in the choroid plexus
- Brain herniation when tissue is pushed down foramen magnum, putting pressure on the brainstem
What determines cerebral blood flow?
- ANS vasoconstricts when there is too much cerebral blood flow
- PaCO2 increases will cause vasodilation, as will hypoxemia (as long as blood flow is preserved). Increasing PaO2 through hyperventilation will cause vasoconstriction.
- Myogenic autoregulation will constrict or dilate cerebral blood vessels in response to systemic blood pressure changes in order to maintain a steady flow state. Note, this mechanism fails when MAP falls below 65mmHg
- Metabolic activity will cause an increase of blood flow to an active area due to neurovascular coupling - this is why sedation can assist in reducing CBF in rising ICP.
Techniques for reducing ICP
Paranchyma: osmotics, sedation, temperature goal of normothermia
CSF: EVD
Vessels: PaCO2 goal 35, oxygenation, HOB 30 degrees, loosen collar, reduce PEEP (no more than 12 cmH2O), minimize OG/cuff pressure
Bone: Surgery
This is all in an attempt to ensure continued CDO2, which is represented by the equation: CBF x O2 Content. CBF represents cerebral perfusion pressure, which is MAP - ICP.
Cranial nerve checks!
- Sensory nerve #2 (optic) receives light stimulus and relays to motor nerve #3 (oculomotor) for response when doing a pupil check. These come from direct white matter tracts in the thalamus and midbrain.
- Corneal reflex tests motosensory nerves #5 (trigeminal) and #7. Doll’s eye tests sensory nerve #8 (vestibulocochlear). All are located in the pons.
- A gag or gag/cough will show function or somatosensory nerves #9 (glossopharangeal) and #10 (vagus), which are located in the medulla oblongata , just above the respiratory centre.
Level of consciousness assessment
If the patient opent their eyes to verbal or tactile stimulation, the arousal or reticular activating centre located in the brainstem, is intact.
Awareness, asessed via A&O questioning indicates an intact cerebral cortex
GCS and RASS should both be evaluated for a complete picture.
Subarachnoid factoids…
- Most are from aneurysms at branch points in the Circle of Willis.
- Blood in CSF is the diagnostic.
- BP goal should be equal or less than 140 systolic
- Treat seizures agressively
4 major SAH risks
- They often cause massive catecholemine relase, which can lead to arrythmias (torsades), and heart failure (from apex).
- Hydrocephalus from blood pooling in the ventricles
- Vasospasm often happens by day 3-11 if no clip or coil placed. Nimodipine may help prevent this: do NOT use phenytoin for seizure as it will negate the action of nimodipine.
- Rebleed
Classic clinical signs of increased ICP
- Significant pupillary asymmetry: unilateral or bilateral fixed & dilated pupils
- Decorticate or decerebrate posturing, ALOC
- Respiratory depression
- Cushing’s triad (HTN, bradycardia, and irregular resps)
Where are ICH’s usually located?
Most commonly off MCA in the lenticulostriate arteries, and related to hypertension.
What is the mechanism of autonomic dysreflexia?
Consequence of spinal injury at or above T6, usually triggered by bladder or bowel issues in a paralyzed patient.
The SNS responds to sensory input putting patient into significant hypertension. The motor tracts to reduce this impulse are damaged, so the SNS does not receive the message to vasodilate. When high pressures are sensed by the carotid baroreceptors can cause reflex bradycardia.
In emergencies, hydralazine is the choice to reduce hypertension as it does not reduce HR. Nitrates can also be considered.
