WK 11- Neurological Emergencies Flashcards
What are the differentials for headache- especially if febrile
- Malaria (people in Townsville travel a lot)
- Dengue, chikungunya, (Zika),
- Other arboviruses
- Meningitis, encephalitis
- Q fever
- Leptospirosis
- Rickettsial disease- scrub typhus
What history would be noted in someone with meningitis/encephalitis
FEVER (may not have fever now, could be hypothermic, but must have had fever)/neck stiffness/vomiting/photophobia, ALOC (altered LOC due to lack of perfusion/oxygen or due to the result of the infection of the brain tissue)
What history would be noted in someone with dengue
FEVER, Wet Season?, overseas travel (possible exposure), Retro-orbital headache, severe aches and pains,
What history would be noted in someone with a brain tumour
Do not hurt initially (cause pain when they grow and build up pressure), Persistent headache, worse in mornings, focal neurology, vomiting (CSF pressure increase) Past hx cancer (breast cancer)
What other non sinister causes of head ache are there
Alcohol, drugs
- Coffee use–> especially withdrawa
- Eye strain
- Viral symptoms
- Earache, tooth problems→ ie. temperoarteritis
- Stress
- Muscular aches in the neck/upper back
What important questions are required in regards to pain history of the headache
Important to note description and onset of paint→ was it sudden onset? (sudden onset often indicates acute bleed), what were they doing when the headache came on (does it happen when they sit up→ epidural leak of CSF), how do they describe it→ ‘thunderclap’ ‘like being hit with an axe/sledgehammer’
On examination, what are the key points that should be noted for headache
- Conscious state→ GCS
- Pupils→ dilated? Responsive?
- Focal neurology
- Fever→ infective, rheumatological disorders
- Neck pain→ is there stiffness or pain
- Photosensitivity
- Rash
- Posture of patient
What is coning
squeezing of the brain and brainstem through the foramen magnum as a result of swelling → may lea to loss of basic cardiorespiratory function
What is an altered level of consciousness
-is any state other than fully alert and aware
Two possible underlying pathophysiological mechanisms:
- Global impairment of cerebral cortices
-Impairment of reticular activating system
in brainstem
How can you assess altered level of consciousness
Glasgow Coma scale
-Eyes, Verbal, Motor
Gives score out of 15. Still get 3 if you’re dead!
What are the GCS scores for;
- Mild brain injury
- Moderate brain injury
- Severe brain injury
Mild= GCS of 14/15 Moderate= GCS 9-13 Severe= GCS below 9
What are the primary and secondary classifications of headache
- Primary = migraine/cluster/tension headaches
- Secondary = due to a specific pathology e.g. Meningitis, brain tumour
What are examples of neurological primary injuries
- Concussion→ technically not detectable on CT
- Contusion
- Laceration
- Diffuse axonal injury
What are examples of neurological secondary injuries
Cerebral ischeamia→ hypoxia, hypoventilation, decreasing ICP, decreasing BP, inadequate cerebral blood flow
-Hypoglycaemia→ DKA
-cerebral perfusion pressure= BP- ICP (intercranial pressure)
→ first 5 minutes are enough to reduce oxygenation to brain
How do you manage a neuro emergency (primary survey)
- Airway, Breathing→ maintain oxygenation
- Circulation→ maintain adequate BP to maintain cerebral perfusion pressure (as if you decrease BP you will decrease cerebral perfusion)→ aim for 100mmHg
- Disability= determine using glasgow coma scale
- Glucose→ hypo lead to DKA
How do you maintain ICP
- adequate fluid resuscitation→ you want it to be to a target to give the least possible amount to prevent potential harm
- Decreasing ICP→ drain IC haemorrhage, possibly hypertonic saline/mannitol (gradient drags fluid out of cranial vault)
What are the 4 examples of traumatic brain injury
- extradural haematoma (EDH)
- subdural haematoma (SDH)
- subarachnoid haemorrhage (SAH)
- intracranial haemorrhage (ICH)
What is meningism
Meningism involves the triad (3-symptom syndrome) of nuchal rigidity (neck stiffness), photophobia (intolerance of bright light), and headache.
What surface anatomy landmark(s) guide you to (L3/L4)?
-L4 is found at the top of the iliac crest–> draw a line straight across and feel for L3
Where do you want to put a LP and why
use lumbar as the spinal cord often terminated at L2→ means that by using a lower intervertebral space you will avoid hitting the spinal cord
Complications of LP
haemorrhage, infection, coning, headache, nerve damage
What structures must the needle traverse (from skin inwards) to reach the CSF?
1- Skin
2- Facia and SC fat
3- Surpaspinous ligament (outside of vertebrae)
4- Interspinous ligament
5- Ligamentum flavum (base of the vertebrae)→ creates pop-first main resistance
6- Epidural space and fat (epidural anesthesia needle stops here)
7- Dura
8- CSF space
How might coning manifest
→ Cushings triad– bradycardia and hypertension with altered respiration
Pupil change late
Rapid deterioration and death
What bacteria are the most likely causes of bacterial meningitis in a young adult group?
Young adult – N. meningitides and S. Pneumonia
What bacteria are most likely to cause meningitis in neonate
E.coli, listeria, group B strep (strep agalactiae)
What artery(ies) supplies the anterior cerebral circulation?
→ anterior cerebral artery
→ middle cerebral artery
→ internal carotid arteries
What artery(ies) supplies the posterior cerebral circulation?
→ vertebral arteries
→ basilar arteries
→ posterior cerebral artery
→ posterior communicating artery
What limbs would be affected if there was damage to the ACA circulation
-Legs
What limbs would be affected if there was damage to the MCA circulation
Arms and Face
What limbs would be affected if there was damage to the PCA circulation
Vision/cerebellar function
What would you expect to happen to limb reflexes after a period of time following a complete cord lesion and why does this occur?
-‘Spinal shock’ with loss of reflexes and flaccid paralysis occurs immediately after cord transection. Subsequently motor reflexes return and become hyperactive
What are focal neurological signs
-Focal neurologic signs also known as focal neurological deficits or focal CNS signs are impairments of nerve, spinal cord, or brain function that affects a specific region of the body, e.g. weakness in the left arm, the right leg, paresis, or plegia
If cerebral perfusion is decreased to the point where cerebral ischaemia ensues, what is the CVS-haemodynamic response
Cushings response – bradycardia, hypertension, decreased respiration. All due to pressure on vagus, vasomotor and respiratory centres
What effect does a high PCO2 have on cerebral blood flow?
Low = vasoconstriction High = vasodilation
What implication does the effect of very low and very high P02 have for the management of a patient with an acute head injury/cerebral oedema?
Keep oxygenated
-Keep pCO2 normal to slight decrease (35mmHg)
What is the normal intracranial pressure-
0-15mmHg
What are the red flags of a headache
- Never had migraines before
- sudden onset
- headache that wakes them from sleep/prevents them from sleeping
- morning headaches
- neck stiffness
- fever
What are the 3 main spinal cord tracts
spinothalamic, corticospinal and dorsal column
Which is the descending tract
-what are they responsible for
corticospinal-> aid in motor movements
Which is the ascending tracts-what are they responsible for
dorsal column (fine touch, proprioception, vibration), spinothalamic (pain, temperature and crude touch) →relays sensory information
What is anterior cord syndrome
- how does it occur
- what does it cause
- what cord does it affect
- most common cause is hyperflexion injury (due to compression of the anterior segment of the spinal cord→ causes paralysis from the waste down due to damage of the corticospinal pathways
- numb from the waste down→ due to damage of the spinothalamic pathway
- but dorsal column is in tact so can still feel vibration and fine touch
- -> so corticospinal and spinothalamic are damaged
What is central cord syndrome
- how does it occur
- what does it cause
- what cord does it affect
- hyperextension of the neck-> damage corticospinal tract-> but only interior/central part of the cord
- upper limb control is in the inside of the corticospinal tract, and leg movement is in the outside
- if someone has central cord syndrome there will be loss of movement of arms (as central portion is affected)→ upper limb weakness and loss of sensation
What is Brown sequard syndrome
- how does it occur
- what does it cause
- what cord does it affect
- hemi-section of the spinal cord (ie. knife wound)
- lose movement and fine touch on the side the lesion (stabbing) occurs on as the cord has already crossed in the brain, but lose pain on the opposite side, as the spinothalamic tract crosses at the level of the vertebrae it is exiting
Does upper motor neuron lesion cause flaccid or spastic paralysis
upper motor neuron lesion= spastic paralysis
-upper motor neuron is in charge of inhibitory lesions→ will have a larger reflex and hypetonia, positive babinski
Does lower motor neuron lesion cause flaccid or spastic paralysis
lower motor neuron lesion= flaccid paralysis
-hypotonia, hyporeflexia, atrophy, absent babinski reflex, +/- vesiculation (muscle twitching)
What are the categories of AVPU
-how does it score
-AVPU→ This is the most simple and categories the patient into one of four states.
Alert = awake but may be confused
Verbal = responding to verbal stimulus
Pain = responding only to painful stimulus
Unresponsive = no response to any stimulus
-put the letter that the patient corresponds to
What is a quick way to assess GCS and how does it work
COWS–> if the patient responds to voice, opens their eyes (obeys commands), verbally communicates and squeezes your hand then they have a normal GCS–> assess eye opening, verbal response and motor
What GCS is comatose
8
Why is knowing the GCS important for airway management
Low GCS = Loss of protective airway reflexes and increased risk of aspiration
-Airway obstruction,
How does phenytoin work
- acts on sodium channels on the neuronal cell membrane→ promotes sodium efflux from neurons→ stabilize the threshold against hyperexcitability caused by excessive stimulation→ prevents propagation of abnormal impulses (seizure activity).
What is meant by first order kinetics
-first order kinetics assumes that rate of elimination of the drug is proportional to plasma→ a constant proportion of the drug is eliminated over time
What is meant by zero order kinetics
-Amount of drug is eliminated over time is constant (not related to plasma conc)→ caused by saturation of drug metabolism
What are the 2 types of strokes
Haemorrhagic and embolic
-most common is embolic
What are the CT features of an epidural bleed
- what is an epidural bleed also called
- what artery is most commonly damaged
mainly arterial bleed, fresh blood is white→ will get lemon shaped lesion on CT scan
-aka extradural haemorrhag
→ mainly damage the middle meningeal artery→ commonly damaged by temporal bone break
-mainly in physical violence (ie punch)
What are the CT features of a subdrual haemorrhage
-who is most commonly affected
venous bleed with slow onset of symptoms→ due to being a chronic bleed the blood will be darker (not white)→ the bleeding is between skull and brain so will take a few days for the blood to be large enough to compress the brain→ banana shaped lesion
-mainly bridging veins bleed in old people during a fall (as the brain moves and the bridging veins will tear)
What are the CT features of a subarachnoid haemorrhage
bleeding will be between the gaps in the brain→ white blood will fill the spaces
- traumatic→ fall, MVA- rupture the small arteries, punch
- spontaneous→ burst of aneurysm
- thunderclap headache→ severe occipital headache with neck stiffness and syncope
What causes interparenchymal bleeding
due to uncontrolled hypertension
What are the CT features of an ischemic stroke
will occlude blood flow to portions of brain and cause it to become necrotic→ the dead tissue is darker than the surrounding areas
-if do CT scan to early, may not always pick up bleeds
What is a concussion
brief LOC with no structural damage→ will have normal anatomy/imaging
Why would ketamine not be a good drug to use in cranial bleed/high icp
increases BP→ increases cerebral blood flow
cerebral blood flow= MAP(pressure pushing blood into brain)- ICP (pressure inside skull)
What are the types of seizures mainly occurring in encephalitis
most common seizures in encephalitis= focal seizures due to temporal lobe being effected
what sense would be affected by infarction in the posterior cerebral circulation
vision due of occipital lobe losing perfusion
why are the arms affected in central cord syndrome
corticospinal tract has axons to the arms more centrally
