pathophysiology Flashcards
what is delirium?
Delirium: disturbance of consciousness and cognition that develops over a short period of time (hours to days) and fluctuates over time
what type of conditions can include delirium?
o ICU psychosis
o ICU syndrome – type of organic brain syndrome manifested by variety of psychological reactions including fear, anxiety, depression, hallucinations and delirium
o Acute confusional state
o Encephalopathy
o Acute brain failure
hoe prevalent is delirium?
occurs in between 20-80% of medical and surgical patients
what is seen in hypoactive delirium?
decreases responsiveness, withdrawal and apathy
what is seen in hyperactive delirium?
agitation, restlessness and emotional lability
which type of delirium has better outcomes?
hyperactive
the pathophysiology of delirium is poorly understood, what are potential hypothesis behind it?
o Neurotransmitter imbalance: excess of dopamine and depletion of Ach, but other NT are likely to be involved
o Inflammation: abnormalities induced by endotoxin and cytokines play a role. The mediators that cross BBB in animal studies increase vascular permeability changes seen on EEG. Inflammation may also reduce cerebral blood flow via formation of microaggregates of fibrin, platelets, neutrophils and erythrocytes
o Impaired oxidative metabolism: the reduction is in oxidative metabolism
what can cause delirium?
- D: drugs
- E: eyes and ears
- L: low O2 – MI, ARDS, PE, CHF, COPD
- I: infection
- R: retention of stool/ urine
- I: ictal
- U: underhydrated and under nutrition
- M: metabolic
- S: shock, sleep deprivation
if cerebellum pathology what signs would be seen?
affects fine motor
ataxia
speech/ language deficits
dysdiachokinesia
past pointing
uncoordinated walking
what is intentional tremor?
tremor on nose to finger exam
rhythmic, oscillatory, and high amplitude tremor during a directed and purposeful motor movement, worsening before reaching the endpoint
how would an upper motor lesion present?
flexed
hypertonia
spasticity
positive toe test - flexed toe on babinski test
how would lower motor lesion present?
hypotonia
floppy
fasculitations
how is bells palsy managed?
50mg 10 day course of pred - step down
eye drops for lubrication
what are the signs of cerebellar dysfunction?
DANISH
D: dtsdiachokinesia
- A: ataxia
- N: nystagmus (coarse)
- I: intention tremor
- S: scanning speech
- H: hypotonia
what is nystagmus?
involuntary repetitive eye movements
side to side
up and down
circular motions
what is the function of the midbrain?
- Helps with sleep cycle
- Pain
- Movement
- Transmitting info about hearing
what info does the ascending tracts relay?
sensory from peripheries to brain
what are the two tracts within ascending tracts?
- Conscious: dorsal column-medial lemniscal and anterolateral
- Unconscious: spinocerebellar
the conscious ascending tract is the dorsal column-medial, what info does it carry?
tactile sensation - fine touch ]
vibration and proprioception
the anterolateral conscious tracts is split into anterior and lateral spinothalamic, what info do they carry?
anterior spinothalamic: crude touch and pressure
lateral spinothalamic: pain and temperature
what info does the spinocerebellar - unconscious tracts send?
proprioception
are tracts contralateral?
Most is contralateral opposite side (90%)
why can some people recover from spinal tract injury?
10% of info remains ipsilateral
can relearn using these tracts if not damaged
what pathology would be seen with damage to dorsal column medial tract?
affects conscious
deficits in fine touch eg cotton wool - can not feel
can not feel vibration
proprioception - moving toe/ thumb up or down
what pathology would be seen if damage to spinothalamic ascending tract?
conscious sensory
anterior: can not detect pressure
lateral: can not detect pain (pin prick) or temperature (distinguish between hot or cold)
how would spinocerebellar pathology present?
unconscious activity
gait ataxia, dysphagia, dysarthria, oculomotor disturbances
- deficits in proprioception
positive rhombergs
what is the function of descending tracts?
motor signals from brain to lower motor neurones
what is pyramidal?
originate in cerebral cortex, carry info from spinal cord to brain stem
what type of blood collects in an extradural haematoma?
arterial
where does an extradural haematoma occur?
: blood collecting between skull and periosteal layer of dura usually middle meningeal artery
what shape is an extradural haematoma?
dome
what type of blood is a subdural
venous
what usually causes extradural haematoma?
trauma
where does a subdural haematoma occur?
: venous blood collects between dura and arachnoid mater no hole into skull.
venous sinuses
what shape is subdural haematoma?
follows shape of skull
crescent
what can disuse atrophy cause within an upper motor lesion?
not using muscles enough
fixed tightening of muscle, tendons, ligaments or skin
how can increased tone present due to UM lesion?
spasticity/ rigidity
what is the pathology within an UM lesion?
loss of inhib tone leading to constant contraction
what can cause a UM lesion?
ischaemic/ haemorrhagic stroke, amyotrophic lateral sclerosis, MS
how can lower MN lesion present?
marked atrophy
fasciculations
- Reduced tone
- Variable patterns of weakness
- Reduced or absent weakness
- Downgoing plantars or absent response
what are fasciculations?
– involuntary rapid muscle twitches that are too weak to move limb
what is the pathology of LM lesion?
no signal to tell muscles what to do
what is the aetiology behind LM lesion?
peripheral nerve trauma/ compression, spinal muscular atropy, amyotrophic lateral sclerosis, GBS, poliomyelitis
what is neuromyelinitis optica?
severe rare demyelinating disorder previously considered as a form of MS rare and characterised by bilateral optic neuritis and transverse acute myelitis with no other neurological involvement
what is useful is diagnostics in optic nerve neuropathies?
visual evoked potentials
what does demyelination have within it?
conduction block and slowing conduction
related to modifications in distributions of voltage gated sodium
what is seen within upper motor neurone damage?
- Hypotonia
- Due to no signalling
- No tone/ power
- Fistulations
- Floppy/ droopiness
what is the pathophys of myasthenia gravis?
autoimmune condition where antibodies are produced and affect NMJ
- They block, alter or destroy the receptors for Ach at NMJ which prevents muscle from contracting
what are the symptoms of myasthenia gravis?
- Symptoms: weakness of eye muscles, drooping of one or both eyelids, blurred/ double vision, changes in facial expressions, difficulty in swallowing, SoB, weakness in arms, legs, fingers, neck
what is the management of myasthenia gravis?
- Management: using immunosuppression drugs, anticholinesterase (neostigmine)
what is the pathophys of MND?
variety of specific diseases affecting motor nerves
progressive degeneration of upper and lower motor neurones
what is the most common type of MND?
- Amyotrophic lateral sclerosis is most common and well known type of MND
what are signs of MND?
lower motor wasting, reduced tone, fasciculations, reduced reflexes and upper increased tone or spasticity, brisk reflexes and upgoing plantar reflex
what is riluzole used for in MND?
riluzole: can slow progression of disease and extend survival,
what is measured within GCS?
eyes
voice
motor
how do you mark eyes on GCS?
4 pt; spontaneous
3pt: speech
2: pain
1: none
how do you mark verbal response on gcs?
- orientated
- confused
- inappropriate sounds
- incomprehensive sounds
- none
how do you assess motor response on GCS?
O: obeys - 6
L: localises pain -5
D: draws back -4
B:bends - 3
E: extends -2
N: none -1
what GCS requires airway management?
8 or less
between vancomycin and gentamycin, which can not be used if there is MRSA resistance?
vancomycin
