PBL2 Flashcards
what happens when you bleed
HR goes up to compensate for drop in BP in order to maintain cardiac output. CO=HRxSV
how do we know that Cody is not bleeding
- we know he is not bleeding because his heart rate decreases from 82 to 64
why is Cody still breathing but has shallow breathing
- he has a C5/C6 fracture, but c3 c4 c5 phrenic nerve innervation keeps the diaphragm alive, therefore he has breathing but restricted breathing
what is the babinski sign a sign of
Positive babinski sign is a sign of upper motor neurone damage in the corticospinal tract
what is spinal cord shock
A state of temporary loss of function in the spinal cord
All functions below lesion are depressed or absent due to removal of all descending motor pathways
Gives impression of flaccid paralysis and loss of sensation
how long does spinal cord shock last for
- often only lasts 1 day
- can last months
what happens after spinal cord shock
Neurones gradually regain their excitability and the flaccid paralysis gives way to spastic paralysis
Oedema and inflammation reduced
what happens when you have upper motor neurone lesions
Damage to the CNS
Spastic paresis
Hypertonia
Clonus
- Distributed to groups of muscles, never individual muscles. Stretch reflexes hyperactive
what happens when you have lower motor neurone lesions
Damage to PNS
Flaccid paralysis
Limited to muscles innervated by damaged motor neurones or axons
Pronounced atrophy
hypoactive stretch reflexes
where does the corticospinal tract decussates
Corticospinal tract – decussates at the medulla, damage leads to ipsilateral motor deficits
where does the spinothalmic tract decussate
Spinothalamic tract – decussates in spinal cord – lesions lead to a contralateral deficit at the level of lesion
where does the DCML decussate
DCML – gracile and cuneate fasciculi. Decussates at medulla. Damage leads to ipsilateral loss of proprioception
what are the pyramidal tracts
- lateral and anterior corticopsinal tracts
what are the extrapyramidal tracts
rubrospinal
reticulospinal
vestibulospainl tract
what is the prognosis of Cody
Further functional recovery is poor. CNS regeneration is poor, lost neurons won’t be replaced
why can’t Cody maintain his blood pressure and why does he have warm peripheries
In spinal cord injury, lose the inability to vasoconstrict. Vasodilation causes warm peripheries and low BP.
why is the heart rate low
Also because of the feedback mechanism to the heart, HR does not increase to compensate
what is shock
Shock is inadequate perfusion to tissue, sufficient to cause end organ damage
what are the 2 main sensory tracts in the spinal cord
spinothalamic and dorsal columns
describe input into spinothalamic tract
- smal diameter sensory neurones which are unmyelianted or thinly myelinated
what information does the spinothalmic tract relay
- crude touch, pain, temperature
where is the spinothalamic tract in the spinal cord
ventrolateral spinal tract
what are the inputs into the DCML
- carry information from larger diameter myelinatedneurones
What information is in the DCML
- vibration
- proprioception
- discriminatory touch
what is the babinskin response to
- it is in response to a polysyantpic reflex
- it is evoked to by stimulation to the sole of the foot
- this normally produces a flexion withdraws reflex
what is the normal response to the babinski when the corticospainl tract is normals
- toes curl down and adduct together
what is the abnormal baninskin sign when the corticospainl tract is damaged
- big toe dorsiflexes and the other toes fan out
- this is normal in a baby
what does the babinski sign due to
upper motor neurone damage
Define the term spasticity and state its clinical significance
Increased muscle tone and exaggerated tendon reflexes; Sign of upper motoneuron damag
State two reasons for weakness in Cody’s breathing.
Damage to the motoneurons of C5 innervating the diaphragm.
Complete injury at C5 level results in loss of control on lower motoneurons innervating external intercostal and abdominal muscles
