Define an obtunded patient?
Altered level of consciousness, can be found in any situation
Most history will come from bystanders or paramedics
How do you assess an obtunded patient?
- Glasgow Coma Scale (Usually detecting some sort of perfusion issue)
- Pupils (Strange pupils may mean cerebral herniation
How do we calculate Cerebral Perfusion Pressure
CPP = MAP - ICP
How does ICP change as the volume inside the skull increases? (E.g. froma haemorrhage)
At first the ICP stays relatively normal as the body compensates by shunting out CSF and blood
But after that it rises rapidly with increases in volume
(Monro-Kelly Doctrine - CSF+Blood+Brain+Other = VolumeICspace)
How would examining the pupil indicate cerebral herniation?
Parts of temporal lobe can herniate through the tentorium cerebelli (Uncal Herniation), pressing on the III nerve causing relative afferent pupillary defect
What is the cushing response?
A physiological response to raised ICP, usually indicating terminal head injury and imminent herniation:
- Raised Systolic BP (Wide Pulse Pressure)
- Irregular breathing
How would you assess a non-communicating patient?
- Posture, movements, neglect, eye movement
- Mini-mental score
What tests can we use to assess what parts of the cortex and spinal cord are involved in different functions?
- Functional MRI scans
- Diffusion Tensor Imaging (Tractography) to see active fibres in spinal cord
which cerebral hemisphere handles language/speech?
Well both but in 90% of people the left is dominant
What are the major Brodmans areas we need to know?
1-3 - Post Central Gyrus - Primary Somatosensory cortex
4- Precentral Gyrus - Primary Motor Cortex
5 - Sup Parietal Lobule - Somatosensory Association Cortex
6 - Pre motor & Supplementary motor areas
17 - Primary Visual Cortex
18 & 19 - Secondary Visual & Association Visual Cortex
22 - Sup Temporal Gyrus - includes Wernicke’s Area
41 & 42 - Heschl Gyrus -
Primary Auditory Cortex
44 & 45 - Inferior Frontal Gyrus - Broca’s Area
How does a myelopathy present?
- USually cervical or thoracic
- Produces a motor and sensory level
- Babinski’s Sins
- Hoffman’s Sign
- Increased Tone/Spasticity
- Impaired proprioception
How does a radiculopathy (e.g. Slipped Disc) present?
- Sensory disturbance in a single dermatome
- Weakness in matching myotome
How do numbers of a spinal nerve and its vertebrae relate?
Most spinal nerves exit under the peduncle of the same numbered vertebra.
In the C-spine there are 7 vertbrae and 8 nerves so they are numbered by the vertebrae they come above
What is cauda equina syndrome?
Something compresses the nerve roots in the cauda equina.
e.g. herniated disc
Some good example cases in this ppt