Neurosurgical Clinical Assessment Flashcards
Define an obtunded patient [2]
People who are obtunded have a more depressed level of consciousness [1] and cannot be fully aroused [1]
How do you assess an obtunded patient? [3]
- ABC
- 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. from a haemorrhage) [2]
At first the ICP stays relatively normal as the body compensates by shunting out CSF and blood
But after that it rises exponentially with increases in volume
(Monro-Kelly Doctrine - CSF+Blood+Brain+Other = VolumeICspace)
How would examining the pupillary reflexes indicate cerebral herniation?
Parts of temporal lobe can herniate through the tentorium cerebelli (Uncal Herniation), [1] pressing on the III nerve causing relative afferent pupillary defect [1]
What is the Cushing response? [4]
A physiological response to raised ICP, usually indicating terminal head injury and imminent herniation: [1]
- Raised Systolic BP (Wide Pulse Pressure)
- Bradycardia
- Irregular breathing
How would you assess a non-communicating patient? [3]
- Speech
- 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? [2]
- Functional MRI scans
- Diffusion Tensor Imaging (Tractography) to see active fibres in spinal cord
Which cerebral hemisphere handles language/speech? [1]
Well both but in 90% of people the left is dominant
Major Brodman’s Areas (BA)
State name of gyrus and BA number [6]
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
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 vertebrae and 8 nerves so they are numbered by the vertebrae they come above
Major BA part 2 [5]
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
Recall the 2 meningeal folds
Falx cerebri
Tentorium
What are the 2 classifications of brain herniation
Supratentorial (cerebrum)
Infratentorial (cerebellum)
What is an uncal herniation? [2]
What signs would you see? [3]
Displacement of the uncus of the temporal lobe [1] under the tentorium cerebelli. [1]
Clinical consequences include:
- an ipsilateral fixed, dilated pupil (due to parasympathetic compression of the third cranial nerve)
- and contralateral paralysis (due to compression of the cerebral peduncle)
- compression of PCA causing homonymous hemianopia
