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
What is a Central herniation
Downwards displacement of the brain
What is a Subfalcine herniation
Displacement of the cingulate gyrus under the falx cerebri
What is a tonsillar herniation?
What are 2 main symptoms?
Displacement of the cerebellar tonsils through the foramen magnum.
Headache and neck stiffness
What are the 2 types of infratentorial herniation
Upward: cerebellum displaced upwards
Tonsillar: cerebellar tonsils slip through foramen magnum and compress brainstem
Wernicke’s (receptive) aphasia
Lesions result in sentences that make no sense, word substitution and neologisms but speech remains fluent
Comprehension is impaired
Broca’s (expressive) aphasia
Speech is non-fluent, laboured, and halting
Comprehension is normal
Conduction aphasia
Speech is fluent but repetition is poor. Aware of the errors they are making
Comprehension is normal
Classically due to a stroke affecting the arcuate fasiculus
