Neuro - masterclass Flashcards
When is non contrast CT used for the brain?
detecting acute haemorrhage in the brain.
First line imaging for brain scanning?
CT – first line, fast, well tolerated. With or without IV contrast, specialist investigations such as angiography, venography.
MRI in brain scan?
MRI – better soft tissue resolution, longer duration, contra-indicated for some, can be poorly tolerated. With or without IV contrast, specialist investigations and sequences
What is an ischaemic stroke?
Sudden cessation of adequate amounts of blood reaching parts of the brain – deprivation of oxygen and glucose
Process and presentation of ischaemic stroke?
This initiates a cascade of events at a cellular level which, if circulation is not re-established in time, will lead to cell death, mostly through liquefactive necrosis.
Typically presents with rapid onset neurological deficit, which is determined by the area of the brain that is involved
The neurological deficit a patient presents with depends on the ANATOMICAL SITE of the insult to the brain parenchyma. true/false?
True
How to image acute stroke quickly?
Non-contrast CT scan
Why is it important to image patients with acute stroke?
Exclude intracranial haemorrhage,
Confirm ischaemia
Exclude other intracranial pathologies that may mimic a stroke, eg tumour
PERMIT RAPID TREATMENT eg THROMBOLYSIS or MECHANICAL THROMBECTOMY
What is the early sign of ischaemic stroke in CT?
Hypoattenuation (darkening of areas on CT scan).
What occurs after hypoattenuation on CT scan?
With more time, gliosis occurs eventually appearing as a region of low density with volume loss
Gliosis = occurs when your body creates more or larger glial cells (cells that support nerve cells). These new glial cells can cause scars in your brain that impact how your body works.
Gliosis appearance on CT brain?
Dark area with loss of volume
What are intra-axial and extra-axial haemorrhage?
Intra-axial haemorrhage = within brain substance
Extra-axial haemorrhage = outwith brain parenchyma but within skull.
Extra-axial haemorrhage is divided into what groups?
Extradural
Subdural
Subarachnoid
What is an extradural (epidural) haemorrhage?
Collection of blood between the inner surface of the skull and outer layer of the dura.
Usually associated with trauma, frequently associated skull fracture.
How does bleeding mostly occur in extra-dural haemorrhage?
Usually arterial cause due to torn middle meningeal artery. Lies underneath the pterion which is weakest point of skull.
Shape of epidural (extra-dural haemorrhage) on CT?
Biconvex (“lemon” shaped).
Mass effects of epidural haemorrhage?
Sulcal effacement - a local secondary sign of mass effect in the cranium. Any lesion exerting mass effect on brain parenchyma can push adjacent gyri together, thereby displacing the CSF from the sulci.
Midline shift
What is a subdural haemorrhage?
Collection of blood accumulating in the subdural space, the potential space between the dura and arachnoid mater
SDH can happen in any age group, is mainly due to head trauma.
CT scan mainstay of investigation
Features of subdural haemorrhage?
Semilunar shape (“banana” shaped)
Crosses the sutures - unlike epidural, it not limited by the cranial sutures.
Mass effect
What is a subarachnoid haemorrhage?
Extra-axial intracranial haemorrhage
Blood within the subarachnoid space
Most commonly around the circle of Willis
85% are associated with a berry aneurysm
Common clinical symptom of subarachnoid haemorrhage?
“Thunderclap” headache
Sudden throbbing headache at the back of the head.
For subarachnoid haemorrhage, where are large volumes of high attenuation acute blood found?
Suprasellar cistern
Sylvian fissures
Sulci
3 S’s
Blood from a subarachnoid haemorrhage complications?
can cause complications such as HYDOCEPHALUS, VASOSPASM and INFARCTION
Vasospasm = sudden constriction of blood vessel, reducing diameter and flow rate.
Majority of brain tumours are primary. true/false?
False
Metastases from secondary cancers are more common. Commonly from lung, breast, melanoma, renal cell, and colorectal cancers.
Imaging for intracranial masses?
CT usually first test
hypo- or hyperdense, often rounded
Solitary or multiple
useful to determine oedema / mass effect
The skull is a closed space containing brain, blood vessels and CSF, if one of those things increases or something is added, something else gets squashed and eventually herniated out.
What is the name of this principle?
Munro-kellie doctrine
mass effect in intracranial masses?
Shift of cerebral tissue from its normal location, into an adjacent space as a result of mass effect.
Is the spinal cord part of the CNS?
Yes
What is the spinal cord contained within?
The thecal sac
The membranous sheath (theca) or tube of dura mater that surrounds the spinal cord and the cauda equina.
How many vertebrae of the spine?
33 vertebrae
7 cervical
12 thoracic
5 lumbar
5 sacral
4 coccyx
Where does spinal cord start and end?
Extends from the corticomedullary junction at the foramen magnum of the skull down to the tip of the conus medullaris
Where does the spinal cord end and the cauda equina start?
Conus medullaris (L1 vertebral level)
Spinal cord emergency is a surgical emergency. true/false?
True
