Neurological Diseases 1 Flashcards
What are 3 unique aspects of the CNS?
- The physical environment - skull (own boney case), surrounded by fluids, closed system (BBB), high metabolic rate - 20% of body’s oxygen)
- Specialised function in different areas - helps with predictions after disease/injury has occurred
- Limited neuron repair after damage
Astrocytes attach/interact with many things. What are 4? What is the role of astrocytes?
- Adjacent astrocytes
- Neurons
- Blood vessels - BBB
- Brain-CSF barrier
*** They’re the predominant cell in creating barriers in the brain. Also important role in disease/damage.
What are the 2 important membranes in the brain? What do they separate?
Tentorium cerebelli - hindbrain from midbrain
Falx cerebri - L and R hemispheres
What are the main functions of the: Frontal Parietal Occipital Temporal lobes?
F: executive, working memory, motor
P: visiospatial
O: vision
T: language, memory
The brain receives blood supply from __ arteries. Circle of Willis.
Why is this good?
4 arteries.
Allows some redundancy if one BV gets damaged - can still get blood.
Both the brain and the rest of the body respond in a similar way to injury - swelling? Do both ultimately have the same outcome though?
Body - swelling, eventual recovery. HEALING, REGENERATION, FULL RECOVERY.
Brain - swelling, fatal event/a lot worse. LIMITED REGENERATIVE CAPACITY.
CNS pathological conditions can be classified as either ____ or ____. What are some examples of each?
Inherited/genetic: chromosomal abnormality, metabolic, organ specific, somatic
Acquired: infectious, immunological, vascular, traumatic, neoplastic, metabolic, degenerative, demyelinative
There are 5 types of SPACE-OCCUPYING LESIONS? What are they?
- Haemorrhage: extradural, subdural, subarachnoid, intracerebral
- Tumour: intrinsic, extrinsic
- Infection: abscess, cyst
- Oedema: where the brain increases in size
- Hydrocephalus: where the CSF increases in size
A space-occupying lesion can be accommodated to by the brain if it develops under 2 conditions. What are they?
- If they develop slowly over time
2. If the amount of CSF decreased as it develops.
What are the 4 structural consequences that can occur as a result of a space-occupying lesion?
- Gyral flattening (almost all CSF has been absorbed), sulci narrowing
- Midline shift
- Compression of the vessicles
- Herniations
What are the 3 types of herniations that can result due to a space-occupying lesion?
- Subfalcine herniation (under falx cerebri): causes midline shift
- Transtentorial herniation (through the tentorium cerebelli)
- Tonsillar herniation (through the foramen magnum)
What is the Monro-Kellie Doctrine?
- Volume of the skull is fixed, can’t excede it! - it comprises the blood, CSF and brain.
- If there is an increase in one component then there must be a decrease in one or multiple of the other components in order to accomodate this
What is INTRACRANIAL PRESSURE and what is the normal range?
At high pressures, a small change in volume causes a large/small change in pressure?
ICP = the pressure of CSF in the cranial cavity Normal = 0 - 15 mmHg (if >30 mmHg then needs urgent treatment)
Large!
What is the formula for CEREBRAL PERFUSION PRESSURE?
What has to happen for there to be no net flow?
CPP = arterial pressure - intracranial pressure (this allows net flow of oxygen constantly from the BVs to the brain)
If ICP >/= to AP then no net flow into the brain = brain death
There are 4 SECONDARY PATHOLOGIES that arise as a result of space-occupying lesions. What are they?
If a person has one of these how will they present clinically?
- Haemorrhages in brainstem - ‘duret haemorrhages’
- Compression of cranial nerves
- Compression of arteries –> infarction and then necrosis of this ischaemic tissue
- Oedema: two types - vasogenic + cytotoxic
Presentation: headache, messed up neurological signs, decreased consciousness, death
