Neuropathology Flashcards
What are the special features of the CNS?
- In a rigid container-only exit for brain is foramen magnum,
- Cells in the brain are very sensitive to things like ischemia, certain infections
- Arteries and arterioles have thinner walls
- Auto regulation of local blood flow
- No lymph system
- Not as many fibroblasts so can’t wall things off as effectively
- Isolated by a blood brain barrier
- Unique immune status
- Neuronal and axonal regeneration does not occur
Cerebral edema
Increased water content in the brain
Vasogenic edema
Results from breakdown of blood brain barrier
Cytotoxic edema
Due to increased intracellular water content
Cell damage leads to defective ion transport and water exits
Hydrocephalus
An increased intraventricular CSF
May be due to increased production, decreased absorption, or outflow obstruction
Communicating hydrocephalus vs non communicating
Obstruction to absorption is occurring outside the ventricles- communicating
Obstruction occurring within ventricles or at foramina of luschka and magendi
Causes of hydrocephalus
Communicating: resolving meningitis or subarachnoid hemorrhage
Non communicating: neoplasms, congenital stenosis
Triad of raised intracranial pressure
Headaches
Vomiting
Papilledema
Cushing response
Decreased heart rate, increased blood pressure, irregular breathing as a result of raised intracranial pressure
Subfalcine herniation
Cingulate gyrus pushed under Falx Cerebri
May compress anterior cerebral artery-ischemia
Motor and sensory abnormalities of the legs
Central herniation
Downward displacement of the brain stem from generalized edema
Compression will compromise cardiac and respiratory centres
Uncal herniation
Trans tentorial herniation, uncus protrudes over the tentorium cerebelli.
Compression of CNIII: pupillary dilation and occulomotor dysfunction
Compression if posterior communicating artery: ipsilateral hemmorhage of mesial occipital lobe
