Parks: CNS Pathology Basic Concepts Flashcards
What is a contusion?
contusion is a lesion in the brain that occurs when the brain hits the skull
What happens to the brain after an acute contusion?
necrosis and hemorrhage; in addition, the brain swells and causes cerebral edema
What is one type of brain hernia that you should really worry about? Why?
uncal/transtentorial herniation; this might affect the brain stem
What are three types of hernias of the brain?
subfalcine (falx) herniation
transtentorial herniation
tonsillar herniation
When the uncus protrudes underneath the tentorium, what is this called?
uncal herniation
Which nerve is the uncus likely to impinge? What is one symptom that may occur as a result?
ipsi CN 3 (occulomotor); dilated pupil initially - eventually, the pupil may move down and out
When the uncus compresses the third nerve, what causes the coma that follows?
compression of the midbrain against the opposite tentorial edge
What is Duret hemorrhage?
hemorrhage in the mid-brain and pons
Why is duret hemorrhage such a problem?
can compress important components of the brain stem, such as the brain stem respiratory center
When you have ischemic necrosis of the occipital lobe, what are the consequences? What is the artery involved?
vision loss; posterior cerebral artery
What time period during embryonic development is most critical for CNS development?
weeks 3-5
**this is when neural tube defects are most likely to occur
What is the difference b/w a meningocele and a myelomeningocele?
meningocele is when there is a sac like protrusion off of the meninges;
myelomeningocele is when the spinal cord actually herniates out into the sac like protrusion in addition to the meninges
What test do you use to look for neural tube defects?
Alpha fetal protein
Recommendations for decreasing the risk of neural tube defects?
iron and folic acid supplements
Enlargement of ventricles
hydrocephalus
One of the most frequent congenital malformations of the CNS
hydrocephalus
Risk factors for hydrocephalus?
lack of prenatal care maternal diabetes maternal HTN maternal consumption of alcohol infections (parvo B19) maternal antidepressant use
Localized obstruction within ventricular system. Only that focal ventricle enlarges while the other ventricles do NOT enlarge.
non-communicating hydrocephalus
Entire ventricular system enlarges. This usually from reduced CSF resorption
communicating hydrocephalus
What are most cases of hydrocephalus caused by?
impaired resorption or an obstruction; rarely overproduction of CSF
Two forms of cerebral edema
vasogenic edema
cytotoxic edema
Following trauma; tumors also show this as does inflammation such as encephalitis. Fluid shifts from vascular into extracellular space.
vasogenic edema
Following stroke and hypoxic-ischemia insult (cardiac arrest); neurons, glia are injured.
cytotoxic edema
Lateral displacement of the midbrain may compress the opposite (blank), producing a Babinski’s sign and hemiparesis contralateral to the original hemiparesis. This is called (blank) sign
cerebral peduncle; Kernohan-Woltman
Which arteries may be compressed when herniation occurs?
anterior and posterior cerebral arteries
What is Kernohan’s notch?
compression of opposite cerebral peduncle
What is tonsillar herniation?
when the cerebellum herniates downward through the foramen magnum
