Lecture 23 - Nervous System pathologies

Question 1

Hydrocephalus

Answer 1

• accumulation of excessive cerebrospinal fluid (CSF) in the ventricular system = leads to brain swelling
• CSF produced by choroid plexus in ventricles, circulates into subarachnoid space; absorbed by arachnoid granulations (adults)

Question 2

Types of Hydrocephalus

Answer 2

1. Non-communication - localized obstruction; parts of ventricle enlarge
2. Communicating - entire ventricular system expands
3. Hyprocephalus ex vacuo - enlargement of ventricles due to loss of brain tissue (granulations, seen in older individuals )

Question 3

Herniation

Answer 3

• brain expands (swells) beyond the limits of the cranial vault
• leads to ischemia of affected areas; infarction and increased swelling/herniation

Question 4

Types of Herniation

Answer 4

1. Subfalcine (cingulate) - unilateral/asymmetric herneation under the edge of the falx cerebri (divides right/left hemispheres)
2. Transtentorial (uncinate) - temporal lobe against free margin of the tentorium cerebelli; compresses the third cranial nerve - get dilation of pupils
3. Tonsillar - displacement of cerevellar tonsils through the foramen magnum, usually life threatening; compromises respiratory center of brain (Brain is pushed down through wear the spinal cord goes)

Question 5

Subarachnoid hemorrhage

Answer 5

• most common cause is rupture of saccular (berry) aneurysm

- occurs outside the brain, below arachnoid layer, deep in meningeal layer

Question 6

Epidural hematoma

Answer 6

• results from damage usually of middle meningeal artery which run within the dura
• typically caused by skull fractures
• on top of dura mata

Question 7

Subdural hematoma

Answer 7

• occurs from trauma to veins that run from cerebrum through subarachnoid space and subdural space to empty to dural sinues
• underneath the dura mata

Question 8

Gliomas

Answer 8

• primary brain malignancies (malignant tumor)

- glioblastoma = the highest grade of astrocytoma = poor prognosis

Question 9

Meningiomas

Answer 9

• benign tumors from the meninges
• usually attached to the dura
• can be on outer surface of brain or in ventricular system

Question 10

Multiple Sclerosis

Answer 10

• myelin disease, degenerative disease of brain

- autoimmune demyelinating disorder (immune system attack myelin sheath)

Question 11

Parkisonism

Answer 11

• another degenerative disease of the brain
• caused by damage of dopaminergic neurons (neurons that produce dopamine)
• pathologically: pallor of pigmented regions of brain (ex: substantia nigra)
• Microscopically = see lewy bodies (intracytoplasmic inclusions)

Question 12

Huntington disease

Answer 12

• inherited autosomal dominant disease
• another degenerative disease of the brain
• characterized by progressive movement disorders (chorea) and dementia

Question 13

Mengiomyelocele / Meningocele

Answer 13

• a type of neural tube defect (congenital malformation associated w. folate deficiency)
• involves distal end of neural tube - defect in vertebral column through which protrudes meninges or/and spinal cord
• meninges = Meningocele
• meninges + spinal cord = Mengiomyelocele

Question 14

Anencephaly

Answer 14

• a type of neural tube defect (congenital malformation associated w. folate deficiency)
• absence of top of skull and thus brain
• entire cranium doesn’t develop