Neuro Clinical Pathology

Question 1

Spina Bifida definition

Answer 1

Failure of vertebral spines or arches to develop

Question 2

Spina Bifida Occulta

Answer 2

arches missing, spine and meninges intact

-symptomless, diagnosed by x-ray

Question 3

Meningocele

Answer 3

arches missing, meninges project through space, spinal cord intact
-Cystic swelling beneath skin filled with CSF

Question 4

Myelomeningocele

Answer 4

arches missing, meninges and spinal cord project through space
-damage to nerves

Question 5

Myelocele

Answer 5

arches missing, neural tube fails to fuse and there is no overlying skin

• most severe
• Leakage of CSF
• Death can occur from infection

Question 6

Anencephaly

Answer 6

• Brain/cranial vault missing due to failure of rostral neuropore fusion; results in brain being open and exposed with skull which is fatal
• occurs in 1:1000 births

Question 7

Microcephaly

Answer 7

Small calvaria and brain due to lack of development

Question 8

Holoprosencephaly

Answer 8

Forebrain defect due to telencephalon and diencephalon not separating properly

Question 9

Fetal Alcohol Syndrome

Answer 9

-Lack of a corpus callosum due to mother drinking during pregnancy

Question 10

Non-Migration of neurons

Answer 10

-Lack of telencephalon development

Question 11

Hydrocephalus

Answer 11

Obstruction to normal circulation of CSF

• Causes ventricles proximal to site to distend
• Causes compression and atrophy of brain tissue around dilated ventricles

*Atrophy of structures is seen in adults as the skull cannot adjust to the increase in size, in infants the skull increases in size to adjust to the increase in size

Question 12

Congenital Hydrocephalus

Answer 12

• Congenital obstruction or abnormal formation of aqueduct or absence of openings in the fourth ventricle
• Head enlarges

Question 13

Acquired Hydrocephalus

Answer 13

• Obstruction of CSF by tumor or adhesions blocking opening in 4th ventricle
• Damage to structures around the enlarged ventricles as the head cannot grow with increased pressure

Question 14

Treatment for Hydrocephalus

Answer 14

• Shunt CSF into venous system: reroutes CSF from dilated ventricles into another part of the body where it can be absorbed
  2 types:
  -Ventriculoatrial Shunt
  -Ventriculoperitoneal Shunt

Question 15

Principle of X-Ray

Answer 15

• Use of high energy radiation waves to produce images to help diagnose disease

Question 16

Principle of Computed Tomography (CT) Scan

Answer 16

• Radiation detectors record amount of X-Rays or ionizing radiation absorbed by the body and feed the data into a computer that reconstructs the data into an image

Question 17

Principle of Magnetic Resonance Imaging (MRI)

Answer 17

Computer constructed image of the body based on the response of hydrogen protons in water molecules when placed in a strong magnetic field

Question 18

Positron Emission Tomography (PET) Principle

Answer 18

Measures metabolism of biomechanical compounds that are labeled with positron-emitting isotopes to measure organ function
- ex. glucose, tumors in the thyroid

*Very expensive and not widely available

Question 19

Curare

Answer 19

• Neurotoxin used to bind and effectively close nicotinic (muscle) acetylcholine receptors
• Prevents muscle contraction and neuromuscular junction

Question 20

Botulism Toxin

Answer 20

• Prevent acetylcholine release from pre-synaptic cell

- causes weakness or flaccid paralysis

Question 21

Myasthenia Gravis

Answer 21

• Autoimmune response to nicotinic acetylcholine receptors

- causes weakness or flaccid paralysis

Question 22

Tetanus Toxin

Answer 22

• Blocks release of glycine, causing spastic paralysis

Question 23

Tetrodotoxin (AP Conductance)

Answer 23

• Selective voltage Na+ channel blocker

- Stops action potential conductance - motor neurons cannot function - muscles stop moving

Question 24

Periodic Paralysis

Answer 24

• Mutation on Voltage Gated Na+ so that incomplete closure of channel
• Partial depolarization of motor neurons by 35mV and cannot fire APs

Question 25

Guillan Barre Syndrome

Answer 25

• Viral infection and subsequent auto-immune inflammatory process
• Schwann cells degraded by overactive immune system
• Ascending Paralysis

Question 26

Multiple Sclerosis

Answer 26

• Demyelinating CNS Axons
• Autoimmune attack of oligodendrocytes
• May be due to genetic predisposition, viral infection and/or various environmental factors