Neuro

Question 1

neural crest go on to develop

Answer 1

PNS,

Question 2

The walls of the neural tube go on to form what?

Answer 2

The CNS

Question 3

The lumen of the neural tube go on to form what?

Answer 3

The ventricles and the spinal cord canal.

Question 4

What is the direction of formation of the neural tube?

Answer 4

cranial to caudal

Question 5

Neural tube defects are associated with what?

Answer 5

Low folate levels PRIOR to conception.

Question 6

How can neural tube defects be detected?

Answer 6

elevated AFP in amniotic fluid and/maternal blood.

Question 7

What is Anencephaly?

Answer 7

• Failure of the neural tube closing at the cranial aspect. •Eyes have a frog like appearance.
• Results in maternal polyhydramnios.

Question 8

What is maternal polyhydramnios?

Answer 8

Increased amniotic fluid.

Question 9

What is Spina Bifida?

Answer 9

•Failure to close the caudal aspect of neural tube, specifically the posterior vertebral arch.

Question 10

What are variations of Spina Bifida?

Answer 10

• Spina Bifida Occulta→ dimple or patch of hair overlying the vertebral defect.
• Spina Bifida→ meningocele or menignomylocele (see other flashcard)

Question 11

What are the ‘true’ Spina Bifida?

Answer 11

• Meningocele→ meninges only herniates through defect.

* Myelomeningocele→ meninges +/- spinal cord herniates through defect.

Question 12

What is Cerebral Aqueduct Stenosis?

Answer 12

• congenital stenosis of the channel that drains CSF from 3rd to 4th ventricle.
• leads to accumulation of CSF in the ventricles and enlargement of head circumference.

Question 13

What is Dandy -walker Malformation?

Answer 13

•Congenital failure of the cerebellar vermis presenting as massively dilated 4th ventricle with an absent cerebellum.
-often with hydrocephalus.

Question 14

What is Arnold Chiari Malformation?

Answer 14

•Congenital extension of the cerebellar tonsils through the foramen magnum.
Two Types:
Chiari I: can be asymptomatic
Chiari II: obstruction of CSF flow.

Question 15

What is Syringomyelia?

Answer 15

• cystic degeneration of the spinal cord; •typically occurs at C8-T1 with sensory loss of pain and temperature.
• fine touch and position sense are spared in the upper extremities.

Question 16

What is the result of knocking out of the anterior white commissure

Answer 16

• pain and temp loss on both sides.

Question 17

What is the route of the pain ⅋ temperature sensation from the stimulus entering to the cortex?

Answer 17

The pain-temp sensation comes from the sensory nerve⅋ synapses on the post-horn, the 2nd neuron decussates at the anterior white commissure, this nerve then enters the spinothalamic tract ⅋ synapses on the thalamus, then this travels to synapses again on the cortex.

Question 18

What is Syrinx expansion?

Answer 18

•the cyst expands in syringomyelia and compresses other spinal tracts, if it involves:

1. anterior horn→ Damaged LMN (LMN signs)
2. lateral horn→ knocks out sympathetic tone to the face (ptosis, miosis)

Question 19

What is Poliomyelitis?

Answer 19

• poliovirus damages anterior motor horn

* Signs are those of LMN lesions.

Question 20

What is the result of knocking out the anterior motor horn?

Answer 20

• the LMN gets knocked out, resulting in LMN signs.

LMN signs= flaccid paralysis w/ muscle atrophy, fasciculations, weakness, ↓muscle tone, ↓ reflexes, ⊖Babinski sign

Question 21

What is Werding-Hoffman Disease?

Answer 21

• Inherited degeneration of the anterior motor horn, autosomal recessive
• Presents as a ‘floppy baby’.
• Baby will die in a few years.

Question 22

What is the disorder of ALS?

Answer 22

• Degenerative disorder of UMN ⅋ LMN.

* Involves signs of both UMN ⅋ LMN lesions.

Question 23

What are signs of UMN degeneration?

Answer 23

•Degenerative UMN signs= spastic paralysis with hyperretlexia, increased muscle tone, and ⨁Babinski sign.

Question 24

How is syringomyelia distinguished from ALS?

Answer 24

• Syringomyelia has loss of pain and temperature

Question 25

Most cases of ALS are sporadic, but the familial cases may involve mutation of ___?

Answer 25

Zinc-copper superoxide dismutase (SOD)

Question 26

What is Friedreich Ataxia?

Answer 26

* Degeneration of cerebellum and spinal cord → ataxia & multiple tracts involvement. * Involves Frataxin gene (mitochondrial iron regulation) * Associated with hypertrophic cardiomyopathy.

Question 27

What is the leptomeninges?

Answer 27

* The Pia and arachnoid together | * This is the structure that is inflamed in meningitis.

Question 28

What is the most common causal organism of meningitis in neonates?

Answer 28

* Group B streptococci, * E coli * Listeria monocytogenes

Question 29

What is the most common causal organism of meningitis in children and teenagers?

Answer 29

* N. meningitidis | * this typically enters through the nasal pharynx and enters the blood.

Question 30

What is the most common causal organism of meningitis in adults and elderly?

Answer 30

•Streptococcus-pneumoniae

Question 31

What is the most common causal organism of meningitis in unvaccinated infants?

Answer 31

•H influenza

Question 32

How does a LP help diagnosed bacterial from viral meningitis?

Answer 32

* Bacterial—neutrophils with low glucose; gram stain and culture help identify the organism. * Viral—lymphocytes with normal CSF glucose * Fungal—lymphocytes with low CSF glucose

Question 33

What layers are crossed in a lumbar puncture?

Answer 33

* skin, ligaments, epidural space, dura, and arachnoid | * but you will NOT pierce the Pia.

Question 34

What are the clinical features of Global Cerebral Ischemia?

Answer 34

•based on duration and magnitude of the insult but can be boiled down three severities: 1. Mild Global ischemia→ transient confusion 2. Severe Global ischemia→ death or vegetative 3. Moderate Global Ischemia→ cortico laminar necrosis

Question 35

What are two types of ischemia the brain can experience?

Answer 35

Global and focal.

Question 36

How do we distinguish a TIA from an ischemic stroke?

Answer 36

TIA→ focal defecit is less than 24hrs | Ischemic Stroke → deficits last more than 24hrs.

Question 37

What are the 3 main causes of stroke?

Answer 37

* thrombotic→ rupture of an atherosclerotic plaque * embolic→ due to thromboemboli usually from Left side of the heart in a patient with A-fib. * lacunar→ secondary to hyaline arteriolosderosis. The wall thickens and the lumen narrows.

Question 38

Which is a pale stroke and which is a hemorrhagic stroke?

Answer 38

* thrombotic stroke= pale infarction. | * embolic stroke = hemorrhagic infarction

Question 39

The brain undergoes ____ necrosis. _____ are early findings of this necrosis.

Answer 39

liquefactive; Red neurons;

Question 40

What occurs at 1 day, 1 week and 1 month in liquefactive necrosis of the brain?

Answer 40

* 1 day→ Red neurons (12 hrs) then coagulative necrosis (1 day). * 1 week→ infiltration by neutrophils and microglial cells. with formation of granulation-like tissue * 1 month- formation of a fluid filled cyst (gliosis).

Question 41

What are the two types of hemorrhage in the brain?

Answer 41

* Intracerebral hemorrhage | * Subarachnoid hemorrhage

Question 42

What is the cause of Intracerebral hemorrhage and where does it most commonly occur?

Answer 42

* rupture of Charcot-Bouchard microaneurysms a complication of hypertension. * Basal ganglia is the most common site

Question 43

What is the cause of subarachnoid hemorrhage and where does it most commonly occur?

Answer 43

• (85%) due to rupture of a berry aneurysm in the anterior circle of willis at the branch points of the anterior communicating arteries.

Question 44

Why do berry aneurysms rupture so easily? | What other conditions are they associated with?

Answer 44

* They lack a media layer. | * associated with Marfan and AD Polycystic Kidney disease.