Intro to Neuropath

Question 1

Glial Cell Type and Functions:

Answer 1

Question 2

What protects the brain?

Answer 2

The blood brain barrier and the 3 meninges

Question 3

Is the CNS ‘immune priveleged’?

Answer 3

• believed to have been shielded away from the
  rest of the body’s immune response
• however there may be a connection between
  lymphatic system and brain

Question 4

What is the main immune cell of the brain?
Where is it derived from?
Actions?

Answer 4

• microglial cell = APC
• from embryonic yolk sac progenitor cells
• major antigen presenting cells
• dendritic cells (checkpoint inhibitor)

Question 5

Neuroinflammation:

Answer 5

• facilitates the delivery of effector molecules to
  aid repair through signals
• vascular dilatation = increased permeability =
  alterations in adhesion
• microglia activate and macrophages outside
  the CNS are recruited
• astrocytes repair
• demyelination

Question 6

Neuroinflammation Flowchart:

Answer 6

Question 7

Two types of neuroinflammation are:

Answer 7

• vasogenic = extracellular
• cytotoxic = intracellular

Question 8

What is shown below?

Answer 8

Neuroinflammation

Question 9

What is shown below?

Answer 9

Microglia (L-R)
1) resting
2) become activated, larger, higher turnover of
ATP = more circular, spherical cells
3) evidence of inflammation, larger, angrier
4) resting state in older patients; more worn
down cells, impairs function of microglia

Question 10

Which types of oedema correspond to the CAT below?

Answer 10

• left is vasogenic, cellular ‘ boundaries are seen,
  clear grey and white differntiation
• right is cytotoxic and less clear differentiation

Question 11

Chronic changes to neural damage (3):

Answer 11

• neural degeneration
• demyelination
• gliotic scars: possible epileptic foci

Question 12

Retrograde Neural Degeneration:

Answer 12

when the main axon is damaged there is degeneration of the neurone as well as the classical distal degeneration of the axon

Question 13

Trans-Synaptic Degeneration:

Answer 13

injured neurons spread injury to previously uninjured neurons connected by a synapse (diaschisis)

Question 14

VITAMIN C:

Answer 14

Question 15

What is a meningioma?

Answer 15

a tumour of the meninges

Question 16

What is now used to define patient subgroups in oncology?

Answer 16

Molecular classification
precision cancer medication

Question 17

Paraneoplastic Syndrome:

Answer 17

• remote effect of a cancer
• abnormal immune response to a cancer eg
  lung/breast/ovarian
• antibodies to T-cells begin to fight the normal
  brain (AUTOIMMUNE)
• symptoms develop over days to weeks
• involve peripheral (Lambert Eaton (small cell
  lung cancer, causes weakness that improves
  over time) or cns (NMDA encephalitis(presents
  with psychosis but is actually ovarian tumour)
• rare but presentation may be the first
  symptom of an underlying malignancy

Question 18

Meningoencephalitis:

Answer 18

• non-localised/diffuse problem
• meningitis = inflammation of the meninges
  - presents as headache, nuchal rigidity (neck
  stiffness), and photophobia
  - leptomeninges (pia+arachnoid) = infection
  - pachymeninges (arachnoid + dura) =
  cancer (both are usually not always)
• encephalitis = alteration in the
  sensorium/cognitive state due to
  inflammation (infection/autoimmune)
  - drowsy, confused, less responsive

Question 19

Decompression of the spinal compartment for example during a lumbar puncture could result in a brain herniation when

Answer 19

there is unequal pressures in the intracranial compartment eg cerebellar tumour

removal of fluid can cause the brain to fall and herniation

STOP = shift, trauma, obstruction, posterior fossa mass

Question 20

Causes of Meningoencephalitis:

Answer 20

Question 21

What are coup and contre-coup injuries?

Answer 21

direct and indirect

Question 22

Traumatic Brain Injury: Blunt Force:
- concussion
- contusion
- secondary consequences of blunt force
trauma c

Answer 22

• concussion: clinical syndrome with immediate
  and transient alteration in brain function can
  result in headache, drowsiness, concentration
  and amnesia for months
• contusion: pathological term (seen on scan)
  meaning bruising of the brain tissue, can result
  in confusion, altered consciousness and focal
  neurological deficits within days or weeks
• due to moving the brain backwards = contre-
  coup
• eg boxer is punched and becomes blind, but
  not because of punch to eye but due to
  contusion at visual cortex at the back of the
  skull
• secondary effects:
  
  • cerebral oedema and ischaemia
  • vascular damage

Question 23

Traumatic Brain Injury: Acceleration-Deceleration:
- examples of such injuries
- caused
- what scans are needed

Answer 23

• car accidents, shaken baby syndrome
• rotational movements of the brain in the skull
  result in shearing forces causing axons to
  stretch = diffuse axonal injury
• can result in loss of consciousness or coma
• may need MRI with T2 flair images; may be a
  delay in injury showing up on scan

Question 24

Increased Cerebral Pressure:

Answer 24

• brain expands in very small space available
• results in herniation
• headaches, meningism, vision changes, CN6
  palsy
• high bp, redlexive bradycardia,, irregular
  respiration = Cushings reflex (high bp, low
  heart rate, erratic breathing)

Question 25

Chronic Traumatic Encephalopathy:

Answer 25

- recurrent head injuries - deposition of beta amyloid plaques. diffuse plaques and tau mostly TAU - below pia mater - was classified as a tauopathy - present with dementia like features decades after recurrent head injuries

Question 26

Headaches: Categories:

Answer 26

- Primary: tension-type, migraine, trigeminal autonomic cephalagias - Secondary: infection, neoplasm, stroke, meds, toxins

Question 27

Headaches: Red Flags:

Answer 27

- worsens with valsalva - wakes you up whilst sleeping - change in character: - age of onset - sudden onset - focal neurological deficits - constitutional symptoms: fever, weight loss, meningism, rash

Question 28

Mneumonic for headache history taking = SNNOOP10:

Answer 28

Question 29

Primary Headaches: Tension-Type:

Answer 29

- 90% headaches - featureless,, band-like pressure, stress - pathophysiology is unknown - episodic: frequent if at least 10 headaches on 1-14 days a month for >3 months - chronic: headaches on >14 days/ month for >3months

Question 30

Primary Headaches: Migraine:

Answer 30

- photophobia - incapacity - nausea/vomiting - episodic: without aura, with aura ( visual: zigzags, olfactory hallucinations) - chronic: at least 15 days/month for more than 3 months, which on at least 8 days a month has the features of a migraine headache - status migrainosus: an attack lasting longer than 72 hours

Question 31

Primary Headache: TACs:

Answer 31

- trigeminal parasympathetic reflex with clinical signs of cranial sympathetic dysfunction being secondary - cluster headache: male predisposition, excruciating pain causing agitation, autonomic features - paroxysmal hemicrania - short-lasting unilateral neuralgliform headache attacks - hemicrania continua

Question 32

Primary Headache: Summary:

Answer 32

Question 33

Pathophysiology of Headache (Migraine):

Answer 33

- neurovascular theory - sensory neurons of the trigeminocervicocomplex is the source of pain resulting in the release of inflammatory and noiciceptive mediators which over time can result in central sensitisation responses

Question 34

Trigeminal Nerve: Sensory Pathway:

Answer 34

- 1st order - 2nd order - 3rd order = ventromedial nucleus of the thalamus - 4th order = sensory cortex, insula, cingulate cortex trigeminal cervical complex is a physiological complex probably one of the reasons there is neck pain and pain is not localised

Question 35

Trigeminocervical Complex:

Answer 35

- physiological complex not anatomic - how head and neck sensory information combine - innervation of large cerebral vessels, pia vessels, dura mater, large venous sinuses - anterior = mostly V1 (ophthalmic) - posterior = mostly upper cervical roots

Question 36

Trigeminal Autonomic Reflex pathway explains why

Answer 36

autonomic system activates running nose, eyes on the same side as the headache pain is felt ipsilateral autonomic features from cranial parasymapthetic activation (lacrimation) and sympathetic hypofunction due to neurpraxic effect of the carotid wall swelling afferent = trigeminal efferent = superior salivatory nucleus via the 7th (facial) cranial nerve to synapse nicotinic post-ganglionic parasympathetic neurons)

Question 37

We prevent medication overuse for headaches by

Answer 37

limiting monthly use of the medications eg triptans < 10 days non-opiod analgesics < 15 days opiods < 10 days chronic headaches should be managed with preventative strategies

Question 38

Anoxic Brain Injury:

Answer 38

- hypoxia: drowning, strangulation, CO, asphyxia - ischaemia: cardiac arrest, increased intracrania pressure, hypovolaemia - may result in: - seizures and myoclonus - coma - minimally conscious state - unresponsive wakefulness syndrome - brain death

Question 39

What is shown below?

Answer 39

anoxic brain injury

Question 40

Histopathology classifies the tumour but genotyping will dictate treatment in the future. True or False?

Answer 40

True