Wk11 Damage And Repair In The CNS Flashcards

1
Q

Head injury facts

A
  • in 2013-14 there were 162,544 admissions for head injury
  • admissions in uk with brain injury related diagnosis increased by 10% since 2005-6
  • men are 1.6x more likely than females to be admitted for head injury
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2
Q

Why is repair in the Injured CNS so complicated?

Cell to tissue

A
Proliferation and migration
Contact inhibition of proliferation 
Loss of neighbouring cells
Réactivation of neighbouring cells
Réactivation of proliferation
Tissue repair (damage accumulates)
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3
Q

From multipotent cell to neuronal networks

A

Proliferation and migration
Neuronal differentiation —> synapse formation
Synapse plasticity —> altered connectivity and network reorganisation

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4
Q

C1 to C8 functions affected

A
Cervical nerves
Head and neck
Diaphragm
Wrist extenders
Triceps and hand
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5
Q

T1 to t12 functions affected

A

Thoracic nerves
Chest muscles
Abdominal muscles

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6
Q

L1 to L5 functions affected

A

Lumbar nerves

Leg muscles

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7
Q

S1 to S5 functions affected

A

Sacral nerves
Bowel
Bladder

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8
Q

what do functional consequences of injury rely on?

A

Depend on the site and size of the injury not the type of injury

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9
Q

Energy supply - brain

A

– 2% of the total body mass
– consumes 15% of the energy generated in the body
– no energy stores of its own (small amount of glycogen in astrocytes)
– energy is derived exclusively from glucose metabolism.

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10
Q

Cerebral amyloid angiopathy and lobar hemorrhage

A

Alzheimer’s

Fibrous protein deposits become brittle leading to giant haemorrhage

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11
Q

Arterio-venous malformations

A

Large number of dilated blood vessels with bad walls - can form embolisms

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12
Q

Aneurisms

A

Blood coagulated over time - increased inter cranial pressure

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13
Q

Lacunar infarcts and white matter damage

A

Tissue dies and leads to liquid filled hole

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14
Q

Traumatic brain injury

A
  • Impact - cerebral contusions and lacerations
  • Movement of the brain inside the skull - subdural hematoma and diffuse axonal injury

Consequences:
• Hematomas (epidural and subdural ) – compression of the brain, raised intracranial pressure
• Contusions and diffuse axonal injury - structural brain damage
• Hypoxic injury, focal ischemic lesions
• Multiple lesions and different types of lesions

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15
Q

Hypoxia - ischemic brain injury

A
– Drop in cerebral perfusion (Global ischemia) - cardiac arrest or severe hypotension (shock)
– Hypoxia - CO poisoning
– Hypoglycemia
– severe anemia
– generalized seizures
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16
Q

Anoxic neurons

A

Differential sensitivity of different neuronal populations:
– Ischemia lasting 4-5 minutes – irreversible damage:
• hippocampal and neocortical pyramidal cells
• striatal neurons
• Purkinje cells
– More protracted ischemia – irreversible damage:
• thalamic and brainstem neurons

17
Q

Pseudolaminar and laminar necrosis

A

Selective vulnerability of different neuronal populations

18
Q

The progressive changes following a cerebral infarct

A

1-2 days tissue swelling Anoxic neurones
2 weeks tissue necrosis neovascularisation
2 months – glial scar

19
Q

Consequence of CNS injury

A
• Loss of cells and connections 
– Functional deficit
– BBB breach
• Response to injury
– Inflammatory response 
– Oedema
– Gliosis
• Long term consequences
20
Q

Traumatic brain injury

A
Long term consequences of severe TBI:
– Seizures
– Focal neurologic deficits
– Dementia
– Persistent vegetative state
– Increased risk of Alzheimer's disease.
21
Q

Features of CNS injury

A

CNS axons intrinsic capacity for regeneration

Inhibitory environment

  • lack of neurotrophic stimulation
  • neuronal death
  • demyelination
  • glial scar
  • inhibitory molecules: associated with glial scar proteoglycans and associated with damaged mussel in Nogo, MAG, OMgp
22
Q

Treatment options for CNS injury

A
• Surgery
– remove a hematoma 
– repair skull fractures 
– decompression
• Medication
– Anti-seizure medication 
– reduce risk for seizures
– Reduce oedema 
– diuretics
– Induced coma 
- reduce oxygen and nutrient requirements
• Rehabilitation
23
Q

Types of recovery

A

• Neurological recovery
– Early recovery (Local Processes)
– Late recovery (Neuroplasticity) modification in structural and functional organization
• Functional recovery
– Recovery in everyday function with adaptation and training in presence/ absence of natural neurologic recovery
– Dependent on quality ,intensity of therapy & patient’s motivation

24
Q

Neuroplasticity Principles

A
  1. Use It or Lose It
  2. Use It and Improve
  3. Specificity
  4. Repetition Matters
  5. Intensity Matters
  6. Time Matters
  7. Salience Matters
  8. Age Matters
  9. Interference
25
Q

CNS injury prognosis

A
  • Most improvements in ADLs occurs during the 1st 6 months
  • Up to 5% of patients may show improvement even at 12 months post- stroke
  • Recovery could take 2 years or more
  • Prognosis in patients with mild or moderate stroke is usually excellent
26
Q

Experimental strategies for treatment of CNS injury

A
• Trophic support
– Neurotrophic factors to neuronal cell bodies
• Inhibiting the inhibitors
– NOGO antibodies
– Digestion of GSPG – Chondroitinase 
– Rho inhibitors (siRNA)
• Endogenous stem cells
– Neurogenesis – subventricular zone, subgranular