Symptoms, signs, pathological processes, cerebral haemodynamics Flashcards
1
Q
What are the words describing different levels of loss of sensation?
A
loss- Anaesthesia
heightened- Hyperasthesia
altered- Parasthesia
2
Q
What are the words describing different levels of sense of smell?
A
lost- Anosmia
diminished- Hyposmia
3
Q
What are the words describing different levels of sense of taste?
A
lost- Ageusia
diminished- agueusie
4
Q
What is the difference between monoplegia, paraplegia, hemiplegia and quadriplegia?
A
Muscle paralysis of:
one limb -Mono
2 limbs -Para
one side of the body -Hemi
4 limbs -Quadri
5
Q
What are the words describing different types of altered movements?
A
Kinesia:
Hyper- excess normal or abnormal movements Dys- impairment of voluntary movement Hypo- decreased bodily movement A- lost movement Brady- slow movement
6
Q
List examples of hyperkinesias
A
- tremors
- convulsions
- chorea
- athetosis
7
Q
Convulsion
A
- seizure
* sudden, violent, irregular movement of the body, caused by involuntary contraction of muscles
8
Q
Chorea
A
• jerky involuntary movements
9
Q
Athetosis
A
- abnormal muscle contraction causes involuntary writhing movements
- ex. pill rolling in cerebral palsy
10
Q
What are the words describing different types of altered speech?
A
Dysphasia -deficiency in the generation of speech
Aphasia -inability to generate speech
11
Q
dysarthria
A
difficult or unclear articulation of speech that is otherwise linguistically normal
12
Q
apraxia and dyspraxia
A
difficulty planning a movement, even though they know what it is and how to do it
13
Q
What are the words describing different types of altered reflexes?
A
hyperreflexia
hyporeflexia
14
Q
Pathologic changes in the NS can be classified in what 3 broad groups?
A
a) Focal lesions
b) Diffuse/generalised disorders
c) Systemic nervous diseases
15
Q
What is a NS focal lesion?
A
causes localized disturbance of function
16
Q
What is a NS diffuse/generalised disorder?
A
- infective, metabolic, toxic, vascular
* affect NS and supporting elements throughout NS
17
Q
What is a NS systemic nervous disease?
A
- pathologic process shows predilection for a particular neuronal structure or group
- anterior horn cells, cerebellum, corticospinal tracts
18
Q
Gliosis
A
Damage to brain -> multiplication and enlargement of neuroglia with increased fibril production -> cell atrophy -> dense meshwork of fibres -> scarring
19
Q
Satellitosis
A
- oligodendrocytes increased in number and size when neurones are damaged
- microglia phagocytose damaged cells and their degradation products
20
Q
What are the fundamental types of nerve injury?
A
a) neuropraxia
b) axonotmesis
c) neurotmesis
21
Q
What is neuropraxia?
A
- transient iteration of nerve conduction WITHOUT loss of axonal continuity
- Schwann cells start to remyelinate the axon
22
Q
What is axonotmesis?
A
- transection of axons (or loss of integrity) with preservation of endoneurium
- wallerian degeneration -> repair if cell body intact
- Schwann cells functional -> some scar tissue
23
Q
What is neurotmesis?
A
- complete disruption of nerve fibre and connective tissue surrounds
- loss of normal architecture
- wallerian degeneration
- needs surgical intervention repair
24
Q
What occurs following axon damage?
A
a) chromatolysis- nissl bodies break into finer masses
b) (distal) Wallerian degeneration- swelling, neurofilament hypertrophy, myelin sheath shrinks and disintegrates, neurolemma remains; axon disappears
c) (proximal) swelling and dispersal of Nissl substance, cell increase metabolic activity, protein synthesis, mitochondrial activity; new terminal sprouts project
25
What occurs during axon regeneration?
1) macrophage phagocytose debris
2) protein synthesis accelerates
3) Schwann cells multiply and connect both ends
4) regenerating axon evade Schwann tube, growing toward distal part of axon (if gap not too large)
26
What factors influence cerebral oxygenation?
* cerebral blood volume
* cerebral blood flow
* cerebral perfusion pressure
* intracranial pressure
27
What determines cerebral blood volume?
* diameter of blood vessels
* arterial blood pressure
* total blood volume
* brain activity
28
What determines cerebral blood flow?
cerebral perfusion pressure divided by cerebrovascular resistance (influenced by length, diameter, laminar flow, arrangement of vessels)
29
What is cerebral perfusion pressure? what influences it?
* pressure gradient btw arteries and veins
* influenced by mean arterial pressure and intracranial pressure
* usually constant
30
What is intracranial pressure (ICP)? influenced by?
* pressure in skull, external to blood vessels
* normal is 7-15mmHg
* influenced by: brain volume, blood volume, CSF volume
31
What are the compensatory mechanisms to increases in ICP?
* CSF reabsorption outside cranial vault
* vasoconstriction and compression of veins to reduce blood volume
* then systemic blood pressure increases (due to systemic vasoconstriction)
32
What are the causes of increased ICP?
* tumour
* cerebral oedema
* increased CSF: production, obstruction, absorption
* haemorrhage
* craniosyntosis
* cerebral venous thrombosis
* increase intracranial venous pressure
33
What are the consequences of increased ICP?
* vascular damage: papilloedema
* intracranial nerve damage (CNIII and VI)
* obstruction of CSF flow
* changes skull bones
* reduced cerebral blood flow and perfusion pressure (causes more ischemia)
* distortions and dislocations of brain substance (herniation)
34
What are the clinical manifestations of increased ICP?
* consciousness change (confused, drowsy, coma)
* increased arterial blood pressure
* decreased HR
* altered respiration (hyperventilation, cheyne-strokes resp.)
* nausea, vomiting
* headache
* pupils dilated (CNIII damage from herniation)
35
List the major types of cerebral oedema?
* vasogenic
* cytotoxic
* interstitial
36
What is vasogenic cerebral oedema?
* disruption in integrity of BBB, so that plasma proteins and water move into interstitial tissue
* mostly occurs in white matter
* caused by: infarcts, neoplasms, abscesses
37
What is cytotoxic cerebral oedema?
* cellular injury -> disruption of active transport systems
* water enters cells -> swell
* occurs in grey matter
* caused by: general ischaemia, infarcts
38
What is interstitial cerebral oedema?
* trans-ependymal movement of CSF from ventral to extracellular spaces
* caused by non-communicating hydrocephalus
39
What are the effects of cerebral oedema?
* increases ICP
* disturbs level of consciousness
* focal neurological deficits
* progress -> more ischemia -> more oedema
* herniation
40
Define herniation
abnormal movement of tissue through an opening
41
List the different types of brain herniation?
* uncle
* cerebellar tonsillar
* cingulate
* transcalvarial
42
Uncal herniation
* uncut is medial projection of temporal lobe
* herniates under tentorium cerebella
* compresses oculomotor nerve (pupil dilation, strabismus)
* compress posterior cerebral artery (occipital lobe infarct)
* alter respiration (cheyne-strokes resp)
43
Cerebellar tonsillar herniation
* cerebellar tonsils go into foramen magnum
* compresses brainstem (cardiac, resp, consciousness)
* cheyne-stroke resp
* death
44
Cingulate herniation
* cingulate gyrus herniates under falx cerebri
| * anterior cerebral artery maybe compressed (infarct)
45
Transcalvarial herniation
* result of post-surgical oedema or trauma
| * brain through defect in skull
46
Neuron vs neuroglia
Neuron:
• functional unit of NS
• propagate electrical impulses
• 3 types
Neuroglia:
• supportive cells
• 6 types
47
List and describe the glial cells of the PNS?
PNS:
• Schwann- myelin production
• Satellite- regulate and support
```
CNS:
• Oligodendrocytes- myelin production
• Astrocytes- regulate and support BBB
• Microglia- phagocytosis
• Ependymal cells- produce and circulate CSF in choroid plexus
```
48
Graded potentials
* small changes in resting membrane potential due to opening of ion channels in response to signal
* don't propagate
* at synapse or sensory receptor
* summate up to threshold potential
49
List the sequence of events occurring in an action potential?
1) Resting membrane potential: voltage-gated Na+ channels rest, voltage-gated K+ channels closed
2) Stimulus depolarized to threshold
3) Voltage-gated Na+ channel gates open
4) Voltage-gated K+ channels open and Na+ channels inactive
5) Voltage-gated K+ channels remain open, Na+ channels rest
50
Absolute vs relative refractory period
Absolute
• voltage-gated Na+ gates are open and cannot be opened more (cant get 2nd AP)
Relative
• Na+ channels are in resting state
• need higher than usual stimulus for 2nd AP
51
What determines speed propagation of APs in neurons?
* amount of myelination
* axon diameter
* temperature
52
What are the words describing different levels of loss of muscle tone?
decrease- hypotonia
loss- atonia
increase- hypertonia
53
Rigidity
increase in muscle tone which does not alter with the speed of passive movement
54
Clasp knife spasticity
increase in muscle tone which changes with the speed of passive movement and at the extremes of the movement arc
55
What are the words describing different levels of loss of tactile sensation?
decrease- hypoesthesia
loss- anesthesia
peculiar (pins and needles)-paraesthesia
heightened- hyperaesthesia
56
Loss of ability to contract skeletal muscle
Paralysis
57
Decrease in the ability contract skeletal muscles
Paresis
58
Slow, irregular, twisting movement of 1 part of the body
Athetosis
59
Irregular, jerky, involuntary movements no purpose
Chorea
60
Involuntary movement of part or parts of the body, resulting from alternating contractions of skeletal muscles
Tremor
61
A lack of muscle co-ordination. Often used to describe a ‘staggering'
Ataxic gait
62
Inability to perform a purposeful, learned motor activity, although they are willing to do so and there is no associated motor or sensory deficit
Apraxia
63
Reduced ability to perform a purposeful, learned motor activity, although they are willing to do so and there is no associated motor or sensory deficit
Dyspraxia
64
Presence of involuntary movements
hyperkinesia ???
65
What are the words describing different levels of loss of voluntary movement?
without- Akinesia
slowness- Bradykinesia
reduced- hypokinesia
66
Absence in either comprehension or expression of speech
aphasia
67
Disturbance in comprehension or expression of speech
dysphasia
68
Decrease in bulk of 1 or more muscles
atrophy
69
Type of dizziness where individual feels as if they or the environment is moving or spinning
vertigo
70
Partial or complete loss of memory
amnesia
71
Alteration in the level of consciousness, characterised by varying degrees of disorientation, with impairment in perceiving, thinking, responding and remembering events currently occurring
coma
72
What is the importance of cerebral autoregulation to normal neuronal functioning?
* neurons exclusively run on glucose
* can only get it from blood supply
* neurons use 20% of body blood glucose
* small changes have big effects
73
What are the possible consequences of cerebral oedema?
* increase ICP
* herniation
* disturbance in consciousness level
* focal neurological deficit
74
What is the difference between supratentorial and infratentorial brain herniation?
above vs below the tentorium cerebellae (divides cerebellum from cortex)
