case 13 - traumatic head injury Flashcards

(87 cards)

1
Q

What are the 5 lobes of each hemisphere of the brain?

A

Frontal, parietal, temporal, occipital, insular

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2
Q

Which arteries supply the brain?

A

Internal carotid arteries, vertebral arteries

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3
Q

What parts of the brain does the Anterior Cerebral Artery (ACA) supply?

A

The anterior 2/3 of the medial aspect of the cerebral hemipsheres

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4
Q

What parts of the brain does the Middle Cerebral Artery (MCA) supply?

A

The lateral surface of most of the brain, including the superior part of the temporal lobe, but excluding the occipital lobes

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5
Q

What parts of the brain does the Posterior Cerebral Artery (PCA) supply?

A

The posterior 1/3 of the medial part of the cerebral hemispheres, as well at the occipital lobes, inferior temporal lobes and the superior brain stem

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6
Q

Which artery supplies the dura mater and cranium?

A

The middle meningeal artery (MMA)

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7
Q

Which artery is the MMA a branch of?

A

External carotid artery

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8
Q

What are the 8 bones of the cranium?

A

Frontal (1), Parietal (2), Temporal (2), Occipital (1), Sphenoid (1), Ethmoid (1)

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9
Q

What part of the brain sits in the anterior cranial fossa?

A

frontal lobe

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10
Q

What part of the brain sits in the middle cranial fossa?

A

temporal lobe

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11
Q

What part of the brain sits in the posterior cranial fossa?

A

The cerebellum

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12
Q

Which artery is usually implicated in an epidural hematoma?

A

Middle meningeal artery, following fracture to the temporal lobe and an arterial tear

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13
Q

Which layers of the meninges are separated by an epidural hematoma?

A

The skull is separated from the dura mater

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14
Q

What are the CT scan findings of an acute epidural hematoma?

A

Hyperdense biconvex mass. Midline shift and ipsilateral ventricular compression.

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15
Q

What limits the expansion of epidural hematomas?

A

Suture lines - haemorrhage stops at suture lines where the dura is adherent to the cranium

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16
Q

What are the temporal CT changes in epidural hematoma?

A

As the blood ages its hyperdensity on CT reduces - i.e. it becomes darker

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17
Q

What is the time course for symptom onset in an epidural hematoma?

A

There is usually a period of lucidity before rapid loss of consciousness after several hours

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18
Q

What are the clinical signs of symptomatic epidural hematoma?

A

They are symptoms of raised ICP and potentially herniation - fixed pupils, facial weakness, paralysis, coma, etc.

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19
Q

Which vessels are usually implicated in a subdural hematoma?

A

Bridging veins running from the cerebral cortical surface through the subdural surface and into the dural sinuses

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20
Q

Which layers of the meninges are filled with blood in a subdural hematoma?

A

Blood between the dura mater and arachnoid mater

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21
Q

Why are elderly patients at increased risk of subdural hematoma?

A

As brain ages it atrophies, leading to increased traction on veins, predisposing them to tearing

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22
Q

What are the CT scan findings in a subdural hematoma?

A

Sickle shaped accumulation of blood, usually over the cerebral convexity. Blood will be acutely hyperdense, but darker with age. May be slow accumulation of blood. Midline shift and ipsilateral ventricular compression.

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23
Q

What are the temporal CT changes in subdural hematoma?

A

Increase in volume of blood overtime as venous leakage is slow. Blood will become less hyperdense with time.

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24
Q

What are clinical findings in subdural hematoma?

A

Fluctuating levels of consciousness, seizures, signs of raised ICP - however, chronic SDH may cause vague neurological symptoms such as headache

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25
What are the 2 key causes of subarachnoid haemorrhage?
Trauma, cerebral aneurysm rupture
26
What is key cause of spontaneous subarachnoid haemorrhage?
Rupture of an aneurysm in the Circle of Willis
27
What are the CT scan findings in a subarachnoid haemorrhage?
Dancing man sign, hyperdense blood in the pericollosal cistern on sagittal CT, hyperdense blood in sulci between gyri.
28
What is the ‘dancing man sign’ on CT?
A sign of subarachnoid haemorrhage - hyperdense blood in the basilar cisterns
29
What are the clinical findings of spontaneous subarachnoid haemorrhage?
Thunderclap headache, neck stiffness, photophobia (absence of fever eliminates bacterail meningitis), symptoms of raised ICP, seizures, coma
30
What is the diagnostic criteria for epilepsy?
Patient must have 2 unprovoked epileptic seizures occurring more than 24 hours apart.
31
What are some examples of CNS insults that have a temporal relationship with acute symptomatic seizures?
Metabolic, toxic, structural, infectious, traumatic, inflammatory
32
What are the 3 types of seizures, categorised by onset?
Generalised onset, Focal onset, unknown onset
33
What are generalised onset seizures?
Seizures that originate at some point within the CNS and rapidly engage bilaterally distributed networks
34
What are the 2 subtypes of generalised seizures?
Tonic-clonic - Generalised Tonic-Clonic Seizures (GTCS), Absence seizures
35
What pattern of symptoms characterises Generalised Tonic-Clonic seizures?
Abrupt onset of bilateral tonic contraction of limbs and body, followed by bilateral clonic movements. Patient is unaware during the event.
36
What is the tonic component of a tonic-clonic seizure?
Increased muscular tone - causes contraction of muscles in the limbs and body
37
What is the clonic component of a tonic-clonic seizure?
Regular jerking movements
38
What happens in the posticatal period of a generalised tonic-clonic seizure?
Patient is confused, weak and drowsy.
39
What pattern of symptoms characterises Generalised Absence seizures?
Abrupt onset and offset of impaired awareness, with no postictal changes. Episode generally has short duration (~10s)
40
What EEG changes are seen in generalised tonic-clonic seizures?
Change in activity across all EEG leads
41
What EEG changes are seen in absence seizures?
Change in activity in some, but not all, leads
42
What are focal onset seizures?
Seizures that originate with networks limited to one hemisphere, and may be discreetly localised.
43
What is Status Epilepticus, and how is it defined?
A state of prolonged seizure activity, typically generalised or focal to bilateral tonic-clonic seizures, lasting longer than 5 minutes
44
What is the time frame for serious long-term brain damage or death in status epilepticus?
After 30 minutes of continuous seizure activity there is a high risk, mostly due to respiratory and airway dysfunction.
45
What are the assessment/management approaches a bystander can take for a patient who has just had a seizure?
Call an ambulance, place patient on their side, remove any dangerous items, check airway is clear, first aid for any wounds
46
What are steps in acute assessment management of a patient who has had a seizure by responding paramedics/doctors on the scene?
Position patient on their side on the ground/bed with a pillow under their head, Reassure family/bystanders, Assess airway potency and respiratory rate - nasopharyngeal airway if required for apnoea, Administer oxygen therapy following and during seizures, IM or IV benzodiazepines - Diazepam or Midazolam first line Gain a history from patient/family Head-to-toe check, for injurty, tongue biting, urinary/faecal incontinence Look for signs of stroke
47
What points should be covered in a history from a patient/family following a stroke in the community?
History of epilepsy, last known seizure, AEDs taken and any skipped doses, typical seizure presentation and any changes, recent injury/illness, withdrawal from alcohol/benzos, type of seizure based on eye-witness account
48
Which 3 key drugs are used to treat focal and generalised tonic-clonic seziures?
Valproate, Levetiracetam, Phenytoin
49
Which drug is used exclusively for the treatment of Absence seizures?
Ethosuximide
50
Which 2 AEDs can be used to treat absence seizures?
Ethosuximide, valproate
51
What is the first-line treatment for status epilepticus?
Benzodiazepines - Diazepam, Midazolam
52
What is the mechanism of action of benzodiazepines?
Act as positive allosteric receptor modulators of the GABA-A receptor, increasing the effect of GABA on the GABA-A receptor.
53
What is the second-line treatment of status epilepticus?
Phenytoin
54
What are the drug targets of Valproate?
Sodium and Calcium channels
55
What is the mechanism of action of valproate?
Inhibits repetitive firing of neurons by increasing the number of sodium channels in their inactivate state. ALSO inhibits T-type Calcium channels
56
What are the indications for valproate?
Focal & generalsied tonic-clonic seizures & absence seizures
57
What are the adverse effects of valproate?
nausea, weight gain, hair loss, bleeding, congenital birth defects
58
What is the key warning required for prescription of valproate?
Risk of congenital birth defects - take particular care in women to prevent pregnancy
59
What is the drug target of phenytoin?
Sodium channels
60
What is the mechanism of action of phenytoin?
Inhibits repetitive firing of neurons by increasing the number of sodium channels in the inactivated state.
61
What are the indications for phenytoin?
Focal & generalised tonic clonic seizures, status epilepticus
62
What are the adverse effects of phenytoin?
vertigo, ataxia, nystagmus, confusion
63
What is the key warning required for prescription of phenytoin?
The therapeutic range is very narrow - patient must report any bad side effects in case of toxicity
64
What is the drug target of Levetiracetam?
Calcium channels
65
What is the mechanism of action of Levetiracetam?
Inhibits presynaptic calcium influx, reducing neurotransmitter release in the brain
66
What are the indications for levetiracetam?
Focal and generalised tonic-clonic seizures
67
What are the adverse effects of levetiracetam?
Lethargy, fatigue, poor motor coordination, behavioural abnormalities
68
What is the drug target of diazepam?
GABA-A receptors
69
What drug class is diazepam?
Benzodiazipine
70
What is the mechanism of action of diazepam?
Increases the effect of GABA on GABA-A receptors by acting as a positive allosteric receptor modulator
71
What is the indication for diazepam in epilepsy?
Status epilepticus, or seizures recurring very close together
72
What are the adverse effects of diazepam?
drowsiness, ataxia, decreased alertness
73
Why must repeated diazepam use in epilepsy be monitored?
Tolerance may develop
74
What is the drug target of ethosuximide?
Calcium channels
75
What is the mechanism of action of ethosuximide?
Inhibits T-type calcium channels in the thalamus, reducing thalamocortical oscillations typical of absence seizures.
76
What are the indications of ethosuximide?
absence seizures only
77
What are the adverse effects of ethosuximide?
GI disturbances, headache, fatigue
78
What health care professional assess an individuals fitness to work in certain industries?
Occupational health practitioner
79
What health care professional assess an individuals ability to undertake specific work tasks and can help adapt job responsibilities?
Vocational rehabilitation consultant
80
What are some accommodations that can be made to allow an individual to return to work after a head injury?
Flexible hours, remote work, not working alone, mobility modifications to workplace, counselling for psychological challenges
81
What are some of the cognitive challenges following brain injury/epilepsy?
memory/attention/decision making difficulties, difficulty following and remembering social interactions/conversations
82
What are some of the physical challenges following brain injury/epilepsy?
paralysis, weakness, poor coordination, difficulty with tasks of everyday living
83
What are some of the emotional challenges following brain injury/epilepsy?
brain damage induced depression, anxiety, mood disorders. frustration and depression to recovery challenges
84
What are some of the social challenges following brain injury/epilepsy?
Poor mobility and cognition leading to social isolation and difficulty maintaining relationships.
85
What are some of the employment/financial challenges following brain injury/epilepsy?
cognitive and physical difficulties making it difficult to return to work, cost of treatment and unemployment leading to financial stress and anxiety about the future
86
What are some of the safety challenges following brain injury/epilepsy?
Epileptics may have seizures in dangerous environments causing injury, brain injury can impair awareness and judgement, leading to an increased likelihood of accident.
87
What are some of the medication challenges following brain injury/epilepsy?
side effects can cause unpleasant symptoms, poor adherence can worsen symptoms and disease control