Raise ICP, SOLs and trauma Flashcards Preview

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Flashcards in Raise ICP, SOLs and trauma Deck (77)
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1
Q

What is the normal volume of CSF?

A

120-150ml

500ml a day

2
Q

What produces CSF?

A

Choroid plexus in the lateral and 4th ventricles of the brain

3
Q

What absorbs CSF?

A

Arachnoid granulations

4
Q

What do lymphocyres in the CSF suggest?

A

Infection; viral or fungal
Autoimmune infection
Inflammation

5
Q

What do neutrophils in the CSF suggest?

A

Bacterial meningitis

6
Q

What is the definition of hydrocephalus?

A

Accumulation of excessive CSF within the ventricular system of the brain

7
Q

What can cause hydrocephalus?

A

Obstruction to flow: inflammation, pus, tumours
Decreased reabsorption; post SAH, meningitis
Overproduction; very rare cause due to choroid plexus tumour

8
Q

What is non-communicating hydrocephalus?

A

Obstruction to flow of CSF occuring within the ventricular system

9
Q

What is communicating hydrocephalus?

A

Obstruction to flow of CSF outside of the ventricular system e.g. in subarachnoid space or at the arachnoid granulations

10
Q

What occurs if hydrocephalus occurs before the closure of the cranial sutures?

A

Cranial enlargement occurs

11
Q

What occurs if hydrocephalus occurs after the closure of the cranial sutures?

A

Expansion of the ventricles with an increase in intracranial pressure

12
Q

What is hydrocephalus ex vacuo?

A

Dilation of the ventricular system and an increase in compensatory CSF volume secondary to the loss of brain parenchyma for example in alzheimer’s disease

13
Q

What are the causes of increased ICP?

A
Hydrocephalus 
SOL 
Diffuse lesion in brain e.g. oedema 
Increased venous volume
Physiological; hypoxia, hypercapnia, pain
14
Q

What are the consequences of raised ICP?

A
Intracranial shifts and herniations
Midline shift
Distortion and pressure on CNs and vital neurological centres
Impaired blood flow
Reduced level of consciousness
15
Q

How is cerebral perfusion pressure calculated?

A

MAP - ICP; therefore ICP is too high, it will reduce blood flow

16
Q

What are the 4 types of shifts and herniations within the brain?

A

Subfalcine
Tentorial
Cerebellar
Transcalvarial

17
Q

What is a subfalcine herniation?

A

Unilateral or asymmetrical expansion of the cerebral hemisphere which displace the cingulate gyrus underneath the falx cerebri

18
Q

What does a subfalcine herniation result in?

A

Compression of the anterior cerebral artery resulting in weakness and/or sensory loss on the contralateral side

19
Q

What is a tentorial herniation?

A

Medial aspect of the temporal lobe (uncus) herniates over the tentorium cerebellar

20
Q

What will a tentorial herniation result in?

A

Compression of the ipsilateral CN3; resulting in a blown pupil with impairment of ocular movement on the side of the lesion

21
Q

What is a tonsillar herniation?

A

Displacement of the tonsillar cerebellum through the foramen magnum

22
Q

What will a tonsillar herniation result in?

A

Compression of the respiratory centers of the medulla oblongata

23
Q

What is a transcalvarial herniation?

A

Brain herniating through any defect in the skull e.g. fracture

24
Q

What are the clinical signs of an increased ICP?

A

Papilloedema
Headache
N+V
Neck stiffness

25
Q

What are the different types of SOLs?

A

Tumours; primary brain tumours, mets
Abscess; single/multiple
Haematomas
Localised brain swelling; swelling and oedema around cerebral infarct

26
Q

What are the Si/Sy of brain tumours?

A

Sy: focal, headache, vomiting, seizures, visual disturbances

Signs; focal deficit, papilloedema

27
Q

What is the difference in location of brain tumours between children and adults?

A

Children; 70% below tentorium cerebelli

Adults; 70% above tentorium cerebelli

28
Q

What common cancers will metastasize to the brain?

A

Breast, bronchus, kidney, thyroid, colon and melanomas

29
Q

What is used to grade primary brain tumours?

A

Mitoses
Neovascularization
Necrosis
Atypia, cellularity

30
Q

What are the common malignant primary intracranial tumours?

A
Astrocytoma
Oligodendroglioma
Ependymoma 
Medulloblastoma 
Haemangioblastoma
Lymphoma
Pineal
31
Q

What are the common benign primary brain tumours?

A

Meningioma
Schwannoma
Craniopharyngioma
Pituitary adenoma

32
Q

What is the commonest brain tumour in children?

A

Medulloblastoma

Astrocytoma; pilocytic

33
Q

Describe a pilocytic grade 1 astrocytoma

A

Common in children
Benign behaving
Long hair like processes
Cystic area

34
Q

Describe a grade 2; low grade astrocytoma

A

Nuclear atypia

35
Q

Describe a grade 3 anaplastic astrocytoma

A

Greater nuclear atypia

Mitotic activity

36
Q

Describe a grade 4 glioblastoma

A

Extreme nuclear atypia
Mitotic activity
Necrosis
Neovascularization

37
Q

What can be seen histologically from a glioblastoma?

A

Anaplastic
Proliferation; numerous mitotic figures
Necrosis with assoc nuclear palisading
Neoangiogenesis

38
Q

Describe a medulloblastoma?

A

20% of paeds CNS neoplasms
Poorly differentiated/embryonal
Occurs in midline of cerebellum and can easily disrupt CSF flow resulting in hydrocephalus

39
Q

How are medulloblastomas treated?

A

Radiotherapy

40
Q

What can result in a single brain abscess?

A

Local extension from:
Mastoditis, chronic otitis media, paranasal sinusitis, nasal facial and dental infection
Direct implantation: skull fracture

41
Q

What can result in multiple brain abscesses?

A

Haematogenous spread; bronchopneumonia, bacterial endocarditis, bronchiectasis, lung abscesses, congenital heart disease (left to right shunt)
PWID

42
Q

Where will multiple brain abscesses occur?

A

Grey and white matter boundary

43
Q

What will occur with brain abscesses?

A
Central necrosis
Oedema
Fibrous capsule 
Hypoxia and ischaemia
Excitotoxic injury
44
Q

What are the symptoms of a brain abscess?

A

Fever

Increased ICP

45
Q

How are brain abscesses diagnosed?

A

CT or MRI

46
Q

How are abscesses treated?

A

Aspiration for culture and treatement

47
Q

What is bacterial meningitis?

A

Inflammation of the leptomeninges and SF within the subarachnoid space

48
Q

What can be seen on an LP from bacterial meningitis?

A

Abundant polymorphs and neutrophils

Decreased glucose

49
Q

What can arachnoiditis result in?

A

Lack of CSF absorption
Hydrocephalus
Increased ICP

50
Q

What organism causes bacterial meningitis in neonates?

A

E.coli; gram negative rods

51
Q

What organism causes bacterial meningitis in infants and children?

A

Haemophilus influenzae; gram negative cocco-bacilli

52
Q

What organism causes bacterial meningitis in adolescents and young adults?

A

Neisseria meningitis; gram negative diplococci

53
Q

What organism causes bacterial meningitis in older adults or children?

A

Streptococcus pneumoniae; gram positive cocci in chains

54
Q

What organism causes bacterial meningitis in older adults and those immunocompromised?

A

Listeria monocytoggene; gram positive rod

55
Q

How can head trauma be classified?

A

Missile or non-missile (penetrating or blunt)

56
Q

What can result from head trauma?

A

Skull #

Parenchymal and vascular injuries

57
Q

What will a penetrating head trauma result in?

A

Focal damage
Lacerations in region of brain damage
Haemorrhage

58
Q

What does the severity of a blunt injury rely on?

A

Initial velocity and the contact time; the smaller the contact time, the larger the force

59
Q

What are causes of blunt head injuries?

A

RTCs
Falls
Assaults
Alcohol related injuries

60
Q

What will the primary (impact) injury do?

A

Injury to neurones
Irreversible
Preventative measures; wearing a helmet and seat belts for example

61
Q

What are the secondary head injuries?

A

Haemorrhage
Oedema
Potentially treatable

62
Q

What is the clinical hallmark of head injuries?

A

Immediate change in conscious level is dependent on the scale of neuronal damage

63
Q

What are examples of primary head injuries?

A
Scalp lesions
Skull fractures
Surface contusions and lacerations
Diffuse axonal injury
Diffuse vascular injury 
Petechial haemorrhages
64
Q

What are the 3 types of skull fractures?

A

Linear
Compound
Depressed

65
Q

What is a linear skull#?

A

Straight sharp fracture line, that may cross sutures

66
Q

What is a compound skull#

A

Assoc with full thickness scalp lacerations

67
Q

Are base of skull fractures open or closed?

A

ALWAYS consider compound because there is a high change that base of skull fractures will lacerate the paranasal sinuses giving bacteria a route for entrance to the cranium

68
Q

What is a contra-coup injury?

A

Injury to the non-impact side diametrically opposite the point of impact
Occurs as a rebound

69
Q

What is a diffuse axonal injury?

A

Occurs at the moment of injury due to shearing strains on the axonal bulbs
Affects central areas

70
Q

What will a diffuse axonal injury lead to?

A

Reduced consciousness and coma

Lead to vegetative state

71
Q

What are secondary head injuries?

A
Intracranial haemorrhage
Reduced brain flow
Hypoxic brain damage
Excitotoxicity 
Oedema
Raised ICP
Infection
72
Q

What oedema is assoc with trauma?

A

Vasogenic oedema

73
Q

What are the percentages surrounding traumatic intracranial haematoma?

A

20% are extradural

80% are intradural

74
Q

What does a traumatic extradural haematoma result from?

A

Fracture of pterion rupturing the middle meningeal artery

75
Q

What causes an acute SAH?

A

Disruption of bridging veins that extend from the surface of the brain into the subdural space

76
Q

What are chronic subdural haematomas assoc with?

A

Brain atrophy

77
Q

What is a chronic subdural haematoma composed of?

A

Liquefied blood/ yellow tinged fluid separated from inner surface of dura mater and underlying brain by neomambrane