Flashcards in Raise ICP, SOLs and trauma Deck (77):
1
What is the normal volume of CSF?
120-150ml
500ml a day
2
What produces CSF?
Choroid plexus in the lateral and 4th ventricles of the brain
3
What absorbs CSF?
Arachnoid granulations
4
What do lymphocyres in the CSF suggest?
Infection; viral or fungal
Autoimmune infection
Inflammation
5
What do neutrophils in the CSF suggest?
Bacterial meningitis
6
What is the definition of hydrocephalus?
Accumulation of excessive CSF within the ventricular system of the brain
7
What can cause hydrocephalus?
Obstruction to flow: inflammation, pus, tumours
Decreased reabsorption; post SAH, meningitis
Overproduction; very rare cause due to choroid plexus tumour
8
What is non-communicating hydrocephalus?
Obstruction to flow of CSF occuring within the ventricular system
9
What is communicating hydrocephalus?
Obstruction to flow of CSF outside of the ventricular system e.g. in subarachnoid space or at the arachnoid granulations
10
What occurs if hydrocephalus occurs before the closure of the cranial sutures?
Cranial enlargement occurs
11
What occurs if hydrocephalus occurs after the closure of the cranial sutures?
Expansion of the ventricles with an increase in intracranial pressure
12
What is hydrocephalus ex vacuo?
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
What are the causes of increased ICP?
Hydrocephalus
SOL
Diffuse lesion in brain e.g. oedema
Increased venous volume
Physiological; hypoxia, hypercapnia, pain
14
What are the consequences of raised ICP?
Intracranial shifts and herniations
Midline shift
Distortion and pressure on CNs and vital neurological centres
Impaired blood flow
Reduced level of consciousness
15
How is cerebral perfusion pressure calculated?
MAP - ICP; therefore ICP is too high, it will reduce blood flow
16
What are the 4 types of shifts and herniations within the brain?
Subfalcine
Tentorial
Cerebellar
Transcalvarial
17
What is a subfalcine herniation?
Unilateral or asymmetrical expansion of the cerebral hemisphere which displace the cingulate gyrus underneath the falx cerebri
18
What does a subfalcine herniation result in?
Compression of the anterior cerebral artery resulting in weakness and/or sensory loss on the contralateral side
19
What is a tentorial herniation?
Medial aspect of the temporal lobe (uncus) herniates over the tentorium cerebellar
20
What will a tentorial herniation result in?
Compression of the ipsilateral CN3; resulting in a blown pupil with impairment of ocular movement on the side of the lesion
21
What is a tonsillar herniation?
Displacement of the tonsillar cerebellum through the foramen magnum
22
What will a tonsillar herniation result in?
Compression of the respiratory centers of the medulla oblongata
23
What is a transcalvarial herniation?
Brain herniating through any defect in the skull e.g. fracture
24
What are the clinical signs of an increased ICP?
Papilloedema
Headache
N+V
Neck stiffness
25
What are the different types of SOLs?
Tumours; primary brain tumours, mets
Abscess; single/multiple
Haematomas
Localised brain swelling; swelling and oedema around cerebral infarct
26
What are the Si/Sy of brain tumours?
Sy: focal, headache, vomiting, seizures, visual disturbances
Signs; focal deficit, papilloedema
27
What is the difference in location of brain tumours between children and adults?
Children; 70% below tentorium cerebelli
Adults; 70% above tentorium cerebelli
28
What common cancers will metastasize to the brain?
Breast, bronchus, kidney, thyroid, colon and melanomas
29
What is used to grade primary brain tumours?
Mitoses
Neovascularization
Necrosis
Atypia, cellularity
30
What are the common malignant primary intracranial tumours?
Astrocytoma
Oligodendroglioma
Ependymoma
Medulloblastoma
Haemangioblastoma
Lymphoma
Pineal
31
What are the common benign primary brain tumours?
Meningioma
Schwannoma
Craniopharyngioma
Pituitary adenoma
32
What is the commonest brain tumour in children?
Medulloblastoma
Astrocytoma; pilocytic
33
Describe a pilocytic grade 1 astrocytoma
Common in children
Benign behaving
Long hair like processes
Cystic area
34
Describe a grade 2; low grade astrocytoma
Nuclear atypia
35
Describe a grade 3 anaplastic astrocytoma
Greater nuclear atypia
Mitotic activity
36
Describe a grade 4 glioblastoma
Extreme nuclear atypia
Mitotic activity
Necrosis
Neovascularization
37
What can be seen histologically from a glioblastoma?
Anaplastic
Proliferation; numerous mitotic figures
Necrosis with assoc nuclear palisading
Neoangiogenesis
38
Describe a medulloblastoma?
20% of paeds CNS neoplasms
Poorly differentiated/embryonal
Occurs in midline of cerebellum and can easily disrupt CSF flow resulting in hydrocephalus
39
How are medulloblastomas treated?
Radiotherapy
40
What can result in a single brain abscess?
Local extension from:
Mastoditis, chronic otitis media, paranasal sinusitis, nasal facial and dental infection
Direct implantation: skull fracture
41
What can result in multiple brain abscesses?
Haematogenous spread; bronchopneumonia, bacterial endocarditis, bronchiectasis, lung abscesses, congenital heart disease (left to right shunt)
PWID
42
Where will multiple brain abscesses occur?
Grey and white matter boundary
43
What will occur with brain abscesses?
Central necrosis
Oedema
Fibrous capsule
Hypoxia and ischaemia
Excitotoxic injury
44
What are the symptoms of a brain abscess?
Fever
Increased ICP
45
How are brain abscesses diagnosed?
CT or MRI
46
How are abscesses treated?
Aspiration for culture and treatement
47
What is bacterial meningitis?
Inflammation of the leptomeninges and SF within the subarachnoid space
48
What can be seen on an LP from bacterial meningitis?
Abundant polymorphs and neutrophils
Decreased glucose
49
What can arachnoiditis result in?
Lack of CSF absorption
Hydrocephalus
Increased ICP
50
What organism causes bacterial meningitis in neonates?
E.coli; gram negative rods
51
What organism causes bacterial meningitis in infants and children?
Haemophilus influenzae; gram negative cocco-bacilli
52
What organism causes bacterial meningitis in adolescents and young adults?
Neisseria meningitis; gram negative diplococci
53
What organism causes bacterial meningitis in older adults or children?
Streptococcus pneumoniae; gram positive cocci in chains
54
What organism causes bacterial meningitis in older adults and those immunocompromised?
Listeria monocytoggene; gram positive rod
55
How can head trauma be classified?
Missile or non-missile (penetrating or blunt)
56
What can result from head trauma?
Skull #
Parenchymal and vascular injuries
57
What will a penetrating head trauma result in?
Focal damage
Lacerations in region of brain damage
Haemorrhage
58
What does the severity of a blunt injury rely on?
Initial velocity and the contact time; the smaller the contact time, the larger the force
59
What are causes of blunt head injuries?
RTCs
Falls
Assaults
Alcohol related injuries
60
What will the primary (impact) injury do?
Injury to neurones
Irreversible
Preventative measures; wearing a helmet and seat belts for example
61
What are the secondary head injuries?
Haemorrhage
Oedema
Potentially treatable
62
What is the clinical hallmark of head injuries?
Immediate change in conscious level is dependent on the scale of neuronal damage
63
What are examples of primary head injuries?
Scalp lesions
Skull fractures
Surface contusions and lacerations
Diffuse axonal injury
Diffuse vascular injury
Petechial haemorrhages
64
What are the 3 types of skull fractures?
Linear
Compound
Depressed
65
What is a linear skull#?
Straight sharp fracture line, that may cross sutures
66
What is a compound skull#
Assoc with full thickness scalp lacerations
67
Are base of skull fractures open or closed?
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
What is a contra-coup injury?
Injury to the non-impact side diametrically opposite the point of impact
Occurs as a rebound
69
What is a diffuse axonal injury?
Occurs at the moment of injury due to shearing strains on the axonal bulbs
Affects central areas
70
What will a diffuse axonal injury lead to?
Reduced consciousness and coma
Lead to vegetative state
71
What are secondary head injuries?
Intracranial haemorrhage
Reduced brain flow
Hypoxic brain damage
Excitotoxicity
Oedema
Raised ICP
Infection
72
What oedema is assoc with trauma?
Vasogenic oedema
73
What are the percentages surrounding traumatic intracranial haematoma?
20% are extradural
80% are intradural
74
What does a traumatic extradural haematoma result from?
Fracture of pterion rupturing the middle meningeal artery
75
What causes an acute SAH?
Disruption of bridging veins that extend from the surface of the brain into the subdural space
76
What are chronic subdural haematomas assoc with?
Brain atrophy
77