Neurology/Neurosurgery Flashcards
(141 cards)
1
Q
What are the two types of brain injury?
A
Focal
Diffuse
2
Q
Give examples of focal brain injuries
A
Contusion
Haematoma
3
Q
Give an example of a diffuse brain injury
A
Diffuse axonal injury
4
Q
What is the mechanism behind diffuse axonal injury?
A
Physical shearing forces following deceleration cause disruption and tearing of axons
5
Q
What are contusions?
A
Micro-haemorrhages into brain parenchyma?
6
Q
What are coup and contra-coup contusions?
A
Coup - adjacent to side of impact
Contra-coup - contralateral to impact
7
Q
Give examples of secondary brain injury?
A
Cerebral oedema Ischaemia Infection Tonsillar herniation Tentorial herniation
8
Q
How does the disruption of normal cerebral auto-regulatory processes following trauma affect the brain?
A
Renders the brain more susceptible to blood flow changes and hypoxia
9
Q
What is the Cushing’s reflex?
A
Bradycardia and Hypertension
10
Q
What is Cushing’s triad?
A
- Bradycardia
- Cheyne-Stokes respirations
- Widened pulse pressure
11
Q
How does increased ICP activate Cushing reflex?
A
- As ICP increases, it becomes greater than Mean Arterial Pressure. (ICP must be less than MAP for adequate cerebral perfusion)
- This causes decreases Cerebral Perfusion Pressure
- Decreased cerebral perfusion pressure activates sympathetic system
- HTN and initially tachycardia
- HTN triggers carotid and aortic baroceptors to activate parasympathetic nervous system
- Parasympathetic leads to bradycardia
- Continually increasing ICP causes brainstem dysfunction -> Cheyne-Stokes breathing
12
Q
How do you treat raised ICP?
A
IV Mannitol
13
Q
How does mannitol work?
A
osmotic diuretic
14
Q
What is normal ICP?
A
7-15mmHg in supine position
15
Q
How do you calculate Cerebral perfusion pressure?
A
MAP - ICP
16
Q
What are the symptoms of raised ICP?
A
Headaches Vomiting Reduced consciousness Papilloedema Cushing's reflex: - Bradycardia - Cheyne-Stokes breathing - Widened pulse pressure
17
Q
How do you monitor ICP?
A
Invasive monitoring:
- Catheter placed into the lateral ventricles
- Catheter may also be used to collect CSF samples/drain CSF to reduce pressure
18
Q
What is the cut-off used to determine if further treatment is required to reduce ICP?
A
> 20mmHg
19
Q
How is raised ICP treated?
A
- Treat underlying cause
- Head elevation to 30º
- IV mannitol
- Controlled hyperventilation
- CSF removal
20
Q
How does controlled hyperventilation aid in reducing CSF pressure?
A
Reduces PCO2 -> vasoconstriction of cerebral arteries -> reduced ICP
21
Q
Why is caution needed when using controlled hyperventilation to reduce ICP?
A
May reduce blood flow to parts of brain which are already ischaemic
22
Q
List 3 ways of removing CSF
A
- Drain from intraventricular monitor
- Repeated lumbar puncture (used in idiopathic intracranial hypertension)
- Ventriculoperitoneal shunt (hydrocephalus)
23
Q
Where is the falx cerebri?
A
Fold of dura between cerebral hemispheres of brain
24
Q
What structures are involved in subfalcine herniation?
A
Cingulate gyrus displaced beneath the falx cerebri
25
What is central herniation?
Downwards displacement of brain
26
What is transtentorial/uncal herniation?
Uncus of the temporal lobe is displaced beneath the tentorium cerebelli (tent above cerebellum)
27
What are the clinical consequences of transtentorial herniation?
Third nerve parasympathetic compression - ipsilateral fixed dilated pupil, looking down and out
Compression of cerebral peduncle - contralateral paralysis
28
What is tonsillar herniation?
Displacement of cerebellar tonsils through foramen magnum (aka coning - brainstem compression)
29
What are the two main causes of tonsillar herniation?
Raised ICP
| Chiari malformation
30
What happens as a result of tonsillar herniation due to raised ICP?
Respiratory depression. Does not occur with chiari malformation
31
What is the calvaria?
Top part of skull
32
What is transcalvarial herniation?
Brain is displaced through defect in skull (eg fracture or craniotomy site)
33
What are the cerebral peduncles?
connect the cerebrum with spinal cord (compression causes contralateral paralysis)
34
Binocular vision post-facial trauma is suggestive of fracture of what? (+pain on opening mouth)
Depressed fracture of the zygomatic bone
35
What is the most sensitive investigation for diffuse axonal injury?
MRI brain
36
What are the layers of the dura?
Periosteal layer
| Meningeal layer
37
Where does the haematoma form in a subdural haematoma?
In the potential space between the dura and the arachnoid
38
How do you test for each nerve root?
C5,6 pick up sticks (biceps reflex)
C7,8 lay them straight (triceps reflex)
S1,S2 buckle my shoe (ankle reflex)
L3/L4 kick the door (patellar reflex)
39
What nerve is at risk in a Smith's fracture?
Median nerve
40
How can you test for median nerve damage following a Smiths fracture?
Thumb opposition (loss of function of the thenar eminence
41
Which nerves are at risk during axillary dissection (eg in mastectomy and lymph node clearance)?
Intercostobrachial - if damaged, loss of cutaneous axillary sensation
42
What nerve is responsible for fore-arm pronation?
Median nerve - also responsible for thumb opposition and thenar eminence muscles
43
What is pituitary apoplexy?
Haemorrhage in the pituitary gland - usually due to a pituitary adenoma
44
How does pit. apoplexy present?
Sudden onset headache, similar to SAH
Visual field defects
Evidence of pituitary insufficiency - hypoadrenalism
45
How are prolactinomas treated?
Cabergoline
46
How would hypoadrenalism present?
Caused by pituitary tumour
hyponatraemia
hypotension
47
How can neuroleptic malignant syndrome affect the kidneys?
Can cause AKI
| - abnormal U&Es
48
What is the most common complication following meningitis?
Sensorineural hearing loss
49
When are triptans contra-indicated?
Coronary artery disease
50
Why are triptans contra-indicated in coronary artery disease?
Can cause vasospasm
51
Which vitamin in pabrinex can prevent Wernicke's encephalopathy
B1
52
Which sign, if positive, points to a diagnosis other than Carpal tunnel syndrome?
Hoffmann's sign
53
Which anaesthetic agents are likely to be ineffective in patients with myasthenia gravis?
Suxamethonium (Sucks in MG)
54
Which anaesthetic agent would you need to reduce the dose for for a patient with myasthenia gravis?
Rocuronium (Rocks in MG)
55
What is the best initial treatment for MG (if no myasthenic crisis)
Pyridostigmine
56
What happens in a myasthenic crisis?
Respiratory muscles affected - treat with IVIg and plasmapheresis
57
How to differentiate between chronic and acute subdural haematoma?
```
Acute = HYPERdense
Chronic = HYPOdense
```
58
How is Bell's palsy treated
If presented within 3 days of onset - prednisolone + artificial tears + advise eye taping at night
If not, artificial tears +advise eye taping at night
59
What is Lambert-Eaton syndrome?
Paraneoplastic syndrome associated with SCLC
60
What are the features of lambert eaton syndrome?
autonomic symptoms = dry mouth, impotence, difficulty micturating
limb-girdle weakness - waddle gait (lower limbs affected first)
hyporeflexia
61
How is LEMS managed?
treat cancer
immunosuppression with pred/azathioprine
3,4 diaminopyridine is trialled
IVIg and plasmapheresis may be beneficial
62
How to check if fluid draining from nose is CSF in basal skull fracture?
Check for glucose
63
What happens in Lhermitte's sign?
parasthesiae in limbs on neck flexion
64
What are the most common cause of brain mets?
Lung Ca
65
how does acoustic neuroma present?
- sensorineural hearing loss
- vertigo
- tinnitus
- absent corneal reflex
- sense of fullness in ear
66
what investigations for acoustic neuroma
audiogram
| MRI cerebellopontine angle
67
what treatment for acoustic neuroma
conservative
radiotherapy
surgery
68
what risks associated with treatment in acoustic neuroma
- facial nerve or vestibulocochlear nerve damage
69
what symptoms in bells palsy
- unilateral facial nerve paralysis (forehead affected)
- hyperacusis
- altered taste
- postauricular pain
- dry eyes
70
when should referral be considered in bell's palsy
if no sign of improvement in 3 weeks ENT referral
| if months - plastic surgery referral
71
what causes of brain abscess
- emboli from infective endocarditis
- extension of infection from middle ear/sinuses
- penetrating head injury
- trauma/injury to scalp
- neurotoxoplasmosis infection
72
what symptoms of brain abscess
- headache
- fever
- pressure effects - focal neuro: oculomotor/abducens nerve palsy
raised ICP features:
seizures
nausea
papilloedema
73
how are brain abscess managed
1. surgical drainage
2. IV cefotaxime and metronidazole
3. dexamethasone for raised ICP
74
what cancers met to brain
```
breast
skin
kidney
pancreas
lung
```
75
what types of diabetic neuropathy
- sensory peripheral polyneuropathy
- autonomic neuropathy
- mononeuritis multiplex
- diabetic amyotrophy
76
what symptoms/signs of diabetic peripheral neuropathy
- glove and stocking, burning pain, pins and needles
- worse at night
- no ankle reflex
- no vibration sense
77
what features of ischaemic diabetic foot
- claudication and pain at rest
- trophic changes - pale pulseless hairless cold paraesthesia paralysis
- painful ulcers on heels/toes
78
what features of neuropathic diabetic foot
- usually painless
- high arched foot, clawed toes
- warm, bounding pulses
- painless ulcers at soles where shoes rub
79
what is autonomic neuropathy in diabetes
- gastroparesis - bloating, vomiting, erratic BM control
- chronic diarrhoea worse at night
- GORD (decreased LOS pressure)
- postural hypotension
- erectile dysfunction
- urinary retention/incontinence
- gustatory sweating
80
how can gastroparesis be treated in diabetic neuropathy
metoclopramide, domperidone or erythromycin
81
how can hypotension be treated in diabetic neuropathy
fludrocortisone or midodrine
82
what are the main side effects of valproate
```
teratogenic
liver damage
tremor
weight gain
curly hair
drug interactions (CYP450)
```
83
what are the main side effects of carbamazepine
agranulocytosis
aplastic anaemia
CYP450 inducer
84
what are the main side effects of lamotrigine?
steven johnson syndrome
| leukopaenia
85
what are the main side effects of phenytoin
folate deficiency - megaloblastic anaemia
| vit D deficiency - osteopaenia
86
define status epilepticus
seizure lasting more than 5 minutes
| more than 3 seizures in an hour
87
how is status treated
IV lorazepam
buccal midazolam
rectal diazepam
if established, refractory - IV phenytoin/phenobarbital
if unable to control seizure activity, induce general anaesthesia.
88
what differential diagnoses of essential tremor
```
WILSON'S DISEASE
parkinson's
MS
Huntington's chorea
hyperthyroidism
fever
drug induced - antipsychotics
```
89
what are the symptoms of essential tremor
symmetrical tremor affecting mainly upper limbs, head voice, worse when arms outstretched/in attempt to carry out voluntary movements
exacerbated by stress, caffeine
better with rest/alcohol
90
what mode of inheritance in essential tremor
autosomal dominant
91
what mgmt of essential tremor
- propranolol
| - primidone
92
what happens in a third nerve palsy
eye down and out
ptosis
pupil FIXED AND DILATED
93
what causes lyme disease
Borrelia burgdorferi a spirochaete spread by ticks
94
what symptoms of lyme disease
- erythema migrans (bullseye rash)
- headache, fever, lethargy, arthralgia
- myocarditis, pericarditis, heart block
- facial nerve palsy, radiculopathy, meningitis
95
what investigations for lyme disease
elisa
| immunoblot
96
what management of early lyme disease
doxycycline
97
what management of disseminated lyme disease
ceftriaxone
98
what reaction can occur after Abx treatment in lyme disease and syphilis
jarisch-herxhaimer reaction - fever, rash, tachy
99
what are the main umn and lmn signs
umn signs:
hypertonia, spasticity
hyperreflexia
upgoing plantars
```
lmn
fasciculations
muscle wasting
hypotonia
hyporeflexia
downgoing plantars
```
100
how can mnd present
- mixture of umn and lmn signs
- muscle wasting (tibialis anterior, small muscles of hand)
- weakness, fatigue when exercising
- clumsiness, tripping over, dropping things
- fasciculations
- dysarthria
- no cerebellar signs
- no sensory signs
- external ocular muscles not affected
101
what investigations can be done for MND and what would they show?
nerve conduction - normal motor conduction
EMG - reduced number of action potentials, but higher amplitude
MRI - exclude DCM/cervical cord compression
102
what symptoms of MS
lethargy, uhthoff's phenomenon
- optic neuritis
- abducens lesions:
- internuclear ophthalmoplegia
- conjugate lateral gaze disorder
- focal weakness:
- bell's palsy
- Horner's syndrome
- Limb paralysis
- Incontinence
- focal sensory signs
- Lhermitte's sign - shooting pain down spine limbs on neck flexion
- trigeminal neuralgia
- numbness, paraesthesia
- ataxia: cerebellar or proprioceptive (positive Romberg)
103
what investigations for MS
- Contrast-enhanced MRI brain and spine
- LP for CSF - oligoclonal bands
- visual evoked potentials - delayed, but well-preserved waveform
104
what MRI changes in MS
- high signal hyperintense T2 lesions
- periventricular lesions
- Dawson's fingers projecting from near the corpus callosum
105
how are MS relapses treated
steroids - high dose methylpred
| orally or IV
106
what treatments for MS
beta-interferon
galatiramer acetate
natalizumab
fingolimod
107
what treatment for MS fatigue
amantadine
108
what treatment for MS spasticity
baclofen
| gabapentin
109
what treatment for MS incontinence
- if significant residual post-void volume, intermittent self-catheterisation
- if urge incontinence - oxybutynin/tolterodine. (anticholinergics can worsen cognitive impairment)
110
what is oscillopsia in MS and how is it treated
visual fields appear to oscillate
| treat with gabapentin
111
what is uhthoff's phenomenon?
worsening of symptoms following rise in body temp (when taking a hot bath)
112
what is internuclear ophthalmoplegia and how does it present
lesion in the median longitudinal fasciculus (3rd, 4th, 6th CNs)
causes:
- impaired adduction of eye on same side of lesion
- horizontal nystagmus of abducting eye on contrallateral side
113
what is conjugated lateral gaze disorder
eye on same side of lesion unable to abduct. double vision.
114
explain pathophys of myasthenia gravis
- auto-antibodies against post-synaptic Ach receptors at neuromuscular junction
115
what symptoms of myasthenia gravis
- fatigability following repetitive movements, slow improvement with rest
- ptosis
- diplopia
- slurred speech
- weakness in chewing
- dysphagia
- proximal limb girdle, head, shoulder and neck muscles
116
what investigations for myasthenia gravis
- single fibre EMG
- anti-AChR antibodies
- anti-Muscle-specific tyrosine kinase antibodies
- CT thorax to exclude thymoma
- Creatinine Kinase - normal
tensilon no longer used (edrophonium) as risk arrhythmias
117
how is myasthenia gravis treated
- pyrodostigmine (long acting acetylcholinesterase inhibitor)
- can add immunosuppressants (pred, aza, mycophenolate mofetil)
In myasthenic crisis, plasmapharesis, IVIg
118
what is a myasthenic crisis?
- acute worsening of symptoms often triggered by other illness e.g. respiratory tract infection
- respiratory muscle weakness
119
how is myasthenic crisis treated
plasmapharesis, IVIg
| needs ventilatory support, either NIV (bipap) or full intubation and ventilation
120
explain briefly pathophys of parkinsons
alpha synuclein deposits
| loss of dopaminergic neurons in substantia nigra
121
what features of parkinson's disease
asymmetrical: TRAP: tremor rigidity akinesia postural instability
- impaired olfaction
- mask like face
- flexed posture
- reduced arm swinging
- depression, dementia, psychosis, sleep disorders
- micrographia
- autonomic instability - postural hypotension
122
what drug classes can be used to treat parkinson's
- levodopa (co-careldopa carbidopa (decarboxilase inhibitor) to prevent peripheral breakdown of levodopa before it reaches the brain)
- dopamine agonists
- COMT inhibitors
- MAOB inhibitors
- amantadine
123
list some dopamine agonists
cabergoline
bromocriptine
pergolide
ropinirole
124
give an example of a comt inhibitor
entacapone
125
list some maob inhibitors
silegiline
| rasagiline
126
what is amantadine and how does it work in parkinsons
works against dyskinesia and rigidity
127
what side effects of dopamine agonists?
- cabergoline, bromocriptine
- impulse control disorders
- hallucinations
- excessive daytime sleepiness
- pulmonary/cardiac fibrosis
128
why must parkinsons medication not be missed?
prevent akinesia, acute dystonia, neuroleptic malignant syndrome
129
how should orthostatic hypotension in parkinsons be treated
midodrine
130
how should drooling in parkinsons be treated
glycopyrrhonium
131
what investigations for raised icp
- MRI/CT to find underlying cause
| - invasive ICP monitor with catheter in ventricles
132
what treatment for raised ICP
- treat underlying cause
- raise head to 30degrees
- controlled hyperventilation
- drain CSF
- via ICP monitor
- repeated LP (idiopathic intracranial hypertension)
- ventriculoperitoneal shunt (NPH)
- IV mannitol/dexamethasone
133
how does controlled hyperventilation decrease ICP
decreased CO2 causes vasoconstriction of cerebral arteries therefore reduced ICP
134
what is LEMS
antibodies against voltage gated calcium channels in presynaptic terminal at neuromuscular junction
135
what symptoms of lems
- muscle weakness (improves after repetitive contractions) but then weakens again
- hyporeflexia
- hyporeflexia improves after sustained muscle contraction (post-tetanic potentiation)
- autonomic symptoms - dry mouth, difficulty micturating, impotence, blurred vision, dizziness
136
what investigation for LEMS
EMG - incremental response to repeated electrical stimulaiton
137
what treatment for LEMS
treat underlying ca (SCLC, brca, ovarian ca)
amifampridine
immunosuppressants (steroids etc.)
plasmapharesis and IVIg
138
which medications can exacerbate myasthenia gravis
- lithium
- suxamethonium
- penicillamine
- beta blockers
- phenytoin
- procainamide, quinidine
- Abx: gentamicin, quinolones, macrolides, tetracyclines
139
what treatment for neuroleptic malignant syndrome
dantrolene or bromocriptine (dopamine agonist)
140
what are some side effects of levodopa
```
dyskinesia
psychosis
on-off effect
worsening effectiveness with time
postural hypotension
cardiac arrhythmias
reddish discolouration of urine when standing
nausea and vomiting
```
141
what staining for cryptococcus in HIV neuroinfection
india ink
