Neurology Flashcards
Absolute contraindications to thrombolysis
- Known hypersensitivity/anaphylaxis reactions to the medication or related excipients (increased risk with ACEi use)
- Active internal bleeding
- Current intracranial haemorrhage
- Intracranial neoplasm, arteriovenous malformation, aneurysm, or other conditions that may increase haemorrhage
- Bleeding diathesis (e.g. von Willebrand disease, haemophilia, advanced liver disease etc.)
- Recent (i.e. within 3 months) intracranial or intraspinal surgery, major surgery
- Recent (i.e. within 3 months) serious head trauma
- Recent (i.e. within 3 months) stroke, for patients with acute myocardial infarction or pulmonary embolism
- Severe uncontrolled hypertension
- Subarachnoid haemorrhage
- Active peptic ulcer disease
- Prolonged CPR
- Active seizure
- Patient <18yo
- BSL <2.8 or >22.2
- Already anticoagulated
Antiepileptics in acute seizure management incl. doses
Levetiracetam
- 10-40mg/kg max 3g paeds
- 20-60mg/kg max 4.5g adults
- Best choice in females due to lower risk pregnancy category
Sodium valproate
- 10-40mg/kg, max 3g
- Contra-indicated in: prgenancy, drug tox seizures, children <2 years, known urea cycle disorders
Phenytoin
- 15-20mg/kg max 1-1.5g
- Poorly effective in alcohol withdrawal seizures, partial seizures
- Contraindicated in Na channel tox-related seizures
- Incompatible with glucose, most other drugs
Uthoff’s phenomenon
Reduced vision secondary to:
- Exercise
- Hot meal
- Hot bath
Seen in MS
Lhermitte’s sign
Sudden “electric” sensation down back on neck flexion.
Classically associated with MS
Also seen in transverse myelitis, Behcet’s, osteogenesis imperfecta, trauma, radiation myelopathy, B12 deficiency
Optic neuritis features
- decreasing visual acuity over days
- central scotoma, usually unilateral
- visual field deficits
* associated with pain on eye movement
* disturbed colour perception an early sign
* 50% have papillitis on fundoscopy
* 40% go on to have multiple sclerosis- occurs in 40% at some stage of disease
- presenting symptom in 20%
* prognosis
- 1/3 completely recover - 1/3 partially recover
- 1/3 not at all
- visual evoked potentials delayed in 80%
Diagnostic criteria for multiple sclerosis
Clinical attacks and MRIB+spine-confirmed lesions disseminated in time (DIT) and space (DIS)
i.e.
>=2 clinical attacks with >=2 lesions with objective clinical evidence
>=2 clinical attacks with 1 lesion with objective clinical evidence + clinical history suggestive of previous lesion
>=2 clinical attacks with 1 lesion disseminated in space evident of MRI
1 clinical attack with >=2 lesions on MRI
1 clinical attack with 1 lesion on MRI, disseminated in space
MS management
In acute attacks:
- High dose methylpred - 500-1000mg IV for 3-7 days
- Pred 75mg daily with wean for milder attacks
- Plasma exchange in steroids ineffective
Prevention:
- Azathioprine
- Cyclophosphamide
- Plasmapharesis
- Natalizumab - 300mg IV monthly ( expensive)
- Glatiramer acetate - 20mg subcut daily
- Interferon
- Copolymer I
Lifestyle
- Low saturated fat diet
- Omega 3 fatty acid supplementation
- Vit D via sunlight or supplementation
- Meditation and exercise
MS epidemiology
* commonest chronic neurological condition
* first onset most commonly in patients 30 - 40 years of age
* about 60% of cases are women
* rare in children
* temperate zone prevalence
* higher incidence in Tasmania, lower in QLD
* loss of suppressor T cells prior to attacks
MS vs ADEM
Age group
- ADEM typically <10yo
- MS rare in children, age typically 3rd-4th decade of life
ADEM monophasic demyelination
Sudden-onset multiple defects rare in MS
Seizures, meningism rare in MS
ADEM typically following a febrile illness or vaccination
FVC treatment thresholds in GBS with suspected diaphragmatic involvement
Components of Ottawa SAH rule for headache evaluation
Age >= 40
Neck pain or stiffness
Limited neck flexion on examination
Witnessed LOC
Onset during exertion
Thunderclap headache
Only used in patient >=15yo with new, severe, atraumatic headache without focal neurology, prior aneurysm, SAH, brain tumour or chronic recurrent headache
LP vs CTA for SAH >6 hours post-onset - pros and cons
Two major vessels involved in blunt cerebrovascular injury and their clinical features
Internal carotid artery dissection
- Unilateral headache, typically frontotemporal; severity may mimic SAH/migraine
- Anterior neck pain
- Partial Horner syndrome: miosis and ptosis
- Cranial nerve palsies
Vertebral artery dissection
- Headache, typically occipital
- Posterior neck pain
- Facial paraesthesias
- Lateral medullary syndrome
- Diplopia, ataxia
Tool for evaluating possibility of blunt traumatic cerebrovascular injury
Denver screening criteria
Broken down into signs and symptoms and risk factors
Signs and symptoms
- Focal neurological defecit
- Cervical bruit
- Infarct on CTB
- Expending neck haematoma
- Neuro exam inconsistent with CTB
Risk factors
- Neck trauma with cervical spine injury
- Severe facial injuries; Le Fort II or III
- Base of skull fractures
- Cervical manipulation
- Connective tissue disease
- Near hanging with anoxic brain injury
- Scalp degloving
Hunt and Hess classification for SAH
Grade I
- Asymptomatic or minimal headache
- Mild nuchal rigidity
Grade II
- Moderate to severe headache
- Nuchal rigidity
- Cranial nerve palsy only
Grade III
- Drowsiness or confusion
- Mild focal deficit
Grade IV
- Stupor
- Hemiparesis
- Vegetative disturbance
Grade V
- Deep coma
- Decerebrate
- Moribund
Outcomes:
Grade I-II - independent 90-95%, death 1-2%
Grade IV-V - independent 10%, death 80%
World Federation of Neurological Surgeons grading for SAH
Grade I - GCS 15 w/ no motor deficit
Grade II - GCS 13-14 w/ mo motor deficit
Grade III - GCS 13-14 w/ motor deficit
Grade IV - GCS 7-12, w/ or w/o motor deficit
Grade V - GCS <7, w/ or w/o motor deficit
Fischer scale for CT evaluation of SAH
Grade I - No blood detected
Grade II - Diffuse deposition of blood without clots or layers of blood >1mm
Grade III - Localised clots and/or layers of blood >1mm thick; no IVH (highest risk of vasospam; 37%)
Grade IV - Intracerebral or intraventricular clots present
Components of cerebellar exam
Nystagmus
Speech
Past-pointing/dysmetria
Dysdiadochokinesis
Intention tremor
Ataxia
Romberg’s
Rinne vs Weber’s
Rinne’s test
- Place 256Hz tuning fork on mastoid
- When no longer audible, place over external auditory meatus
- Positive: air conduction > bone (normal or sensorineural loss)
- Negative: bone > air conduction (conductive hearing loss)
Weber’s test
- Place 256 Hz tuning fork on middle of forehead
- If sound midline, normal
- Heard loudest in:
* Normal ear in sensory deficit
* Abnormal ear in conductive deficit
Features of oculomotor nerve palsy
Motor
- Ptosis
- Eye in “down and out” position
- Inability to elevate, depress or turn medially
Pupillary
- Mydriasis
- Absent direct light reflex
- Absent accommodation reflex
Motor features predominate in intrinsic disease (e.g. diabetic neuropathy, arteritis, MS, GBS/MFv)
Pupillary features predominate in extrinsic compression (e.g. raised ICP, tumour, aneurysm)
Associated symptoms with CN III palsy at varying sites of lesion
Features and causes of facial nerve palsy
Features
- Weakness of facial musculature including forehead
- Decreased taste ipsilateral anterior 2/3rds tongue
- Ipsilateral hyperacusis
- Ipsilateral reduced tear production
Causes
- Malignancy: Acoustic neuroma, facial neuroma, meningioma, cholesteatoma etc.
- Trauma: Temporal bone fracture, facial laceration, mastoid surgery
- Infectious: Acute or chronic supperative otitis media, Lyme disease, HIV, syphillis, EBV
- Guillain-Barre
- Bell’s palsy
- Ramsay Hunt
- Diabetes
- Botulism
Bell’s Palsy - Prognosis and prognostic factors
86% complete recovery at 2 months
Poorer outcome in:
- Complete paralysis
- Pregnancy
- Diabetes
- Taste disorder
- Older age
Indications for clot retrieval
Requires all the following:
- Potentially disabling stroke (NIHSS score ≥ 5)
* Adult with pre-stroke modified Rankin Scale score ≤ 2
- patients with mRS 3 or more do not benefit
* Acute ischaemic stroke from occlusion of major named vessel
- e.g. internal carotid, M1, dominant vertebral, basilar
- Can be M2 if NIHSS >10 and if ineligible for thrombolysis
- Unclear if posterior cerebral artery occlusions benefit
* Alberta Stroke Program Early Computed Tomography Score (ASPECTS) ≥ 6
- Thrombolyisis (if used) able to be given within 4.5 hours after stroke onset
* Arterial access can occur within 24 hours of stroke onset
Rate of decrease in BP for hypertensive emergency
Decrease MAP by 15-25% within 1-2 hours
OR
Decrease MAP by 20% in first hour, aim 160/100 mmHg in 4-6 hours
Features of nystagmus that suggest a central cause
Bi-directional
Direction-changing
Vertical or purely rotational
Non-fatiguable
No latency to onset post-Dix-Hallpike
Fixation does not inhibit or worsens
Spontaneous
HINTS in central vs peripheral vertigo
Antibiotics for VP shunt-associated ventriculitis
Vancomycin 25mg/kg
+
Meropenem 2g q8hrly
OR cefepime 2g q8hrly
CTB: 24M prev hydrocephalus with VP shunt in situ, intermittent severe headaches
Slit ventricle syndrome
Often presents with waxing and waning symptoms. Secondary to over-drainage, tissues occlude the orifices of the proximal shunt apparatus. As ICP increases, occluding tissue disengages with resolution of symptoms until drainage and occlusion may occur again.
Potential sites for venticular shunt drainage
Peritoneum (VP shunt)
Pleural cavity
Right atrium
Ureter
Gall bladder
Components and use of of ABCD2 score
Predicts risk of stroke following suspected TIA
Age >=60 +1
BP >140/90 (initial; either) +1
Clinical features
- Speech disturbance w/o motor +1
- Unilateral weakness +2
Duration
- <10 mins +0
- 10-59 mins +1
- >=60 mins +2
Diabetes +1
Differentials for ring-enhancing lesion on CTB
Primary malignancy (Glioblastoma Multiforme most likely, others include anaplastic astrocytoma)
Cerebral metastasis (Lung, Breast)
Cerebral abscess
Primary CNS lymphoma
Cerebral toxoplasmosis
Cerebral Tuberculosis
Subacute cerebral infarction
Tumefactive dymeylination
List of unstable cervical spine fractures
Jefferson’s fracture (C1 burst)
Bilateral Cervical facet dislocation
Odontoid fracture, type II or III
Atlanto-occipital dissociation
Hangman’s fracture (bilateral C2 pedicle fracture)
Flexion teardrop
Mnemonic: “Jefferson Bit Off A Hangman’s Thumb”
Triptans contra-indicated in…
Coronary artery disease
PVD
Cerebrovascular disease
Uncontrolled hypertension
Migraine with hemiplegia
