Neurology Flashcards
Frontal Lobe function
- Difficulties with task sequencing
- Difficulties with executive skills
- Expressive aphasia (Broca’s) : located
in the posterior aspect of the frontal
lobe, in the inferior frontal gyrus - Anosmia
- Primitive reflexes
- Perseveration (repeatedly asking
same question or doing same task) * Changes in personality - Inability to generate a list
- Disinhibition
Parietal Lobe
Apraxias: loss of the ability to execute learned purposeful movements
* Neglect
* Astereognosis (unable to recognise
object by feeling) = tactile agnosia
* Homonymous inferior quadrantanopia * Sensory inattention
Acalculia: inability to perform mental arithmetic
* Gerstmann’s syndrome (lesion of dominant parietal):
o Alexia: in ability to read o Acalculia
oFinger agnosia oRight-left disorientation.
Temporal Lobe
Homonymous superior quadrantanopia
* Prosopagnosia (difficulty recognising
faces)
* Wernike’s (recepTive) aphasia * Memory impairment
* Auditory agnosia
Occipital Lobe
Cortical blindness (blindness due to damage to visual cortex, may present as Anton syndrome: there is blindness but patient is unaware or denies blindness)
* Homonymous hemianopia
* Visual agnosia (seeing but not percieving objects - it is different to neglect since in agnosia the objects are seen and followed but cannot be named)
DRIVING RULES (DVLA): Neurological aspect specific rules:
First seizure: 6 months off driving (if the licence holder has undergone assessment by an appropriate specialist and no relevant abnormality has been identified on investigation, for example EEG and brain scan where indicate). For patients with established epilepsy they must be fit free for 12 months before being able to drive.
* Stroke or TIA: 1 month off driving
* Multiple TIAs over short period of times: 3 months off driving
* Craniotomy e.g. For meningioma: 1 year off driving (With benign tumors and if there is no seizure history, licence can be reconsidered in 6 months if remains seizure free)
* Pituitary tumour: craniotomy: 6 months; trans-sphenoidal surgery ‘can drive when there is no debarring residual impairment likely to affect safe driving’
* Narcolepsy/cataplexy: cease driving on diagnosis, can restart once ‘satisfactory control of symptoms’
Homonymous Hemianopia
- Incongruous defects = optic tract lesion
- Congruous defects (defect is approximately the same in each eye)
optic radiation lesion or occipital cortex - Macula sparing: lesion of occipital cortex (9)
Homonymous Quadrantanopias
Homonymous Quadrantanopias
* Superior: lesion of temporal lobe
* Inferior: lesion of parietal lobe
* Mnemonic = PITS (Parietal-Inferior, Temporal-Superior)
Bitemporal Hemianopia
Lesion of optic chiasm
* Upper quadrant defect > lower quadrant defect = inferior chiasmal
compression, commonly a pituitary tumour
Lower quadrant defect > upper quadrant defect = superior chiasmal compression, commonly a craniopharyngioma
Nystagmus causes
Causes:
* Visual disturbances
* Lesions of the labyrinth
* The central vestibular connections
* Brain stem or cerebellar lesions.
Nystagmus which changes with the direction of gaze
nvolvement of vestibular nuclei.
Pendular Nystagmus
mostly due to loss of macular vision, but could be in diffuse brain stem lesions.
Nystagmus Jerking on lateral gaze,
brain stem or cerebellum lesion.
- Nystagmus confined to one eye
nerve or muscle lesion, or medial longitudinal bundle lesion.
Nystagmus restricted to the abducting eye on lateral gaze (ataxic nystagmus)
due to a lesion
of the medial longitudinal bundle between the pons and mid-brain as in multiple sclerosis (MS).
Upbeat nystagmus
Cerebellar vermis lesions
Downbeat nystagmus - foramen magnum lesions
Arnold-Chiari malformation
Subdural Hemorrhage
Basics
* Most commonly secondary to trauma e.g. Old person/alcohol falling over
* Initial injury may be minor and is often forgotten
* Caused by bleeding from damaged bridging veins between cortex and venous sinuses
Features
* Headache
* Classically fluctuating conscious level
* Raised ICP
Treatment
* Needs neurosurgical review
* Burr hole →
Subarachnoid Hemorrhage causes
Causes
* 85% are due to rupture of berry aneurysms (conditions associated with berry aneurysms include adult polycystic kidney disease, Ehlers-Danlos syndrome and coarctation of the aorta).
* AV malformations.
* Trauma.
* Tumours
Subarachnoid Hemorrhage investigations
- CT: negative in 5%.
- LP: done after 12 Hrs (allowing time for
xanthochromia to develop) If the CSF examination did not reveal xanthochromia, or there was still a high level of clinical suspicion, then cerebral angiography would be the next step
Subarachnoid Hemorrhage management
Neurosurgical opinion: no clear evidence over early surgical intervention against delayed intervention
* Nimodipine (e.g. 60mg / 4 hrly, if BP allows) has been shown to ↓ the severity of neurological deficits but doesn’t ↓ rebleedi
Extradural hematoma
Bleeding into the space between the dura mater and the skull. Often results from acceleration-deceleration trauma or a blow to the side of the head. The majority of epidural Hematomas occur in the temporal region where skull fractures cause a rupture of the middle meningeal artery.
Features
* Features of raised intracranial pressure
* Some patients may exhibit a lucid interval
Intracranial Venous Thrombosis
Can cause cerebral infarction, much less common than arterial causes
* 50% of patients have isolated sagittal sinus thromboses - the remainder have coexistent lateral
sinus thromboses and cavernous sinus thromboses
Features
* Headache (may be sudden onset)
* Nausea & vomiting
* Papilledema
Sagittal sinus thrombosis
May present with seizures and hemiplegia
* Parasagittal biparietal or bifrontal hemorrhagic infarctions are sometimes seen
Cavernous sinus thrombosis
Other causes of cavernous sinus syndrome: local infection (e.g. Sinusitis), neoplasia, trauma
* Ophthalmoplegia due to IIIrd, IVth and VIth nerve damage
* Trigeminal nerve involvement may lead to hyperaesthesia of upper face and eye pain
* Central retinal vein thrombosis
* Swollen eyelids
Wernicke Encephalopathy pathophisology
yndrome caused by lesions in the medial thalamic nuclei, mammillary bodies, periaqueductal and periventricular brainstem nuclei, and superior cerebellar vermis, often resulting from inadequate intake or absorption of thiamine (Vitamin B1), especially in conjunction with carbohydrate ingestion.
Wernicke Encephalopathy features
Features
* Nystagmus
* Ophthalmoplegia
* Ataxia
* Confusion, altered GCS
* Peripheral sensory neuropathy
* Impairment of short-term memory
Wernicke Encephalopathy Investigations
Investigations
* ↓ Red cell transketolase * MRI
Marchiafava Bignami syndrome:
Corpus callosum degeneration from chronic alcohol excess
Urinary incontinence + gait abnormality + dementia
= normal pressure hydrocephalus
Idiopathic Intracranial Hypertension features
Features
* Headache
* Blurred vision
* Papilledema (usually present)
* Enlarged blind spot
* Sixth nerve palsy may be present
Idiopathic Intracranial Hypertension risk factors
Risk factors
* Obesity
* ♀sex
* Pregnancy
* Drugs (in this case it is not idiopathic): oral contraceptive pill, steroids, tetracycline, vitamin A
IIH Management
- Weight loss
- Diuretics e.g. Acetazolamide
- Corticosteroids can be given
- Repeated lumbar puncture
- Surgery: optic nerve sheath decompression and fenestration may be needed to prevent damage
to the optic nerve. A lumboperitoneal or ventriculoperitoneal shunt may also be performed to ↓ intracranial pressure
TIA - ABCD2 score of ≥4:
Aspirin (300 mg daily) started immediately
seen within 24hrs
TIA ABCD2 risk score ≤ 3:
Specialist assessment within 1 week of symptom
onset, including decision on brain imaging
* If vascular territory or pathology is uncertain,
refer for brain imaging
crescendo TIAs (≥2 episodes in a week)
treated as being at high risk of stroke, even though they may have an ABCD2 score of 3 or below.
Selected points relating to the management of acute stroke include:
Blood glucose, hydration, oxygen saturation and temperature should be maintained within
normal limits
* BLOOD PRESSURE SHOULD NOT BE LOWERED in the acute phase unless there are
complications e.g. Hypertensive encephalopathy (the 2009 Controlling hypertension and hypotension immediately post-stroke (CHHIPS) trial may change thinking on this but guidelines have yet to change to reflect this)
* ASA 300mg orally or rectally should be given as soon as possible if a hemorrhagic stroke has been excluded
* With regards to AF, the RCP state: ‘anticoagulants should not be started until brain imaging has excluded hemorrhage, and usually after 14 days from the onset of an ischemic stroke’
* If the cholesterol is > 3.5 mmol/l patients should be commenced on a statin
Thrombolysis
It is administered within 3 hours (SIGN recommend a window of 4.5 hours) of onset of stroke
symptoms (unless as part of a clinical trial)
* Hemorrhage has been definitively excluded (i.e. Imaging has been performed)
* If patient is awaked with stroke, do not thrombolyse (even if reached in < 3 hours), exact time
of stroke is unknown
Secondary Prevention stroke
. Clopidogrel
2. Dipyridamole MR + ASA
3. Dipyridamole MR
Anterior stroke
Contralateral hemiparesis and sensory loss, lower extremity > upper
* Disconnection syndrome (akinetic mute patient)
Middle stroke
Contralateral hemiparesis and sensory loss, upper extremity > lower
* Contralateral hemianopia
* Aphasia (Wernicke’s)
* Gaze abnormalities
Posterior stroke
Contralateral hemianopia with macular sparing
* Disconnection syndrome
Lacunar stoke
Present with either isolated hemiparesis, hemisensory loss or hemiparesis with limb ataxia
Lateral medulla (posterior inferior cerebellar artery- PICA)
- Ipsilateral: ataxia, nystagmus, dysphagia, facial numbness, cranial nerve palsy
- Contralateral: limb sensory loss
Pontine stroke
VI nerve: horizontal gaze palsy
* VII nerve
* Contralateral hemiparesis
Basilar Artery CVA
typically associated with a poor prognosis
* Most of patients present with nausea, vertigo and vomiting
* Some present with motor deficits, dysarthria and speech involvement or headaches
* May present with visual disturbances. This includes abducens nerve palsy, conjugate gaze palsy,
internuclear ophthalmoplegia and ocular bobbing
PACS (partial anterior circulatory stroke)
2 of the 3 elements above, or new higher cerebral
dysfunction.
TACS (total anterior circulatory stroke):
Higher cerebral dysfunction
Contralateral sensory/motor deficit
Visual field defect.
- LACS (lacunar stroke):
Pure motor or pure sensory syndrome or
Ataxic hemiparesis or
Dysarthria or
Clumsy-hand syndrome
POCS (posterior circulation syndrome):
Bilateral motor/sensory deficit or
Disorder of conjugate eye movement, or
Solitary visual field defect, or
Cerebellar dysfunction, or
Crossed cranial nerve and sensory/motor signs.
Lateral Medullary Syndrome:
lso known as Wallenberg’s syndrome, occurs following occlusion of the posterior inferior cerebellar artery, resulting in sensory and sympathetic disturbances
Cerebellar features
* Ataxia
* Nystagmus
Brainstem features
* Ipsilateral: dysphagia, facial numbness, cranial nerve palsy e.g. Horner’s
* Contralateral: limb sensory loss (pyramidal tract signs)
Pituitary Apoplexy:
sudden enlargement of pituitary tumour secondary to hemorrhage or infarction
Features
* Sudden onset headache similar to that seen in subarachnoid hemorrhage
* Vomiting
* Neck stiffness
* Visual field defects: classically bitemporal superior quadrantic defect
* Extraocular nerve palsies
* Features of pituitary insufficiency e.g. Hypotension secondary to hypoadrenalism
* Electrolytes disturbance.
Brown-Séquard syndrome:
s a loss of sensation and motor function (paralysis and ataxia) that is caused by the lateral hemisection of the spinal cord.
Features:
* Ipsilateral loss of fine touch, vibration and proprioception
* Ipsilateral hyper-reflexia and extensor plantar reflex
* Contralateral loss of pain and temperature sensation occurs affecting the side.
* Segmental anaesthesia at the level of the lesion
* Complete syndrome picture is rare and many patients may only exhibit some features.
* Trauma is a common cause; demyelination due to multiple sclerosis is another common cause
but any lateral cord lesion (ischaemia, hemorrhage, granuloma, tumour etc) may give this picture.
Syringomyelia
Syringomyelia - spinothalamic sensory loss (pain and temperature)
Syringomyelia Features
Maybe asymmetrical initially
* Slowly progressives, possibly over years
* Motor: wasting and weakness of arms
* Sensory: spinothalamic sensory loss (pain and temperature)
* Loss of reflexes, bilateral upgoing plantars
* Also seen: horner’s syndrome
Syringomyelia Localization of the lesion (for Part II):
At syrinx (there is anterior horn cell involvement) → lower motor
neuron pattern of weakness.
* At central decussating fibres (spinothalamic tract) → dissociated
sensory loss with late development of neuropathic arthropathy.
* At corticospinal tracts below the level of the syrinx results in
spastic paraparesis.
Transverse Myelitis:
inflammatory lesion that can affect the cord. Constitutional symptoms such as headache and fever are common as is pain. Signs are indistinguishable from those caused by cord compression and again all sensory aspects are equally affected with no sparing of proprioception.
Subclavian Steal Syndrome:
s associated with retrograde flow in the vertebral artery due to proximal subclavian artery stenosis. Neurological symptoms are precipitated by vigorous exercise with the arm above the head, such as painting a wall.
* Diagnosis is often confused with transient ischemic attacks or epilepsy.
* Duplex ultrasound and MRA are the investigations of choice.
* Endarterectomy and stenting are common surgical methods involved in relieving symptoms
associated with this condition.
Subacute Combined Degeneration of Spinal Cord features
Patchy losses of myelin in the dorsal and lateral columns.
* Present with progressive weakness of legs, arms, trunk,
tingling and numbness.
* Visual & Mental changes may also be present.
* Bilateral spastic paresis may develop and pressure, vibration
and touch sense are diminished.
* Positive Babinski sign may be seen.
* Prolonged deficiency (> 3 months) of vitamin B12 leads to
irreversible nervous system damage.
* If someone is deficient in vitamin B12 and folic acid, the
vitamin B12 deficiency must be treated first to avoid
precipitating subacute combined degeneration of the cord.
* Therapy with vitamin B12 results in partial to full recovery,
depending on the duration and extent of neurodegeneration
Von Hippel-Lindau: features
Von Hippel-Lindau (VHL) syndrome is an autosomal dominant condition predisposing to neoplasia. It is due to an abnormality in the VHL gene located on short arm of chromosome 3
Cerebellar hemangiomas (Can secret crythyropiotiene that causes secondary polycythemia)
* Retinal hemangioma: vitreous hemorrhage
* Renal cysts (premalignant)
* Pheochromocytoma
* Extra-renal cysts: epididymal, pancreatic,
hepatic
* Endolymphatic sac tumours
Friedreich’s Ataxia
most common of the early-onset hereditary ataxias. It is an autosomal recessive, trinucleotide repeat disorder characterized by a GAA repeat in the X25 gene on chromosome 9 (frataxin). Friedreich’s ataxia is unusual amongst trinucleotide repeat disorders in not demonstrating the phenomenon of anticipation. The typical age of onset is 10-15 years old
Friedreich’s Ataxia features
Neurological features
* Absent ankle jerks/extensor plantars
* Cerebellar ataxia
* Optic atrophy
* Spinocerebellar tract degeneration
Other features
* Hypertrophic obstructive cardiomyopathy (90%, most common cause of death)
* Diabetes mellitus (10-20%)
* High-arched palate
Tuberous Sclerosis (TS)
genetic condition of autosomal dominant inheritance. Like neurofibromatosis, the majority of features seen in TS are neuro-cutaneous
Tuberous Sclerosis Cutaneous features
Cutaneous features
* Depigmented ‘ash-leaf’ spots which fluoresce under UV light
* Roughened patches of skin over lumbar spine (Shagreen patches)
* Adenoma sebaceum: butterfly distribution over nose
* Fibromata beneath nails (subungual fibromata)
* Café-au-lait spots may be seen
Tuberous Sclerosis Neurological features
Neurological features
* Developmental delay
* Epilepsy (infantile spasms or partial)
* Intellectual impairment
Neurofibromatosis NF1
Café-au-lait spots (= 6, 15 mm in diameter) Axillary/groin freckles
Peripheral neurofibromas
Iris: Lisch nodules in > 90%
Scoliosis
It is caused by a gene mutation on chromosome 17 which encodes neurofibromin and affects around 1 in 4,000
Neurofibromatosis NF2
Bilateral acoustic neuromas
NF2 is caused by gene mutation on chromosome 22 and affects around 1 in 100,000
Hereditary Sensorimotor Neuropathy (HSMN)
HSMN type I
HSMN type I
* Autosomal dominant
* Due to defect in PMP-22 gene (which codes for myelin) (PMP = Peripheral Myelin Protein)
* Features often start at puberty
* Motor symptoms predominate
* Distal muscle wasting, pes cavus, clawed toes
* Foot drop, leg weakness often first features
* Nerve Conduction Velocity is greatly ↓ <30m/second
Amyotrophic lateral sclerosis
Typically LMN signs in arms and UMN signs in legs
* In familial cases the gene responsible lies on chromosome 21 and codes for superoxide
dismutase
Progressive muscular atrophy
- LMN signs only
- Affects distal muscles before proximal
- Carries best prognosis
Bulbar palsy
Palsy of the tongue, muscles of chewing/swallowing and facial muscles due to loss of function of brainstem motor nuclei
* Carries worst prognosis
There are a number of clues which point towards a diagnosis of motor neuron disease:
Fasciculation
* Absence of sensory signs/symptoms (vague sensory symptoms may occur early in the disease
(e.g. Limb pain) but ‘never’ sensory signs)
* Lower motor neuron signs in arms and upper motor neuron signs in legs
* Wasting of the small hand muscles/tibialis anterior is common (tibialis anterior functions to
stabilise the ankle as the foot hits the ground during the contact phase of walking [eccentric contraction] and acts later to pull the foot clear of the ground during the swing phase [concentric contraction]. It also functions to ‘lock’ the ankle, as in toe-kicking a ball, when held in an isometric contraction)
