General Flashcards
Examples of 5HT3 antagonists and their mechanism?
Ondansetron and palonsetron
5HT3 receptor antagonist - centrally acting in medulla oblongata in chemoreceptor trigger zone
Side effects of 5HT3 antagonists?
Constipation
QT prolongation
Advantage of palonsetron vs ondansetron?
Second generation 5HT3 antagonist
Less QT prolongation
Who do absence seizures mostly affect?
onset of 3-10 years old and girls are affected twice as commonly as boys
Features of absence seizures?
absences last a few seconds and are associated with a quick recovery
seizures may be provoked by hyperventilation or stress
the child is usually unaware of the seizure
they may occur many times a day
EEG: bilateral, symmetrical 3Hz spike and wave pattern
EEG: bilateral, symmetrical 3Hz spike and wave pattern, suggestive of?
Absence seizure
Management of absence seizures?
sodium valproate and ethosuximide are first-line treatment
good prognosis - 90-95% become seizure free in adolescence
Cause of absent plantar reflexes + extensor planters
subacute combined degeneration of the cord
motor neuron disease
Friedreich’s ataxia
syringomyelia
taboparesis (syphilis)
conus medullaris lesion
Where is the lesion if plantar reflexes + extensor planters
lesion producing both upper motor neuron (extensor plantars) and lower motor neuron (absent ankle jerk) signs
What is acute disseminated encephalomyelitis?
autoimmune demyelinating disease of the central nervous system
post-infectious encephalomyelitis
Some causes of acute disseminated encephalomyelitis?
Common infections include measles, mumps, rubella and varicella and more
Clinical course of acute disseminated encephalomyelitis ?
Lag time, followed by acute onset multifocal neurological symptoms with rapid deterioration
Nonspecific features: Fever, nausea. vomiting, oculomotor effects
MRI imaging may show areas of supra and infra-tentorial demyelination
No biomarkers
Treatment of disseminated encephalomyelitis?
intravenous glucocorticoids and the consideration of IVIG
What is anti NMDA encephalitis?
Anti-NMDA receptor encephalitis is a paraneoplastic syndrome, presenting as prominent psychiatric features
Features of anti-NMDA encephalitis ?
agitation, hallucinations, delusions and disordered thinking; seizures, insomnia, dyskinesias and autonomic instability
Associated findings with anti-NMDA receptor encephalitis?
Ovarian teratomas are detected in up to half of all female adult patients
CSF finding in anti-NMDA receptor encephalitis ?
Pleocytosis
If not normal
Management of anti-NMDA receptor encephalitis?
based of immunosuppression with intravenous steroids, immunoglobulins, rituximab, cyclophosphamide or plasma exchange, alone or in combination. Resection of teratoma is also therapeutic.
What antibodies are associated in anti-NMDA receptor encephalitis?
Anti-GM1
Anti-MuSK
Important points about wernicke’s area
lesion of the superior temporal gyrus
Blood supply: Inferior division left MCA
Area ‘forms’ the speech before ‘sending it’ to Broca’s area.
Features of wernicke’s aphasia (receptive aphasia) ?
Lesions result in sentences that make no sense, word substitution and neologisms but speech remains fluent - ‘word salad’
Comprehension impaired
Important points about Broca’s area (expressive aphasia)?
Due to a lesion of the inferior frontal gyrus. It is typically supplied by the superior division of the left MCA
Features of Broca’s aphasia?
Speech is non-fluent, laboured, and halting. Repetition is impaired
Comprehension is normal
Features of conductive aphasia ?
Speech is fluent but repetition is poor. Aware of the errors they are making
Comprehension is normal
What causes a conductive aphasia?
Classically due to a stroke affecting the arcuate fasiculus - the connection between Wernicke’s and Broca’s area
Features of global aphasia
Large lesion affecting all 3 of the above (Brocas, wernickes and arcuate fasiculus) resulting in severe expressive and receptive aphasia
May still be able to communicate using gestures
What is an Arnold chiari malformation ?
Arnold-Chiari malformation describes the downward displacement, or herniation, of the cerebellar tonsils through the foramen magnum.
Malformations may be congenital or acquired through trauma.
Features of Arnold chair malformation?
non-communicating hydrocephalus may develop as a result of obstruction of cerebrospinal fluid (CSF) outflow
headache
syringomyelia
In ataxia telectangesia, what is the genetic mutation and its impact?
Defect in the ATM gene which encodes for DNA repair enzymes.
It is one of the inherited combined immunodeficiency disorders.
Features of ataxia telengectasia?
Autosomal recessive
cerebellar ataxia
telangiectasia (spider angiomas)
IgA deficiency resulting in recurrent chest infections
10% risk of developing malignancy, lymphoma or leukaemia, but also non-lymphoid tumours
Differences between Fredrick’s ataxia and ataxia telengectasia?
Features of autonomic neuropathy?
impotence, inability to sweat, postural hypotension
postural hypotension e.g. drop of 30/15 mmHg
loss of decrease in heart rate following deep breathing
pupils: dilates following adrenaline instillation
Causes of autonomic neuropathy?
diabetes
Guillain-Barre syndrome
multisystem atrophy (MSA), Shy-Drager syndrome
Parkinson’s
infections: HIV, Chagas’ disease, neurosyphilis
drugs: antihypertensives, tricyclics
craniopharyngioma
Mechanism of baclofen and its use?
agonist of GABA receptors
acts in the central nervous system (brain and spinal cord)
Used to treat spasticity
What is Bell’s palsy?
acute, unilateral, idiopathic, facial nerve paralysis.
Possible associated herpes simplex virus
Peak incidence 20-40 yrs
In lower motor neurological facial palsy, is forehead affected?
Yes
Features of Bell’s palsy?
lower motor neuron facial nerve palsy - forehead affected
in contrast, an upper motor neuron lesion ‘spares’ the upper face
patients may also notice post-auricular pain (may precede paralysis), altered taste, dry eyes, hyperacusis
Management in Bell’s palsy?
oral prednisolone within 72 hours of onset of Bell’s palsy
eye care is important to prevent exposure keratopathy
- prescribe tears and tape
Features of BPPV?
Vertigo with change of head position
vertigo triggered by change in head position (e.g. rolling over in bed or gazing upwards)
may be associated with nausea
each episode typically lasts 10-20 seconds
positive Dix-Hallpike manoeuvre, indicated by:
patient experiences vertigo
rotatory nystagmus
Treatment for BPPV and how successful is it?
Epley manoeuvre (successful in around 80% of cases)
teaching the patient exercises they can do themselves at home, termed vestibular rehabilitation, for example Brandt-Daroff exercises
Benign rolandic epilepsy features?
seizures characteristically occur at night
seizures are typically partial (e.g. paraesthesia affecting face) but secondary generalisation may occur (i.e. parents may only report tonic-clonic movements)
child is otherwise normal
Normally resolves by adolescence
Erbs palsy?
damage to C5,6 roots
winged scapula
may be caused by a breech presentation
Waiter’s tip
Klumpkes palsy?
damage to T1
loss of intrinsic hand muscles
due to traction
Claw hand
How do brain abscesses occur?
extension of sepsis from middle ear or sinuses, trauma or surgery to the scalp, penetrating head injuries and embolic events from endocarditis
Features of brain asbcess?
headache
- often dull, persistent
fever
- may be absent and usually not the swinging pyrexia seen with abscesses at other sites
focal neurology
e.g. oculomotor nerve palsy or abducens nerve palsy secondary to raised intracranial pressure
other features consistent with raised intracranial pressure
nausea
papilloedema
seizures
Management of brain abscess?
surgery
- a craniotomy is performed and the abscess cavity debrided
- the abscess may reform because the head is closed following abscess drainage.
IV antibiotics: IV 3rd-generation cephalosporin + metronidazole
intracranial pressure management: e.g. dexamethasone
Features of lesions in the parietal lobe?
sensory inattention
apraxias
astereognosis (tactile agnosia)
inferior homonymous quadrantanopia
Gerstmann’s syndrome (lesion of dominant parietal): alexia, acalculia, finger agnosia and right-left disorientation
Occipital lobe lesion?
homonymous hemianopia (with macula sparing)
cortical blindness
visual agnosia
Temporal lobe lesion?
Wernicke’s aphasia: this area ‘forms’ the speech before ‘sending it’ to Brocas area. Lesions result in word substituion, neologisms but speech remains fluent
superior homonymous quadrantanopia
auditory agnosia
prosopagnosia (difficulty recognising faces)
Frontal lobe lesion?
expressive (Broca’s) aphasia: located on the posterior aspect of the frontal lobe, in the inferior frontal gyrus. Speech is non-fluent, laboured, and halting
disinhibition
perseveration - repeating particular phrase
anosmia
inability to generate a list
Cerebellum lesion ?
midline lesions: gait and truncal ataxia
hemisphere lesions: intention tremor, past pointing, dysdiadokinesis, nystagmus
Area affected in Wernicke and Korsakoff syndrome
Medial thalamus and mammillary bodies of the hypothalamus
Area affected in hemiballisus
Subthalamic nucleus of the basal ganglia
Area affected by Huntington’s chorea?
Striatum (caudate nucleus) of the basal ganglia
Area affected by Kluver-Bucy syndrome (hypersexuality, hyperorality, hyperphagia, visual agnosia
Amygddala
Features of brown sequared syndrome?
Lateral hemisection of the cord
ipsilateral weakness below lesion
ipsilateral loss of proprioception and vibration sensation
contralateral loss of pain and temperature sensation
What is CADASIL?
Cerebral Autosomal Dominant Arteriopathy with Subcortical Infarcts and Leukoencephalopathy (CADASIL)
rare cause of multi-infarct dementia
patients often present with migraine
What is CADASIL?
Cerebral Autosomal Dominant Arteriopathy with Subcortical Infarcts and Leukoencephalopathy (CADASIL)
rare cause of multi-infarct dementia
patients often present with migraine
Uses of carbsmazepine?
Trigeminal neuralgia
Bipolar
Epilepsy
Adverse side effects of carebmazepine ?
P450 enzyme inducer
dizziness and ataxia
drowsiness
headache
visual disturbances (especially diplopia)
Steven-Johnson syndrome
leucopenia and agranulocytosis
hyponatraemia secondary to syndrome of inappropriate ADH secretion
Why may patients see new seizures after start carbamazepine ?
exhibit autoinduction,
Induces the enzyme that metabolisies it
hence when patients start carbamazepine they may see a return of seizures after 3-4 weeks of treatment.
What is cataplexy?
sudden and transient loss of muscular tone caused by strong emotion (e.g. laughter, being frightened). Around two-thirds of patients with narcolepsy have cataplexy.
Unilateral cerebellar lesions affects ipsilateral or contralateral side?
Ipsilateral
Features of cerebellar syndrome?
D - Dysdiadochokinesia, Dysmetria (past-pointing), patients may appear ‘Drunk’
A - Ataxia (limb, truncal)
N - Nystamus (horizontal = ipsilateral hemisphere)
I - Intention tremour
S - Slurred staccato speech, Scanning dysarthria
H - Hypotonia
Causes of cerebellar syndrome
Friedreich’s ataxia, ataxic telangiectasia
neoplastic: cerebellar haemangioma
stroke
alcohol
multiple sclerosis
hypothyroidism
drugs: phenytoin, lead poisoning
paraneoplastic e.g. secondary to lung cancer
Normal values for cerebrospinal fluid?
Normal values of cerebrospinal fluid (CSF) are as follows:
pressure = 60-150 mm (patient recumbent)
protein = 0.2-0.4 g/l
glucose = > 2/3 blood glucose
cells: red cells = 0, white cells < 5/mm³
Associatied with high lymphocytes in CSF?
viral meningitis/encephalitis
TB meningitis
partially treated bacterial meningitis
Lyme disease
Behcet’s, SLE
lymphoma, leukaemia
What is the mechanism behind chorea?
Chorea is caused by damage to the basal ganglia, especially the caudate nucleus.
What is chorea?
Chorea describes involuntary, rapid, jerky movements which often move from one part of the body to another.
Causes of chorea?
Huntington’s disease, Wilson’s disease, ataxic telangiectasia
SLE, anti-phospholipid syndrome
rheumatic fever: Sydenham’s chorea
drugs: oral contraceptive pill, L-dopa, antipsychotics
neuroacanthocytosis
pregnancy: chorea gravidarum
thyrotoxicosis
polycythaemia rubra vera
carbon monoxide poisoning
cerebrovascular disease
What is athetosis?
Sinuous movement of the limbs is termed athetosis
Features of cluster headache?
pain typical occurs once or twice a day, each episode lasting 15 mins - 2 hours
clusters typically last 4-12 weeks
intense sharp, stabbing pain around one eye (recurrent attacks ‘always’ affect same side)
the patient is restless and agitated during an attack
accompanied by redness, lacrimation, lid swelling
nasal stuffiness
miosis and ptosis in a minority
Management of cluster headache?
acute: 100% oxygen (80% response rate within 15 minutes), subcutaneous triptan (75% response rate within 15 minutes)
prophylaxis: verapamil is the drug of choice. There is also some evidence to support a tapering dose of prednisolone
NICE recommend seeking specialist advice from a neurologist if a patient develops cluster headaches with respect to neuroimaging
What are the autonomic cephalgia?
cluster headache, paroxysmal hemicrania and short-lived unilateral neuralgiform headache with conjunctival injection and tearing (SUNCT)
What does the sciatic nerve divide into?
The sciatic nerve divides into the tibial and common peroneal nerves. Injury often occurs at the neck of the fibula
Common pudenal nerve injury?
weakness of foot dorsiflexion
weakness of foot eversion
weakness of extensor hallucis longus
sensory loss over the dorsum of the foot and the lower lateral part of the leg
wasting of the anterior tibial and peroneal muscles
Types of chronic regional pain syndrome?
type I (most common): there is no demonstrable lesion to a major nerve
type II: there is a lesion to a major nerve
Features of chronic regional pain syndrome ?
progressive, disproportionate symptoms to the original injury/surgery
allodynia
temperature and skin colour changes
oedema and sweating
motor dysfunction
the Budapest Diagnostic Criteria are commonly used in the UK
Management of chronic regional pain syndrome?
early physiotherapy is important
neuropathic analgesia in-line with NICE guidelines
specialist management (e.g. Pain team) is required
Mechanism in CJD?
Progressive neurological condition caused by prion proteins. These proteins induce the formation of amyloid folds resulting in tightly packed beta-pleated sheets resistant to proteases.
Features of CJD?
Myoclonus
Dementia rapid onset
Investigation summary in CJD?
CSF is usually normal
EEG: biphasic, high amplitude sharp waves (only in sporadic CJD)
MRI: hyperintense signals in the basal ganglia and thalamus
Types of CJD?
Sporadic
New variant
Features of new variant CJD?
psychological symptoms such as anxiety, withdrawal and dysphonia are the most common presenting features
Prion protein is new variant CJD is encoded by what chromosome?
Chromosome 20
Risk factor for developing new variant CJD?
methionine homozygosity at codon 129 chromosome 20
Risk factor for developing new variant CJD?
methionine homozygosity at codon 129 chromosome 20
Other forms of prion diseases?
kuru
fatal familial insomnia
Gerstmann Straussler-Scheinker disease
Presentation of degenerative cervical myelopathy?
Pain (affecting the neck, upper or lower limbs)
Loss of motor function (loss of digital dexterity, preventing simple tasks such as holding a fork or doing up their shirt buttons, arm or leg weakness/stiffness leading to impaired gait and imbalance
Loss of sensory function causing numbness
Loss of autonomic function (urinary or faecal incontinence and/or impotence) - these can occur and do not necessarily suggest cauda equina syndrome in the absence of other hallmarks of that condition
Hoffman’s sign: is a reflex test to assess for cervical myelopathy. It is performed by gently flicking one finger on a patient’s hand. A positive test results in reflex twitching of the other fingers on the same hand in response to the flick.
What are risk factors of degenerative cervical myelopathy?
Occupation
Smoking
Genetics
Signed used to test for degenerative cervical myelopathy?
Hoffman’s sign: is a reflex test to assess for cervical myelopathy. It is performed by gently flicking one finger on a patient’s hand. A positive test results in reflex twitching of the other fingers on the same hand in response to the flick.
Best imaging for degenerative cervical cord myelopathy?
MRI
Treatment of cervical myelopathy?
Decompressive surgery
Urgent referral - should be seen / treated within 6 months of diagonosis
Prevents further damage
Drugs that cause peripheral neuropathy?
amiodarone
isoniazid
vincristine
nitrofurantoin
metronidazole
Driving advice: Once off seizure + No structural brain damage?
6 months
Driving advice: Once off seizure + structural brain damage?
12 months
Seizure free for 12 months?
Can apply for driving liscence
No seizure for 5 years - driving?
Can apply for a until 70 driving licence
Driving advice after one episode of syncope?
4 weeks once treated and explained
Driving advice for syncope when unexplained?
6 months off
Two or more episodes of syncope?
12 months off
Time off driving from stroke or TIA?
1 month
Driving advice: Multiple TIAs ?
3 months
Driving advice after craniotomy? Including transpheoidal surgery
If well - consider after 6 months
If not 1 year
Narcolepsy / cataplexy - driving?
Once symptoms satisfactorially under control
What is the function of dystrophin?
large membrane associated protein in muscle which connects the muscle membrane to actin, part of the muscle cytoskeleton
Inheritence of the muscular dystrophies?
X linked
Genetic mutation in duchene muscular dystrophy?
frameshift mutation resulting in one or both of the binding sites ( of the protein) are lost leading to a severe form
Genetic mutation in becker’s muscular dystrophy?
non-frameshift insertion in the dystrophin gene resulting in both binding sites being preserved leading to a milder form
Features of duchene muscular dystrophy?
progressive proximal muscle weakness from 5 years
calf pseudohypertrophy
Gower’s sign: child uses arms to stand up from a squatted position
30% of patients have intellectual impairment
Features of becker muscular dystrophy?
progressive proximal muscle weakness from 5 years
calf pseudohypertrophy
Gower’s sign: child uses arms to stand up from a squatted position
30% of patients have intellectual impairment
Features of infantile spasms? (West syndrome)
Brief spasms beginning in the first few months of life
key features:
- flexion of head, trunk, limbs → extension of arms (Salaam attack); last 1-2 secs, repeat up to 50 times
progressive mental handicap
- EEG: hypsarrhythmia
usually secondary to serious neurological abnormality (e.g. tuberous sclerosis, encephalitis, birth asphyxia) or may be idiopathic
Treatment of west syndrome?
possible treatments include vigabatrin and steroids
has a poor prognosis
Features of petit Mal seizure? Absence seizures?
onset 4-8 yrs
duration few-30 secs; no warning, quick recovery; often many per day
EEG: 3Hz generalized, symmetrical
good prognosis: 90-95% become seizure free in adolescence
Treatment of absence seizures?
sodium valproate, ethosuximide
Features of Lennox- gas taut syndrome?
may be an extension of infantile spasms
onset 1-5 yrs
features:
atypical absences, falls, jerks
90% moderate-severe mental handicap
EEG: slow spike
Treatment of Lennox-gas taut syndrome?
treatment: ketogenic diet may help
Features of benign rolandic epilepsy?
most common in childhood, more common in males
features: paraesthesia (e.g. unilateral face), usually on waking up
Features of juvenile myoclonic epilepsy? Jana syndrome
typical onset is in the teenage years, more common in girls
features:
infrequent generalized seizures, often in morning//following sleep deprivation
daytime
s
sudden, shock-like myoclonic seizure (these may develop before seizures)
treatment: usually good response to sodium valproate
What is a focal seizure ?
previously termed partial seizures
these start in a specific area, on one side of the brain
awareness depends on area affected
How can focal seizures be classified?
focal seizures can be classified as being motor (e.g. Jacksonian march), non-motor (e.g. déjà vu, jamais vu; ) or having other features such as aura
Must classify by awareness: focal aware vs focal impaired awareness
Features of generalised seizures?
engage or involve networks on both sides of the brain at the onset
consciousness lost immediately.
How can generalised seizure be divided?
Motor: tonic clonic
Non-motor: absence
Localising feature of temporal lobe epilepsy?
An aura occurs in most patients
typically a rising epigastric sensation
also psychic or experiential phenomena, such as déjà vu, jamais vu
less commonly hallucinations (auditory/gustatory/olfactory)
Localising feature of frontal lobe epilepsy?
Head/leg movements, posturing, post-ictal weakness, Jacksonian march
Localising features of partial lobe epilepsy?
Paraesthesia
Localising features of occipital lobe epilepsy?
Floaters/flashes
What should women with epilepsy do before becoming pregnant?
Folic acid 5mg
How much does taking anti-epileptics during pregnant increase risk of neural tube defect?
1-2% normal patients
3-4 in epilepsy
How should you aim to manage patients with epilepsy wishing to become pregnant?
Aim for mono therapy
Should not need to monitor medication levels
Congenital defect associated with sodium valporate?
Neural tube defect
Neurodevelopmental delay
Women of child bearing age should not be put on this drug if possible
Which anti-epileptic is considered to have the least teratogenic effect?
carbamazepine
Congenital defect associated with phenytoin?
cleft pallet
Is breast feeding safe?
Yes
Providing not on barbiturate
When should anti-epileptics be started?
Generally after second seizure
When should anti-epileptics be started after first seizure?
- The patient has a neurological deficit
- Brain imaging shows a structural abnormality
- The EEG shows unequivocal epileptic activity
- The patient or their family or carers consider the risk of having a further seizure unacceptable
Treatment of generalised tonic clonic seizure?
Male: sodium valproate
Female: Lamotrigene
Treatment of focal seizures?
- Lamotrigene, leveiteracetam
- carbamazepine, oxcarbazepine or zonisamide
Myoclonic seizure treatment?
males: sodium valproate
females: levetiracetam
Treatment of absence seizure?
first line: ethosuximide
second line:
male: sodium valproate
female: lamotrigine or levetiracetam
carbamazepine may exacerbate absence seizures
Treatment of tonic and atonic seizures?
males: sodium valproate
females: lamotrigine
Inheritance of essential tremor?
Autosomal dominant
Features of essential tremor?
postural tremor: worse if arms outstretched
improved by alcohol and rest
most common cause of titubation (head tremor)
Treatment of essential tremor?
propranolol is first-line
primidone is sometimes used
Mechanism of ethosuximide?
blocks T-type calcium channels in thalamic neurons
What is the afferent and efferent function of the facial nerve?
It is a mostly efferent nerve
Afferent: Taste (genicular ganglion)
Efferent: muscles of facial expression, digastric muscle and glands
Supply - ‘face, ear, taste, tear’
face: muscles of facial expression
ear: nerve to stapedius
taste: supplies anterior two-thirds of tongue
tear: parasympathetic fibres to lacrimal glands, also salivary glands
Causes of bilateral facial palsy?
sarcoidosis
Guillain-Barre syndrome
Lyme disease
bilateral acoustic neuromas (as in neurofibromatosis type 2)
as Bell’s palsy is relatively common it accounts for up to 25% of cases f bilateral palsy, but bilateral is only 1% of total Bell’s palsy cases
Causes of lower motor neurone facial nerve palsy?
Lower motor neuron
Bell’s palsy
Ramsay-Hunt syndrome (due to herpes zoster)
acoustic neuroma
parotid tumours
HIV
multiple sclerosis*
diabetes mellitus
Cause of upper motor neurone facial nerve?
Stroke
How do you determine a LMN vs a UMN facial palsy?
upper motor neuron lesion ‘spares’ upper face i.e. forehead
lower motor neuron lesion affects all facial muscles
Where are the sensory and motor nuclei of the facial nerve?
Motor: Pons
Sensory: Nervus intermedius
petrous temporal bone into the internal auditory meatus with the vestibulocochlear nerve. Here they combine to become the facial nerve.
What is facioscapulohumeral dystrophy?
Autosomal dominant dystrophy
facial muscles are involved first - difficulty closing eyes, smiling, blowing etc
weakness of the shoulder and upper arm muscles
abnormal prominence of the borders of the shoulder blades - ‘winging’
lower limb: hip girdle weakness, foot drop
Causes of foot drop?
Occurs due to weakness in foot dorsiflexors
common peroneal nerve lesion - the most common cause
L5 radiculopathy
sciatic nerve lesion
superficial or deep peroneal nerve lesion
other possible includes central nerve lesions (e.g. stroke) but other features are usually present
Features of an isolated peroneal nerve neuropathy?
if the patient has an isolated peroneal neuropathy there will be weakness of foot dorsiflexion and eversion. Reflexes will be normal
weakness of hip abduction is suggestive of a L5 radiculopathy
CN IV palsy?
supplies superior oblique (depresses eye, moves inward)
vertical diplopia
classically noticed when reading a book or going downstairs
subjective tilting of objects (torsional diplopia)
the patient may develop a head tilt, which they may or may not be aware of
when looking straight ahead, the affected eye appears to deviate upwards and is rotated outwards
Genetic mechanism behind Fredrick’s ataxia?
Autosomal recessive, trinucleotide repeat disorder characterised by a GAA repeat in the X25 gene on chromosome 9 (frataxin).
Does not demonstrate anticipation
Fredrick’s ataxia phenotype?
Gait ataxia and kyphoscoliosis are the most common presenting 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
Causes of gingival hyperplasia?
Drug causes of gingival hyperplasia
phenytoin
ciclosporin
calcium channel blockers (especially nifedipine)
Other causes of gingival hyperplasia include
acute myeloid leukaemia (myelomonocytic and monocytic types)
What triggers Guillain barre syndrome?
Triggered by an infection (classically Campylobacter jejuni)
Pathogenesis of Guillain barre syndrome?
cross-reaction of antibodies with gangliosides in the peripheral nervous system
correlation between anti-ganglioside antibody (e.g. anti-GM1) and clinical features has been demonstrated
anti-GM1 antibodies in 25% of patients
What is Miller Fischer Syndrome?
variant of Guillain-Barre syndrome
associated with ophthalmoplegia, areflexia and ataxia. The eye muscles are typically affected first
usually presents as a descending paralysis rather than ascending as seen in other forms of Guillain-Barre syndrome
anti-GQ1b antibodies are present in 90% of cases
Features of Guillain barre syndrome?
Initial symptom: Backpain
Guillain-Barre syndrome is progressive, symmetrical weakness of all the limbs.
Weakness is typically ascending
Reduced / absent reflexes
Other features
- There may be a history of gastroenteritis
- Respiratory muscle weakness
- Cranial nerve involvement
1.diplopia
2.bilateral facial nerve palsy
3.oropharyngeal weakness is common
- Autonomic involvement
urinary retention
diarrhoea
Investigations in Guillain barre syndrome?
lumbar puncture
rise in protein with a normal white blood cell count (albuminocytologic dissociation) - found in 66%
Nerve condution studies may be performed
decreased motor nerve conduction velocity (due to demyelination)
prolonged distal motor latency
increased F wave latency
Management of Guillain barre?
- Intravenous immunoglobulin
- REGULAR MONITORING OF RESPIRATORY FUNCTION
- Plasma exchange
Poor prognostic factors for Guillain barre?
age > 40 years
poor upper extremity muscle strength
previous history of a diarrhoeal illness (specifically Campylobacter jejuni)
high anti-GM1 antibody titre
need for ventilatory support
Factors indicating a head CT within 1 hour?
GCS < 13 on initial assessment
GCS < 15 at 2 hours post-injury
suspected open or depressed skull fracture
any sign of basal skull fracture (haemotympanum, ‘panda’ eyes, cerebrospinal fluid leakage from the ear or nose, Battle’s sign).
post-traumatic seizure.
focal neurological deficit.
more than 1 episode of vomiting
Factors indicating a head CT within 8 hours?
age 65 years or older
any history of bleeding or clotting disorders including anticogulants
dangerous mechanism of injury (a pedestrian or cyclist struck by a motor vehicle, an occupant ejected from a motor vehicle or a fall from a height of greater than 1 metre or 5 stairs)
more than 30 minutes’ retrograde amnesia of events immediately before the head injury
warfarin who have sustained a head injury with no other indications for a CT head scan, perform a CT head scan within 8 hours of the injury.
What is a primary brain injury?
focal (contusion/haematoma) or diffuse (diffuse axonal injury)
diffuse axonal injury occurs as a result of mechanical shearing following deceleration, causing disruption and tearing of axons
Headinjury: Haematoma vs contusion?
haematomas can be extradural, subdural or intracerebral, while contusions may occur adjacent to (coup) or contralateral (contre-coup) to the side of impact
What is a secondary brain injury?
occurs when cerebral oedema, ischaemia, infection, tonsillar or tentorial herniation exacerbates the original injury. The normal cerebral auto regulatory processes are disrupted following trauma rendering the brain more susceptible to blood flow changes and hypoxia
What is Cushing’s reflex?
hypertension and bradycardia) often occurs late and is usually a pre terminal event
Where is the bleed in a extradural bleed?
Bleeding into the space between the dura mater and the skull
Bleed from middle meningeal artery
Exhibit a lucid interval –> crash
Features: Raised intracranial pressure
Where is the bleed in a subdural haematoma?
Bleeding into the outermost meningeal layer. Most commonly occur around the frontal and parietal lobes.
Risk factors include old age, alcoholism and anticoagulation.
Slower onset of symptoms than a epidural haematoma. There may be fluctuating confusion/consciousness
Features of migraine?
Severe headache which is usually unilateral and throbbing in nature
May be be associated with aura, nausea and photosensitivity
Aggravated by, or causes avoidance of, routine activities of daily living. Patients often describe ‘going to bed’.
In women may be associated with menstruation
Features of tension headache?
Recurrent, non-disabling, bilateral headache, often described as a ‘tight-band’
Not aggravated by routine activities of daily living
Cluster headache features?
Pain typical occurs once or twice a day, each episode lasting 15 mins - 2 hours with clusters typically lasting 4-12 weeks
Intense pain around one eye (recurrent attacks ‘always’ affect same side)
Patient is restless during an attack
Accompanied by redness, lacrimation, lid swelling
More common in men and smokers
Temporal arteritis?
Typically patient > 60 years old
Usually rapid onset (e.g. < 1 month) of unilateral headache
Jaw claudication (65%) - tiredness of muscles of mastication
Tender, palpable temporal artery
Raised ESR
Medical overuse headache?
Present for 15 days or more per month
Developed or worsened whilst taking regular symptomatic medication
Patients using opioids and triptans are at most risk
May be psychiatric co-morbidity
Causes of acute headache?
meningitis
encephalitis
subarachnoid haemorrhage
head injury
sinusitis
glaucoma (acute closed-angle)
tropical illness e.g. Malaria
Causes of chronic headache?
chronically raised ICP
Paget’s disease
psychological
Damage to what causes hemiballism?
Subthalamic nucleus
What is hemiballism?
involuntary, sudden, jerking movements which occur contralateral to the side of the lesion.
ballisic movements primarily affect the proximal limb musculature whilst the distal muscles may display more choreiform-like movements
Treatment of hemiballism?
Anti-dopamine
Halloperidol
What lobes of the brain does herpes simplex encephalitis typically affect?
Temporal lobes most
Can affect inferior frontal
Features of herpes simplex encephalitis?
fever, headache, psychiatric symptoms, seizures, vomiting
focal features e.g. aphasia
peripheral lesions (e.g. cold sores) have no relation to the presence of HSV encephalitis
What virus is implicated in hopers simplex encephalitis?
HSV1
Investigation finding in herpes simplex encephalitis?
CSF: lymphocytosis, elevated protein
PCR for HSV
CT: medial temporal and inferior frontal changes (e.g. petechial haemorrhages) - normal in one-third of patients
MRI is better
EEG pattern: lateralised periodic discharges at 2 Hz
Investigation in herpex simplex encephalitis?
CSF: lymphocytosis, elevated protein
PCR for HSV
CT: medial temporal and inferior frontal changes (e.g. petechial haemorrhages) - normal in one-third of patients
MRI is better
EEG pattern: lateralised periodic discharges at 2 Hz
Treatment of herpes simplex encephalitis?
Intravenous acyclovir
What is charco-marie tooth called now?
Hereditary sensorimotor neuropathy
What are the two types of HSMN?
HSMN type I: primarily due to demyelinating pathology
HSMN type II: primarily due to axonal pathology
Features of HSMN type 1 ?
autosomal dominant
due to defect in PMP-22 gene (which codes for myelin)
features often start at puberty
motor symptoms predominate
distal muscle wasting, pes cavus, clawed toes
foot drop, leg weakness often first features
Features of Huntington disease?
Features typical develop after 35 years of age
chorea
personality changes (e.g. irritability, apathy, depression) and intellectual impairment
dystonia
saccadic eye movements
Genetics behind Huntington’s disease?
autosomal dominant
trinucleotide repeat disorder: repeat expansion of CAG
- anticipation occurs
results in degeneration of cholinergic and GABAergic neurons in the striatum of the basal ganglia
due to defect in huntingtin gene on chromosome 4
Risk factors of idiopathic intracranial hypertension?
obesity
female sex
pregnancy
drugs*
combined oral contraceptive pill
steroids
tetracyclines
vitamin A
lithium
Features of idiopathic intracranial hypertension
headache
blurred vision
papilloedema (usually present)
enlarged blind spot
sixth nerve palsy may be present
Management of idiopathic intracranial hypertension
weight loss
diuretics e.g. acetazolamide
topiramate is also used, and has the added benefit of causing weight loss in most patients
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 reduce intracranial pressure
Where is the lesion in internuclear ophthalmoplegia ?
Lesion in the medial longitudinal fasciculus (MLF)
controls horizontal eye movements by interconnecting the IIIrd, IVth and VIth cranial nuclei
located in the paramedian area of the midbrain and pons
Features of internuclear ophthalmoplegia?
impaired adduction of the eye on the same side as the lesion
horizontal nystagmus of the abducting eye on the contralateral side