Neurology Flashcards
Myasthenia Gravis Diagnosis
ACh and MuSK antibodies test
TFTs
Ice pack Test
EMG ( gold standard)
CT/MRI thorax for thymoma
FVC ( Forced Vital capacity)
Myasthenia Gravis Rx
Pyridostigmine
Corticosteroids
Steroid sparing agents
Plasmapheresis and IVIG
Monoclonal antibody Rituximab, Belimumab
Thymectomy
Guillain Barre Syndrome
Also known as Acute Inflammatory demyelinating polyneuropathy.
URTI/UTI
The organism is Campylobacter jejuni
Progressive symmetric Ascending muscle weakness with absent reflexes.
IVIG and plasma exchange
Lateral Medullary syndrome
Infarction of the posterior inferior cerebellar artery results in lateral medullary syndrome
Ischemic Stroke
-Intravenous thrombolysis with alteplase should be administered within 4.5 hours of ischaemic stroke onset, provided there are no contraindications such as haemorrhage.
-If thrombolysis is not given, then aspirin 300mg PO stat can be given.
Epilepsy
Sodium valproate is associated with an increased risk of neural tube defects when used in pregnancy
L5 radiculopathy
Acute back pain followed by weakness of dorsiflexion of the left foot are assocaited with sensory loss in the dorsum of the foot which suggests L5 radiculopathy.
Lesions of the Brain
Lesions of the frontal lobe include difficulties with task sequencing and executive skills.
Other symptoms include:
Expressive aphasia (receptive aphasias are due to a temporal lobe lesion)
Primitive reflexes
Perseveration (repeatedly asking the same question or performing the same task)
Anosmia, and
Changes in personality.
Lesions of the parietal lobe include:
Apraxias
Neglect
Astereognosis (unable to recognise an object by feeling it), and
Visual field defects (typically homonymous inferior quadrantanopia).
They may also cause alcalculia (inability to perform mental arithmetic).
Lesions of the temporal lobe cause:
Visual field defects (typically homonymous superior quadrantanopia)
Wernicke’s (receptive) aphasia
Auditory agnosia, and
Memory impairment.
Occipital lobe lesions include:
Cortical blindness (blindness due to damage to the visual cortex and may present as Anton syndrome where there is blindness but the patient is unaware or denies blindness)
Homonymous hemianopia, and
Visual agnosia (seeing but not perceiving objects - it is different to neglect since in agnosia the objects are seen and followed but cannot be named).
Bicker’s staff Encephalitis
-Affects the brainstem causes drowsiness, ophthalmoparesis, ataxia and brisk reflexes.
- caused by campylobacter jejuni
- associated with autoantibodies against gangliosides typically antiGQ1b IgG in the serum.
Rett Syndrome
Rett syndrome is a neurodevelopmental disorder mostly affecting girls. There is repetitive hand movements, such as hand wringing syndrome related to the MECP2 gene on the X chromosome.
Median Nerve Neuropathy
Entrapment of the median nerve by pronator teres causes a median nerve neuropathy, which is worse during pronation of the forearm.
Atypical parkinsonism
A lack of response to Levodopa in a patient with parkinsonian features should raise suspicion of atypical parkinsonism such as progressive supranuclear palsy or multiple system atrophy where dopaminergic therapy is less effective.
Lyme disease
Lyme disease is spread by the bite of ticks of the genus Ixodes that are infected with Borrelia burgdorferi
Oculogyric crisis
An oculogyric crisis is a dystonic reaction to certain drugs or medical conditions
Features
restlessness, agitation
involuntary upward deviation of the eyes
Causes
antipsychotics
metoclopramide
postencephalitic Parkinson’s disease
Management
cessation of causative medication if possible
intravenous antimuscarinic: benztropine or procyclidine
Syringomyelia
Syringomyelia (‘syrinx’ for short) describes a collection of cerebrospinal fluid within the spinal cord.
Syringobulbia is a similar phenomenon in which there is a fluid-filled cavity within the medulla of the brainstem. This is often an extension of the syringomyelia but in rare cases can be an isolated finding.
Causes include:
a Chiari malformation: strong association
trauma
tumours
idiopathic
Features
a ‘cape-like’ (neck, shoulders and arms)
loss of sensation to temperature but the preservation of light touch, proprioception and vibration
classic examples are of patients who accidentally burn their hands without realising
this is due to the crossing spinothalamic tracts in the anterior commissure of the spinal cord being the first tracts to be affected
spastic weakness (predominantly of the lower limbs)
neuropathic pain
upgoing plantars
autonomic features:
Horner’s syndrome due to compression of the sympathetic chain, but this is rare
bowel and bladder dysfunction
scoliosis will occur over a matter of years if the syrinx is not treated
Investigations
-full spine MRI with contrast to exclude a tumour or tethered cord
-a brain MRI is also needed to exclude a Chiari malformation
LMS/ Wallenberg syndrome
Lateral medullary syndrome - PICA lesion - cerebellar signs, contralateral sensory loss & ipsilateral Horner’s
Locked in syndrome
-patients are awake but are unable to move or verbally communicate, also called ‘Locked-in syndrome’
Friedreich’s Ataxia
Friedreich’s ataxia is the most common of the early-onset hereditary ataxias. It is an autosomal recessive, trinucleotide repeat disorder characterised by a GAA repeat in the X25 gene on chromosome 9 (frataxin). Friedreich’s ataxia is unusual amongst trinucleotide.
The typical age of onset is 10-15 years old. 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
Narcolepsy
- Associated with HLA-DR2
it is associated with low levels of orexin (hypocretin), a protein which is responsible for controlling appetite and sleep patterns
early onset of REM sleep
Features
typical onset in teenage years
hypersomnolence
cataplexy (sudden loss of muscle tone often triggered by emotion)
sleep paralysis
vivid hallucinations on going to sleep or waking up
Investigation
- Multiple Sleep Latency EEG
Management
- daytime stimulants (e.g. modafinil) and nighttime sodium oxybate
Intracranial Venous Thrombosis
Specific syndromes
Sagittal sinus thrombosis
may present with seizures and hemiplegia
parasagittal biparietal or bifrontal haemorrhagic infarctions are sometimes seen
‘empty delta sign’ seen on venography
Cavernous sinus thrombosis
other causes of cavernous sinus syndrome: local infection (e.g. sinusitis), neoplasia, trauma
periorbital erythema and oedema
ophthalmoplegia: 6th nerve damage typically occurs before 3rd & 4th
trigeminal nerve involvement may lead to hyperaesthesia of upper face and eye pain
central retinal vein thrombosis
Lateral sinus thrombosis
6th and 7th cranial nerve palsies
Intracranial Venous Thrombosis
Overview
can cause cerebral infarction, much lesson common than arterial causes
50% of patients have isolated sagittal sinus thromboses - the remainder have coexistent lateral sinus thromboses and cavernous sinus thromboses
General features
Common features
headache (may be sudden onset)
nausea & vomiting
reduced consciousness
Investigation
MRI venography is the gold standard
CT venography is an alternative
non-contrast CT head is normal in around 70% of patients
D-dimer levels may be elevated
Management
- anticoagulation
Typically with low molecular weight heparin acutely
Warfarin is still generally used for longer term anticoagulation
Neuropathic Pain
Drugs for neuropathic pain are typically used as monotherapy, i.e. if not working then drugs should be switched, not added
Juvenile Myoclinic epilepsy (JME)
Juvenile myoclonic epilepsy (JME), also known as Janz syndrome, typically presents in teenage years with a triad of:
1- Myoclonic seizures (sudden, shock-like muscle jerks), present in all cases by definition, may cause patients to drop things.
2- Generalised tonic-clonic seizures, present in 2/3 of the cases, may develop later.
3- Absence seizures (daytime ‘staring spells’), present in 1/3 of the cases.
Hemiballism
- Hemiballism occurs following damage to the subthalamic nucleus.
-Symptoms may decrease whilst the patient is asleep.
- Antidopaminergic agents (e.g. Haloperidol) are the mainstay of treatment
