Neuro Flashcards
Anterior Spinal Artery infarct
Anterior spinal artery infarctions can occur after damage to the aorta, including both aneurysm repair and dissection.
single anterior spinal artery running down the midline of the spinal cord (in the anterior median fissure), blockage causes loss of pain, temperature, motor and autonomic function below that level.
Dorsal column function is preserved.
Causes of autonomic neuropathy
Diabetes mellitus
Infections (including HIV, lyme and chagas)
Autoimmune disease (including SLE)
Amyloidosis
Bell’s Palsy
Acute (but not sudden) onset, unilateral, lower motor neuron facial weakness, sparing the extraocular muscles and muscles of mastication.
Mild-moderate postauricular otalgia (which may precede paralysis).
Hyperacusis (actually quite uncommon).
Nervus intermedius symptoms (altered taste and dry eyes/mouth).
Bell’s Palsy management
he central component of Bell’s Palsy management is the prompt administration of oral steroids: 50mg OM for 10 days, followed by a taper.
Supportive treatments including artificial tears and ocular lubricants, and an eye patch/tape (especially if protective Bell’s phenomenon is absent) should be considered
Erb’s palsy
Involves the C5-6 nerve roots with corresponding dermatomal sensory loss, and the so-called “waiter’s tip” sign with shoulder adduction, elbow extension, forearm pronation and wrist flexion. It is most typically associated with shoulder dystocia and traumatic childbirth.
Klumpke’s palsy
Involves the C8-T1 nerve roots with corresponding dermatomal sensory loss, and weakness of the intrinsic muscles of the hand. Uncommonly, T1 involvement may also result in an ipsilateral Horner’s syndrome
Brown-Sequard Syndrome
Disruption of descending lateral corticospinal tracts, ascending dorsal column and ascending spinothalamic tracts leads to the following findings below the level of the injury:
Ipsilateral hemiplegia
Ipsilateral loss of proprioception and vibration
Contralateral loss of pain and temperature sensation
Common causes of BSS include:
Brown-Sequard Syndrome
Cord trauma (penetrating injuries being the most common) Neoplasms Disk herniation Demyelination Infective/ inflammatory lesions Epidural hematomas
Bulbar palsy
bulbar palsy is a ‘lower motor neurone’ lesion affecting cranial nerves 9, 10 and 12
Clinical signs include an absent or normal jaw jerk reflex, an absent gag reflex, a flaccid fasciculating tongue, nasal quiet speech, and signs suggestive of the cause e.g. limb fasciculations of motor neurone disease.
Cauda Equina Syndrome
management
Management
Patient with clinical features suggestive of spinal cord compression or cauda equina syndrome should have an urgent WHOLE spine MRI, with an aim (in appropriate cases) to surgically decompress within 48 hours.
In patients where malignancy is demonstrated on MRI, or in patients where clinical suspicion is high, administration of dexamethasone 16 mg daily in divided doses (with PPI cover) is indicated.
he features of cerebellar dysfunction can be remembered by the acronym DANISH:
Dysdiadochokinesia (an inability to perform rapid alternating hand movements)
Ataxia (a broad-based, unsteady gait)
Nystagmus (involuntary eye movements)
Intention tremor (seen when the patient is asked to perform the ‘finger-nose test’)
Slurred speech
Hypotonia
Cervical Spondylosis
Manifestations include:
Neck pain
Radiculopathy due to compression of nerve roots at the site of foraminal exit
Myelopathy, probably due to dynamic stretch of the spinal cord over impinging spinal osteophytes.
On examination, neck pain is accompanied by flaccid upper limb paresis (due to radiculopathy), variable sensory changes (sometimes including the Lhermitte phenomenon), and spastic paraparesis (with variable involvement of the upper limbs depending on the site of the lesion, and degree of radiculopathy).
Charcot-Marie-Tooth Syndrome
most common being an autosomal dominant mutation in the peripheral myelin protein 22 gene (PMP22..
There are two broad groups of disease: type 1 which is a demyelinating condition which is more common (and includes the PMP22 subtype), and type 2 which is axonal.
Clinical features
As disease progresses (most commonly over decades) some key clinical features may be noted: (1. thickening and enlargement of the nerves themselves, (2. symmetrical distal muscular atrophy (champagne bottle legs, and claw hand), and (3. pes cavus (high-arched feet).
Diagnosis
Diagnosis is made with a combination of nerve conduction studies and genetic testing. Patients with type 1 have reduced conduction velocity, whereas this is normal in type 2. While the disease may be incurable, most have a normal lifespan with expert supportive management. Majority require walking aids eventually, though requiring a wheelchair is uncommon.
Clinical features of Huntington’s disease
It is characterised by the triad of
Dominant inheritance
Choreoathetosis
Dementia
MRI and CT scans in moderate to severe disease can show loss of striatal volume and increased size of the frontal horns of the lateral ventricles.
Management of Huntington’s disease
Patients and their families require a significant amount of physical and emotional support from a multidisciplinary team.
Chorea can be managed with a number of medications, with tetrabenazine having the most evidence-base.
Depression can be treated with Selective serotonin reuptake inhibitors (SSRIs) as a first choice.
Psychosis can be managed with antipsychotics, preferably newer atypical agents due to lower rates of extrapyramidal side effects.
most common cause of Encephalitis
herpes simplex virus type 1
Investigating encephalitis
Encephalitis should be suspected in any patient with sudden onset behavioural change, new seizures and unexplained acute headache with meningism.
Standard work up for encephalitis is similar to that for meningitis, with a routine panel of blood tests, blood cultures and viral PCR. CSF should also be sent for viral PCR in addition to standard tests, and malaria blood films should be considered if exposure is suspected.
CNS imaging may also be helpful – HSV has a predilection for the temporal lobes and bilateral multifocal haemorrhage is typical.
treatment of encephalitis
Treatment of suspected encephalitis is empirical and should involve broad spectrum antimicrobial cover with 2g IV ceftriaxone BD and 10 mg/kg aciclovir TDS for two weeks.
Supportive management of complications including prompt termination of seizure activity with anticonvulsants (such as phenytoin) also important.
clinical presentation - Absence seizures
Patients, often children, pause briefly, for less than 10 seconds, and then carry on where they left off.
Treatment: Ethosuximide 1st line Sodium Valproate (SE: weight gain, hair loss which grows back curly, oedema, ataxia, tremor, teratogenicity)
Tonic-clonic seizures:
Patients lose consciousness; their limbs stiffen (tonic) and start jerking (clonic). Post-ictal confusion is common.
Treatment: Sodium Valproate or Lamotrigine is first-line.
Myoclonic seizures:
udden jerk of a limb, trunk, or face.
Treatment: Sodium Valproate is first-line unless the patient is a female of childbearing age where Levetiracetam or Topiramate should be used instead as first-line; avoid Carbamazepine as it worsens seizures.
Atonic seizures:
Atonic seizures: Sudden loss of muscle tone, causing the patient to fall, whilst retaining consciousness. Treatment: Sodium Valproate or Lamotrigine is first-line.
Essential tremor
mainly the upper limbs distally and is postural or kinetic.
amplitude increases with time, and patients experience difficulty in writing, eating, holding objects and doing fine motor tasks, dressing, and speaking
increares with stress
Essential tremor management
Management
The management of a patient with ET includes:
Behavioural techniques and physical therapy Medical (pharmacological) therapy (with agents such as propranolol, primidone, topiramate, gabapentin, clonazepam etc.) Surgical treatment (such as deep brain stimulation, focused ultrasound thalamotomy and radiosurgical (Gamma Knife) thalamotomy)
Extradural Haemorrhage
brief loss of consciousness, followed by regaining of normal consciousness level (the lucid interval), with subsequent deterioration of consciousness and headache.
Other causes of peripheral nerve disease include:
Other causes of peripheral nerve disease include:
Physical lesions of the cerebellopontine angle (including the classical acoustic neuroma)
Basal meningitis (which is often bilateral and may be infective or inflammatory, including lyme disease and sarcoidosis).
Ramsay Hunt syndrome (herpes zoster of the facial nerve)
Trauma
Diseases of the middle/inner ear
Mononeuritis multiplex
Fibromuscular dysplasia
Fibromuscular dysplasia (FMD), formerly called fibromuscular fibroplasia, is a group of non-atherosclerotic, non-inflammatory arterial diseases that most commonly involve the renal and carotid arteries.
Causes of Foot Drop
L5 root lesion (radiculopathy) – distinguished by loss of inversion (inversion is a tibial nerve function and is not lost in patients with a common peroneal nerve lesion). Sensory loss is over the L5 dermatome, and sciatica-type shooting leg pain may also be present. Lumbosacral disc herniation is the most common cause.
Distal motor neuropathy – often associated with glove and stocking sensory disturbance, and loss of all movements of the foot.
Small cortical lesions – often with though other upper neuron features may be present.
Uncommonly: intrinsic cord disease, partial sciatic nerve disease and myopathy may also mimic foot drop.
Friedreich’s ataxia
autosomal recessive trinucleotide repeat disorder resulting in reduced level or function of the frataxin protein.
Patients typically present in their teenage years with lower limb weakness, gait abnormalities, or falls.
On physical examination there may be cerebellar signs (due to involvement of the spinocerebellar tracts) or mixed upper and lower motor neurone signs e.g. absent knee/ankle reflexes but upgoing plantars (due to involvement of the corticospinal tracts and peripheral nerves).
Involvement of the dorsal columns can lead to impaired joint/vibration sense. Other clues on physical examination include a high-arched palate, pes cavus, and kyphoscoliosis.
Non-motor features include: hypertrophic obstructive cardiomyopathy, reduced visual acuity, type 1 diabetes mellitus, and deafness.
Miller-Fisher syndrome
(a variant of GBS) presents with ataxia, ophthalmoplegia, and areflexia. The condition is typically positive for anti-GQ1b antibodies.
Acute management of haemorrhagic stroke
Neurosurgical and neurocritical care evaluation due to the potential for surgical intervention (e.g. decompressive hemicraniectomy).
Admission to the neuro ICU or stroke unit (the patient may require intubation and ventilation or invasive monitoring of ICPs).
Aim to keep blood pressure <140/80 as poor blood pressure control in the acute stage is associated with poorer outcomes later on
Diagnosis of Migraine
Presence of an aura confirms the diagnosis. Otherwise, in headaches with no aura, the following criteria is required - at least 5 headaches lasting 4-72 hours, with nausea/vomiting or photo/phonophobia AND 2 of: unilateral headache, pulsating character, impaired or worsened by daily activities.
Management of Migraine
Avoid triggers; prophylaxis with Propranolol (CI: asthma) or Topiramate;
managing an acute attack with an oral triptan such as Sumatriptan (CI: ischaemic heart disease), in addition to Paracetamol or an NSAID. Ensure that female patients are not taking combined oral contraceptive pills as it increases their risk of ischaemic stroke.
Management of Cluster Headaches
Avoid triggers; prophylaxis with Verapamil; managing an acute attack with 100% oxygen via non-rebreathable mask (CI: COPD) with a subcutaneous or nasal Triptan (CI: ischaemic heart disease).
Symptoms of Raised intracranial pressure
Headaches which are worse in the morning and upon bending over, and improve after vomiting and lying down. May be associated with neurological deficits due to compression of cranial structures by a space-occupying lesion, such as a tumour or haemorrhage.
Hereditary spastic paraparesis d
main pathological feature is axonal degeneration of the corcisopinal tracts in the spinal cord.
Diagnostic criteria include: a family history, progressive gait disturbance, spasticity of lower limbs, hyper-reflexia of lower limbs, and extensor plantar responses. Typically the power in lower limbs muscles is normal/only mildly reduced.
Idiopathic Intracranial Hypertension
Classical clinical features include headache and visual disturbance.
The headache is classically non-pulsatile, bilateral, and worse in the morning (after lying down or bending forwards).
Patients may even report morning vomiting. A key differential diagnosis for morning headache in these obese patients is sleep apnoea.
Visual disturbances include transient visual darkening or loss, probably due to optic nerve ischaemia, and bilateral papilloedema is seen on fundoscopy.
If left untreated, permanent visual damage may result (untreated, 1-3% of patients may lose vision by year).
Drug associationsIdiopathic Intracranial Hypertension
It is associated with a number of drugs including:
Oral contraceptive pill Steroids Tetracycline Vitamin A Lithium
Management Idiopathic Intracranial Hypertension
First line management of idiopathic intracranial hypertension (and the only intervention supported by good evidence) is weight loss.
Failing this, patients often try carbonic anhydrase inhibitors, such as acetazolamide, but its extensive profile of side effects (peripheral paraesthesia, anorexia and metallic dysgeusia) mean that it is poorly tolerated. Topiramate and furosemide are also commonly tried.
More invasive strategies to lower CSF pressure including therapeutic lumbar punctures and surgical CSF shunting are tried in resistant cases.
In patients with prominent visual symptoms (but otherwise manageable headache), optic nerve sheath fenestration may protect against visual loss.
Internuclear ophthalmoplegia
caused by a lesion of the medial longitudinal fasciculus
= Ipsilateral impaired adduction in the eye
Nystagmus in the abducting eye
Intracranial Venous Thrombosis
Intracranial venous thrombosis refers to occlusion of venous vessels in the cranial cavity.
common symptoms include headache, confusion/drowsiness, impaired vision, and nausea/vomiting.
Other signs include seizures, reduced consciousness, focal neurological deficitis, cranial nerve palsies, and papilloedema.
Investigations
Non-contrast CT reveals a hyperdensity in the affected sinus.
CT venogram is used to look for a filling defect (‘the empty delta sign’).
Treat LMWH
Subdural haemorrhage
tend to occur in older patients. Other risk factors include historic head trauma, alcoholism, and anticoagulation. On CT, a crescent-shaped haematoma is diagnostic.
(hyper dense = acute and hypodense = chronic))
The key steps in secondary stroke prevention can be remembered by the mnemonic HALTSS:
Hypertension: studies show there is no benefit in lowering the blood pressure acutely (as this may impair cerebral perfusion) unless there is malignant hypertension (systolic blood pressure >180 mmHg). Anti-hypertensive therapy should, however, be initiated 2 weeks post-stroke.
Antiplatelet therapy: patients should be administered Clopidogrel 75 mg once daily for long-term antiplatelet therapy. In patients with ischaemic stroke secondary to atrial fibrillation, however, warfarin (target INR 2-3. or a direct oral anticoagulant (such as Rivaroxaban or Apixiban) is initiated 2 weeks post-stroke.
Lipid-lowering therapy: patients should be prescribed high dose atorvastatin 20-80 mg once nightly (irrespective of cholesterol level this lowers the risk of repeat stroke).
Tobacco: offer smoking cessation support.
Sugar: patients should be screened for diabetes and managed appropriately.
Surgery: patients with ipsilateral carotid artery stenosis more than 50% should be referred for carotid endarterectomy.
Lambert-Eaton Myasthenic Syndrome
auto-immune disorder characterised by antibodies against the pre-synaptic voltage-gated calcium channels.
Clinical features
Patients typically present with limb weakness and autonomic features (xerostomia, orthostatic hypotension, and impotence). Clues on examination include reduced or absent tendon reflexes that are potentiated by brief contraction of the relevant muscle (due to the build up of acetylcholine in the synaptic cleft with repeated contraction, overcoming the inhibitory effect of pre-synaptic voltage-gated calcium channel blockade).
Investigations
Bloods for anti-voltage-gated calcium channels
Nerve conduction studies will show a doubling of muscle action potential amplitude with exercise.
It is important to carry out further investigation, as guided by the history, to rule out underlying malignancy or autoimmune disease. Chest x-ray and CT chest, for example, should be carried out to rule out small cell lung cancer.
LEMS management
The mainstay of management is to address the underlying cause e.g. small cell lung cancer.
Amifampridine has been used to manage LEMS. Amifampridine blocks pre-synaptic potassium channels in the nerve terminals. This prevents potassium efflux, prolonging the action potential in the nerve terminal. This prolongs the opening time of voltage-gated-calcium channels, augmenting the release of acetylcholine in the synaptic cleft.
In severe respiratory impairment or bulbar weakness intubation and ventilation and plasma exchange/intravenous immunoglobulin (IVIG) may be necessary.
Medical third nerve palsy
ptosis (due to impaired innervation to levator palpebrae superioris) and a ‘down and out’ pupil (due to unopposed activation of lateral rectus and superior oblique).
In a ‘medical’ third nerve palsy there is pupil sparing. This is because the parasympathetic (constrictive) fibres run on the outside of the nerve. Medical lesions will affect the blood supply to the inner (motor) fibres of the nerve (the vasa vasorum), leaving the outer parasympathetic fibres intact.
The most common cause of a medical third nerve palsy is diabetes. Other causes include those that increase the risk of atherosclerosis, such as hypertension, and vasculitis.
Meralgia paresthetica
compression of the lateral cutaneous nerve of the thigh underneath the inguinal ligament. It is characterised by shooting pains along the outer aspect of the upper leg.
The four clinical groups are: MND
Spinal ALS (the classic MND syndrome)
Bulbar ALS (with early tongue and bulbar involvement)
Progressive muscular atrophy (with only lower motor neuron features)
Primary lateral sclerosis (with only upper motor neuron features).
Acute management of MS
An acute attack of multiple sclerosis should be treated with glucocorticoids.
1g of intravenous methylprednisolone every 24 hours for 3 days is a typical regimen, however oral courses are probably equally as effective. Infections must first be excluded.
Severe acute attacks who do not respond to glucocorticoids should be covered with plasma exchange.
While these interventions does not appear to affect long term outcome, it does appear to reduce the duration and severity of individual attacks.
In practical terms, it is usually necessary to involve the local neurology team for guidance on when to start steroids for patients with an acute flare of multiple sclerosis.
Always ensure to check routine bloods and urine dip to rule out any intercurrent infection.
Chronic management of MS
First-line injectables such as beta-interferon and glatiramer
New oral agents such as dimethyl fumarate, teriflunomide and fingolimod
Biologics such as natalizumab and alemtuzumab.
Myasthenia Gravis
antibodies against the nicotinic acetylcholine receptors on muscle fibres
weakness affecting limb muscles, extra-ocular muscles (drooping eyelids, diplopia), facial muscles (difficulty smiling or chewing), and bulbar muscles (change in speech or difficulty swallowing).
Myasthenia Gravis investigations
Investigations
Blood tests for serum acetylcholine receptor antibody (detected in 80-90% with generalised myasthenia gravis, >90% sensitivity in generalised myasthenia gravis, 99% specificity), muscle-specific tyrosine kinase antibodies (should be ordered if the acetylcholine receptor antibody is negative or equivocal).
Imaging investigations include CT of the chest (65% have thymic hyperplasia, 12% have a thymoma. This will inform the decision regarding consideration for thymectomy).
Special tests include repetitive nerve stimulation (in myasthenia gravis there is a >10% fall in muscle action potential between the 1st and 4th action potential in a series of 10 stimulations of the alpha motor neurone).
Myasthenia Gravis management
nservative management includes regular review in neurology outpatients, with involvement of the MDT as required (occupational therapist, physiotherapist, speech and language therapist if the patient suffers from dysarthria etc.)
Medical management is with immunosuppressive therapy (such as steroids, given acutely) and anticholinesterase inhibitors (such as pyridostigmine or neostigmine).
Acetylcholinesterase inhibitors (AKA anticholinesterases) inhibit the breakdown of acetylcholine in the synaptic cleft, increasing acetylcholine concentrations in the synaptic cleft, and increasing activation of nicotinic acetylcholine receptors at the neuromuscular junction. Acutely, intravenous immunoglobulin or plasmapheresis may be considered in severe, steroid-refractory, cases.
Side effects of acetylcholinesterase inhibitors include diarrhoea, salivation, lacrimation, and urinary frequency.
Surgical management with thymectomy is considered in some patients.
Neuromyelitis optica (Devic’s disease)
Optic neuritis
Transverse myelitis,
Positive NMO-IgG (an antibody targeting aquaporin 4..
Management
Management of Devic’s disease is with immunosuppression (e.g. with the anti-CD20 agent rituximab).
Optic neuritis
Visual loss
Periocular pain
Dyschromatopsia
first line of treatment for ON is intravenous methylprednisolone
simple first-step in the management of patients with raised ICP
Head elevation to 30º
typically spared in motor neurone disease
Eye movements
MS investigation
MR with contrast
tremor seen in Parkinson’s disease
unilateral tremor that improves with voluntary movement
Core features of Parkinson’s disease
Its core motor features include bradykinesia, asymmetric 3-5Hz “pill-rolling” tremor, and lead pipe rigidity.
The combination of lead pipe rigidity and tremor results in the phenomenon known as cogwheeling, a jerkiness felt when testing a patient’s tone.
Side effects of L-dopa
Common side effects include:
Hypotension
Restlessness
Gastrointestinal upset
In rare cases, dopamine excess can result in psychiatric reactions including acute psychosis.
Peripheral side effects are reduced by the co-administration of a peripheral dopa decarboxylase inhibitor, such as carbidopa.
A pseudobulbar palsy
bilateral lesion affecting the corticobulbar tracts (running from the motor cortex to the motor nuclei of cranial nerves 9, 10, and 12 in the medulla)
Clinical features
Clinical signs include a spastic tongue, a slow thick (“hot-potato”) speech, a brisk jaw jerk reflex, and emotional lability. Other upper motor neurone features in the limbs may be present e.g. spastic hypertonia, pyramidal weakness, and hyper-reflexia.
Features of pseudoseizures
Pseudoseizures (now known as psychogenic nonepileptic attacks, PNEAs) are often prolonged episodes (rarely <1 minute, often >30 minutes), usually in front of a witness during which the patient exhibits fluctuating motor activity and seizure-like convulsions. Tongue biting is rare. In equivocal cases, video EEG recording may be indicated to differentiate PNEAs from true seizures.
The extended differential diagnosis includes hemiplegic migraine, and cerebrovascular events, though consciousness is typically preserved and the neurological pattern of suggestive. In patients with true seizure activity and focal weakness, differentiating seizure plus Todd’s paresis from stroke with seizure at onset is difficult clinically and often requires imaging.
Suspect a spastic hemiparesis if the following signs are present:
unilateral spastic hypertonia, hyper-reflexia, ankle clonus, and upgoing plantar.
Central Causes of Spastic hemiparesis
auses of lesions in the cerebral hemisphere include: multiple sclerosis, a space-occupying lesion (such as a tumour or a cerebral abscess), a stroke, or hemiplegic cerebral palsy.
Peripheral Causes of Spastic hemiparesis
Causes of lesions in the hemicord include multiple sclerosis, cord compression (although this is more likely to present with bilateral upper motor neurone signs in the lower limbs).
Clinical Features of Spastic paraparesis
Spastic paraparesis presents with: lower limb spastic hypertonia, ankle clonus, pyramidal weakness (extensors stronger than flexors in the lower limbs), hyper-reflexia and upgoing plantars (upper motor neurone signs). There is scissoring gait.
Spinal Stenosis
Lumbar spinal stenosis is an important differential diagnosis for a patient with leg pain brought on by exercise, which is often misattributed to the intermittent claudication of peripheral vascular disease.
Neurogenic claudication more commonly manifests as proximal thigh or buttock pain, which is cramping in character and may be associated with other neurological symptoms such as burning or tingling.
It is worse with exercise, but is often not immediately relieved when standing still, and may be worse in extension (descending stairs) and improved in flexion (some patients describe being able to cycle far in excess of their exercise tolerance on foot).
Acute management of status epilepticus
Premonitory stage (0-10 minutes) - Diazepam 10−20 mg given rectally, repeated once 15 minutes later if status continues to threaten, or midazolam 10 mg given buccally. If seizures continue, treat as below.
Early status (0-30 minutes) - Lorazepam (intravenous) 0.1 mg/kg (usually a 4 mg bolus, repeated once after 10−20 minutes; rate not critical). Give usual AED medication if already on treatment. For sustained control or if seizures continue, treat as below.
Established status (0-60 minutes) - Phenytoin infusion at a dose of 15–18 mg/kg at a rate of 50 mg/minute or phosphenytoin infusion at a dose of 15−20 mg phenytoin equivalents (PE)/kg at a rate of 50–100 mg PE/minute and/or phenobarbital bolus of 10–15 mg/kg at a rate of 100 mg/minute.
Refractory status (30-90 minutes) - General anaesthesia, with one of:
Propofol (1–2 mg/kg bolus, then 2–10 mg/kg/hour) titrated to effect
Midazolam (0.1–0.2 mg/kg bolus, then 0.05–0.5 mg/kg/hour) titrated to effect
Thiopental sodium (3–5 mg/kg bolus, then 3–5 mg/kg/hour) titrated to effect; after 2–3 days infusion rate needs reduction as fat stores are saturated
Anaesthetic continued for 12−24 hours after the last clinical or electrographic seizure, then dose tapered.
Surgical third nerve palsy
In a ‘surgical’ third nerve palsy there is pupil involvement. This is because the parasympathetic (constrictive) fibres run on the outside of the nerve. External compression will impair function of these fibres, causing pupil dilation.
Benign positional paroxysmal vertigo (BPPV) features
The presence of debris in the semicircular canals of the ears causes vertigo upon head movement.
The Hallpike manoeuvre is diagnostic, where certain movements of the head causes fatiguable nystagmus.
Epley manoeuvres treat BPPV by clearing the debris.
Acute labyrinthiti
cute severe vertigo, which may be associated with vomiting.
plus hearing loss and tinnitus,
Ménière’s disease feature
Endolymphatic system pressure increases causes recurrent episodes of vertigo, sensorineural hearing loss, tinnitus, and a feeling of aural fullness.
Treatment involves antihistamines and bed rest.
Acoustic neuroma features
Actually a vestibular schwannoma.
They usually present with unilateral hearing loss and progress to involve cranial nerves 5, 6, 9, 10, and the ipsilateral cerebellum.
Visual field loss at Optic nerve:
Monocular visual loss
Visual field loss at Optic chiasm
Bitemporal hemianopia
Visual field loss at Optic tract
Contralateral homonymous hemianopia
Visual field loss at Optic radiation
Optic radiation (backward extension of the optic tract - from the lateral geniculate body of the thalamus to the ipsilateral primary visual cortex): Contralateral homonymous hemianopia
Visual field field loss at temporal lobe , parietal lobe, occipital lobe
A lesion in the temporal lobe would cause contralateral homonymous superior (upper) quadrantanopia
A lesion in the parietal lobe would cause contralateral homonymous inferior (lower) quadrantanopia
A lesion in the occipital lobe would cause contralateral homonymous hemianopia
pellagra
B3 def
3 d’s - dementia, dermatitis, diarrhoea
Causes of autonomic neuropathy includes:
Diabetes mellitus
Infections (including HIV, lyme and chagas)
Autoimmune disease (including SLE)
Amyloidosis
Myotonic dystrophy
myotonic dystrophy is a trinucleotide repeat disorder affecting muscle-specific chloride channels. It is inherited in an autosomal dominant pattern.
Clinical features: patients typically present in their 20s. It is useful to think of the clinical features from head to toe:
Features in the face: frontal balding, myopathic facies (a long and thin face), bilateral ptosis, cataracts.
Features in speech: dysarthria (caused by a myotonic tongue and pharyngeal muscles).
Features in the neck: wasted sternocleidomastoid muscles.
Features in the hands: distal wasting and weakness, slow relaxing grip, percussion myotonia (thumb flexion on percussion of the thenar eminence).
Internal features: insulin resistance/metabolic syndrome, cardiomyopathy/arrhythmia, testicular atrophy.
one treatment to extend life in MND
Riluzole
