Neurology Flashcards
What is MS?
MS is an acquired, immune-mediated inflammatory condition that affects both the brain and spinal cord.
It does not affect the peripheral nervous system.
MS is commoner in women
Typically occurs in temporal regions. Symptoms typically commence in early life (20s and 30s) in the form of visual or sensory disturbances.
Weakness and clumsiness of the limbs combined with bladder symptoms are common.
Typically the early symptoms will relapse and remit but over time progressive disability will occur.
It is thought to be an abnormal immune response to environmental triggers in people who are genetically predisposed.
It leads to immune-mediated demyelination in CNS neurones and ultimately nerve cell degeneration.
What are the variants of MS?
There are 3 main patterns of clinical presentation:
- Relapsing remitting.
- Secondary progressive.
- Primary progressive.
What is relapsing remitting MS?
Symptoms come and go. Periods of good health or remission are followed by sudden symptoms or relapses (80% of people at onset).
What is secondary progressive MS?
Follows on from relapsing-remitting MS. There are gradually more or worsening symptoms with fewer remissions (about 50% of those with relapsing-remitting MS develop secondary progressive MS during the first ten years of their illness).
What is primary progressive MS?
From the beginning, symptoms gradually develop and worsen over time (10-15% of people at onset).
Clinical presentation of MS
Optic neuritis.
Double vision.
Sensory disturbance in face or limbs.
Weakness due to upper motor neurone involvement.
Impaired balance between or clumsiness of the limbs.
Neuropathic pain (e.g. trigeminal neuralgia).
Bladder symptoms.
Cognitive impairment ( although this usually occurs late)
Presentation of optic neuritis
A visual disturbance evolves over a few days with distortion of the central vision and impairment of COLOUR perception.
There may be PAIN on eye movement.
VISUAL LOSS can be mild to severe.
Patients have a relative afferent pupillary defect and a CENTRAL SCOTOMA. .
The optic disc usually appears normal though may be swollen with papillitis.
Vision improves over months, though may be incomplete, particularly if visual loss was severe initially.
Optic atrophy may develop following an episode of optic neuritis
Trigeminal neuralgia - features
Trigeminal neuralgia symptoms may include one or more of these patterns:
- UNILATERAL
- Episodes of severe, shooting or jabbing PAIN that may feel like an ELECTRIC shock
- Spontaneous attacks of pain or attacks triggered by things such as touching the face, chewing, speaking or brushing teeth, washing, shaving, and frequently occurs SPONTANEOUSLY
- Bouts of pain lasting from a few seconds to several minutes - abrupt in onset and termination
- Pain in areas supplied by the trigeminal nerve, including the cheek, jaw, teeth, gums, lips, or less often the eye and forehead
- small areas in the nasolabial fold or chin may be particularly susceptible to the precipitation of pain (trigger areas)
- the pains usually remit for variable periods
Aetiology of MS
It is thought to be an abnormal immune response to environmental triggers in people who are genetically predisposed.
It leads to immune-mediated demyelination in CNS neurones and ultimately nerve cell degeneration. Initially, after the acute inflammatory stage, neurones may remyelinate and recover leading to
clinical remission. Recurrent episodes eventually lead to neuronal degeneration that, in turn, will produce a permanent clinical deficit.
Features of temporal lobe seizures?
(HEAD)
Hallucinations (auditory/gustatory/olfactory), Epigastric rising/Emotional, Automatisms (lip smacking/grabbing/plucking), Deja vu/Dysphasia post-ictal)
Features of Frontal lobe seizures?
(motor)
Head/leg movements, posturing, post-ictal weakness, Jacksonian march
Features of parietal lobe seizure ?
(sensory)
Paraesthesia
Features of occipital lobe seizure?
(visual)
Floaters/flashes
What is a juvenile myoclonic epilepsy?
Juvenile myoclonic epilepsy is a genetic GENERALISED epilepsy syndrome including ABSENCE, MYOCLONIC and generalised TONIC-CLONIC seizures.
Features of Extradural haemorrhage?
Usually caused by trauma - typically ‘low impact’
Usually in the TEMPORAL region as the thin skull at he pterion overlies the middle meningeal artery - venerable to injury
Appears as a biconvex on CT
Lucid interval
Tx of extradural haematoma?
Craniotomy and evacuation of the haematoma
Complication of extradural haematoma
As the haematoma expands the uncus of the temporal lobe HERNIATES around the tentorium cerebelli and the patient develops a FIXED and DIALTED pupil due to the compression of the parasympathetic fibers of the third cranial nerve.
Management of migraine during pregnancy
- paracetamol 1g is first-line
- aspirin 300mg or ibuprofen 400mg can be used second-line in the first and second trimester
Management of Migraine and the combined oral contraceptive (COC) pill?
If patients have migraine with aura then the COC is absolutely CONTRAINDICATED due to an increased risk of STROKE (relative risk 8.72)
Management of Migraine and menstruation?
Many women find that the frequency and severity of migraines increase around the time of menstruation
SIGN recommends that women are treated with MEFANAMIC ACID or a combination of aspirin, paracetamol and caffeine. TRIPTANS are also recommended in the acute situation
Management of Migraine and hormone replacement therapy (HRT)?
safe to prescribe HRT for patients with a history of migraine but it may make migraines worse
Left homonoymous hemianopia with macular sparing?
lesion at occipital cortex
As there is macular sparing, lesion likely to be at occipital cortex rather then optic tract
Bitemporal hemianopia
Lesion at the optic chiasm
e.g. patient could have a pituitary tumour causing compression of the optic chiasm and bitemporal hemianopia.
Secondary to acromegaly - have sweating and headaches (acromegaly is a hormonal disorder that develops when your pituitary gland produces too much growth hormone during adulthood)
family history of early blindness
developing ‘tunnel vision’.
??
Retinitis pigmentosa
Extensive pigmentations would be noted on fundoscopy
Visual field defects
- Left homonymous hemianopia means visual field defect to the left, i.e. Lesion of right optic tract
- Homonymous quadrantanopias: PITS (lesion in Parietal-Inferior, lesion in Temporal-Superior)
- incongruous defects = optic tract lesion; congruous defects = optic radiation lesion or occipital cortex
Neuropathic pain- examples
Neuropathic pain may be defined as pain which arises following damage or disruption of the nervous system. It is often difficult to treat and responds poorly to standard analgesia.
Examples include:
- diabetic neuropathy
- post-herpetic neuralgia
- trigeminal neuralgia
- prolapsed intervertebral disc
Management of neuropathic pain
first-line treatment*:
- amitriptyline, duloxetine, gabapentin or pregabalin
- if the first-line drug treatment does not work try one of the other 3 drugs
- tramadol may be used as ‘rescue therapy’ for exacerbations of neuropathic pain
- topical capsaicin may be used for localised neuropathic pain (e.g. post-herpetic neuralgia)
- pain management clinics may be useful in patients with resistant problems
*please note that for some specific conditions the guidance may vary. For example carbamazepine is used first-line for trigeminal neuralgia
Patients who present with falls soon after a diagnosis of Parkinson’s disease… what to do?
Investigate for alternative diagnoses.
- initial investigation - assessment of CN III,IV and VI
This is because a common sign of PSP (progressive supranuclear palsy), the most likely alternative diagnosis (and a ‘Parkinson’s plus’ syndrome), commonly manifests with a VERTICAL SUPRANUCLEAR GAZE PALSY.
Even if the diagnosis is not PSP, assessment of cranial nerves should be performed in anyone who presents with a fall.
Progressive supranuclear palsy
aka Steele-Richardson-Olszewski syndrome
a ‘Parkinson Plus’ syndrome
Features
- impairment of VERTICAL GAZE (DOWN gaze worse than up gaze - patients may complain of difficultly reading or descending stairs)
- parkinsonism
- falls
- slurring of speech
- cognitive impairment
Management
- poor response to L-dopa
Cluster headache
They typically occur in clusters lasting several weeks, with the clusters themselves typically once a year.
Cluster headaches are more common in men (3:1) and smokers. ALCOHOL may trigger an attack and there also appears to be a relation to nocturnal SLEEP.
Features
- 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)
- 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 headaches
Management
- acute: 100% oxygen (80% response rate within 15 minutes), SUBC triptan (75% response rate within 15 minutes)
triptans are contraindicated in patients with CAD as they have the potential to cause coronary vasospasm
- 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 is right?
To replace vit b12 first before folate or folate before vit b 12?
Always replace VITAMIN B12 BEFORE folate - giving folate to a patient deficient in B12 can precipitate SUBACUTE COMBINED DEGENERATION of the cord
Subacute combined degeneration of spinal cord
Due to vitamin B12 DEFICIENCY
- Dorsal + lateral columns affected
- Joint position and vibration sense lost first then distal paraesthesia
- upper motor neuron signs typically develop in the legs, classically extensor plantars, brisk knee reflexes, absent ankle jerks
- ## if untreated stiffness and weakness persistDamage to the posterior columns - loss of proprioception, light touch and vibration sense (sensory ataxia and a positive Romberg’s test).
Damage to lateral columns - spastic weakness and upgoing plantars (UMN signs).
Damage to peripheral nerves - absent ankle and knee jerks (LMN signs).
- When there is a mix of UMN and LMN signs in a patient, always consider SCDC.
------ Therefore the classic triad of symptoms is: 1. Extensor plantar response 2. Brisk knee jerks 3. Absent ankle jerks
What is Amyotrophic lateral sclerosis
A subtype of MND
May present with mixed UMN and LMN - no sensory deficits
Death of both upper and lower motor neurons in the motor cortex of the brain, the brain stem, and the spinal cord.
Myasthenia Gravis
Autoimmune disease affecting the neuromuscular junction so will NOT present with UMN signs or sensory loss.
Charcot-Marie-Tooth- features and overview
Charcot-Marie-Tooth disease is a hereditary SENSORY and MOTOR PERIPHERAL neuropathy. It results in a predominantly motor loss.
UMN signs are NOT present in these patients.
However, patients can present with LMN signs in all limbs and REDUCED SENSATION (more pronounced distally).
Charcot-Marie-Tooth Disease is the most common hereditary peripheral neuropathy
Features:
- There may be a history of frequently sprained ankles
- Foot drop
- High-arched feet (pes cavus)
- Hammer toes
- Distal muscle weakness
- Distal muscle atrophy
- Hyporeflexia
- Stork leg deformity
What needs to be considered when starting Phenytoin infusion?
CARDIAC monitoring is required due to the pro-arrhythmogenic effects it elicits.
Phenytoin
Phenytoin is used in the management of seizures.
Mechanism of action:
binds to sodium channels INCREASING their REFRACTORY PERIOD
Adverse effects:
Phenytoin is associated with a large number of adverse effects. These may be divided into acute, chronic, idiosyncratic and teratogenic.
Phenytoin is also an INDUCER of the P450 system.
Acute
- initially: dizziness, diplopia, nystagmus, slurred speech, ataxia
- later: confusion, seizures
- reduced sensation in a glove-and-stocking distribution
- reduced ankle reflex
Chronic
- common: gingival hyperplasia (secondary to increased expression of platelet derived growth factor, PDGF), hirsutism, coarsening of facial features, drowsiness
- megaloblastic anaemia (secondary to altered folate metabolism)
- peripheral neuropathy
- enhanced vitamin D
- metabolism causing osteomalacia
- lymphadenopathy
- dyskinesia
Idiosyncratic - fever - rashes, including severe - reactions such as toxic epidermal necrolysis hepatitis - Dupuytren's contracture* - aplastic anaemia - drug-induced lupus
Teratogenic
- associated with cleft palate and congenital heart disease
Monitoring
Phenytoin levels do not need to be monitored routinely but trough levels, immediately before dose should be checked if:
- adjustment of phenytoin dose
- suspected toxicity
- detection of non-adherence to the prescribed medication
*although not listed in the BNF
Normal pressure hydrocephalus - features
- Progressive mental impairment and dementia
- Difficulty walking
- Impaired bladder control
The gait disturbance is often the most noticeable symptom, it can resemble a parkinsonian gait but unlike Parkinson’s there is no rigidity or tremor.
Progressive supranuclear palsy
Starts with patients having IMPAIRED BALANCE and therefore being prone to many FALLS.
On examination, they have a VERTICAL GAZE PALSY. It has a SYMMETRICAL onset and is poorly responsive to levodopa, unlike Parkinson’s disease.
What does PSP stand for?
Progressive supra nuclear palsy
Corticobasal syndrome
Corticobasal syndrome begins as a MOVEMENT disorder, with a UNILATERAL ABSENCE of movements and muscle RIGIDITY with a TREMOR.
It is a progressive neurological disorder that can also affect cognition.
Multiple system atrophy
There are 2 predominant types of multiple system atrophy
1) MSA-P - Predominant Parkinsonian features
2) MSA-C - Predominant Cerebellar features
Shy-Drager syndrome is a type of multiple system atrophy.
Features
- parkinsonism
- autonomic disturbance (atonic bladder, postural hypotension, erectile dysfunction)
- cerebellar signs
Bulbar palsy
ONLY lower motor signs
UM signs are not present
Pseudobulbar palsy
Only present with UMN signs and not LMN signs.
Types of MND
Amyotrophic lateral sclerosis (50% of patients)
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
Primary lateral sclerosis
UMN signs only
Progressive muscular atrophy
LMN signs only
affects distal muscles before proximal
carries best prognosis
Progressive 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
(note: MND can initially present with limb weakness, it is progressive so wont resolve in a couple days)
Spontaneous intracranial hypotension
Low CSF can occur due to spontaneous intracranial hypotension (not necessarily post-LP) and are classically WORSE ON STANDING and improve when lying flat
Lack of associated features, all the other types of headache can be excluded.
Results from a CSF leak. The leak is typically from the thoracic nerve root sleeves.
Risk factors include connective tissue disorders such as Marfan’s syndrome.
Investigations:
MRI with gadolinium: typically shows pachymeningeal enhancement
Management:
usually conservative
if this fails an epidural blood patch may be tried
Which parkinson drugs are most associated with impulse control disorder?
Dopamine receptor agonists are associated with the highest chance of inhibition disorders out of the antiparkinsonian medications
Levodopa
Usually combined with a decarboxylase inhibitor (e.g. carbidopa or benserazide) to PREVENT PERIPHERAL metabolism of levodopa to dopamine
- reduced effectiveness with time (usually by 2 years)
- unwanted effects: DYSKINESIA (involuntary writhing movements), ‘on-off’ effect, dry mouth, anorexia, palpitations, postural hypotension, psychosis, drowsiness
- no use in neuroleptic induced parkinsonism
- it is important not to acutely stop levodopa, for example if a patient is admitted to hospital. If a patient with Parkinson’s disease cannot take levodopa orally, they can be given a dopamine agonist patch as rescue medication to prevent acute dystonia
Bell’s palsy
An ACUTE, UNILATERAL, idiopathic, facial nerve PARALYSIS. The aetiology is unknown although the role of the herpes simplex virus has been investigated previously. The peak incidence is 20-40 years and the condition is more common in pregnant women.
Features:
- LOWER motor neurone facial nerve palsy - FOREHEAD AFFECTED
- patients may also notice post-auricular PAIN (may precede paralysis), altered TASTE, DRY eyes, HYPERACUSIS
Management:
- PREDNISOLONE 1mg/kg for 10 days should be prescribed for patients within 72 hours of onset of Bell’s palsy. Adding in aciclovir gives no additional benefit
- EYE CARE is important - prescription of ARTIFICIAL TEARS and eye lubricants should be considered
Prognosis:
if untreated around 15% of patients have permanent moderate to severe weakness
Autonomic dysreflexia
This clinical syndrome occurs in patients who have had a SPINAL CORD INJURY at, or above T6 spinal level.
Briefly, AFFERENT signals, most commonly triggered by faecal impaction or urinary retention (but many other triggers have been reported) cause a SYMPATHETIC SPINAL REFLEX via thoracolumbar outflow.
The usual, centrally mediated, parasympathetic response however is prevented by the cord lesion. The result is an unbalanced physiological response, characterised by EXTREME HTN, FLUSHING and SWEATING above the level of the cord lesion, agitation, and in untreated cases severe consequences of extreme hypertension have been reported, e.g. haemorrhagic stroke.
The combination of severe hypertension, flushing and sweating WITHOUT a congruent response in heart rate in the context of spinal cord injury indicates an autonomic dysreflexia and this is an important presentation to be aware of as it is one of the few unique medical emergencies that can occur to spinal cord injured patients. There is often a clear NOXIOUS STIMULUS which has triggered the episode (in this case a catheter change).
- The cause of a dysreflexia is a discontinuity between the nociceptors (pain receptor - sensory neurone) on the viscera and the brain stem autonomic centres due to the cord injury.
- All the pain receptors on smooth muscle on the abdominal and some pelvic viscera are carried by the sympathetics and the specific nerve which extends to the pelvis is the greater splanchnic nerve (which has its lowest innervation at T6 and so this is the lowest level at which autonomic dysreflexia can still occur).
Management of autonomic dysreflexia involves removal/control of the stimulus and treatment of any life-threatening hypertension and/or bradycardia.
Autonomic dysreflexia occurs when?
Autonomic dysreflexia can only occur if the spinal cord injury occurs above the T6 level
Tuberous sclerosis
Tuberous sclerosis (TS) is a genetic condition of autosomal dominant inheritance. Like neurofibromatosis, the majority of features seen in TS are NEUROCUTANEOUS
Cutaneous features:
- DEPIGMENTED ‘ash-leaf’ SPOTS which fluoresce under UV light
- roughened PATCHES of skin over LUMBAR spine (Shagreen patches)
- adenoma sebaceum (angiofibromas): BUTTERFLY distribution over nose
- fibromata beneath nails (subungual fibromata)
- café-au-lait spots may be seen
Neurological features:
- developmental delay
- epilepsy (infantile spasms or partial)
- intellectual impairment
Also:
- retinal hamartomas: dense white areas on retina (phakomata)
- rhabdomyomas of the heart
- gliomatous changes can occur in the brain lesions
- polycystic kidneys, renal angiomyolipomata
- lymphangioleiomyomatosis: multiple lung cysts
Migraine: management
Acute treatment:
- first-line: offer combination therapy with an oral TRIPTAN and an NSAID
or an oral TRIPTAN and PARACETAMOL
- not effective or not tolerated offer a non-oral preparation of metoclopramide* or prochlorperazine and consider adding a non-oral NSAID or triptan
Prophylaxis:
prophylaxis should be given if patients are experiencing 2 OR MORE ATTACKS PER MONTH.
- Either TOPIRAMATE or PROPRANOLOL
Propranolol should be used in preference to topiramate in women of child bearing age as it may be teratogenic and it can reduce the effectiveness of hormonal contraceptives
if these measures fail NICE recommend ‘a course of up to 10 sessions of acupuncture over 5-8 weeks’ or gabapentin
NICE recommend: ‘Advise people with migraine that riboflavin (400 mg once a day) may be effective in reducing migraine frequency and intensity for some people’
for women with predictable menstrual migraine treatment NICE recommend either frovatriptan (2.5 mg twice a day) or zolmitriptan (2.5 mg twice or three times a day) as a type of ‘mini-prophylaxis’
pizotifen is no longer recommend. Adverse effects such as weight gain & drowsiness are common
*caution should be exercised with young patients as acute dystonic reactions may develop
General rule of acute treatment of migraine
As a general rule 5-HT receptor agonists are used in the acute treatment of migraine whilst
5-HT receptor antagonists are used in prophylaxis.
Acute treatment of cluster headache
SUBCUTANEOUS sumatriptan + 100% O2
First line long term prevention of cluster headaches
verapamil.
Red flag symptoms and signs of trigeminal neuralgia - suggests serious underlying cause
- SENSORY changes
- DEAFNESS or other ear problems
- History of skin or oral lesions that could spread perineurally
Pain only in the ophthalmic division of the trigeminal nerve (eye socket, forehead, and nose), or bilaterally - Optic neuritis
- A family history of multiple sclerosis
- Age of onset BEFORE 40 years
Management of trigeminal neuralgia
- CARBAMAZEPINE is first-line
- failure to respond to treatment or atypical features (e.g. < 50 years old) should prompt referral to neurology
Widespread convulsions without conscious impairment…
is likely to represent a pseudoseizure
Psychogenic non-epileptic seizures- features suggesting?
(pseudoseizure)
Factors favouring pseudoseizures:
- pelvic thrusting
- family member with epilepsy
- much more common in females
- crying after seizure
- don’t occur when alone
- GRADUAL onset
- remains conscious during whole-body convulsions
- no post-ictal state
- can remember what happened
Factors favouring true epileptic seizures
- tongue biting
- raised serum prolactin*
Video telemetry is useful for differentiating
C8 radiculopathy
Reduced sensation in C8 dermatome - medial side of hand over little finger
Weakness in the C8 myotome - flex of the vital interpahalngeal and maetacarpophalangeal joints
normal elbow flexion and thumb sensation - what nerve root?
C6
sensation of middle finger
C7
Which cervical root exits BELOW the vertebrae
C8
Where does C8 exit in relation to the vertebrae?
Below the vertebrae
- is the only one that does
Parkinson’s features
Parkinson’s disease is a progressive NEURODEGENERATIVE condition caused by degeneration of dopaminergic neurons in the substantia nigra.. This results in a classic triad of features: BRADYKINESIA , TREMOR and RIGIDITY. The symptoms of Parkinson’s disease are characteristically ASYMMETRICAL.
Bradykinesia:
poverty of movement also seen, sometimes referred to as hypokinesia
short, shuffling steps with reduced arm swinging
difficulty in initiating movement
Tremor:
most marked at rest, 3-5 Hz
worse when stressed or tired, improves with voluntary movement
typically ‘pill-rolling’, i.e. in the thumb and index finger
Rigidity:
lead pipe
cogwheel: due to superimposed tremor
Other characteristic features: mask-like facies flexed posture micrographia drooling of saliva psychiatric features: depression is the most common feature (affects about 40%); dementia, psychosis and sleep disturbances may also occur impaired olfaction REM sleep behaviour disorder fatigue autonomic dysfunction: postural hypotension
DRUG-induced parkinsonism has slightly different features to Parkinson’s disease:
motor symptoms are generally RAPID onset and BILATERAL
rigidity and rest tremor are uncommon
Diagnosis is usually clinical. However, if there is difficulty differentiating between essential tremor and Parkinson’s disease NICE recommend considering 123I‑FP‑CIT single photon emission computed tomography (SPECT).
Most common complication of bacterial meningitis
Sensorineural hearing loss
Hearing tests are routinely performed to assess this
Meningitis complications
SENSORINEURAL HEARING LOSS (most common)
other neurological: epilepsy, paralysis
infective: sepsis, intracerebral abscess
pressure: brain herniation, hydrocephalus
Myasthenia Gravis pathophysiology
autoantibodies to postsynaptic nicotinic acetylcholine receptors at the neuromuscular junction
Myasthenia Gravis and anaesthesia
There are significant implications in the administration of anaesthesia, in particular muscle paralysis.
What anaesthetic drug should be avoided in those with myasthenia gravis?
SUXAMETHONIUM
Suxamethonium is a depolarising NMBD - it acts by binding to Ach receptors and activating the receptor, at first causing muscle contraction, then paralysis - as they are desensitised and stop firing.
Again, due to a decreased number of available receptors for Sux to bind to, MG patients are typically resistant to depolarising NMBDs and may require significantly higher doses.
Therefore they should be used extremely cautiously, if at all, in myasthenic patients.
Myasthenia gravis: exacerbating factors
The most common exacerbating factor is exertion resulting in FATIGABILITY, which is the hallmark feature of myasthenia gravis . Symptoms become MORE MARKED DURING THE DAY
The following drugs may exacerbate myasthenia:
penicillamine
quinidine, procainamide
beta-blockers
lithium
phenytoin
antibiotics: gentamicin, macrolides, quinolones, tetracyclines
Myasthenia Gravis
Myasthenia gravis is an autoimmune disorder resulting in INSUFFICIENT FUNCTIONING ACETYLCHOLINE RECEPTORS
Myasthenia is more common in women (2:1)
The key feature is MUSCLE FATIGABILITY - muscles become progressively weaker DURING PERIODS OF ACTIVITY and slowly improve after periods of rest:
- extraocular muscle weakness: diplopia
- PROXIMAL muscle weakness: face, neck, limb girdle
- ptosis
- dysphagia
Associations
THYMOMAS in 15%
autoimmune disorders: pernicious anaemia, autoimmune thyroid disorders, rheumatoid, SLE
thymic hyperplasia in 50-70%
Investigations
- single fibre electromyography: high sensitivity (92-100%)
- CT thorax to exclude thymoma
- CK normal
- autoantibodies: around 85-90% of patients have antibodies to acetylcholine receptors. In the remaining patients, about about 40% are positive for anti-muscle-specific tyrosine kinase antibodies
- Tensilon test: IV edrophonium reduces muscle weakness temporarily - not commonly used anymore due to the risk of cardiac arrhythmia
Management - long-acting ANTICHOLINESTERASE INHIBITORS inhibitors e.g. PYRIDOSTIGMINE immunosuppression: - prednisolone initially - thymectomy
Third nerve palsy features
Features:
- eye is deviated ‘DOWN AND OUT’
- PTOSIS
- pupil may be DILATED (sometimes called a ‘surgical’ third nerve palsy)
Causes of third nerve palsy
Causes:
- diabetes mellitus
- vasculitis e.g. temporal arteritis, SLE
- false localizing sign* due to uncal herniation through tentorium if raised ICP
- posterior communicating artery aneurysm
- pupil dilated
- often associated pain - cavernous sinus thrombosis
- Weber’s syndrome: ipsilateral third nerve palsy with contralateral hemiplegia -caused by midbrain strokes
- other possible causes: amyloid, multiple sclerosis
*this term is usually associated with sixth nerve palsies but it may be used for a variety of neurological presentations
What supplementation is indicated in Parkinson’s?
Vitamin D
Essential tremor
autosomal dominant condition which usually affects both upper limbs
Features
- postural tremor (associated with a tremor present with sustained muscle tone): worse if arms outstretched
- improved by alcohol and rest
- most common cause of titubation (head tremor)
- it can also affect the vocal cords
Management
- PROPANOLOL is first-line
- primidone is sometimes used
Peripheral neuropathy
Peripheral neuropathy may be divided into conditions which predominately cause a motor or sensory loss
Peripheral neuropathy - Predominately motor loss
Guillain-Barre syndrome
porphyria
lead poisoning
hereditary sensorimotor neuropathies (HSMN) - Charcot-Marie-Tooth
chronic inflammatory demyelinating polyneuropathy (CIDP)
diphtheria
Peripheral neuropathy - Predominately sensory loss
diabetes uraemia leprosy alcoholism vitamin B12 deficiency amyloidosis
Alcoholic neuropathy
- secondary to both direct toxic effects and reduced absorption of B vitamins
- sensory symptoms typically present prior to motor symptoms
Vitamin B12 deficiency - neurological symptoms
- subacute combined degeneration of spinal cord
- dorsal column usually affected first (joint position, vibration) prior to distal paraesthesia
Facial nerve supplies…
‘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 nerve 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 of bilateral palsy, but this represents only 1% of total Bell’s palsy cases
Causes of unilateral facial nerve palsy
Lower motor neuron:
- Bell’s palsy
- Ramsay-Hunt syndrome (due to herpes zoster)
- acoustic neuroma
- parotid tumours
- HIV
- multiple sclerosis (may also cause UMN palsy)
- diabetes mellitus
Upper motor neuron
- stroke
LMN vs. UMN
face
upper motor neuron lesion ‘spares’ upper face i.e. forehead
lower motor neuron lesion affects all facial muscles
Branches of the facial nerve
3 branches:
- greater petrosal nerve
- nerve to stapedius
- chorda tympani
Intracranial venous thrombosis- features, causes and more
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
Features
headache (may be sudden onset)
nausea & vomiting
Sagittal sinus thrombosis
may present with seizures and hemiplegia
parasagittal biparietal or bifrontal haemorrhagic infarctions are sometimes seen
Cavernous sinus thrombosis
other causes of cavernous sinus syndrome: local infection (e.g. sinusitis), neoplasia, trauma
periorbital 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
What will lesions of T1 cause?
Causes finger abduction weakness
It affects thumb adduction and finger abduction) and a loss of sensation over the medial epicondyle
results in is Klumpke’s paralysis.
Klumpke’s paralysis
damage to T1
loss of intrinsic hand muscles
due to traction
Definition of an ataxic gait
A WIDE-based gait with loss of heel to toe walking
Causes of ataxic gait
Typically occur following cerebellar injury, the causes can be remembered by the mnemonic ‘pastries’
P - Posterior fossa tumour A - Alcohol S - Multiple sclerosis T - Trauma R - Rare causes I - Inherited (e.g. Friedreich's ataxia) E - Epilepsy treatments S - Stroke
Management of bell’s palsy
Prednisolone
Eye care - artificial tears and eye lubricants
Common reflexes
Ankle S1-S2
Knee L3-L4
Biceps C5-C6
Triceps C7-C8
Syringomyelia
Presents with CAPE-like LOSS of PAIN and TEMPERATURE due to COMPRESSION of the SPINOTHALAMIC tract fibres decussating in the anterior white commissure of the spine
Syringomyelia
Syringomyelia is a condition whereby fluid filled cavities develop within the spinal cord. Pressure can increase resulting in compression of the spinal cord tracts.
(The syrinx can extend to and damage the anterior horn cells, thereby resulting in lower motor neurone features. The spinothalamic tract axons decussate to the other side of the spinal cord via the anterior white commissure, and they are particularly susceptible to damage from the syrinx. Pain and temperature sensation are lost due to spinothalamic tract damage, and one side may be affected more than the other. Classically, the sensation loss is experienced in a shawl-like distribution over the arms, shoulders and upper body. Light touch, vibration and proprioception may also be affected as the syrinx enlarges into the dorsal columns.)
Causes include:
- a Chiari malformation: strong association
- trauma
- tumours
- idiopathic
The classical presentation of a syrinx is a patient who has a ‘CAPE-like’ (neck and arms) loss of SENSATION to but 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.
Other symptoms and signs include SPASTIC WEAKNESS (predominantly of the upper limbs), paraesthesia, neuropathic pain, UPGOING PLANTARS and bowel and bladder dysfunction.
Scoliosis will occur over a matter of years if the syrinx is not treated. It may cause a Horner’s syndrome due to compression of the sympathetic chain, but this is rare.
Investigation requires a full SPINE MRI with contrast to exclude a tumour or tethered cord. A brain MRI is also needed to exclude a Chiari malformation.
Treatment will be directed at treating the cause of the syrinx. In patients with a persistent or symptomatic syrinx, a shunt into the syrinx can be placed.
Wernicke’s encephalopathy
Wernicke’s encephalopathy is a neuropsychiatric disorder caused by THIAMINE DEFICIENCY which is most commonly seen in ALCOHOLICS.
Rarer causes include: persistent vomiting, stomach cancer, dietary deficiency.
A classic triad of ophthalmoplegia/nystagmus, ataxia and confusion may occur.
In Wernicke’s encephalopathy petechial haemorrhages occur in a variety of structures in the brain including the mamillary bodies and ventricle walls
Features
- nystagmus (the most common ocular sign)
- ophthalmoplegia
- ataxia
- confusion, altered GCS
- peripheral sensory neuropathy
Investigations
- decreased red cell transketolase
- MRI
Treatment is with urgent REPLACEMENT OF THIAMINE
What can happen if Wernicke’s encephalopathy is untreated.?
Korsakoff’s syndrome may develop as well.
This is termed Wernicke-Korsakoff syndrome and is characterised by the addition of antero- and retrograde AMNESIA and CONFABULATION in addition to the symptoms of Wernicke’s (nystagmus, opthalmoplegis,ataxia)
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
- non-communicating hydrocephalus may develop as a result of obstruction of cerebrospinal fluid (CSF) outflow
- headache
- syringomyelia
Charcot-maire-tooth disease - what it affects?
Can affect both MOTOR and SENSORY PERIPHERAL nerves
Duchenne muscular dystrophy
Inherited myopathy.
It is caused by progressive degeneration and weakness of SPECIFIC MUSCLE GROUPS.
- Most patients lose the ability to walk by 12 years of age and require ventilatory support by the age of 25.
- Sensation is intact in these patients.
Cervical spondylosis
Term used for OSTEOARTHRITIS of the SPINE and can result in COMPRESSION of the SPINAL CORD.
This is more likely to result in LMN signs at the level of the compression (ie. upper limb if the lesion is below C5) with UMN signs below (in the lower limb).
Patients usually complain of neck pain and stiffness.
Subacute combined degeneration of the cord -summary
- Ataxic Gait - due to degeneration of the dorsal columns
- Mixed UMN and LMN signs - due to degeneration of lateral motor tracts and peripheral nerves
- Subacute history - occurs over months
- Often notice sensory symptoms before weakness
Hereditary sensorimotor neuropathy (HSMN)
Term which encompasses Charcot-Marie-Tooth disease (also known as peroneal muscular atrophy).
HSMN type I: primarily due to demyelinating pathology - features
- 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
Multiple system atrophy vs Parkinson’s
UNILATERAL Parkinsonism + severe AUTONOMIC DISTURBANCE (postural hypotension/erectile dysfunction).
- more likely to be multiple system atrophy than Parkinson’s disease
Progressive supranuclear palsy has…
The presence of ocular pathology
Pabrinex
contains vitamins B and C.
It does not vitamin D.
Vitamin B1
Vitamin B1, also called thiamine, is essential for GLIAL cells of the nervous system, as well as other bodily systems.
Deficiency can cause Wernicke’s encephalopathy and if left untreated can lead to irreversible Korsakoff’s syndrome.
Vitamin B1 AKA…
Thiamine
