Neurology Flashcards
Guillain Barre syndrome presents how long after an URTI or gastroenteritis
1-4 weeks
Pathogens associated with Guillain Barre syndrome
Viral - CMV, EBV, HIV, influenza, HSV, cytomegalovirus
Bacteria - campylobacter, mycoplasma pneumoniae, E.coli
Parasites - toxoplasmosis
Non-infectious triggers for Guillain Barre syndrome
Systemic illness - Hodgkins lymphoma, CLL, hyperthyroidism, sarcoid, renal disease
Pregnancy
Surgery
Immunisation
Pathogenesis of Guillain Barre syndrome
Post-infectious autoimmune reaction that generates cross-reactive antibodies (molecular mimicry)
Clinical features of Guillain Barre syndrome
Symmetrical/bilateral ascending flaccid paralysis, stocking glove distribution from lower limbs to upper limbs
Back and limb pain
Neuropathic pain
Peripheral symmetrical paraesthesia hands/feet
Reduced/absent reflexes
Cranial nerve involvement - bilateral facial nerve paralysis/facial diplegia, ophthalmoplegia - Miller Fisher syndrome
Involvement of respiratory muscles
Voiding dysfunction
Intestinal dysfunction
Arrhythmia
CSF findings in Guillain Barre syndrome
Cytoalbuminologic dissociation - normal cell count but raised protein level
Cell counts <50
Antibodies associated with Guillain Barre syndrome
Anti-GM1 antibodies (antibodies directed against gangliosides)
What happens to nerves in Guillain Barre syndrome
Demyelination
Differential diagnosis for Guillain Barre syndrome
Acute myelopathies (would have sensory levels and bowel/bladder involvement)
Botulism (would be descending)
Diphtheria
Lyme disease
Porphyria (would have abdo pain and prominent ANS fluctuation)
Management of Guillain Barre syndrome
Monitor cardiac and respiratory function Consider ICU/HDU care VTE prophylaxis High dose IV immunoglobulins Plasmapheresis
Prognosis of Guillain Barre syndrome
Progression peaks around 2-4 weeks after symptom onset
Symptoms recede in reverse order of their development
80% recover by 6 months
3-5% mortality
15% get severe disability
At how many weeks does disability peak in a) acute b) subacute c) chronic Guillain Barre syndrome
a) 4 weeks
b) 4-8 weeks
c) >8 weeks
Features that suggest an UMN lesion
Increased tone (spasticity) Weakness (variable) Brisk reflexes Sustained clonus Babinski reflex
Features that suggest a LMN lesion
Decreased/normal tone Weakness Reduced/absent reflexes Muscle wasting Fasciculations No pathological reflexes
GBS mimics
Poliomyelitis: prodromal flu symptoms, rapid deterioration, proximal > distal asymmetrical paralysis, no sensory deficit, recent travel
Enterovirus 71: prodromal illness, acute flaccid paraparesis, outbreaks in Australia and Cambodia
Rabies: acute flaccid paraparesis 1-2 months after exposure
C
Acute transverse myelitis
Anterior spinal artery occlusion
What blood tests would you order if a patient presents with limb weakness
FBC U+E LFTs CRP/ESR K Ca PO4 Mg
Inheritence pattern of Charcot-Marie-Tooth
Autosomal dominant
What is the most common inherited peripheral neuropathy
Charcot-Marie-Tooth
Features of Charcot-Marie-Tooth
Predominantly distal weakness Distal muscle wasting Sensory loss Proximally progresses Foot deformities - pes cavus, high arch, hammer toes, pes plantus
Causes of a predominant sensory loss with a glove and stocking distribution
Diabetes
Alcohol
B12 deficiency
Features of carpal tunnel
Pain and paraesthesia in the distribution of the medial nerve
Tinnels test positive
Phalens test positive
Where do you insert the needle for lumbar puncture
Above or below L4
Risks of lumbar puncture
Post lumbar puncture headache Infection Bleed Neuropathy Brain herniation
Description of CSF in MS
Clear
Normal pressure, lactate, glucose
Normal/slightly raised protein
WBCs raised <50
Description of CSF in GBS
Clear
Normal pressure, lactate, glucose
Really high protein
WBC raised <10
Description of CSF in SAH/stroke
Bloody/pink/yellow (xanthochromia) Pressure normal/slightly increased Normal lactate and glucose Raised gamma globulin protein Raised RBCs and WBCs
Lumbar puncture is most sensitive for SAH if performed how long after symptom onset?
12 hours
Description of CSF in bacterial meningitis
WBCs really raised >100-5000 Neutrophil predominant Raised protein Very low glucose Very low CSF:plasma glucose ratio
Description of CSF in viral meningitis
WBCs raised 5-1000 Lymphocyte predominant Mildly raised protein Normal/low glucose Normal/low CSF:plasma glucose ratio
What is Bells Palsy
An acute facial nerve palsy
Cause unknown but thought to be viral
Diagnosis of exclusion
Prognosis of Bells Palsy
70% completely recover (without treatment). 13% minor permanent, 16% major permanent
Onset of Bells Palsy
Evolved within 72hours
Symptoms may worsen in the first few days
When does recovery tend to start after Bells Palsy
4-6 months after symptom onset
What features would make Bells Palsy less likely to be the diagnosis of facial droop
Forehead sparing
Waxing and waning
Facial zones unevenly affected
Differential diagnosis for Bells Palsy
Stroke
Ramsay Hunt Syndrome
Lyme disease
Facial nerve schwannoma (benign facial tumour)
Management of Bells Palsy
Steroids early on
Consider Acyclovir
Tape eye shut at night
Artificial tears
What is Ramsay Hunt syndrome
Herpez zoster (shingles) affecting the geniculate ganglion of the facial nerve
What can trigger reactivation of shingles
Immunosuppression
Stress
Clinical features of Ramsay Hunt syndrome
Rash/blisters in or around ear, scalp, hair line, inside mouth
Painful
Generalised burning sensation in the area
Unilateral facial weakness, drooping, difficulty closing eye/blinking, altered taste, difficulty eating/drinking/speaking
Hearing loss, dizziness, vertigo, tinnitus
Management of Ramsay Hunt syndrome
Acyclovir ASAP (ideally within 3 days of symptom onset) Short course of high dose steroids Analgesia - consider neuropathic agents
Prognosis of Ramsay Hunt syndrome
If treated within 3 days 70% fully recover
If treatment delayed >3 days then 50% fully recover
Recovery pattern similar to Bells Palsy
You would refer someone with Ramsay Hunt to a specialist if there is no improvement in facial nerve palsy after how long?
1 month
You would refer someone with Ramsay Hunt to an ophthalmologist if they still can’t close their eye after how long?
2-3 weeks
Differentials for loss of consciousness
Vasovagal syncope Cardiogenic syncope Unprovoked seizure/epilepsy Provoked seizure - substance abuse or withdrawal Non-epileptic attack disorder Migraine events Vestibular disorders TIA
Difference between a simple and complex partial seizure
Simple - fully aware throughout
Complex - consciousness/awareness impaired during the event
Features of temporal lobe seizures
Memory disturbance such as déjà vu
Olfactory and auditory hallucinations
A feeling of a rising epigastric sensation/fear
Bizarre psychic phenomena such as derealisation and depersonalisation and even attacks of elation.
Automatisms: absent-mindedly plucking at clothes, lip-smacking, repetitive mumbling or repetition of a stereotypical phrase. More complex automatisms can occur (for example getting undressed), with no or only partial awareness/recollection subsequently
What is mesial temporal sclerosis
Atrophy and scarring in the temporal lobe, typically hippocampus
Is a cause and effect of temporal lobe seizures/epilepsy
Gliosis (structural lesion) can be seen on MRI
Risk factors for patients with epilepsy having a seizure
Intercurrent illness (chest infection, UTI – check temp + inflammatory markers)
Missing medication (common cause of breakthrough seizure)
New meds that interact with anticonvulsants or lower seizure threshold (tramadol and amitriptyline lower seizure threshold)
Alcohol excess acute binge/chronic heavy drinking (withdrawal seizures)
Use of recreational drugs
Hyponatraemia
Hypoglycaemia
Broken sleep/fatigue/jetlag
GI disturbance that alters absorption
NB: photosensitive epilepsy syndromes are small minority
Sodium Valproate can have serious interactions with which other anticonvulsant?
Lamotrigine
How do you change a patients anticonvulsants
Gradually reduce the dose of one whilst simultaneously gradually increasing the dose of the new one
DVLA advice regarding changing anticonvulsants
If have breakthrough seizure have to stop driving and inform DVLA + licence withheld for 6 months. The DVLA recommend, (but do not legally enforce) that when a patient is changing epilepsy drugs that they stop driving during the changeover period and for six months thereafter: this is because of the recognised risk of breakthrough seizures
If a patient is changing epilepsy meds, what sort of activities do they need to be careful of due to the risk of breakthrough seizures
Working at height, cycling in traffic, working with dangerous machinery, or being alone beside deep water, less obvious things like taking a bath (shower with door open or someone nearby), parents with young children may have to consider activities such as help supervising the child’s bath-time
Definition of epilepsy
Two or more unprovoked seizures separated by more than 24 hours, One unprovoked seizure with an underlying predisposition to seizures (recurrence risk over the next 10 years that is similar to the recurrence risk after two unprovoked seizures), Diagnosis of an epilepsy syndrome
Causes of provoked seizures
Metabolic and electrolyte disturbances: hypoglycemia and hyperglycemia, hyponatremia and hypernatremia, hypocalcemia, uremia, thyroid storm, hyperthermia, water intoxication
Mass: brain tumors and metastases, hippocampal sclerosis
Withdrawal: Alcohol withdrawal (most common trigger in adults), noncompliance with anticonvulsant treatment, medication withdrawal
Intoxication: cocaine, ecstasy, carbon monoxide poisoning, metal poisoning
Meds: amitriptyline, penicillin, maprotiline, lithium, lidocaine, antipsychotics, theophylline
Infections: encephalitis, brain abscess, meningitis, septic shock
Ischemia: stroke, perinatal injuries
Trauma: traumatic brain injury
Increased ICP and cerebral edema: eclampsia, hypertensive encephalopathy, cerebrovascular malformation
Fever in infants and children (see febrile seizures)
What is Todds paralysis
Post-ictal weakness or paralysis of the affected limb or facial muscles. Lasts for minutes up to hours
When do tonic seizures often occur
When the person is drowsy/asleep/waking up
What is a relative afferent pupillary defect and how do you detect it
Its a sign of optic (CNII) neuropathy
Detected with swinging light test - in normal circumstances the pupil remains constricted because of equal direct (light shone into that eye) or indirect (light shone into the other eye) stimulation. In an eye affected by optic neuropathy the pupil paradoxically dilates when light is shone into that eye as the direct stimulus (light via ipsilateral damaged optic nerve) is weaker than the indirect stimulus (light via intact contralateral optic nerve).
Differentials for optic neuritis
MS
B12 deficieny
Systemic inflammatory diseases
Infection (rare)
MRI findings of MS
High signal lesions in the periventricular white matter - represent demyelination
Lesions perpendicular with long axis of lateral ventricles
How can cerebellar lesions affect speech
Can cause staccato speech
What is L’Hermitte’s phenomenon
A sudden electric shock like sensation radiating down and up the spine, provoked by flexion and extension of the neck
It is a characteristic symptom of a patch of inflammation in the cervical spinal cord
Which medication can be used to ease spasticity
Baclofen
Dantrolene
Which medication can be used for neurogenic bladder (common in MS)
Oxybutinin (anticholinergic)
What is MS
A chronic degenerative CNS disease
Auto-immune inflammatory demyelination of white matter in brain and spinal cord
Mean age onset of MS
20-40
Clinical features of multiple sclerosis
Optic neuritis - impaired vision, colour blindness
Internuclear ophthalmoplegia (INO) - affected eye has impaired adduction and when they try the other eye gets nystagmus
Lhermitte’s sign
Absent abdominal reflex
Pyramidal tract lesion - UMN signs
Dorsal column lesion - loss of vibration and fine touch, numbness, paraesthesia, sensory ataxia
Cerebellar - staccato speech, nystagmus, intention tremors
Cranial nerve palsies
Autonomic dysfunction
Cognitive changes
Uhthoff’s phenomenon
What is Uhthoff’s phenomenon
A feature of MS (but can also be triggered by a viral infection)
A reversible exacerbation of neurological symptoms following physical exertion, a warm bath, or fever
What contrast can be used with MRI to differentiate old Vs new MS lesions
Gadolinium contrast
Electrophoresis of CSF in MS shows what
Oligoclonal bands
What are the 3 main types of MS
Relapsing remitting
Secondary progressive
Primary progressive
Definition of an MS relapse/exacerbation
New symptoms or significant worsening of existing symptoms, both of which last at least 24 hours and are preceded by at least 30 days of relative clinical stability
Escalation Vs induction therapy for MS
Escalation - you start with disease modifying drugs first then use stronger meds if not controlled
Induction - if severe at presentation, use strong meds/immunosuppressants at first then long term maintenance with disease modifying drugs
What meds can be used for painful paraesthesias in MS
Carbamazepine
Amitriptylline
How does pregnancy affect MS
Decreased rate of relapses during pregnancy but higher rate in the postpartum period
Long-term clinical course doesn’t change
Treatment for an acute exacerbation of MS
High dose glucocorticoids (methylprednisolone)
Second line: plasmapheresis
Main drug used as a disease-modifying-drug for MS
Interferon beta
