Neurology Flashcards
Mechanism of action of sumatriptan?
5-HT1 agonist
How soon after LP do post-LP headaches usually develop and what is the mechanism?
Usually within 3 days
Worsens when upright
Thought to be due to leakage of CSF from the dura - when withdrawing the stylet a piece of the arachnoid can be pulled through, keeping the dural hole open
What can you treat post-LP headache with if needed?
Blood patch, epidural saline, IV caffeine
What are the symptoms of brachial neuritis?
Acute onset of unilateral severe pain, followed by shoulder and scapular weakness several days later
May be wasting of the arm muscles
What is the treatment for brachial neuritis?
Self-resolves, prognosis is good
What is the pathophysiology of GBS and most common Abs responsible?
Infection causes a production of Abs which attack the bodys nerve myelin (molecular mimicry). This demyelination then causes an acute, inflammatory, ascending polyneuropathy of peripheral nerves.
Anti-GM1 Abs in 25%
What is the most common/other infections that can cause GBS?
Campylobacter jejuni
CMV
Mycoplasma etc
What are the symptoms of GBS?
1-2 weeks post-infection: symmetrical, ascending muscle weakness +/- numbness
Progresses from distal to proximal over 4 weeks
Can get loss of reflexes, develop neuropathic pain and autonomic dysfunction (sweating, tachy etc)
In 20%, resp muscle and facial muscles are affected
What are the investigations in GBS?
LP: increased proteins, WCC normal
Nerve conduction studies: slow nerve conduction (due to lack of myelin), prolonged distal motor latency and increased F wave latency
Spirometry to monitor FVC
Management and prognosis of GBS?
IVIg
Can also do plasma exchange but less common
Monitor respiratory function
15% have ongoing muscle weakness
5% die
Poor prognostic factors associated with GBS?
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
What is Miller Fisher syndrome? Triad of symptoms? Antibody?
Variant of GBS
Opthalmoplegia, ataxia, areflexia
Usually a descending paralysis
Anti-GQ1b positive in 90%
What is the management of medication-overuse headaches?
simple analgesics and triptans should be withdrawn abruptly (may initially worsen headaches)
opioid analgesics should be gradually withdrawn
When does neuroleptic malignant syndrome occur and what are the symptoms?
Occurs within a few days of starting antipsychotic
fever
muscle rigidity
autonomic lability: typically HTN, tachycardia and tachypnoea
Confusion
Investigations (e.g. blood test) and management in neuroleptic malignant syndrome?
Raised CK
Mx: stop drug, IV fluids to prevent renal failure
Can treat with dantrolene or bromocriptine
What is the pathophysiology and symptoms of acoustic neuromas?
- Usually benign SOLs arising from proliferation of Schwann cells around the nerve
- Many are symptomless and only found on autopsy
Unilateral SN hearing loss
Unilateral tinnitis
Vertigo
Absent corneal reflex
CN VIII: vertigo, unilateral sensorineural hearing loss, unilateral tinnitus
CN V: absent corneal reflex
CN VII: facial palsy
Investigations and management of acoustic neuromas?
Audiometry
MRI
Mx is with either surgery, radiotherapy or observation
What is Creutzfeldt-Jakob disease (CJD)?
A rapidly progressive neurological condition caused by PRION proteins. These proteins misfold and induce the formation of amyloid folds resulting in tightly packed beta-pleated sheets resistant to proteases.
sporadic: accounts for 85% of cases
10-15% of cases are familial
mean age of onset is 65 years
What are the features of Creutzfeldt-Jakob disease (CJD)?
dementia (rapid onset)
behavioural changes
Focal signs
myoclonus
(think of the woman found wandering the streets)
Investigations 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
Which should you replace first, B12 or folate?
B12
What are the symptoms of subacute degeneration of the spinal cord?
UMN + LMN signs
Investigations in MS? Diagnostic criteria?
Visual evoked potential studies - delayed nerve conduction
MRI FLAIR scan - periventricular lesions, >90% show white matter irregularities, see Dawson’s Fingers
CSF - oligoclonal bands of IgG, increased protein
Over 2 CNS lesions disseminated in time and space
What type of MRI scan should be performed to visualise thyroid Abs in thyroid eye disease?
MRI STIR