General neurology Flashcards
What % of those with ALS have FTD?
13%
What is the major genetic cause shared by ALS and FTD?
C9orf72
TDP-43 is found in which diseases?
FTD and ALS
What is Onuf’s nucleus responsible for?
Sphincter control
How do triptans work (in migraine)?
Activators of 5-HT receptors, 1B/1D/1F
What options are available for migraine prophylaxis?
Amitriptyline, nortriptyline, pizotifen, candesartan, propranolol, sodium valproate, topiramate, verapamil
Which nerves pass through the jugular foramen?
IX, X, XI
What passes through the cavernous sinus?
CN III, IV, V1, V2, VI
What causes autonomic dysreflexia?
Spinal cord injuries above T6.
- HTN and bradycardia
- Below T6 allows splanchnic innervation and therefore dilatation to bring down BP
What are the common side effects of phenytoin?
Gingival hyperplasia, hirsutism, rash, folic acid depletion, osteoporosis, cerebellar signs
What is the prognosis at diagnosis?
3-5 years
What does reinnervation look like on EMG?
High amplitude CMAPs
How is conduction block defined on Nerve Conduction Studies?
A reduction in CMAP area/amplitude of at least 20% compared with distal CMAP area/amplitude.
The duration of the proximal CMAP should not increase by >20% (see temporal dispersion)
Which antibody is multifocal motor neuropathy associated with?
anti-GM1
How is primary lateral sclerosis distinguishable?
Affects upper motor neurons only
How is progressive muscular atrophy distinguishable?
Affects lower motor neurons only
What are the 2 most commonly found mutations in ALS?
C9orf72 and SOD1
How is EPHA4 implicated in prognosis in ALS?
Lower EPHA4 = longer survival
Which exposure is the strongest risk factor for ALS?
Military service.
How does riluzole work in ALS?
Suppresses excessive motor neuronal firing
How does edaravone work in ALS?
Suppresses oxidative stress
What is the treatment for cluster headaches?
Acute: 100% O2, triptan
- Severe refractory => indomethacin or dihydroergotamine
Bridging: prednisone or occipital nerve block with methylpred
Prophylactic: Verapamil
What is the genetic mutation responsible for Wilson’s disease?
ATP7B mutation on chromosome 13 (autosomal recessive)
Which mutation is associated with the highest risk of multiple sclerosis?
HLA DRB1*1501
Other risk = *0801
What is first line treatment in primary progressive MS and what is its mechanism of action?
Ocrelizumab - fully humanised anti-CD20 that suppresses B cell
What does downbeating nystagmus represent?
Lesion in the foramen magnum
What does upbeating nystagmus represent?
Lesion in the midbrain or floor of the fourth ventricle
How do you distinguish between myositis and myopathy on EMG?
Spontaneous firing in myositis, but not myopathy
What are the causes of predominantly sensory neuropathy?
Diabetes B12 deficiency Uraemia HIV Malignancy Sjogren's Hereditary sensory and autonomic neuropathy Amyloid
What are the causes of predominantly motor neuropathy?
AIDP Acute motor axonal neuropathy Hereditary motor and sensory neuropathy Lead Porphyria Multifocal motor neuropathy Diphtheria Diabetic Amyloid
Painful neuropathy
EtOH Diabetes Cryoglobulinaemia HIV Paraneoplastic GBS B6 toxicity Amyloid
Which antibodies may be positive in GBS?
GM1, GM2 and GD1
What is the triad found in Miller-Fisher and what is the antibody associated with it?
Ataxia, ophthalmoplegia and areflexia
Anti-GQ1
What does CSF show in GBS and CIDP?
Albuminocytologic dissociation - high protein / low cells
What is the treatment for GBS?
IVIG or plasma exchange
What are the treatment options for CIDP?
Steroids
IVIG or plasma exchange
Steroid-sparing agents: AZA or MMF (faster action)
In which variant of CIDP is asymmetry classic?
MADSAM
What is POEMS? Which serum level is diagnostic?
Polyneuropathy Organomegaly Endocrinopathy Monoclonal protein Skin changes
VEGF level is doagnostic
What pedal changes would be seen in Charcot-Marie-Tooth disease?
Pes cavus
Hammer toes
What is the mutation responsible for hereditary sensitivity to pressure palsies (HSPP)?
PMP22
- Prolonged distal motor latencies
What does nerve biopsy show in Charcot-Marie-Tooth disease?
Onion bulbs
Where is a biopsy taken form for diagnosis of amyloidosis? What does it show?
Fat pad
Apple-green birefringence on congo red stain
What are the treatment options for diabetic neuropathy?
1 Amitriptyline,
2 duloxetine or pregabalin or gabapentin
What are the features of Morvan Syndrome and which antibody is implicated?
Features:
- Fasciculations
- Paraesthesia
- Thymoma
- Encephalophathy
- Neuromyotonia
Antibody:
- Caspr-2 => directed at Voltage-gated K channels
Which antibodies are implicated in 60% of cases of stiff person syndrome?
Anti-GAD
What antibodies are associated with myasthenia gravis?
ACh receptor Ab - 80-90% sensitive MuSK Ab - positive in 40% of AChR-negative patients. - more severe weakness, not affecting eyes or limbs - not associated with thymic disease. LRP4 Ab - mild-moderate disease - not associated with thymic disease. Anti-striated muscle Ab - positive in 90% of thymomas Ryanodine receptor Ab - positive in 70% of thymomas with MG - marker for severe disease Titin Ab (in addition to ACh R Ab) - thymoma and late-onset MG Agrin Ab - poor sensitivity but specific for MG
What should be specifically checked for on examination in myasthenia gravis?
- Sustained upward gaze - weakness of eyelid elevators and oculomotor muscles
- Peek sign - eyelids separate after 30sec of closing, and sclera is visible.
- Dysarthria - palate weakness
- Dysphonia on counting - bulbar weakness
- Smiling causes snarling expression
- Neck flexion weakness
- Flap 1 arm then test muscle strength together - asymmetrical due to fatigue of one arm
- Improvement of ptosis with ice cube application
What does EMG show in myaesthenia gravis?
Repetitive stimulation shows progressive decrease in amplitude of action potentials
Needle examination - motor unit potential variation and, sometimes, fibrillation potentials and myopathic changes
Single-fibre EMG - increased jitter (variable interpotential interval). 80% sensitive.
What other investigations should be performed in myaesthenia gravis?
Thymoma search - CXR, chest CT or MRI
Respiratory function tests - weakness in muscles of respiration
What is myasthenic crisis and how is it treated?
Crisis involves respiratory weakness causing respiratory failure. Often caused by an infection.
Treatment: Antibacterial
IVIG or plasma exchange
What is first line treatment for myaesthenia gravis?
Acetylcholinesterases - pyridostigmine
K supplements and K-sparing diuretics may improve symptoms but are rarely used
What if acetylcholinesterase inhibitors fail in myaesthenia gravis?
Steroids - may worsen symptoms and therefore should be monitored closely during initiation.
Immunosuppressants next line - azathioprine may be used as steroid-sparing agent, however should never be used as monotherapy.
Rituximab in desperate cases
What % of myasthenia gravis have isolated ocular signs?
15%
Which antibodies are implicated in isolated ocular myasthenia gravis?
Acetylcholine and LRP4 (not MuSK)
What autoimmune diseases are often associated with myasthenia gravis?
Thyroiditis (most commonly) SLE and RA Polymyositis NMO ALS
Kv1.4, ryanodine and titin antibodies in myasthenia gravis are associated with which coexisting cardiac condition?
Myocarditis
What is the most effective cholinesterase inhibitor used in myasthenia gravis?
Which subpopulation is it less effective in?
Pyridostigmine
Less effective in MuSK positive patients
What is second line Rx for myasthenia gravis?
Third? Fourth?
2nd - Prednisone + AZA
3rd - Mycophenolate (mild) or rituximab (moderate)
4th - Methotrexate, cyclosporin, tacrolimus
How is myasthenic crisis treated?
IVIG or plasmapheresis
Which myasthenia patients should have a thymectomy?
Recommended in:
- Those with thymomas
- Early-onset myasthenia gravis
- Generalised myasthenia gravis and ACh receptor Abs. 70% of these show improvement after thymectomy.
- Seronegative MG with generalised disease and biomarkers similar to early-onset MG
Not recommended in:
- MuSK or LRP4 Ab positive
- Ocular MG
- Seronegative MG
Which medications may precipitate a myasthenic crisis?
Aminoglycosides Tetracyclines Fluoroquinolones Macrolides Muscle relaxants Beta blockers Calcium channel blockers Botox Iodine Penicillamine
What side effects are associated with pyridostigmine?
Abdominal cramps, diarrhoea
Which features of Lambert-Eaton Myasthenic Syndrome distinguish it from myasthenia gravis?
- No ophthalmoparesis, facial weakness or bulbar involvement
- Poor response to cholinesterase inhibitors
- Autonomic symptoms
- Reduced deep tendon reflexes
- Increase in size of CMAP on repetitive nerve stimulation
Anti-Hu antibodies are associated most strongly with which cancer?
What paraneoplastic syndromes are they associated with?
- Lung cancer (mostly small cell)
- Encephalomyelitis, limbic encephalitis, brain stem encephalitis, cerebellar degeneration, multi-segmental myelitis, sensory neuronopathy, sensorimotor neuronopathy, autonomic neuronopathy
Anti-Yo antibodies are associated with which cancers?
Which paraneoplastic syndrome are they associated with?
- Ovarian and breast
- Subacute cerebellar degeneration
Anti-CRMP5 antibodies are associated with which cancers?
- Small cell lung cancer, thymoma
Anti-Ma2 antibodies are associated with which cancers?
- Testicular cancer
Anti-Ri antibodies are associated with which cancers? Which syndrome is most associated with it?
- Breast, ovarian, SCLC
- Associated with opsoclonus-myoclonus syndrome
Anti-amphiphysin antibodies are associated with which cancers?
Which paraneoplastic syndrome are they associated with?
- Breast, SCLC
- Limbic encephalitis, stiff person syndrome
Lhermitte’s sign is suggestive of a lesion in which part of the nervous system?
Dorsal columns of C-spine or caudal medulla
Which antibodies in neuromyelitis optica are associated moreso with optic neuritis than myelitis?
MOG antibodies
- Also found in ADEM
What is the order of progression in multiple sclerosis medications?
- Glatiramer acetate, beta-interferon
- Daclizumab, teriflunomide
- Fingolimod, dimethyl fumarate
- Natalizumab, alemtuzumab
- Autologous HSCT
What is the mechanism of action of fingolimod?
- S1P receptor agonist. Causes
- Prevention of lymphocytes from migrating out of lymph nodes
What side effects are associated with alemtuzumab?
Autoimmune thyroid disease
Immune thrombotic thrombocytopenia
Membranous GN and anti-GBM disease
What does CADASIL stand for and what is the mutation responsible for it?
CADASIL = Cerebral Autosomal Dominant Arteriopathy with Subcortical Infarcts and Leucoencephalopathy
Notch 3 mutation - chromosome 19q12
Which 2 areas of the brain are classically involved in CADASIL?
Anterior temporal lobes
External capsule