Neurology Flashcards
What level of spinal cord injury do you get autonomic dysreflexia?
Above T6
Spinal cord injury and cardiac complications
Increased risk of CAD (including dissection)
In the acute/aubacute setting- concerns with arrhythmias and haemodynamic instability
Peripheral neuropathy
mostly due to axonal neuropathies
- length dependent (there for LL affected first)
- reducec amplitude of evoked potentials with relatively preserved nerve conduction velocity
Parietal lobe lesion - non dominant
- anosognosia (deficit of self-awareness)
- hemisomatognosia (imperception for one half of the body)
- dressing apraxia (the incapacity of effectuating the acts of dressing correctly)
- prosopagnosia (the ability to recognize familiar faces, including one’s own face (self-recognition), is impaired,)
- Visual inattention
GERSTMAN SYNDROME:
Parietal lobe lesion - dominant:
-inferior parietal lobe
Angular and supramarginal gyri (Brodmann Area 39/40) - near temperoparietal junction
- Sx:
> Dysgraphria/agraphia
> acalculia/dysalculia
> finger agnosia
> L/R disorientation
> +/- aphasia
> +/- apraxia
MMN
Pure motor
Subacute
asymmetric
patchy
LMN signs
+/- conduction block and focal demyelination on NCS
Elevated Anti-GM1 (30-80% of pts)
Minimal response to steroids
but higher response to IVIG
PSP
Richardson’s syndrome
clinical sx
Classic features:
- early onset of falls
- classic PSP-RS have a **stiff and broad-based gait, with a tendency to have their knees and trunk extended **(as opposed to the flexed posture of idiopathic Parkinson disease) and arms slightly abducted.
- “drunken sailor gait.”
- supranuclear down gaze palsy and slow vertical saccades “can’t look down - improves with vestibula-ocula reflex
- postural instability
- **Frontal dementia **
PSP-P: tremor and asym onset, eye sx onset later - respond to Levodopa (better prognosis)
“Hummingbird” or “King penguin” sign
Suspect in pt >40
Predominant, otherwise unexplained impairment of episodic memory is suggestive of Alzheimer disease and is considered an exclusion criteria for the diagnosis of PSP.
PSP
Pathophysiology and radiology
- Tauopathy
- Midbrain atrophy
“hummingbird or king penguin” sign
Genetics – Normal brain tau contains six isoforms that are generated by the alternative splicing of a single tau gene (MAPT) on chromosome 17. Dominantly inherited mutations in the MAPT gene cause frontotemporal dementia with and without parkinsonism as well as PSP.
Marked reduction in D2 striatal receptors
Amantadine
- treat dyskinesia in Parkinson’s patients receiving levodopa, as well as extrapyramidal side effects of medications.
- mechanism: ?unknown ?NMDA antagonism
- SE: dry mouth, constipation, N?V, difficulty with sleep, abnormal dreams
Axonal neuropathy
NCS findings
- reduced amplitude of CMAPs
Demyelination
MCS findings
- slowing of conduction velocity
- Prolonged distal latency
- Temporal dispersion
CSF PCR for JC virus
Sensitivity and specificity
Low sensitivity 75%
High specificity 92%
if high pretest probability –> biopsy
MS treatment and pregnancy
Glatiramer, Dimethyl fumarate and ??Natalizumab Natalizumab: fetal haematological abnormalities (anaemia, thrombocytopenia if continued in 3rd trimester) If high risk of relapse, consider continuing until 3rd trimester.* are relatively safer in pregnancy whereas fingolimod, interferons and Teriflunomide are more dangerous
Wash out period prior to conception:
None: Glatiramer, IF beta, Dimethyl, Natalizumab
2 mo: fingolimod
4mo: alemtuzumab
6mo: Cladribine, Ocrelizumab and Ofatumumab
chlestyramine for Teriflunomide
Brachial neuritis
Common peroneal nerve lesion vs L5 radiculopathy
how to differentiate
Ankle inversion
- preserved in CPN injury
Ankle inversion is predominently done by tibialis posterior
Sleep related epilepsy
accounts for 10-15 of all epilepsy syndrome
- exclusively occurs in sleep
- nREM associated
- SHE: hypermotor epilepsy: nocturnal seizures in adolescents. Vigorous hyperkinetic and asymmetric tonic or dystonic features +/- impaired awareness
25% of SHE is inherited as autosomal dominant, with mutations in the CHRNA4 gene, which encodes for the alpha 4 subunit of the neuronal nicotinic acetylcholine receptor, being described.
What causes global wasting of intrinsic muscles of the hand?
T1 lesion, which effects both ulnar and median nerve
Anti-epileptics and the channels they work on
Na: carbamazepine, phenytoin, topiramate, lamotrigine, lacosamide
Ca: Ethosuxamide, Lamotrigine
Glutamate: lamotrigine and topiramate
SV2A modulation: Keppra
EMG/NCS
Assess the peripheral nervous system:
CMAP: motor nerves
SNAP: sensory nerve action potential
Distal latency: prolonged in Carpal tunnel syndrome
Conduction velocity: prolonged in demyelination
Axonal polyneuropathy
commonly seen in diabetic polyneuropathy
- reduced amplitude of CMAPs and SNAPs
Radiculopathy
Proximal to DRG, therefore the SNAPs will be normal
reduced CMAPs proportional to the damage
Plexus lesions
NCS are similar to polyneuropathy as it will be distal to DRG
- reduction in both CMAPs and SNAPs
Conduction block
focal demyelination i.e. GBS
- stimulation proximal to the lesion results in reduction in CMAPs but when stimulated distally you get normal CMAPs
Carpal tunnel syndrome
prolonged sensory and motor distal lantency
NMJ disorder
Repetitive stimualtion:
decremental CMAPs: MG
incremental CMAPs: LES or botulism
EMG terms:
Fibrillations: represents a** single muscle fibre** that’s lost it’s innervation by the nerve, thus it’s dying - could be relation damage in the anterior horn cells, radiculopathy, plexopathy
- regular firing
**- always bad **
- can be due to denervation or myositis
- AXONAL neuropathies
i.e. alcohol
Fasciculations: due to entire motor unit. can visibly see it. A spontaneous, involuntary muscle contraction and relaxation, involving fine muscle fibers.
- can be benign or anything that affects the peripheral nerve fibre
- classically seen in damage to anterior horn neurons
Motor unit potential (MUP):
- neurogenic: less number of MUPs, but bigger due sprouting
- myopathic: smaller MUPs, normal number i.e. DMD
Antibody in inclusion body myositis
Anti NT5c1a
Malignancy secondary to dermatomyositis
Anti p155
Which type of dementia is associated with MND?
FTD
Common mutation in familial MND?
C9ORF72
Poor clinical prognostic factors in ALS
- bulbar involvment
- resp subtype
- severity at baseline
- speed of progression
Subtypes that have a better prognosis in ALS
flail arm or leg syndrome
predominace in UMN or LMN
Worse prognosis for AIDP/GBS
Age >40
Male
Rapid onset
Resp involvement
Preceding diarrhoeal illness
High Anti GM1 titre
Weber’s syndrome
superior alternating hemiplegia
occlusion of the paramedian branches of the PCA or basilar artery
–> infarction of midbrain
ipsilateral occulomotor nerve palsy
contralateral hemiparesis or hemiplegia
Eyes: down and out
Myotonic dystrophy
AD inherited myopathy
20-30y/o
It affects skeletal, cardiac and smooth muscle
CTG repeat disorder
DM1 - **distal **weakness
DM2: prox. weakness
Associated with:
- cataracts
- dysarthria
- frontal balding
- bilateral ptosis
- myotonic facies
- - DM
- testricular atrophy
- cardiac: HB, CM
- dysphagia
DM1 is caused by a CTG repeat at the end of the DMPK (Dystrophia Myotonica-Protein Kinase) gene on chromosome 19
DM2 is caused by a repeat expansion of the ZNF9 gene on chromosome 3
MS and pregnancy
Pregnancy is protective against developing MS - more the better
MS activity increases in the 3 months post partum
Exclusive breastfeeding provides some reduction (30-50%) in MS disease activity postpartum
Where would the lesion be if someone can’t read but able to write and speak?
dominant occipital lobe
CN IV palsy
Trochlear nerve
Ipsilateral: up and out eye
due to inability to abduct, depress and internally rotate
The trochlear nerve is purely a motor nerve and is the only cranial nerve to exit the brain dorsally. The trochlear nerve supplies one muscle: the superior oblique. The cell bodies that originate the fourth cranial nerve are located in ventral part of the brainstem in the trochlear nucleus.
F waves
antidromic second CMAP
slight reduction in axonal neuropathy
highly reduced in demyelination
antiepileptic to use in juvenile myoclonic epilepsy
Sodium valproate
What is a visual sign associated with PML?
Homonomous hemianopia is an example of retrochiasmal visual field defect
RCVS, sometimes called Call-Fleming syndrome
Reversible cerebral vasoconstriction syndrome:
a weeks-long course of thunderclap headaches, sometimes focal neurologic signs, and occasionally seizures. A ‘sausage on string’ appearance is typical on CT angiogram.
Motor fluctuations on Levodopa in PD
Is associated with age of onset and duration of disease (rather than duration of treatment)
Annual incidence is 10%
Improved with increasing the frequency
What’s the median survival for ALS
3-5 years
PErinaud’s syndrome
damage to dorsal mid brain
clinical manifestation:
upward gaze palsy, convergence retraction nystagmus, bilateral lid retraction, Light-near dissociation
Occurs due to damage to dorsal pons
common cause: pineal gland tumour, haemorrhage or infarct
What’s most common clinical manifestation of ALS
- Asymmetric limb weakness
- Bulbar sx
MG - most sensitive test
Single fibre electromyography
Most specific test for MG
Anti ACh - R antibodies
Intraspinal location vs extraspinal location
Intra: C/T
Extra: L/S
Majjority of the spinal supply is by anterior spinal artery
Central cord syndrome presents with dissociative sensory loss
Chiari Malformation
Chiari I malformation (CM-I) is characterized by abnormally shaped cerebellar tonsils that are displaced below the level of the foramen magnum
*Chiari II malformation (CM-II), also known as Arnold-Chiari malformation, is characterized by downward displacement of the cerebellar vermis and tonsils, a brainstem malformation with beaked midbrain on neuroimaging, and a spinal myelomeningocele.
distinguish between radial nerve palsy and C7
C7 radiculopathy - wrist flexors are affected
Lamotrigine and pregnancy
Lamotrigine level is decreased in states of high estrogen i.e pregnancy, OCP
What is the average timeframe for death after developing cognitive disability in PD?
3 years
this is irrespective of age
Interestingly patients who develop Parkinsons at an older age are at a higher risk of mortality and developing dementia compared to younger patients
Posterior visuospatial symptoms correlate with dementia and mortality
What is the average timeframe for death after developing cognitive disability in PD?
3 years
this is irrespective of age
Interestingly patients who develop Parkinsons at an older age are at a higher risk of mortality and developing dementia compared to younger patients
Posterior visuospatial symptoms correlate with dementia and mortality
Tell me about Anti-NT5c1a
highly specific for IBM cf other myositis
only found in about 35 % of IBM
Other facts:
Vacuoles are not present in 20% of IBM
Anti NT5c1a can be seen in patients with SLE and sjogrens but WITHOUT muscle weakness. Anti NTC5c1a also has a prognostic role.
Conus medullaris
L1-2 involvement
Sudden
BILATERAL
less severe radicular pain
More severe back pain
Mixture of both UMN and LMN findings
Early faecal and urinary incontinence
Split hand syndrome
Split hand syndrome is a neurological syndrome in which the hand muscles on the side of the thumb (lateral, thenar eminence) appear wasted, whereas the muscles on the side of the little finger (medial, hypothenar eminence) are spared. Anatomically, the abductor pollicis brevis and first dorsal interosseous muscle are more wasted than the abductor digiti minimi. It is a specific sign for anterior horn cell disease such as ALS
What is:
- prosopagnosia
- anosognosia
- hemisomatognosia
what does the following finding suggestive of?
diffuse meningeal enhancement on brain MRI
RF for MS
female
caucasion
affected sibling (worse in monozygotic twins)
high altitude
low vit D
smoker
obese
** HLA-DRB1*15:01 confers the greatest risk.**
Pathogenesis of MS
Autoreactive T cells (esp Th17) migrate across BBB
reacte to antigen via APC
Secretion of proinflammatory cytokines
Stimulation of astrocytes and microglia
destruction of myelin –> exposed nerve results in axonal death