Neurology Flashcards
30yo man presenting with
- 1/52 right arm weakness
- originally began as neck pain, radiating to right shoulder, followed by weakness
- winged scapula
- weak shoulder abduction and elbow extension
- sensory loss over lateral aspect of right shoulder
- right triceps reflex absent
What is the diagnosis? Options are: A. C7 entrapment radiculopathy B. C5/6 prolapse C. Neuralgic Amyotrophy D. Suprascapular nerve entrapment E. Traction of the lateral cord of the brachial plexus
Neuralgic Amyotrophy is a brachial plexopathy (usually UPPER plexus) usually preceded by an infection.
Presents with severe pain for days to weeks, then weakness and sensory loss over the corresponding territory of the brachial plexus, usually C5-7.
Self limiting condition but may be slow (years).
What are the symptoms of Vit B12 deficiency?
Initially peripheral neuropathy
Loss of vibration and position sense
Then areflexia and weakness
Then spasticity, extensor Babinski and ataxia if left untreated
Triad of Normal Pressure Hydrocephalus?
The 3 W’s
WET, WOBBLY, WACKY
- Urinary Incontinence
- Ataxia
- Memory impairment / confusion
Triad of Wernicke-Korsakoff Syndrome
Caused by thiamine (Vit B1) deficiency.
Wernicke Encephalopathy:
- Confusion
- Ophthalmoplegia
- Ataxia
- -> may progress to Korsakoff Psychosis
1. Irreversible memory loss
2. Confabulation
3. Personality change
Associated with periventricular haemorrhage / necrosis of mammillary bodies.
Treatment is IV Thiamine.
How does Syringomyelia present?
- Headaches
- Motor symptoms - muscle wasting/weakness in hands –> forearms –> shoulders
- Bladder symptoms
- Absent reflexes
- Sensory loss pain and temp, then light touch & proprioception (CENTRAL CORD DEFICITS)
There is a syrinx (fluid-filled cavity) in the spinal cord, usually CERVICAL SPINE. (Mostly C2-T9)
This can elongate and enlarge, causing compression of the corticospinal and spinothalamic tracts and anterior horn cells.
Syringobulbia is the situation where the syrinx extends into the brainstem, commonly due to a Chiari malformation and impaired CSF circulation. More common in men in 20-30’s.
Avoid lumbar puncture due to risk of herniation.
Perform a CT/MRI.
Early surgical decompression with shunt is beneficial.
How do you distinguish between an L5 nerve root lesion and a common peroneal nerve lesion?
Bonus points:
** what muscle/movement is most SPECIFIC for L5 involvement? **
L5 NERVE ROOT RADICULOPATHY:
- L5 innervates everything that the common peroneal nerve does, PLUS TIBIALIS POSTERIOR and the glutei muscles.
Hence:
- LOSS OF FOOT INVERSION (Tib Posterior)
- ABSENT/REDUCED ANKLE JERK
- WEAK HIP ABDUCTION AND INTERNAL ROTATION
- LARGE AREA OF SENSORY LOSS: numbness over dorsum of foot and lateral part of leg (sensory loss is present in L5 radiculopathy but NOT in L5 Anterior horn disorder)
- As well as foot drop (weak dorsiflexion) and weak foot eversion, which is also present in common peroneal lesions
COMMON PERONEAL NERVE:
- foot drop (weak dorsiflexion) and weak foot eversion (peroneus brevis and longus)
- strong plantarflexion, strong foot inversion and strong ankle reflex
- MINIMAL sensory loss over the lateral aspect of the dorsum of the foot only
SCIATIC NERVE:
- WEAK FOOT movements (all) - PLANTARFLEXION, Dorsi, ever/inversion, absent ankle jerk, but..
- STRONG HIP abduction and internal rotation
- sensory loss over the whole leg and foot
** Great toe EXTension (EXTensor Hallucis Longus) is specific for L5 **
Match these antibodies to their conditions:
- Anti NMO
- Anti GQ1b
- Anti GM1
- Anti MAG
- ACh Receptor Ab
- MuSK Ab
- Anti NMO = Devic’s disease
(Anti-NEMO?…you must be a DEVIL!)
(similar to MS except NO OLIGOS in CSF, predominance of polymorphs in CSF and present with vomiting and painful optic neuritis) - Anti GQ1b = Miller Fischer
(“Dr Fischer is the ANTI-GQ Man!) - Anti GM1 = Multifocal Motor Neuropathy / MMN
(LMN, arms > legs, ** RESPONDS TO STEROID and IVIG **)
(“GM1 = Good Morning!! Put on your Multifocal glasses to start the day”) - Anti MAG = (IgM PARAPROTEIN) = either Waldenstroms or DADS / Distal Acquired Demyelinating Symmetric Polyneuropathy (distal sensory loss)
(“Cool MAGs are for DADS that aren’t WALLflowers!” They DONT RESPOND to anyone!”) - ACh Receptor Ab = MYASTHENIA GRAVIS
(fatiguability of ocular/bulbar, limb and respiratory muscles, with PRESERVED reflexes) - MuSK Ab = (“This MUSKy smell burns my throat and lungs!!)
MYASTHENIA GRAVIS but more RESPIRATORY CRISIS and BULBAR involvement. Less eye involvement. Females > M.
Patient unable to differentiate different animals, ie has a SEMANTIC problem. Where is the lesion?
Left (DOMINANT) Lateral Temporal Lobe
What are the clinical characteristics of a Frontal lobe lesion?
PERSEVERATION And reduced: - attention / memory - calculations - planning - activity / spontaneous activity - concern (loss of inhibition)
Patient presents with PURE sensory or pure motor stroke.
Eg. “clumsy hand” syndrome, limb ataxia, facial weakness, dysphagia (all motor)
Where is the lesion?
LACUNAR lesion.
usually discrete lesion in CONTRALATERAL PONS or INT CAPSULE.
Lacunar stroke = good prognosis.
Drug causes of
- DEMYELINATING neuropathy
- AXONAL neuropathy
Only a FEW drugs cause demyelination, the rest are axonal.
- DRUGS that cause a DEMYELINATING neuropathy:
Tacrolimus, Chloroquine, Perhexiline, Procainamide, anti-TNFs Infliximab, Adalimumab
(“DEMI said - “TAKE (Tac) the CHLORine out of my Pool, or you will get the FLICK!!) (FLIX - infliximab)
- AXONAL Neuropathy
alcohol
Thalidomide
Vinca-alkaloids (recall neurotoxic chemo agents “plaits, tuxedos and VINtage wine make my head spin!”)
Give examples of Tauopathies
(“OPERATION TAU: the Australian Federal Police (AFP) PICK and HUNT Criminals”)
TAU OPathies:
Alzheimer’s Disease (Tau protein in neurofibrillary tangles)
Frontotemporal dementia
Progressive Supranuclear Palsy
Pick’s disease (“pick bodies” on histology are Tau)
Huntingtons - CAG repeats
Corticobasal degeneration
Patient presents with pain in the anterior thigh, to the knee.
There is numbness over the anterior thigh.
There weak knee extension and an absent knee jerk.
Where is the lesion?
Classic L4 Radiculopathy
Botox. Site of action?
PRE-synaptic membrane.
Patient presents with acute weakness in the LEG only. What stroke syndrome does this represent (what vessel territory) and what lobes are affected?
ACA territory.
Frontal lobe and superior Medial Parietal lobe.
What are the 2 groups of lesions that are differentiated using Nerve Conduction studies, and how do you interpret the findings?
NCS differentiates between DEMYELINATION vs AXONAL loss.
NCS (motor and sensory) measures:
- Conduction velocity, and
- Amplitude
DEMYELINATION = SLOW CONDUCTION
(“Demi is SLOW to CONceive”)
= “prolonged distal motor latency”
(Eg. AIDP, CIDP, Carpal tunnel which is a Demyelinating disorder due to progressive compression)
- SLOW CONDUCTION
- ABSENT F waves = sensitive for AIDP
- if “conduction block” is also present, then amplitude is affected.
(Conduction block is when a proportion of axons are unable to propagate action potentials past the site of demyelination
–> results in “temporal dispersion”
–> lower amplitudes)
- distal conduction block with demyelination = lowers distal amplitude
- proximal conduction block with demyelination = lowers Prox amplitude
- demyelination with NO conduction block = slow conduction, NO loss of amplitude
AXONAL LESIONS = AMPLITUDE LOW (AL = AL)
(Eg. Radial nerve or common PERONEAL nerve palsies)
- low amplitude due to loss of axons
- normal conduction velocity usually
- ** NCS should be performed AFTER DAY 7 as Wallerian/Axonal degeneration occurs after day 7 if the axon can not be saved **
- 1st degree axonal lesions (neuropraxia) have excellent prognosis because no irreversible axonal damage
Guilian Barre / AIDP.
What are the diagnostic features?
Mx?
- Areflexia
- Ascending weakness - SYMMETRY
- Timecourse of symptoms 0-4 weeks (in contrast to CIDP >8/52)
- CSF Protein = high
- ABSENT F WAVES on NCS = ** most Sensitive test **
and SLOW conduction on NCS (prolonged distal motor latency)
Minimal sensory involvement.
Associations:
- Campylobacter
- viral infections (60%)
- post-op or major trauma
- sarcoid, lymphoma, SLE, leukaemia
MANAGEMENT:
- monitor FVC
- plasma exchange OR IVIG (equally as good)
(Steroids no benefit)
What are the characteristics of Miller Fisher Syndrome?
Miller Fisher is a variant of Guillian Barre (5% of GBS)
(“Dr Fisher is ANTI-GQ man because he wears a TOGA”
ANTI-GQ1b antibodies present in 90%
T = affects TRUNK and SPARES THE LIMBS O = Ophthalmoplegia G = Gait disturbance = ataxia A = Areflexia
What are the characteristics of CIDP?
What investigations would you order?
CIDP
- > 8 weeks
- PROXIMAL muscle weakness
- Areflexia
- usually motor / sensory
- ** associated MGUS or Myeloma **
Invx:
- ALWAYS LOOK FOR MGUS/MYELOMA or 2RY CAUSES (HIV, SLE, Poems Synd, IBD, Hepatitis)
- CSF - high protein
- NCS - slow conduction (prolonged distal motor latency), absent or prolonged F waves
Describe the variants of CIDP – MMN, DADS and Lewis Sumner Syndrome.
MMN / Multifocal Motor Neuropathy:
- associated with Anti-GM1 IgM in 80%
- ** TREATABLE!!! –> IVIG ** (+/- CTX)
- a Lower Motor Neuron Demyelinating neuropathy
- Mostly MEN, upper limbs (wrist drop), asymmetric
- progressive LMN WASTING and Areflexia
- motor only; no sensory deficit
DADS / DISTAL ACQUIRED DEMYELINATING SYMMETRIC POLYNEUROPATHY
(“Cool MAGs are for DADS who aren’t SENSITIVE WALLflowers! They DONT RESPOND to anyone!”)
- Associated with Anti-MAG IgM & Waldenstroms
- Poor response to immunotherapy
- mainly elderly, DISTAL SENSORY loss, Falls, mild distal weakness
LEWIS SUMNER SYNDROME
- Like CIDP but ASYMMETRICAL variant
