Neurology Flashcards
Causes of Peripheral Neuropathy
Diabetes Drugs; (Phenytoin, Isoniazod, Nitrofurantoin) Autoimmune; Gullian Barre, SLE CKD Alcohol/B12 deficiency
Features of neuropathic ulcers
Slouchy Bloody Not painful
Features of diabetic neuropathy
Sensory affected>motor
light touch and vibration go first - loss of protection
Glove stocking distribution - can be painful
Length dependant - feet affected first
Loss of ankle reflexes, then knees etc
Can cause neuritis
Loss of autonomic function later
Ulnar nerve palsy
Weakness/wasting first dorsal interosseous - loss of thumb adduction
Partial claw hand (loss of lumbricals) looks like Dupetryns
Weakness of pincer grip (Frommets)
Sensory loss of fifth and ulnar half of fourth digit
Positive prayer sign
Fixed flexion deformity e.g RA, scleroderma, diabetes, ulnar nerve palsy, dupuytrens
Causes of Carpal Tunnel
RA DM Pregnancy Trauma Hypothyroid
Shoulder Abduction Nerve Root
C5
Elbow Flexion Nerve Root
C6
Wrist Extension Nerve Root
C7
Finger Extension Nerve Root
C8
Finger Abduction Nerve Root
T1
Median Nerve Palsy
e.g carpal tunnel can’t abduct thumb (thenar./APB) sensory loss 3.5 fingers Tinels and Phalens positive Pain in night relieved by shaking
Radial Nerve Palsy
Wrist drop e.g fractured head of humerus loss of sensation dorsum forearm and first 3 fingers dorsum
Hip Flexion Nerve Root
L2
Knee Extension Nerve Root
L3
Inversion and Dorsiflexion of Foot Nerve Root
L4
Dorsiflexion Big Toe Nerve Root
L5
Eversion of Foot Nerve Root
S1
T1 Nerve Supply
Pupil Dilation Axilla and upper inner sensation Intrinsic muscles of hand
T1 Nerve Root Lesion Features
e.g Pancoasts tumour (partial ptosis, small pupil) pain/sensory loss axilla complete claw hand wasting of small muscles hand
Facial paralysis with contralateral body weakness
Brainstem lesion
Isolated hemianopia - where is the lesion/vessel?
Posterior Communicating Artery
Contralateral
(occipital lobe)
Hemianopia plus hemiplegia on same side -
Where is the lesion/vessel?
Middle cerebral artery on contralateral side
(optic radiation temporal and parietal lobes)
Where is the lesion if central scotoma (middle missing)?
Optic Nerve
Where is the lesion if bitemporal hemianopia (outside halves gone)?
Optic Chiasm
Where is the lesion if homonymous hemianopia (left/right half of both gone)
Lobe lesion
Why do you sometimes macular sparing?
Small part of optical lobe supplied by MCA rather than (PCA)
Why do you get forehead sparing in UMNL?
“bilateral cortical representation of upper part of the face”
What are the Parkisons Plus Syndromes?
Multiple system atrophy
Progressive supranuclear palsy
Parkinsonism-dementia-amyotrophic lateral sclerosis complex
Corticobasal ganglionic degeneration
Dementia with Lewy bodies
CNIII Palsy
Partial ptosis
down and out
dilated pupil
Causes of a CNVII LMNL
Acoustic Neuroma
Bells Palsy
Trauma to petrous temporal bone
Ramsay Hunt
Dopamine Agonists
Less effective than Ldopa+inhib
Less motor complications - useful for young
Or in addition in adv disease
Ldopa + dopa decarboxylase inhibitor
Main tx
Good for bradykinesia an rigid but less for tremor
Balance of benefit vs dyskinesias
Useful for 5 years before wearing off - delay start
Side effects of levodopa
End-of-dose effect = wears off earlier and earlier
On-Off effect = unpredicatable fluctuation
Dyskinesias = unwanted movements
Seligiline
Can be used to delay ldopa
Autonomic side effects
COMT inhibitors
inhibit peripheral breakdown
helps w/ end-of-dose
Features of a TACI
Severe, poor recovery
All three of:
- Contralateral hemiparesis
- Contralateral homonymous hemianopia
- Higher cortical dysfunction (speech, attention etc)
Features of a PACI
2 of the 3 TACI features, usually higher cortical dysfunction + contralateral weakness
Features of PoCI
1 of the 3:
- contralateral homonymous hemianopia
- cerebellar signs
- brainstem signs
Features of Lacunar Infarct
No higher coritcal
No homo hemi
No drowsiness
No brainstem
pure motor/pure sensory/sensorimotor/dysarthria+hand/contra hemiballismus
Genetics of Charcot Marie Tooth
Most common is autosomal dominant CMT but other phenotypes
What the underlying pathophysiology of Charcot Marie Tooth?
gene duplication leading to production of abnormal myelin, which is unstable and spontaneously breaks down –> demyelination –> uniform slowing of conduction velocity
onion bulb appearance
Presentation of Charcot Marie Tooth
usually before 10 yr
peripheral muscle weakness and wasting moving distally - inverted champagne legs, claw hands
sensory loss in same pattern - vibration touch then proprioceoption
painful
arreflexia
deformity
palpable nerves
Deformities of Charcot Marie Tooth
pes cavus/pes planus/ hammer toe
spinal eg thorcic scoliosis
Management of Charcot Marie Tooth
physio
orthotics
avoid neuropathic meds
surgery for deformity
analgesia
genetic counselling
DDx of adult onset spastc parapesis
MS
ALS (MND)
B12 deficiency
Transverse myelitis
Investigations of MS
CSF - oligoclonal IgG bands
MRI - plaques
Evoked potentials EEG
but mainly clinical
Why do you get deformity like Z thumb, Boutonnieres etc in RA?
Chronic rheumatoid tenosynovitis damages tendons so they eventually wear out, snap, split etc
Types of diabetic neuropathy?
Peripheral neuropathy - glove stocking
Mononeuropathy
Mononeuropathy multiplex
Diabetic femoral neuropathy - wasting and weakness of quads, loss of knee jerks
Autonomic neuropathy
What peripheral neuropathy affects motor before sensory (unlike most)?
Gullian Barre
Charcot Marie Tooth
How do you manage GCA?
Refer urgently to surgery for temporal artery biopsy
Start high dose steroids immediately
40mg pred (60mg if claudication)
Marcus Gunn Pupil
No RAPD
optic nerve damage
retinal disease
Adie Pupil
Dilated pupil
Slow reactive to light
Damage to parasympathic nerves from infection, often w/ absent knee/ankle jerks
Argyll-Robertson Pupil
Small pupil
Accomodates but doesnt react to bright light
Prostitutes
Diabetic neuropathy, neurosyphilis
Features of NF1
Cafe au lait
Axiary or inguinal freckles
Neurofibromas
Optic nerve gliomas
Lisch nodules
Which common drugs can induce Parkinsonism
Amiodarone
Metocloperamide, Prochlorperazine
Lithium
Cinnarizine/Stugeron
Atypical antipsychotics
Conventional antipsychotics
What are the extra pyradimal side effects?
Tardive Dyskinesia
Parkinsonism
Dystonia
Restlessness
Bacterial Meningitis LP Results
Cloudy and turbid
High WCC (neutrophils)
High protein
Very low glucose
Normal red cells
Viral Meningtis LP Results
Normal appearance
Raised WCC (lymphocytes)
Normal red cells
Protein normal/high
Glucose normal/low
TB Meningitis LP Results
Normal or slight cloudy
Raised WCC (lymphocytes)
Red cells normal
Protein high
Glucose very low
SAH LP Results
Yellow/blood stained appearance
WCC normal
Red cells very high
Protein normal or high
Glucose normal or low
How might you be able to distinguish between bacterial meningitis and TB meningitis on an LP?
TB less cloudy
bacterial predominantly neutrophils
TB predominantly lymphocytes
Gullain Barre LP Results
Appearance
WCC normal
Red cells normal
High protein (after a week)
Glucose normal or low or Low
MS LP Results
Normal appearance
WCC rasied lymphocytes
Red cells normal
Protein high
Glucose normal
