Neurology Flashcards
Ddx for Relative Afferent Pupillary Defect
perform the swinging torch test
- pupil appears to dilate when light is swung from unaffected to affected eye
- decreased response to light from the afferent defect
optic nerve lesion - optic neuritis (MS) - optic nerve ischaemia - optic nerve compression (tumours, thyroid eye disease) - asymmetrical glaucoma severe retinal disease - large retinal detachment - central retinal artery or vein occlusion
Ddx for jaw jerk
UMN lesion of the trigeminal nerve
ALS
MND
Pseudo bulbar palsy
MS
Ddx vertical nystagmus
brain stem lesion (some variations for Courtney)
- malignant - primary or metastatic
- vascular - ischaemic or hemorrhagic
toxic - phenytoin, alcohol
Ddx facial droop
UMN: lower face only
- vascular - ischaemic or hemorrhagic
- tumour
LMN: upper and lower face pontine - vascular, tumour, MS, syringobulbia posterior fossa - acoustic neuroma, meningioma petrous temporal bone - Ramsay Hunt, Bell's palsy, otitis media, fracture parotid - tumour, sarcoid
DDx for diplopia
Disorder of muscle/orbit: thyroid eye disease, trauma, myasthenia
Disorder of cranial nerve: 3/4/6 palsy, Miller-Fischer,
Supranuclear pathology: INO, wernickes, tumour, aneursym, migraine
DDx for vertigo
Peripheral: vestibular neuronitis, Menieres disease, benign paroxysal positional vertigo, Herpes zoster oticus, aminoglycoside toxicity, otitis media, acoustic neuroma
Central: migraine, brainstem stroke/TIA, Wallenburgs syndrome (lateral medullary syndrome), cerebellar infarct or haemorrhage, Chiari malformation, MS
DDx for Horners syndrome
Central: Stroke, demyelination, brainstem/spinal cord tumour, syringomyelia
Pre-ganglionic: subclavian artery aneurysm, apical lung tumour, mediastinal tumour, cervical rib, trauma from IJ line/chest tube, thyroid malignancy
Post-ganglionic: dissection or aneurysm of internal carotid artery, cavernous sinus lesion, cluster headache
DDx for tongue fasciculations
LMN lesion of CN XII
- MND - ALS, SMA
- post polio syndromes
- benign
- drug induced
Patterns of visual field loss
Homonymous hemianopia - optic tract to occipital cortex
Lower quadrant homonymous hemianopia - parietal lobe lesion
Upper quadrant homonymous hemianopia - temporal lobe lesion
Bitemporal hemianopia - optic chiasm lesion
Unilateral field loss - optic nerve lesion
Central scotomata - optic nerve head to chiasm lesion eg demyelination, nutritional, vascular, toxic
Tunnel vision - glaucoma, papilloedema
Enlarged bling spot - optic nerve head enlargement
DDx for horizontal nystagmus
Vestibular
Cerebellar
Internuclear opthalmoplegia
Ddx of predominantly motor peripheral neuropathy
- Guillain-Barre Syndrome and
Chronic Inflammatory Demyelinating Polyradiculopathy - Hereditary motor and sensory neuropathy e.g. CMT
- Diabetes
Others: Lead poisoning, acute intermittent porphyria, Multifocal motor neuropathy
MND and NMJ disorders must be considered in distal motor weakness
remember causes of peripheral neuropathies: 30% diabetes 30% Hereditary 30% idiopathic 10% the rest
Ddx proximal muscle weakness
Myopathy (PACEPODS) NMJ disease e.g. Myasthenia Gravis Neurogenic causes: - MND - polyradiculopathy - Kugelberg-Welander disease
Polymyositis, Dermatomyositis
Alcohol, AIDS (HIV)
Carcinoma
Endocrine - hyper/hypo- thyroids, Cushing’s syndrome, acromegaly,
Periodic paralysis
Osteomalacia
Drugs - steroids, chloroquine, statins
Sarcoidosis
Ddx length-dependent peripheral neuropathies
Same as causes for peripheral neuropathy
Diabetes, diabetes, diabetes
Medications
- Vincristine, Cisplatin, Isoniazid, Phenytoin, Amiodarone, Nitrofurantoin
Toxins - heavy metals, large doses of vitamin B6
Alcohol
Metabolic - diabetes, uraemia, hypothyroidism
Immune mediated - sensory form of GBS
Carcinoma
Vit B12 def
Idiopathic
Connective tissue diseases or vasculitis - SLE, PAN
Hereditary
Chorea
Genetic - Huntingtons - Wilsons disease - Benign hereditary chorea - Fredrichs ataxia - Mitochondrial disorders Aquired - Sydenhams chorea (rheumatic fever) - Drugs (OCP, levodopa, neuroleptics, phenytoin) - SLE - Post infectious autoimmune central nervous system disorders (PANDAS) - chorea gravidarum - antiphospholipid syndrome - PCV
Painful peripheral neuropathy
Hereditary - Fabrys disease - Hereditary amyloid neuropathy Aquired - post herpetic neuralgia - GBS - chemotherapy induced - paraneoplastic - diabetic - HIV associated - CTD related (sjogrens) - Alcoholic neuropathy - Uremic neuropathy
Foot drop
LMN
- trauma -> direct injury to dorsiflexors of foot e.g compartment syndrome
- myopathy e.g fascioscapulohumeral dystrophy
- peroneal nerve lesion
- sciatic nerve lesion
- L5 nerve root compression
- sacral plexopathy
UMN
- spinal cord (myelopathy) - demyelination, compression
- stroke
Bilateral
- hereditary sensorimotor neuropathies e.g CMT
- freiderichs ataxia
Deficits in proprioception/vibration
Spinal cord
- tabes dorsalis (syphillitic myelopathy)
- subacute combined degeneration of the cord due to Vit B12 def, Vit E def, and copper def
- Friedreichs ataxia
- multiple sclerosis
- brown sequard (ipsilateral loss of proprioception/vibration)
Peripheral nerves
(large myelinated nerves so demyelinating processes affect these sensory modalities)
- diabetic neuropathy
- CIDP
- hereditary motor and sensorineuropathies (ie. CMT)
Spastic paraparesis
Hereditary
- hereditary spastic paraparesis
- motor neuron disease
- spinocerebellar ataxia
- chiari malformation
- adrenoleuckodystrophy
Aquired
- spinal cord compression (above conus)
- myelopathy (compressive, demyelinating, malignancy)
- cerebral palsy
- Vitamin B12 def
- Vitamin E def
- syphillis/HIV infection
Cerebellar disease
Congenital malformations e.g. arnold chiari Hereditary e.g Freiderichs ataxia (AR), spinocerebellar ataxias (AD) Aquired - vascular e.g infarction/haemorrhage - space occupying lesion - nutritional e.g. thiamine, gluten - infection - toxins e.g. alcohol, heavy metals - drugs e.g. phenytoin - MS - paraneoplastic cerebellar degeneration (anti-yo) Idiopathic
Wasting of small muscles of the hand
Spinal cord - spinal cord compression - motor neuron disease - syringomyelia - syphillis - poliomyelitis Brachial plexus - apical lung tumor - trauma - cervical rib Peripheral nerve involvement - rheumatoid arthritis - ulnar nerve palsy - median nerve palsy
Tremor
Essential tremor
Parkinsonism
Enhanced physiological tremor (caffeine, anxiety)
Drugs (amiodarone, B-agonists, lithium, valproate etc)
Cerebellar lesion (stroke, MS, brainstem tumors)
Psychogenic tremor
Wilsons disease
Hyperthyroid
Alcohol withdrawl
Hyperparathyroidism
Liver disease/kidney disease
Causes for Brown-Sequard syndrome (stabbed in the back syndrome)
MS CNS tumour Trauma - being stabbed or shot in the back on one side myelitis post-radiation myelopathy
Combination of extensor plantar response and absent reflexes
Extensor plantar response due to UMN signs
Absent reflexes due to peripheral neuropathy
DDx Subacute combined degeneration of the cord (B12) Friedreichs ataxia Syphillis - tabes dorsalis Conus medallris lesion Adrenoleucodystrophy
Myopathic pattern of weakness
Congenital
- muscular dystrophys (FSHD, myotonic dystrophy, DMD, Beckers, limb girdle MD)
- mitochondral disorders
Inflammatory
- inclusion body myositis
- polymyositis/dermatomyositis
- SLE, RA, PMR
- sarcoidosis
Drugs
- statins
- steroids
- alcohol
Endocrine
- hyper/hypothyroidism
- cushings
- acromegaly
- electrolyte abnormalities
- Vit D deficiency
Viral/infection
- HIV, viral
