Differentials Flashcards
(34 cards)
Proximal weakness
MIND:
Metabolic: Cushing’s disease, hypothyroidism
Inflammatory: polymyositis/dermatomyositis, inclusion body myositis*
Neuromuscular: myaesthenia, LEMS
Dystrophies: Becker’s, FSHD, limb girdle
*(note: IBM primarily affects knee extension and finger flexors -> dexterity difficulties)
Bilateral UMN (pyramidal weakness)
3Ms: MS MND --> normal sensation Myelopathy --> sensory level - cervical myelopathy, disc prolapse, SOL, trauma, transverse myelitis, syringomyelia
Others: brainstem stroke, anterior cord infarction (–> sensory level)
Unilateral UMN (pyramidal weakness)
Work down (brain to cord)
- Intracranial: (+/- hemisensory loss): CVA, SOL, MS
- Brainstem: MS
- Spinal cord: –> sensory level. Trauma, SOL, abscess, AVM/haematoma
Bilateral LMN (distal weakness) with abnormal sensation distally
VIT DIM:
Vasculitis (SLE, RA, PAN)
Infection (herpes zoster, HIV)
Toxins (alcohol, TB drugs, vincristine/cisplatin, amiodarone)
Diabetes
Inherited (Charcot-Marie-Tooth)
Metabolic (B12 deficiency, B1 deficiency)
Bilateral LMN (distal weakness) with normal sensation, i.e. distal motor neuropathy
Guillain-Barre, CIDP
Myotonic dystrophy
Inclusion body myositis (proximal in legs but distal weakness in arms)
Progressive muscular atrophy (MND)
Unilateral LMN
Work down (nerve root to peripheral nerve)
- Radiculopathy (disc herniation, cervical spondylosis, spinal stenosis) –> dermatomal sensory loss
- Plexopathy (brachial neuritis, trauma, thoracic outlet syndrome, neoplastic infiltration) –> vast dermatomal sensory loss
- Isolated nerve palsy (median, ulnar, radial, axillary, common peroneal)
Bilateral LMN, acute
CES (leg weakness but also saddle anaesthesia, autonomic symptoms)
Guillain-Barre (sensation normal)
Mononeuritis multiplex
Vasculitis
Autoimmune: RA, SLE, Sjrogren, sarcoidosis
UMN + LMN
- MND
- Dual pathology (e.g. cervical myelopathy + polyneuropathy)
- Cervical radiculomyelopathy (–> LMN arm weakness, UMN leg weakness)
Cerebellar disease
MAVIS:
- MS
- Alcohol
- Vascular (infarction, stroke)
- Inherited (Friedreich’s ataxia, spinocerebellar ataxia, ataxia telangiectasia)
- SOL
Investigations:
- Bloods including thyroid function, WBC (FBC), CRP
- B12, folate, vitamin E, thiamine
- MRI +/- contrast
- LP if suspect infectious/inflammatory cause (MS, infection)
- Genetic testing if this is suspected
Complex ophthalmoplegia
Work posteriorly from the eye, i.e. soft tissue to brainstem:
- Soft tissue: thyroid eye disease
- NMJ: myaesthenia gravis (tip: test fatiguability)
- Multiple CNs: cavernous sinus syndrome, mononeuritis multiplex
- Midbrain/pons: stroke, SOL, trauma
Optic nerve atrophy, i.e. causes of reduced visual acuity
MS Temporal arteritis DM Compression (SOL, raised ICP) Glaucoma
3rd nerve palsy
Medical: diabetes/hypertension/hyperlipidemia (i.e. microvascualr disease), MS, mononeuritis multiplex affecting 3rd nerve. NB: if partial pupil-sparing 3rd, still worry about compression i.e. SOL or aneurysm.
Surgical (ptosis, down and out, dilated pupil): posterior comm. artery aneurysm, epidural haematoma (ipsilateral 3rd palsy), cavernous sinus thrombosis, SOL
6th nerve palsy
Raised ICP
Unilateral 7th nerve palsy LMN
Bell’s palsy, Ramsay-Hunt syndrome, brainstem [SOL, nucleus demyelination, stroke], parotid tumour/surgery, nerve infiltration (sarcoid, lymphoma)
Bilateral 7th nerve palsy LMN
Bilateral Bell’s palsy, nerve infiltration (sarcoid, lymphoma), autoimmune (myaesthenia, vasculitis), inflammatory (GBS), myotonic dystrophy
Bulbar palsy (LMN bulbar weakness)
MND, brainstem infart/SLO, myaesthenia gravis, GBS, syphilis
Pseudobulbar palsy (UMN bulbar weakness due to damage of corticobulbar tracts)
Pathologies: MND, MS, PSP / neurodegenerative disorders
Structural: brainstem infarct/SLO/MS, internal capsule infarct/small vessel disease, high brainstem tumour, PSP
UMN facial weakness (forehead-sparing)
MSA stroke, SOL in pre-frontal gyrus
Multiple cranial nerve lesions: CN 3-6
Cavernous sinus thrombosis
CN 5-8 + cerebellar signs
Cerebellopontine angle lesion
CN 9-10 + 12
Pseudobulbar/bulbar palsy
CN 9-10 + 11
Jugular foramen syndrome
CN 9-10 + Horner’s syndrome + cerebellar disturbance + sensory disturbance (ipsilateral face, contralateral body)
Lateral medullary (Wallenberg) syndrome