Unilateral UMN (pyramidal weakness)

Work down (brain to cord):

• Intracranial – stroke, SOL → hemisensory loss
• Brainstem – stroke, SOL → may be crossed signs
• Spinal cord – MS, infarct/haemorrhage, SOL, disc prolapse, trauma, syringomyelia, congenital → sensory-level/segmental sensory loss

Bilateral UMN (pyramidal weakness)

3M’s:

• MS 
• Motor neurone disease → normal sensation
• Myelopathy – cord compression (e.g. due to cervical myelopathy, SOL, disc prolapse, paraspinal infection), trauma, transverse myelitis,  syringomyelia, congenital → sensory-level/segmental sensory loss
• Others – brainstem stroke, hereditary spastic paraplegia, cerebral palsy, HTLV-1, syphilis

Causes of unilateral LMN lesions – work down (nerve root to peripheral nerve)

Bilateral LMN (distal weakness)

Proximal weakness → Normal sensation  

DENIM:

• Dystrophies – Becker’s/Duchenne, limb girdle, facioscapulohumeral (shoulder, face and truncal weakness) 
• Endocrinological – Cushing’s syndrome, hyper/hypothyroidism, diabetic amyotrophy (lower limbs)
• Neuromuscular – myasthenia gravis (fatigable), Lambert–Eaton myasthenic syndrome
• Inflammatory – dermato-/polymyositis, inclusion body myositis (proximal in legs but distal in arms), viral myositis
• Metabolic/congenital/mitochondrial myopathies

Mononeuritis multiplex

• Vasculitis – granulomatosis with polyangiitis, eosinophilic granulomatosis with polyangiitis, polyarteritis nodosa, microscopic polyangiitis

• Autoimmune – RA, SLE, cryoglobulinaemia, Sjögren’s syndrome, paraneoplastic
• Infectious – Lyme disease, HIV, leprosy
• Others – diabetes mellitus, amyloidosis, sarcoidosis

UMN + LMN

• Motor neurone disease (no sensory deficit) 
• Dual pathology (e.g. cervical myelopathy + polyneuropathy)
• Myeloradiculopathy
• Subacute combined degeneration of the cord (symmetrical UMN signs with absent reflexes, impaired posterior column function, peripheral sensory neuropathy)

NB: spinal cord lesions can cause LMN signs at the site of the lesion and UMN signs below the lesion

Cerebellar disease

MAVIS:

• MS
• Alcohol
• Vascular – thromboembolic, haemorrhagic
• Inherited – Friedreich’s ataxia, spinocerebellar ataxia, ataxia telangiectasia           
• SOL

Cranial nerve palsies

Multiple cranial nerve palsies

• Any = mononeuritis multiplex, leptomeningeal process (e.g. tuberculosis, meningitis), SOLs, trauma, sarcoidosis, Lyme disease, neurosyphilis, vasculitis, botulism
• CN 3-6 = cavernous sinus lesion, Miller-Fisher syndrome
• CN 5-8 + cerebellar = cerebellopontine angle lesion
• CN 9-10
  • + 11 = jugular foramen syndrome
  • + 12 = pseudobulbar/bulbar palsy
  • + Horner’s syndrome + cerebellar + sensory disturbance (ipsilateral face, contralateral body) = lateral medullary (Wallenberg) syndrome

Complex ophthalmoplegia

Work posteriorly (soft tissue to brainstem):

• Soft tissue – Graves’ disease
• Muscle – mitochondrial myopathy
• Neuromuscular junction – myasthenia gravis (test fatigability)
• Multiple CN’s – cavernous sinus lesion, mononeuritis multiplex, MS
• Brainstem – stroke, SOL, trauma 

Ptosis

• Unilateral
  • Third nerve palsy (pupil ‘down and out’, dilated) – complete ptosis
  • Horner’s syndrome (pupil constricted) – partial ptosis
  • Idiopathic
• Bilateral
  • Myasthenia gravis
  • Myotonic dystrophy (frontal balding, facial muscle wasting)
  • Congenital
  • Neurosyphilis (Argyll Robertson pupils)

Horner’s syndrome

• 1^st order (central) – MS, spondylosis, SOL, syringomyelia, stroke/lateral medullary syndrome
• 2^nd order (pre-ganglionic) – Pancoast tumour, cervical rib, thyroid carcinoma/goitre
• 3^rd order (post-ganglionic) –  carotid artery dissection, radical neck dissection

Visual field defects

Choreoathetosis

• Chorea – stroke, Huntington’s disease, Sydenham’s chorea, drugs (e.g. antipsychotics, levodopa), HIV
• Hemiballismus – subthalamic stroke (most), SOL, traumatic brain injury, HIV
• Athetosis – asphyxia, neonatal jaundice, thalamic stroke
• Dystonia – primary dystonia, brain trauma, drugs, Wilson’s disease, PD, Huntington’s disease, stroke, SOL, encephalitis, asphyxia  

• Myoclonus – epilepsy, essential myoclonus, metabolic, psychological, toxins/drugs, SOL, MS, PD, Creutzfeldt-Jakob disease

NB: Wilson’s disease can cause any.

Parkinsonism 

• Parkinson’s disease
• Vascular parkinsonism
• Parkinson-plus syndromes: multi-system atrophy, progressive supranuclear palsy, corticobulbar degeneration, Lewy body dementia
• Other causes: antidopaminergic drugs, Wilson’s disease, communicating hydrocephalus, supratentorial tumours

Now try some viva questions

Now for some stations!

1. Charcot-Marie-Tooth
2. Motor neurone disease
3. Bells palsy
4. Horner’s syndrome
5. There’s lots more!