Clinical Neurologist’s approach to the nervous system Flashcards
“Short game”
Pattern recognition
“Long game”
Deduction from knowledge
“Gelstalt”
Seeing the gaps what is not there
Treating people= biological and psychological factors
Describe the short game approach
- Localisation (where the problem is anatomically, what functional systems affected)
- Generation of differential diagnosis (pathophysiologically)
- Perform tests to confirm or exclude differential diagnostic options
What can we use to rank the differential diagnosis options?
- Speed of evolution (abrupt= vascular, subacute= inflammation/ neoplastic, slow= degenerative)
- Knowledge of disease epidemiology
- Knowledge of risk factors for each
Patterns of visual loss
- Total right eye blindness/ monocular blindness= optic nerve, optic neuropathy
- Bipolar hemianopia= optic chiasm
- Left nasal hemianopia
- Right homonymous hemianopia
- Left homonymous hemianopia with macular sparing
What are the common motor and sensory patterns?
- Hemispheric lesion (one side)
- Brainstem lesion (ipsilateral in face, contralateral in body
- Spinal cord lesion (weakness in legs)
- Polyneuropathy (glove and stocking)
- Myopathy (muscle disease in large proximal muscles)
What helps with spinal root patterns?
- Dermatomes
- Myotomes
- Reflex levels
What conditions should we learn for peripheral NS/ mononeuropathies?
Entrapment syndromes
- Carpal tunnel syndrome
- Cubital tunnel syndrome
- Saturday night palsy
- Common peroneal palsy
What is the clinical presentation approach?
Balance problem/ falls
- Input?= Eyesight, vestibular function, joint position sense
- Processing?= Cerebellar dysfunction (fine tuning)
- Output?= extrapyramidal disorder (tone, posture, reduced speed of righting reflexes), pyramidal disorder (weakness due to corticospinal tract dysfunction)
Non-focal common presentations
- Headache
- Dementia / Cognitive impairment
- Paroxysmal episodes ± reduced consciousness
- Tremor
- Other movement disorders (hypo and hyper-kinetic)
What does a motor deficit suggest?
There’s a problem somewhere along the pathway from pre-central gyrus (motor strip) to muscles in the legs.
What does symmetry suggest?
It affects both legs equally, so let’s test whether there are any parts of the pathway that this might not be possible (so we can exclude them).
What is Parsimony/ Occam’s razor?
we want a single lesion (if any site exists where possible) – because that’s the most likely explanation
Lumbar spinal cord pathology
Compressive lesion
Extradural (e.g. disc/osteophyte bar, tumour, abscess, spondylosis)
Intradural (e.g. tumour)
Intramedullary (tumour / syrinx)
Inflammatory lesion (e.g. MS, Neuromyelitis Optica, sarcoid etc.)
Vascular lesion (e.g. Dural AV Fistula)
