Neurology Flashcards
Functional division of the pyramidal tracts?
What are pyramidal tracts responsible for?
Corticospinal tracts-lateral and anterior
Corticobulbar tracts
Responsible for voluntary control of musculature of body and face
Structure of corticospinal tracts/what path do they follow?
Originate at cerebral cortex and pass through medulla oblongata
- Lateral corticospinal tract (90%) decussate at medulla and terminate in the ventral horn (at all segmental levels)
- Anterior tract remains ipsilateral and decussates/terminates in cervical/upper thoracic segmental levels
What do the extrapyramidal tracts do?
What tracts are there?
Where do they originate, and which decussate?
Involuntary and autonomic control of all musculature eg muscle tone, balance, posture, locomotion
All originate at the brainstem
Vestibulospinal and reticulospinal don’t decussate
Rubrospinal and tectospinal decussate
How many pairs of spinal nerves are there?
31
8C, 12T, 5L, 5S, 1C
What would examination of an UMN lesion show?
Normal muscle bulk, increased tone, decreased strength, no fasciculations, hyperreflexia (brisk)
What would examination of a LMN lesion show?
Decreased bulk/wasting, normal or decreased tone, decreased strength, may have fasciculations, decreased or absent reflexes
Name peripheral neuropathies (polyneuropathy) that are predominantly motor loss
Guillain barre syndrome (GBS), chronic inflammatory demyelinating neuropathy (CIDP ie chronic version of GBS), hereditary sensiromotor neuropathies (HSMN eg Charcot-Marie-Tooth disease), diphtheria, porphyria
Name peripheral neuropathies (polyneuropathy) that are predominantly sensory loss
Deficiency states eg B12/folate, diabetes, alcohol/toxins/drugs, leprosy, amyloidosis, metabolic abnormalities eg uraemia
Defining features of polyneuropathy?
Usually chronic and slowly progressive, starts in legs and longer nerves, can be sensory/motor/both
What is mononeuritis multiplex?
Painful, asymmetrical, sensory and motor neuropathy, subacute presentation.
Inflammatory/immune mediated.
Common causes=vasculitides eg Churg Strauss and connective tissue disorders eg sarcoid
Name 2 common mononeuropathies
Carpal tunnel syndrome-median nerve compression in flexor retinaculum
Common peroneal nerve in the leg
Ulnar nerve at the elbow
Radial nerve in the axilla
What investigations are involved in a neuropathy screen?
FBC, ESR, U+E, glucose, TFT, CRP, serum electrophoresis, B12 and folate, anti gliadin, (TPHA and HIV)
What investigations are involved in a vasculitic screen?
FBC, ESR, U+E, Cr, CRP, ANA, ANCA, anti dsDNA, RhF, complement, cryoglobulins
Principles of treatment of inflammatory neuropathy?
And vasculitic neuropathy?
Inflammatory eg CIDP: prednisolone with steroid sparing agent such as azathioprine
Vasculitic eg with Wegners: prednisolone with immunosuppressant such as cyclophosphamide
How does GBS arise?
What is it?
Autoimmune response leading to demyelination
Post infectious- respiratory or GI (campylobacter)
Subacute (<6 weeks), ascending paralysis/numbness/areflexia
What will you see on LP with GBS?
Raised CSF protein
How to manage GBS?
Treat with IV Ig or plasmapheresis Supportive Monitor FVC Consider ITU review Recovery may take weeks to years
What is Myasthenia Gravis?
Autoimmune disorder with antibodies against nicotinic ACh receptors
Commonly due to thymus dysfunction- hyperplasia and thymomas
Results in generalised and fatiguable weakness
Different potential presentations of MG?
Proximal limbs, neck and face (head drop and ptosis), extraocular (complex diplopia), bulbar (speech and swallow issues especially in elderly), ocular (seen in 10-25%)
NB/ at risk of other AI diseases
How to investigate for MG?
Tensilon test used in the past
Look for AChR antibodies
EMG-looking at NMJ
CT thorax (breathing)
How to treat MG?
Acetycholinesterase inhibitors eg pyridostigmine
Immunosuppressants- steroids started slowly, azathioprine/methotrexate/mycophenolate
Thymectomy if indicated
What is a myasthenic crisis?
Severe weakness including respiratory muscles-high risk of death
Caused by infection/natural disease cycle/under or overdose of medication
Urgent reviews by anaesthetists and neurologists needed
Tx = IV immunoglob and plasma exchange
What is MND? UMN or LMN? How to diagnose? What is spared? Survival?
Degeneration of motor neurons in motor cortex and anterior horns of spinal cord. Asymmetric weakness. Bulbar or limb onset.
UMN and LMN signs
LP/EMG/MRI to rule out, mainly a clinical diagnosis
No sensory, visual or bladder/bowel involvement
Usually 2-5 years survival
Name 2 common muscle disorders
Steroid myopathy, statin myopathy, metabolic and endocrine myopathies, myotonic dystrophy