Weakness and ataxia Flashcards
PRE MOTOR/MOTOR CORTICAL AREAS
i) where is the homunculus found?
ii) which area prepares the limb muscles for action
iii) where do corticospinal/spinal MNs come from in the brain? how do they get to skeletal muscle? (3)
iv) which part of the CS tract degenerates in MND?
i) primary motor area
ii) pre motor area
iii) from primary motor cortex (precentral gyrus) > pyramidal decussation > lat CS tract > skel muscle
iv) lateral CS tract in the spine (aka ALS)
INPUTS TO MOTOR CIRCUITRY
i) which two important areas input to motor system? via which brain area do they do this by?
ii) which part of the BG contains output neurons via direct/indirect pathway
iii) which pathway is the sub thalamic nucleus found in?
iv) where is dopamine released into and has influence?
v) which two nuclei does the cerebellum project to? what role does the cerebellum play?
i) basal ganglia and cerebellum via the thalamus
ii) caudate and putamen
iii) indirect pathway
iv) DA from substantia nigra into caudate and putamen (striatum)
v) ventrolateral and ventromedial nucleus
- smooths out movements to stop them being ataxic
NERVE ROOT DISORDERS (RADICULOPATHIES)
i) what is the most common disease to affect spinal roots? what happens? which two spinal areas are most affected?
ii) name two infective causes that often affect nerve roots?
iii) name two neoplastic causes
i) degenerative spinal disease aka spodylotic disease of the spine
- get hypertrophy of ligaments, disk and facet joint > squeezes disk out
- lumbar and cervical
ii) lyme disease or autoimmine eg CIDP and vasculitis
iii) neurofibromas or mets from breast/lung cancer > meninges
PERIPHERAL NERVE DISORDERS (NEUROPATHIES)
i) are sensory or motor PNDs more common?
ii) name two metabolic causes, toxic, inflam, infective or genetic
iii) which nerves are most affected by paraneoplastic causes? by what mechanism does this occur?
i) sensory (motor are more severe/disabling)
ii) metabolic - B12 defic, diabetes, hypothyroid
toxic - ETOH, drugs, heavy metals
inflam - CIDP, vasculitis
infective - VZV, leprosy, lyme disease
genetic - charcot marie tooth (motor > progressive weak affecting the feet first)
iii) PN > motor nerves due to cross reactivity of antibodies from cancer to glycoproteins in the nerves
DISORDERS OF PLEXI (PLEXOPATHIES)
i) loss of which nerve root will cause shoulder weakness/loss of abduction/biceps
ii) loss of which nerve root will cause triceps weakness?
iii) what does L4/L5 nerve root loss cause?
iv) weakness in which root causes difficulty going up on toes?
v) name a neoplastic, inflamm, vascular cause
i) C5
ii) C7
iii) foot drop > tibialis anterior loss
iv) S1
v) neoplastic - breast/bowel cancer
inflam - brachial neuritis
vascular - diabetes
MYOPATHIES
i) name three neuromuscular disorders
ii) are proximal or distal muscles more commonly affected? why?
iii) which muscles are commonly involved in NM disease?
iv) what is polymyositis?
v) what type mitochondrial disorder causes a ptosis/eye problems?
vi) name two other possible causes of proximal muscle myopathies?
i) myasthenia gravis, eaton lambert, botulism (release of Ach vesicles)
ii) proximal muscles - they are big and powerful (notice it in these muscles first)
iii) facial muscles eg MG see ptosis
iv) inflammatory muscle disorder that causes weakness > co exists with autoimmune diseases
v) kearns sayer syndrome
vi) hypothyroidism and severe vitamin D deficiency >osteomalacia
DISEASE SPECIFIC QUESTIONS IN THE HISTORY
name three specific signs seen in
Multiple sclerosis, migraine, MG, stroke, guillian barre, cauda equina, spinal cord compress/lesion, MND, menieres
MS - prev hs ox optic neuritis, bladder symptoms, L’hermittes symptom (electric shock on neck movement)
migraine - sensory march over mins, scotoma
MG - ptosis, diplopia, jaw/neck drop, dysphagia
stroke - hemi distribution, sudden onset, RFs
GB syndrome - food poisoning/viral illness
CE syndrome - back pain, perineal numbness, loss of bladder control
spinal cord compress - sensory level, bladder urge/freq, neck/back pain
MND - muscle fasiculation, dysphagia, weight loss
Menieres - concurrent deafness, tinnitus, otolithic crises
ANATOMICAL LOCALISATION
i) which areas is affected in hemiparesis involving the face? proximal muscle weakness?
ii) where is the weakness if fluids come from the mouth out the nose?
iii) which neurons are implicated in bulbar/pseubulbar voice?
i) face - contralateral brain
- prox muscle - NM junctions
iii) palatal weakness
iii) bulbar = LMN, pseudobulbar = UMN
BROWN SEQUARD SYNDROME
i) what is it?
ii) what sensation is lost on the opposite side of the lesion?
iii) what two things are lost on the same side as the lesion?
i) are spinal disorder that results from an injury to one side of the spinal cord in which the spinal cord is damaged but is not severed completely. It is usually caused by an injury to the spine in the region of the neck or back.
ii) contra side > loss of pain and temperature (ST tract)
iii) same side > UMN weakness and loss of position/vibration
HIP FLEXION EXAM
i) what position should the leg be in when examining hip flexion? which muscle does this test?
ii) which MNs are tested by this?
iii) what MNs does babinski response test? name two other features
i) flexed position > allows testing of illiopsoas
ii) illiopsoas testing > most sensitive way to test UMN lesions
iii) UMNs > brisk reflexes and spasiticty
FOOT DROP
i) compression of which two nerves can cause it? radiculopathy at which two spinal levels can cause it?
ii) name two muscle causes
i) compress of common peroneal at fib neck and sciatic nerve
- radic L4/5
ii) distal muscle dystrophy, inclusion body myopathy
