motor disorders Flashcards
myasthenia gravis (MG)
- painless weakness and fatiguability of skel muscles
- disease of NMJ
- bimodal age distribution: women 20-30, men 50-60
most common pathophys of MG
- autoab directed against AcH receptors
- decreased AcHR at post synaptic muscle membrane
- causes weak contractions
- AcH does not get repleated fast enough
pathophys of MG in 15% of pts
- MuSK ab -> decreased AChR on membrane
- impacts trafficking of receptors
what is usu assoc with MG
- thymus disorder
- hyperplasia in young
- thymoma in older: benign or malignant
si/sx of MG
- weakness and fatiguability- worse with repetitive stim
- exacerbations and remissions possible
- infx or systemic disorders -> crisis
- diplopia
- ptosis
- facial weakness
- nasal timbre speech
- difficulty swallowing -> aspiration risk
diagnosis of MG
- Ab to AChR, MuSK, or Ipr4
- electro diagnostic testing: repetitive nerve stimulation -> reduced amplitude
- edrophonium -> improved muscle strength
- CT or MRI to exclude intracranial lesions
treatment of MG
- long acting anticholinesterase: pyridostigmine or neostigmine
- immunosuppressants
- surgical thymectomy
- plasmapheresis in crisis
- IV IG in crisis
immunosuppressants used in MG
- steroids*
- cyclosporine A
- azathioprine
- mycophenolate mofetil
- MTX
- cyclophosphamide
what is a tic
- brief, rapid, recurrent, purposeless motor contraction
- motor vs sensory
types of motor tics
- simple: individual muscle groups
complex: multiple muscle groups - phonic ticks: simple vs complex
tourette’s syndrome
- multiple motor tics often present with vocalizations/ phonic tics
- mainly affects males
- can suppress tic for short period of time but then experience irresistible urge to express them
- varies in intensity
etiology and pathogenesis of tourette’s syndrome
- thought to be genetic
- no specific gene mutation
- may have enviorn influence
- possibly d/t decreased dompamine, opioids, second messenger systemics
treatment for tourette’s
- education, counseling
- no singular effective tx
- alpha adrenergic agonists: clonidine, guanfacine
- neuroleptics: typical vs atypical
- botulism inj if focal tic
- deep brain stimulation possible
guillain barre syndrome
- acute, severe fulminant polyradiuclopathy
- acute onset immune mediated demyelinating neuropathy
- does not impact CNS
- majority occur 1-3 weeks after acute respiratory or GI infx
causes of GBS
- campylobacter jejuni most common in US
- CMV, EBV
- HIV
- mycoplasma pneumonia
- flu, rabies vaccine
si/sx of GBS
- rapidly evolving ascending paralysis
- weakness evolves over hours- days
- asoc with tingling dysesthesias in extremities
- legs more affected than arms
- facial diapresis
- pain
- autonomic involvement -> fluctuation in BP, postural hypotension, cardiac dysrhythmias
subtypes of GBS
- acute inflammatory demyelinating polyneuropathy- most common
- acute motor axonal neuropathy
- acute motor sensory axonal neuropathy
pathophys of GBS
- demyelination -> conduction block -> flaccid paralysis and sensory disturbances
- axonal conduction usu remains in tact
- if axonal degeneration -> longer recovery and residual disability
diagnosis of GBS
- based on rapidly evolving paralysis with areflexia, absence of fever, systemic sx, hx
- CSF findings: increased proteins without pleocytosis
- electrodiagnostics- slowed conduction velocity, conduction block, temporal dispersion
treatment of GBS
- IV IG or plasmapheresis
- steroids not effective
- 30% require vents
- most fully recover within few months to a year
- death secondary to pulm complications
cerebral palsy
- neuro dysfunction that occurs in developing brain
- perm affects body mvmt, muscle coord, posture, balance
- not progressive
what is the most common cause of CP
- antenatal causes
- cerebral dysgenesis
- congenital infections (TORCH)
- substance abuse
- prematurity
other causes of CP
- intrapartum: birth asphyxia, trauma
- post natal: intravent hemorrhage/ ischemia, meningitis, encephalitis, head trauma, hyperbilirubinemia
types of CP
- spastic- most common
- dyskinetic
- ataxia
spastic CP
- produces upper motor neuron type disease
- d/t cortex damage
- muscles stiffer than usual
- may only be present in one part of body, half of body, or one side
- extensors of UE
- flexors of LE
- tip toed walk
dyskinetic CP
- d/t basal ganglia damage
- recurrent uncontrollable mvmnt
- tone fluctuates
ataxic CP
- d/t cerebellum damage
- least common type
- generalized hypotonia
- loss of muscle coord
- wide gait
PE findings for CP
- delayed motor dev
- persistent or late primitive reflexes
- spasticity, hyperreflexia, ataxia
- involuntary mvmt
- microcephaly
other neuro disorders assoc with CP
- most have pain
- bladder problems
- seizure disorder
- sleep disorder
- varying degree of language, behavioral, vision, and sensory disorders
diagnosis of CP
- MRI
- genetic and metabolic testing
treatment for CP
- general mgmt- nutrition and proper care
- pharm mgmt based on sx
- surgery to relieve muscle tightness
- physical aids
- rehab services
- family services
pharm options for CP
- botox, baclofen for muscle spasms and seizures
- glycopyrrolate- control drooling
- pamidronate- help with osteoporosis
multiple sclerosis
- autoimmune disease of CNS
- chronic inflammation, demyelination, gliosis, and neuronal loss
- can be relapsing or progressive
- course is VERY variable
risk factors for MS
- genetic predisposition
- vit D def
- EBV exposure after early childhood
- cigarette smoking
- high salt diet
pathogenesis of MS
- perivenular cuffing by inflammatory mononuclear cells, predom T cells and macrophages
- BBB gets disrupted
- demyelination is hallmark
- spares axons usually
si/sx of MS
- optic neuritis
- exs induced weakness of limbs
- facial weakness
- spasticity
- ataxia
- vertigo
- sensory sx: paresthesias, hypesthesia
optic neuritis
- often presenting sx of MS
- diminished visual acuity
- dimness
- decreased color perception
- occurs in central field of vision
clinical types of MS
- remission
- relapsing remitting disease
- secondary progressive disease
- primary progressive disease
remission of MS
- remodeling of demyelinating axonal plasma membrane
- more Na channels to permit conduction despite myelin loss
relapsing remitting disease of MS
- progression with relapses of active disease
- complete recovery during remission
secondary progressive MS
- disease becomes more aggressive
- consistent worsening of function
- usu progression from relapsing remitting disease
primary progressive MS
- sx are progressive from onset
- early disability
- only about 15% of pts
diagnosis of MS
- 2 episodes of 2 that occur at different points in time
- absence of other causes
- MRI shows plaques
- LP- mild pleocytosis and total protein normal
- slowed or abnormal conduction in response to visual or auditory stimuli
treatment for acute attacks of MS
- IV methylprednisolone 3-5 d
- +/- PO taper over 2 weeks
long term tx for MS
- disease modifying therapy
- spasticity: baclofen, cyclobenzaprine
- optic neuritis: steroids
- fatigue: amantidine, anti-depressants
- pain: gabapentin, pregabalin
- tremor: propranolol, primodone
what are the disease modifying agents for MS
- interferon beta
- dimethylfumerate
- natalizumab
- alemtuzumab