Myasthenia Gravis and Multiple Sclerosis Flashcards
what is the most common disorder of neuromuscular transmission
- myasthenia gravis
what is myasthenia gravis caused by
- autoimmune disorder which attacked acetylocholine receptors at the NMJ
- causing weakness and fatigability of muscles
what are the two types of myasthenia gravis
- ocular myasthenia gravis
- generalized myasthenia gravis
myasthenia gravis is associated with what other conditions
-
other autoimmune conditions
- RA, SLE, autoimmune thyroiditis
-
thymus abnormality (75%)
- hyperplasia or thymoma
Myasthenia Gravis is hallmarked by weakness in what 4 things
- ocular
- bulbar (speech, chewing, swallowing)
- limb (typically upper extremities)
- respiratory muscles
what condition is characterized by fluctuating weakness and faitgue of specific. muscle groups. Weakness worse at end of day or after exercise.
myasthenia gravis
myasthenia gravis symptoms are worsened by
- hot temperature
- surgery
- emotional stress
- illness
- menstruation
- medication
List 3 medications that make myasthenia gravis worse
- Fluoroquinolones
- Beta blockers
- Hydroxychloroquine
what is the bimodal distribution of ae for myasthenia gravis
- 20s-30s (female > male)
- 60s-80s (male > female)
what studies would you do to assess for myasthenia gravis
- EMG and nerve conduction study
- will see decreased response on repetitive nerve stimulation
What test can be done for myasthenia gravis
- Edrophonium (Tensilon) test
- inhibits the enzyme acetylcholinesterase and allows the Ach to stimulate the limited number of Ach receptors
what is a quick screening test that can be done to check for myasthenia gravis
- Ice pack test
- cold temperature improve neuromuscular transmission
what are the serologic tests for autoantibodies to make the myasthenia gravis diagnosis
- AChR Ab: acetylcholine receptor antibodies
- MuSK Ab: Muscle specific kinase antibodies
why would you order a CXR or CT chest if you suspect myasthenia gravis
- chest for thymic abnormalities/thymoma
What is Lambert Eaton myasthenic syndrome
- impaired release of Ach
- often associated with small cell lung cancer
how can Lambert Eaton myasthenic syndrome be differentiated from Myasthenia Gravis
- LE:
- leg weakness common
- sx’s worse in morning and improve with exercise
what medication are patients with Myasthenia Gravis commonly put on treat symtpoms
- Pyridostigmine bromide (Mestinon)
- allows for prolonged effect of Ach strength
Pyridostigmine bromide (Mestinon) is best for tx of which symptoms
- limb and bulbar symtpoms
What is Multiple Sclerosis
- immune mediated inflammatory demyelinating disease of the CNS
- attacks myelin sheaths of nerves, causing plaques of demyelination
test of choice for Multiple Sclerosis
- MRI
- white matter changes - represent plaques within the myelin
what is the hallmark characteristic of Multiple Sclerosis
- symptomatic episodes that occur months to years apart and affect different anatomic locations
- seperation of time and space
Multiple Sclerosis usually affects what patient poplulation
- age: 15-45
- female > male
List the 4 types of Multiple Sclerosis
- Relapsing-remitting disease (RRMS)
- Clinically isolated syndrome
- Primary progressive (PPMS)
- Secondary progressive (SPMS)
what is the most common type of Multiple Sclerosis
- relapsing-remitting disease
describe relapsing-remitting disease
- clearly defined relapses with full recovery or some deficit
describe clinically isolated syndrome
- 1st attack of MS symptoms
differentiate between primary progressive MS and secondary progressive MS
- primary progressive: progressive increase in symptoms from disease onset
- secondary progressive: initially RRMS with gradual worsening
typical CNS symtpoms associated with Multiple sclerosis
- optic neuritis (eye pain leading to visual loss)
- paresthesia
- weakness
- cerebellar: nystagmus, incoordination, tremor
- Upper motor neuron signs
Lhermitte’s sign? associated with?
- neck flexion causes electrical shock sensation down back/limbs
- Multiple sclerosis
what is a marcus Gunn pupil and what is associated with
- shining light into eye with optic neuritis causes both pupils to dilate instead of constrict
- Multiple sclerosis
how is Multiple sclerosis diagnosed
- CNS lesion dissemination in TIME and SPACE
- clinical findings + MRI findings
CSF analysis of pt with Multiple sclerosis will likely show
- presence of oligoclonal IgG bands
evoked potential studies are used in Multiple sclerosis as a tool to
- measure the time a stimulus (at eye, ear, or peripheral nerve) takes to reach cerebral cortex
treatment of acute exacerbation of Multiple sclerosis
-
glucocorticoids
- large dose of oral prednisone x 3-7 d or IV methylprednisone
- Adrenocorticotropic injections if can’t use steroids
- plasma exchange if not responsive to steroids
