Myasthenia Gravis

What is an autoimmune disease process that causes a defect in NMJ→ impacts ability of nerve impulses to be transmitted to muscles

Antibodies block or destroy receptors for uptake of ACh→ prevents muscle contraction

Often associated w/ enlarged thymus, diabetes, RA, other immune disorders

Myasthenia Gravis

what is the incidence of Myasthenia Gravis?

20 per 100,000 in US

Females > Males under 40; Males > Females over 50

how is Myasthenia Gravis medically dx?

Primarily thru clinical exam

Lab tests & procedures generally are used to confirm a dx: Serum testing (for antibodies), Electrophysiologic testing (for nerve conduction), Imaging (to look for enlarged thymus OR a lesion that could be causing sxs (not MG)), Other lab testing to rule out other autoimmune disorders

what is the clinical presentation of Myasthenia Gravis?

Fluctuating muscle weakness that varies in severity, gets worse w/ activity, & improves w/ rest. Can fluctuate w/in min OR over a longer time period

Ocular muscles are often affected 1st (diplopia, ptosis)

Bulbar weakness→ dysphagia, dysarthria, CN weakness

Limb weakness: Proximal > Distal; UE > LE

Myasthenia crisis→ impacts to diaphragm & intercostals→ medical emergency

NO autonomic or sensory signs

what is the clinical course of Myasthenia Gravis?

Fluctuating w/ remissions & exacerbations

Fluctuations are usually not complete or permanent

What is the prognosis for Myasthenia Gravis?

Near-normal lifespan

Morbidity occurs generally due to intermittent weakness leading to aspiration pneumonia, adverse effects of meds, or myasthenia crisis. Myasthenia crisis is managed MUCH better today, only about 5% will lead to death

What is the medical mgmt for Myasthenia Gravis?

Cholinesterase enzyme inhibitors→ prevent attack on receptors

Immunosuppressants including corticosteroids→ to reduce immune system response

IVIg or Plasmapheresis→ often used w/ a myasthenia crisis

what are the general PT goals/mgmt for Myasthenia Gravis?

Acquire ‘baseline” respiratory & neuro status & monitor for any changes

Strengthening is helpful when sxs are mild/moderate. Isometrics

Education regarding energy conservation, side effects of pharmacology, signs of respiratory crisis, signs of osteoporosis

AVOID: strenuous exercise, stress, heat/cold