Myasthenia Gravis

Myasthenia Gravis

an autoimmune disease

Learning outcomes

• Definition

• Explain pathophysiology

• Clinical manifestations

• Management & nursing care

Myasthenia Gravis (MG)

• Derived from Greek meaning severe muscle weakness 

• An autoimmune disease where the body attacks the receptors that allow for voluntary muscle control, which leads to muscle weakness.

• Commonly affects muscle innervated by the cranial nerves ( face, lips, tongue, neck and throat )

Multiple Select

Myasthenia Gravis is an autoimmune disorder

• YES

• NO

What voluntary muscles are involved?

• Eyes: most likely will be the first sign something is wrong

• Throat: another common sign…hoarse voice and problems swallowing

• Face

• Arms/Legs

• Respiratory muscles for breathing (in severe cases)

Risk factors

• Onset generally between ages 20 -30 

• 3 times more common in women than in men 

• Occurs along with thymic abnormalities in 75 % of patients 

Open Ended

What is the function of Thymus ?

Open Ended

How thymus abnormalities link to Myasthenia Gravis ?

Clinical Manifestations

Patients tend to notice symptoms in the eyes due to eye muscle weakness of the extraocular muscles or have problems with speaking (slurred) or swallowing….signs and symptoms vary among patients.

**HALLMARK:

muscle weakness becomes worse with activity (especially repetitive activity) but will improve after resting the muscle.

Signs & symtoms : “WEAKNESS”

• Weakness neck, face, arms/legs/hands

• Eyelid drooping…can be one eye or both (Ptosis)

• Appearance mask-like: no expression…looks very sleepy

• Keeps choking or gagging when eating (difficulty swallowing)… muscles help with the swallowing process have become weak

• No energy…very fatigued…gets worse throughout the day as muscles are used

• Extraocular muscle involvement leading to double vision…strabismus

• Slurred speech (voice may be hoarse and very soft)

  Short of breath (can extend to respiratory muscles)

Medical management

•Corticosteroids

•Immunosuppressant drug ( T. Imuran)

•Immunoglobulin therapy ( IVIg therapy )

•Plasma exchange (Therapeutic Plasma Exchange)

Medical management 

• Cholinesterase (ChE) inhibitors eg. Pyridostigmine (T. Mestinon 600mg/day ). 1st line therapy. Inhibit the breakdown of acetylcholine. Therefore, more of it will be available at the neuromuscular junction site , muscle strength improved.

• Patient should take 30 to 60 minutes before a meal to help increase muscle strength with swallowing and chewing.

Produce antigen specific immunosuppressive. Improve symptoms not a cure.

Multiple Choice

Myasthenia gravis is due to ____ receptors being blocked and destroyed by antibodies

• transient

• nicotinic

• epinephrine

• acetylcholine

Multiple Choice

In preparing patient for Tensilon test , the nurse explains the medication will confirm the diagnosis of Myasthenia Gravis if Tensilon produces

• brief exaggeration of symptoms

• prolonged symptomatic improvement

• rapid but brief symptomatic improvement

• symptomatic improvement of just the ptosis

Multiple Choice

The following finding is usually associated with the diagnosis of Myasthenia Gravis.

• Visual disturbances including diplopia

• Muscle rigidity and loss of coordination

• Ascending paralysis and loss of motor function

• Progressive weakness that is worse at the day’s end

Multiple Choice

A patient with Myasthenia Gravis has been receiving Neostigmine (Prostigmin). This drug acts by

• stimulating the cerebral cortex

• replacing deficient neurotransmitters

• blocking the action of cholinesterase

• accelerating transmission along neural junction

Multiple Choice

The most significant initial nursing observations that need to be made about a patient with Myasthenia include

• ability to chew and speak distinctly

• degree of anxiety of the diagnosis

• ability to smile and close her eyelids

• respiratory exchange and ability to swallow