Myasthenia Gravis

Question 1

Myasthenia Gravis

Answer 1

is an autoimmune disease of the neuromuscular junction marked by fluctuating weakness of certain skeletal muscles that worsens with activity.

Question 2

Etiology

Answer 2

is caused by an autoimmune process in which antibodies attack and destroy ACh receptors

Question 3

Clinical Manifestations

Answer 3

The key feature of MG is fluctuating weakness of skeletal muscles

Muscles engaged in repetitive movements are affected the most

This includes muscles used to move the eyes and eyelids, chew, swallow, speak, and breathe.

Muscles are often strongest in the morning.

A period of rest usually restores strength

Question 4

ocular muscles

Answer 4

the first muscles involved causing ptosis (drooping of the eyelids) in 1 or both eyes and double vision

Question 5

Complications

Answer 5

difficulty chewing and swallowing food.

Speech is affected. The voice often is hoarse or fades after long conversations.

The muscles of the trunk and limbs easily fatigue.

Of these, the proximal muscles of the neck, shoulder, and hip are more often affected than the distal muscles.

Question 6

Drugs that can worse MG

Answer 6

β-adrenergic blockers, calcium channel blockers, lithium, quinidine, and aminoglycoside antibiotics

Question 7

Myasthenic crisis

Answer 7

is an acute worsening of muscle weakness triggered by respiratory infection, surgery, stress, pregnancy, exposure to certain drugs, or starting corticosteroid treatment.

Question 8

major complications of a myasthenic crisis

Answer 8

results from muscle weakness in areas that affect swallowing and breathing.

This can result in aspiration or respiratory insufficiency.

The patient may need a ventilator or noninvasive respiratory support (BiPAP).

Question 9

Diagnostic Studies

Answer 9

history and physical assessment

Single-fiber EMG is highly sensitive in confirming MG.

edrophonium test - rapid improvement after administration of edrophonium indicates MG

Question 10

Atropine

Answer 10

cholinergic antagonist, should be readily available to counteract the effects of edrophonium when it is used diagnostically.

Question 11

CT scan

Answer 11

may be done to evaluate the thymus

Question 12

Drug Therapy

Answer 12

anticholinesterase drugs, alternate-day corticosteroids, and immunosuppressants

Question 13

Pyridostigmine (Mestinon)

Answer 13

the best drug of this group for the long-term treatment of MG.

Question 14

cholinergic crisis

Answer 14

involuntary muscle contraction, extreme weakness, flaccid muscle paralysis, sweating, excessive salivation, diarrhea, and constricted pupils.

Question 15

In a cholinergic crisis,

Answer 15

giving edrophonium increases muscle weakness. The use of corticosteroids in addition to edrophonium have reduced the incidence of cholinergic crisis.

Question 16

Corticosteroids

Answer 16

are used to suppress the immune response.

Question 17

Surgical Therapy

Answer 17

thymectomy.

Question 18

Nursing care goals

Answer 18

maintaining adequate ventilation, continuing drug therapy, and watching for side effects of therapy.

Question 19

Nursing Implementation

Answer 19

Teach the patient about a balanced diet that can easily be chewed and swallowed. Semisolid foods may be easier to eat than solids or liquids.

Scheduling doses of drugs to reach peak action at mealtime may make eating easier.

Arrange diversional activities that need little physical effort and match the patient’s interests.

Help the patient plan ADLs to avoid fatigue.