Myasthenia gravis is an autoimmune disorder causing muscle weakness by interfering with signal transmission from nerves to muscles. Antibodies destroy or deform receptors at the neuromuscular junction, preventing normal muscle contraction. Symptoms include drooping eyelids, blurred or double vision, weakness in the face, throat, and limbs. Diagnostic tests include the edrophonium test, blood tests for antibodies, repetitive nerve stimulation, and pulmonary function tests. Treatment involves cholinesterase inhibitors, corticosteroids, immunosuppressants, and plasmapheresis. Nursing care focuses on managing breathing, mobility, communication, and risk of aspiration due to muscle weakness.
3. DEFINITION:
• Myasthenia gravis is an autoimmune
disorder affecting the myoneural
junction, is characterized by varying
degrees of weakness of the voluntary
muscles.
4. CAUSES:
• In MG, the receptors at the muscle
surface are destroyed or deformed by
antibodies that prevent a normal
muscular reaction from occurring.
• The causative factor is unknown, but the
disorder may have a genetic link.
5. RISK FACTORS:
Risk factors for myasthenia gravis
include:
• Female gender and age under 40 years
• Male gender and age over 60 years
• Other autoimmune disorders
6. Factors that can worsen myasthenia
gravis
• Fatigue
• Illness
• Stress
• Extreme heat
• Some medications — such as beta
blockers, calcium channel blockers,
quinine and some antibiotics
8. • Weakness of the muscles of the face and
the throat, and generalized weakness.
Weakness of the facial muscles results in
bland facial expression.
• Laryngeal irritation causes voice
impairment and dysphonias and
increases the patient’s risk for choking
and aspiration.
9. • Generalized weakness of all the
extremities and the intercoastal
muscles resulting in decreased
respiratory capacity and vital capacity.
• Myasthenia gravis is purely a motor
disorder with no effect on the
sensation and coordination.
10. DIAGNOSTIC TEST:
• Edrophonium test:
Injection of the chemical edrophonium
(Tensilon) may result in a sudden,
although temporary, improvement in
muscle strength - an indication that
patient may have myasthenia gravis.
11. Blood analysis
• A blood test may reveal the presence of
abnormal antibodies that disrupt the
receptor sites where nerve impulses
signal muscles to move.
12. Ice Pack Test
• Cooling may improve
neuromuscular transmission. In a
patient with myasthenia gravis who
has ptosis, placing ice over an
eyelid will lead to cooling of the lid,
which leads to improvement of the
ptosis.
16. DIETARY MANAGEMENT
• Reduce protein intake to 10 percent of
total calories; replace animal protein as
much as possible with plant protein
• Eliminate milk and milk products
(substitute other calcium sources).
• Eat more fruits and vegetables (make
sure that they are organically grown).
17. • Eliminate polyunsaturated vegetable
oils, margarine, vegetable shortening, all
partially hydrogenated oils, and all foods
(such as deep-fried foods) that might
contain trans-fatty acids. Use extra-virgin
olive oil as your main fat.
• Take ginger.
18. NURSING MANAGEMENT
• Ineffective breathing pattern related to
intercoastal muscle weakness
• Impaired verbal communication related
to weakness of the larynx ,lips, mouth,
paharynx and jaw
19. • Impaired physical mobility related to
voluntary muscle weakness
• Risk for aspiration related to weakness of
the bulbar muscles
• Disturbed sensory perception related to
ptosis,and decreased eye movements.