• Myasthenia gravis is derived from the Latin and Greek words myasthenia and gravis.
• Myasthenia – weakness
• Gravis – serious.
• This means “muscle weakness”.
• Myasthenia gravis is a neuromuscular disorder.
• Myasthenia gravis occurs due to an antibody-mediated autoimmune attack.

Myasthenia gravis Definition

Myasthenia gravis is an autoimmune disorder that affects the myoneural junction, characterized by weakness of the voluntary muscles and fatigue. Myasthenia gravis is caused by antibodies that interfere with the transmission of acetylcholine at the neuromuscular junction.

Myasthenia gravis of Cause

• Idiopathic
• Autoimmune disorder (antibody formation)
• Genetic factors
• Aging factors
• Enlargement of the thymus gland
• Infection and fever
• Pregnancy
• Decrease secretion of acetylcholine
• Decrease the number of acetylcholine receptor
• Increase concentration of cholinesterase.

Myasthenia gravis Pathophysiology  

Cause

↓

Autoimmune disorder

↓

Antibody formation

↓

Decrease the number of acetylcholine receptor

↓

Decrease the nerve transmission

↓

Muscles weakness and fatigue

↓

Loss of function.

Clinical Manifestation  

• Ptosis (dropping of one or both eyelids)
• Diplopia (double vision)
• Slow or aimless body movement
• Difficulty or swallowing (dysphagia)
• Hanging of jaw
• Chewing difficulty
• Weakness in the chest muscles
• Hoarseness cough voice
• Decrease cough reflexes
• Affect the daily activity
• Dysarthria (altered speaking)
• Dyspnoea
• Diaphragmatic weakness
• Respiratory failure.

Myasthenia gravis Diagnosis

• History collection and physical examination.
• Electromyography (EMG) – To assess muscle weakness and contraction.
• CT scan and MRI.
• Serum test – for acetylcholine receptor or antibodies.
• X-ray.
• Spo2 assess.
• Tensilon test – give tensilon medication.

Treatment of Myasthenia gravis

• Immunosuppressive therapy – prednisolone.
• Anticholinesterase medication – To decrease cholinesterase.
• Intravenous immunoglobulin therapy.
• Plasmapheresis – filtration of plasma.
• Drug of choice of Myasthenia gravis – Neostigmine.
• Ventilatory support.

Myasthenia gravis Surgery

• Thymectomy – surgical is removing the thymus gland.

Complications in Myasthenia gravis 

• Respiratory failure
• Dysphagia
• Myasthenia crisis
• Cholinergic crisis
• Bone marrow suppression.

Nursing Management of Myasthenia gravis

• Nurses monitor patients’ voluntary muscle movement and vital signs.
• Assess patient airway, breathing and Circulation patterns.
• Assess patient swallowing patterns and prevent aspiration.
• Promote energy conservation measures.
• The Administrator prescribed medication as scheduled.
• Nurse maintain the emergency bedside article such as – Airway, ET tube, suction and ventilator etc.
• Maintain a patient diet pattern.
• Provide safety precautions, because they suffer from double vision.
• Manage bedside emergency medication – such as tension and atropine drugs.
• Nurses monitor patients’ ability to cough, swallow and speak.
• The nurse will ask the patient to wear a medical alert bracelet.
• Nurses will educate all the family members of the patient about Patient safety care.
• Nurses will be provided health education.

Myasthenia gravis Key Points

1. Autoimmune neuromuscular disorder of – Myasthenia gravis.
2. Most common cause of MG is – Autoimmune disorder.
3. Common symptoms of MG – Ptosis.
4. Common diagnostic procedure of MG – Tensilon test.
5. Most common surgery used in MG – Thymectomy.
6. Myasthenia gravis mainly affects the gland – Thymus gland.
7. Which finding is associated with MG – Progressive weakness of muscles.
8. Drug of choice for Myasthenia gravis – Neostigmine (pyridostigmine). 
9. Common goal for a client with MG is – Maintain muscles strength.
10. Myasthenia gravis was confirmed by – a positive Tensilon test.