Myasthenia Gravis : Definition, Symptoms, Causes, Types, Diagnosis, Prognosis, Pathophysiology, Complications, Treatment, Living with Myasthenia Gravis

Myasthenia Gravis : Definition, Symptoms, Causes, Types, Diagnosis, Prognosis, Pathophysiology, Complications, Treatment, Living with Myasthenia Gravis
Myasthenia Gravis : Definition, Symptoms, Causes, Types, Diagnosis, Prognosis, Pathophysiology, Complications, Treatment, Living with Myasthenia Gravis

Myasthenia gravis (MG) is a serious neuromuscular and autoimmune disorder that leads to weakness in the skeletal muscles which gets worse after doing any activity. [1] Myasthenia gravis has no known cure yet, but therapies are under practice to improve the quality of life for patients having this autoimmune disorder. The neuromuscular symptoms of myasthenia gravis get better after resting for a period of time. The name of Myasthenia Gravis comes from Latin and Greek origin – which means serious or grave muscular weakness. The immune system mistakenly attacks on the skeletal muscles, these skeletal muscles are responsible for various important functions like moving body parts and breathing. However, the patients having myasthenia gravis can have a normal life expectancy but their quality of life decreases a lot due to inability to move.

The treatments available currently can often allow the patients to have a better quality of life and keep in check the symptoms of myasthenia gravis. The actual cause of myasthenia gravis is still unknown but the studies propose that a communication lag between muscles and nerve cells lead to the development of this neuromuscular disorder. The impairment in communication adversely affects the crucial muscular contractions to occur thus making the muscles weaker. The myasthenia gravis foundation of America reports that myasthenia gravis is one of the commonly occurring primary disorders involving neuromuscular transmission. The prevalence of myasthenia gravis is quite low because it is relatively rare and affects almost 14 to 20 people out of every 100,000 people.

Myasthenia gravis is typically a rarely occurring autoimmune disorder that might results due to a mutation in genes. An antibody mediates in the blockage of neuromuscular transmission that leads to rapid muscular fatigue and skeletal muscle weakness. The autoimmune disorder results from the abnormal autoimmune response when antibodies start forming at the neuromuscular junction of skeletal muscles in response to the nicotinic acetylcholine postsynaptic receptors.    In addition, the autoimmune disorder of myasthenia gravis mainly targets the receptors in skeletal muscles but there is also involvement of other antigenic components of the neuromuscular junction. The breakdown in the continuous nerve impulse transmissions between muscles and nerves results in skeletal muscle pain and fatigue.

In addition to the muscular weakness, a variety of symptoms like double vision, difficulty with speech, drooping eyelids, shortness of breath, and difficulty with swallowing also appear due to myasthenia gravis. [2] Though myasthenia gravis can affect people from any life span but it is more prevalent among men older than 60 years and women younger than 40 years. Facial muscles along with the skeletal muscles of limbs suffer more due to myasthenia gravis and it affects the ability of chewing, swallowing, facial expressions, and even speaking. Scientists believe that there is a malfunction in thymus gland which promotes the autoimmune attack on the neuromuscular transmission thus leading to myasthenia gravis. Thymus gland play important role in the development of immunity from early age but it remains abnormally large in adults thus indicating an autoimmune response leading to myasthenia gravis. The abnormal function of thymus gland might be due to inherited genes.

1Symptoms Of Myasthenia Gravis

Symptoms of Myasthenia Gravis
Symptoms of Myasthenia Gravis

Symptoms of Myasthenia Gravis

The onset of the myasthenia gravis might be sudden so the signs and symptoms might go unnoticeable at the beginning stages. The initial symptoms of myasthenia gravis in majority of the people is frailty of the eye muscles that usually leads to double vision, blurred vision, and drooping of the eyelids. While other people might suffer signs of slurred speech and swallowing problems. The severity of muscle weakness due to myasthenia gravis differs greatly among people, ranging from an isolated form limited to eye muscles weakness to a generalized form which is quite severe and involves numerous muscles. [3]

The severe form of muscular weakness leads to shortness of breath that might require ventilation and creates a medical emergency requiring an immediate medical assistance. Following are the 15 symptoms of myasthenia gravis:

Dropping of eyelids (Ptosis)

Patients having the ocular type of myasthenia gravis might also experience drooping in one or both eyelids which is mainly due to the weaker eye muscles. Drooping of eyelids is a condition known as Ptosis which also causes difficulties in focusing a person’s vision on a thing. The weakness of eyes muscles in ocular myasthenia gravis often causes the difficulties with the upward movement of eye at first and then either drooping of one eyelid or both. The drooping of both eyelids is known as bilateral Ptosis while drooping of one eyelid is known as unilateral Ptosis. Unilateral Ptosis or facial drooping is more common that occurs due to the changing muscle weakness. Ptosis usually occurs due to the disturbances in the levator palpebrae superioris (LPS) complex which changes the stability of eye movements.

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