Myasthenia Gravis: Autoimmune Neuromuscular Paralysis & Its Measurement - Essay Sample

Introduction

Myasthenia Gravis is an autoimmune health condition that causes neuromuscular paralysis. It is characterized by weakness and fatigue of various muscle groups, such as the ocular, bulbar, and the limbs of the patient. The disease is caused by the blockage or destruction of the acetylcholine receptors by antibodies at various neuromuscular junctions, hence inhibiting muscle contraction. In measuring the severity of the diseases, all relevant impairments and their respective variations are reflected in the activity and fatigue.

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ICD-10 Code for the Respective Condition

G70.00

The Naming of the Impaired Structures

The weakness of the muscles and fatigability are the underlying defects of the neuromuscular transmission in MG, which manifests clinically. The impaired muscles include:

• Extra-Ocular
• Bulbar
• Axial/limbs

The affected structures vary in different patients, in which some exhibit only the ocular diseases while others experience a combination of impairments. According to (Barnet et al., 2014), fatigability does affect not only whole body but also affects particular impairments, and therefore affects diagnosis due to fluctuating symptoms.

Overview of the Primary and Secondary Functions for All Specific Structures

Ocular

The six extraocular muscles are innervated by three cranial nerves, namely; oculomotor, trochlear, and abducens nerve. When these nerves are blocked or damaged, both the primary and secondary functions are impaired. All these muscles perform antagonistic actions. For instance, the lateral rectus and medial rectus have only primary functions, which are abduction and adduction, respectively. The superior rectus and inferior rectus are involved in elevation and depression (primary) and incyclotorsion and excyclotorsion (secondary actions), respectively. Finally, the superior oblique and inferior oblique perform incyclotorsion and excyclotorsion (primary) and depression and elevation (secondary), respectively.

Bulbar

The bulbar muscles are all the muscles of the throat and mouth that perform various primary and secondary functions such as ingestion, voice, and speech, respiratory, movement of the lower facial muscles. They enable chewing, swallowing, articulation, and maintain the right voice quality.

Axial/Limbs

The upper limbs are affected by the disease than the lower limbs. In the upper limb, muscles affected include the extensor carpi radialis longus, flexor carpi radialis, and extensor carpi radialis brevis, which function are the extensors of the wrist and the fingers, and the deltoid muscle which abducts the arm. Muscles in the lower limb affected are the quadriceps, which function as a hip flexor and knee extensor, and the hamstring muscles, which are extensors of the hip.

Signs and/or symptoms of a Positive Screen and/or Diagnosis

• Ocular symptoms include difficulty in rising eyelids (ptosis), and double vision.
• Bulbar symptoms are trouble talking, hoarse voice, unusual facial expression, difficulty in swallowing, and chewing.
• Signs involving the limbs include difficulty in lifting objects and walking upstairs.
• General body fatigue.

Relationship Between the Impaired Structures and the Reflected Symptomatology

Unless the extraocular muscles are functioning normally, normal eyesight cannot be maintained. Failure of the impulse to reach the muscles due to blockage of muscle junctions results in paralysis or inability to control eye movement resulting in double vision and drooping eyes.

Additionally, if the muscles of the mouth and throat are affected, then the patient may experience difficulty in chewing, especially if the food is hard, swallowing, and may result in choking, coughing, or even inhaling of fluids (Myasthenia Gravis, n.d.). Sometimes the fluid can come out through the nose. Speech may also become nasal, and one experiences difficulty in smiling if certain muscles are affected, resulting in an unusual smile. This follows the inability of the muscles to receive impulses from the brain that encode for proper mastication and peristalsis.

If there is compromised transmission of an impulse to the mentioned muscles of the leg and arms, then the contraction of these muscles become difficult, hence the inability to perform the intended task. The hamstring muscles, for instance, are important during walking on the flat surface and also aids the gluteal Maximus while climbing stairs. If muscle contraction is inhibited, then walking becomes an issue.

An Example of a Medical Problem and a Goal for the Condition

Myasthenia crisis is a complication resulting from myasthenia gravis. There are a variety of factors that contributes to the complication when one is already diagnosed with myasthenia gravis such as lack of medical treatment, exposure to surgery, emotional stress, and respiratory infections (Chaudhuri & Behan, 2009). It is characterized by extreme muscle weakness, especially to the chest and diaphragm muscles leading to respiratory failure (Myasthenia Gravis Foundation of America, n.d). Airways become blocked, mucus builds up hence ineffective or shallow breathing, racing heart, and pale skin color.

In such a situation, mechanical breathing assistance is required. A ventilator is therefore incorporated to help the patient to breathe. Endotracheal intubation ensures that there is oxygen supply to the lungs regardless of the failure of the muscles to support natural breathing. Additionally, if the crisis has not yet fully developed, one can be admitted and carefully monitored with aggressive specialized medication (Myasthenia Gravis Foundation of America, n.d). This way, the full crisis is prevented.

An Example of a Functional Limitation or Problem With Activity and Participation Limitations and a Functional Goal for the Condition

There are different ways of dealing with the impairments resulting from the disease. The drooping eye can be dealt with by placing an ice pack on the eyelid. The cooling effect resulting from the ice enhances the neuromuscular transmission hence an improvement of the ptosis.

Taking a rest improves the symptoms, especially with people suffering from the impairment of the limbs. According to Brazier, physical activity worsens the symptoms (2018). However, patients that endure long-term vigorous exercise, symptoms tend to reduce with time. This is caused by repetitive nerve stimulation to the muscles. The more they are stimulated, the more likely they are going to transmit the impulse to the muscles, hence leading to improvement.

Admission of the immunosuppressing drugs also helps to reduce the symptoms of the myasthenia gravis, in all the impaired muscles. These drugs lower the body's ability to produce antibodies in response to various antigens in the body. If the antibody count is lowered, then there are fewer chances of destruction or blockage of the neuromuscular junctions. The treatment, therefore, ensures that there is the transmission of nerve impulse and thus muscle action.

Thymectomy may also be a solution to symptoms expressed by the disease. It involves surgically removing the thymus gland (Myasthenia Gravis, n.d). Thus gland plays an important role in the immune system of humans by producing the T-cells. They are also involved in the production of antibodies against infections. If t removed, then there will be fewer antibodies produced by the immune system, thus less likely to block the neuromuscular junctions. The transmission of impulses is improved and hence that muscles can perform the respective actions.

References

Barnett, C., Bril, V., Kapral, M., Kulkarni, A., & Davis, A. M. (2014). A conceptual framework for evaluating impairments in myasthenia gravis. PloS one, 9(5). doi: 10.1371/journal.pone.0098089

Brazier, Y. (2018, January 22). Myasthenia gravis: Treatment, symptoms, and causes. Retrieved from www.medicalnewstoday.com/articles/179968

Chaudhuri, A., & Behan, P. O. (2009).

Chaudhuri, A., & Behan, P. O. (2009). Myasthenic crisis. QJM: An International Journal of Medicine, 102(2), 97-107.

Myasthenia Gravis. (n.d.). Retrieved from www.hopkinsmedicine.org/health/conditions-and-diseases/myasthenia-gravis Kaminski (2017).

Myasthenia Gravis. (n.d.). Retrieved from https://rarediseases.org/rare-diseases/myasthenia-gravis/

MG Crisis. (n.d.). Retrieved from https://myasthenia.org/What-is-MG/MG-Management/MG-Crisis