Myasthenia Gravis Symptoms - Essay Example

Myasthania Gravis Introduction Myasthenia Gravis is an autoimmune disease which is caused by the loss of acetylcholine receptors. These acetylcholine receptors are lost because of the patients own immune responses. The disease is found in 3 out of 100000 individuals (Poulas et al 2000). The disease is characterized by weakness in the individuals with drooping of eyelids i.e. ptsosis and double vision. The disease can be treated by specialized drugs and surgical intervention. This brief would further provide descriptions about the disease (Baets et al 1993, Torpy et al2005 & Knudsen 2006). A brief case history A 30 year old woman was found to be having problems with her vision with droopiness in her eyes. It was found that the woman was also suffering from fever and dysphagia. She had a previous history of easy fatigability of muscles with problems in walking. Moreover it was also seen that the woman was not able to speak properly on several occasions showing signs of stammering. The woman was recommended a physical examination so as to check any problem or disorder with the muscles. Through the physical examination it was found that the woman was suffering from ptosis and diplopia. This showed that the woman maybe suffering from an autoimmune disease and thus she was directly referred a serology test. The serology test did not yet show positive results for any sort of myasthenia gravis and thus she was finally recommended an ultimate test of Edophonium Test. This test concluded that the woman was suffering from low levels of acetylcholine at the muscular junctions and thus the woman is suffering from myasthenia gravis. An end test to check with the problem of mediastinum and thymus is also done. This test is usually Computed Tomography (CT) (Mink et al 1978). Clinical diagnosis Myasthenia Gravis is an autoimmune disease which greatly affects the muscles of the body. Thus the eminent sign for myasthenia gravis can be highlighted to be the fatigability of the muscles. Firstly the patient suffers from a stroke of weakness usually with the extra ocular muscles of the body. This leads to the drooping of eyelids which is known as ptosis or at times double vision too which is known as diplopia. These symptoms are however are not necessary to be present at preliminary stages. The first sign can be for myasthenia gravis is that the person starts feeling weak. It is common for the patient to have different strokes of weakness throughout the day depending upon the time. In some patients it is noted that the weakness increases in the evening. Moreover if the disease is not detected by the doctors and the patient is given antibiotics other than the ones for myasthenia gravis, the patient can get even weaker. Usually in such a situation the patient is given strong dozes of immunosuppressants.These immunosuppressants are usually anticholinesterase agents which directly affect the immunity of the individual and show improvement in his health. Previously it was seen that respiratory diseases were a major cause of death all over the world. However with the advent of new technologies and surgeries it is seen that most of the individuals suffering from respiratory diseases are able to survive. The common treatment for such a disease includes anticholinesterase drugs, plasmapheresis, prednisone and removal of thymus if a problem is found in it (Younger et al 2001, Castleman 1966, Kaminiski et all 2008 & Agius 2003). Anatomy The muscles are made up by muscle fibers which in order to get excited need innervations by the myelinated nerves. In the human beings the many nerve fibers tend to supply the muscles and each nerve fiber branches into several other fibers which then supply three to several skeletal muscle fibers. The nerve endings make a junction at the midpoint of the muscle with the muscle fiber which is known as the neuromuscular junction. The nerve fibers which supply the muscles usually lie outside the muscle sarcoplasm and the whole structure of the branching nerve fibers is known as the motor end plate. Moreover to insulate the nerve fibers from other fluids it is surrounded by Schwann Cells which form the myelin sheath. An invaginated membrane is present in the junction between the axon terminal and muscle fiber membrane. This invaginated portion s known as the synaptic trough. This invaginated portion shows deep dents which depict the subneural clefts. A synaptic end bulb is present on the axons which contain synaptic vesicles and these vesicles then contain the hormone acetylcholine. The axon terminal has several mitochondria present in it which help in the synthesis of acetylcholine. Acetylcholine is released from the axon terminals into the synaptic gutters or troughs. This therefore helps in the activation of the muscle fibers and makes them move. Similarly an enzyme known as acetylcholinesterase is also present in the synaptic trough which destroys the remaining acetylcholine after the activation of the muscle fibers. Following is a diagram which clearly illustrates the above mentioned facts about the neuromuscular junction. In the disease myasthenia gravis the neuromuscular junction is disturbed and the muscle acetylcholine receptors are reduced. (Ciafaloni 2005, Grob 1976, Drachman, Baets et al 1993, Torpy et al2005 & Knudsen 2006) Pathology Myasthenia gravis is an autoimmune disease which is characterized by muscle fatigue. It is caused by autoimmune responses against the acetylcholine hormone because of which the hormone is lost majorly in the body. This happens usually due to the presence of antibodies against the AChr (Ricny et al 2002 & Palace et al 2001). This in turn leads to the loss of AChrs at the neuromuscular junction thus causing weakness. This is usually caused if the post synaptic membrane is damaged because of the antibodies produced, overuse or internalization of the receptors also causes the loss of AChrs. And finally inhibiting the function of acetylcholine greatly affects the receptors. It is noted that only the motor responses of the body are affected mostly by this disease (Castleman 1966 & Grob 1981). On the other hand the sensory and autoimmune responses of the patient are not affected by myasthenia gravis. Usually it is seen that the patients suffering from myasthenia gravis also suffer from cell mediated immunity. This can be concluded from the fact that most of the patients affected by myasthenia gravis have an abnormality in the important organ of thymus. It is believed that the T Cells get activated first to further activate the auto reactive B Cells. These b cells produce antibodies against acetylcholine which therefore causes myasthenia gravis. However the exact link between abnormalities of thymus and myasthenia gravis has not been yet confirmed but in 75% of the cases of myasthenia gravis it is seen that thymus is also affected. Once the autoimmune disorder takes place it starts destroying the ACh receptors. At first it is not felt so strongly in the patients because of the extra amount of ACh present in the fibers. However after strong stimulation it can be noted that the person starts getting weak with repeated problems of muscle fatigue. After the post synaptic receptors are destroyed the cholinergic nerve conduction to the muscle fibers is impaired as acetylcholine cannot enter the muscle fibers and thus it cannot help with the entrance of the sodium ions in the muscle fibers (Castleman 1966). Role of imaging modalities in the diagnosis Imaging modalities are not the primary tests done in order to detect the presence of myasthenia gravis in an individual. Although not primary but they are important tests which can help in ruling out other possibilities which may have the same symptoms as that of myasthenia gravis. Chest X-Ray is one common test done to differentiate between Lambert-Eaton Syndrome and Myasthenia Gravis. Moreover it would also help to see if the mediastinum of the person has been stretched due to any reason. However chest x-ray is not a conclusive test and to confirm the differential diagnosis one has to perform computed tomography (CT) or Single Fiber Electromyography (EMG). Computed Tomography helps to ascertain if a tumor is present in the thymus. And it may also help to find out about any abnormality of the thymus. The Single Fiber Electromyography helps to determine the transmission of nerve signals from a nerve fiber to a muscle fiber. In normal individuals electrical stimulation would be responded back by the nerve fibers. However in people who have neuromuscular disorders the response would not be found. Through this test it can be known if a neuromuscular disorder is present in the patient (Mcloud et al 1979 & Mink et al 1978). Above given diagram shows the thymoma being surrounded by fat Above given diagram shows the thymoma from the computed tomography of anterior mediastinum. Treatment and prognosis The treatment for myasthenia gravis can be classified as treatments to decrease progression and symptomatic treatments. Usually in symptomatic treatments the use of anticholinestarases is found. This anticholinesterase prevents the breakdown of acetylcholine in the body and thus increases its level to the norm. Thymectomy is another method adopted to decrease the progression of the disease. This is a surgical process through which parts or the whole portion of the gland is removed from the body. This has turned out to be quite successful in the recent days. Plasmapheresis helps in eliminating the humoral autoimmune factors in Myasthenia Gravis thus providing relief to the patients. Another type of treatment adopted is that of IVIG therapy. In this therapy IgG is injected in the human patients which like plasmapheresis helps in eliminating the humoral autoimmune factors by binding and reacting with these factors. Corticosteroids are used in order to decrease the progression of the disease further. All the mentioned treatments are being used worldwide with different perspectives and aims to achieve (Bufler et al 1998). Although the disease is not said to be totally curable it is found that individuals who get a treatment usually lead a normal life. However in some conditions when the myasthenia gravis is in its chronic stages it is difficult for the individuals to lead a normal life. Moreover at times the treatment for myasthenia gravis can also prove to be lethal as the immunosuppressants may at times cause such side effects that are incurable (Drachman 1987, Kaminski et all 2008 & Agius 2003). Summary and conclusion Myasthenia gravis is an autoimmune disease which can be detected in its earlier stages if reported to the proper authorities. Usually the patients who come with such a problem should be thoroughly checked with the above mentioned tests in order. The disease can be lethal in the latter stages but if it is treated in its initial stages it can be treated. With the advent of new treatments the disease can successfully be cured with different methods. The most important feature of this disease is the damage to the post synaptic receptors. Thus it is expected that further research is done regarding the post synaptic receptors and neuromuscular junction. This would help the researchers to come up with new treatments which are even more effective in treating this disease (Drachman 1987, Kaminski et all 2008 & Agius 2003). References Top of Form RICNY, J., SIMKOVA, L., & VINCENT, A. (2002). Determination of Anti-Acetylcholine Receptor Antibodies in Myasthenic Patients by Use of Time-resolved Fluorescence. CLINICAL CHEMISTRY -WASHINGTON-. 48, 549-554. Top of Form PALACE J, VINCENT A, & BEESON D. (2001). Myasthenia gravis: diagnostic and management dilemmas.Current Opinion in Neurology. 14, 583-9. Bottom of Form Top of Form YOUNGER DS, & RAKSADAWAN N. (2001). Medical therapies in myasthenia gravis. Chest Surgery Clinics of North America. 11, 329-36. Bottom of Form Top of Form PASCUZZI, R. M. (2002). Myasthenia Gravis and Lambert-Eaton Syndrome. Therapeutic Apheresis. 6, 57-68. Bottom of Form Top of Form POULAS, K., TSIBRI, E., PAPANASTASIOU, D., TSOULOUFIS, T., MARINOU, M., TSANTILI, P., & PAPAPETROPOULOS, T. (2000). Equal male and female incidence of myasthenia gravis. NEUROLOGY -MINNEAPOLIS-. 54 PART 5, 1202. Bottom of Form Top of Form BUFLER, J., PITZ, R., CZEP, M., WICK, M., & FRANKE, C. (1998). Purified IgG from Seropositive and Seronegative Patients with Myasthenia Gravis Reversibly Blocks Currents through Nicotinic Acetylcholine Receptor Channels. Annals of Neurology. 43, 458. Top of Form CASTLEMAN B. (1966). The pathology of the thymus gland in myasthenia gravis. Annals of the New York Academy of Sciences. 135, 496-505. Top of Form CIAFALONI E. (2005). Mycophenolate mofetil and myasthenia gravis. Lupus. 14, 46-9. Top of Form GROB, D. (1976). Myasthenia gravis. New York, New York Academy of Sciences. Top of Form INTERNATIONAL CONFERENCE ON MYASTHENIA GRAVIS AND RELATED DISORDERS, KAMINSKI, H. J., & BAROHN, R. J. (2008). Myasthenia gravis and related disorders: 11th International Conference. Boston, Mass, Published by Blackwell Pub. on behalf of the New York Academy of Sciences. 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