by Kimberly Allen R.N.
Myasthenia Gravis is an autoimmune disorder that progresses over time. In myasthenia gravis, the immune system produces antibodies that block the transmission of messages from the nerve cells to the muscle cells preventing the muscles from contracting. The exact cause of myasthenia gravis is unknown, however, it is believed that there is an abnormality with the thymus gland. The thymus gland is very important in developing the immune system after we are born. It slowly grows until puberty and then gradually gets smaller as we age eventually being replaced by fat. As in many other auto immune disorders there is also believed to be a slight genetic factor that may increase the risk of developing myasthenia gravis.
Myasthenia gravis can affect anyone anytime though it is most commonly diagnosed in women under 40 and men over 60. In cases of neonatal myasthenia gravis, the fetus aquires antibodies from the mother that are already affected with the disease. These cases are generally temporary and the symptoms usually resove and completely disappear with in 2 to 3 months after birth. Myasthenia gravis is also common in juveniles.
Muscle weakness is the hallmark of myasthenia gravis. The muscles become increasingly weak and tired with activity and improve only after resting. Though it can affect any of the voluntary muscles the muscles most commonly affected are the muscles of the eyes, face and throat. In most cases, the first symptoms noticed is weakness in the eye muscles. In some, the first symptoms they notice are slurred speech or difficulty swallowing. The severity of muscle weakness varies from patient to patient, ranging from mild localized weakness to severe generalized weakness involving many muscles including those needed for breathing. Some of the symptoms that vary in severity include drooping of one or both eye lids, blurred vision and sometimes double vision caused by the weakening of the muscles that control eye movements. A waddling or unsteady gait is also common due to the weakness of the muscles in the legs.
A condition known as myasthenia crisis occurs when the muscles of the respiratory system become paralyzed and the patient requires mechanical or assisted ventilation to sustain life. Fortunately, the heart is a muscle that is controlled by the autonomic nervous system so as a rule is not affected by myasthenia gravis.
Unfortunately, because the most common symptom weakness is also a common symptom of many other disorders it’s not unusual for there to be a delay of one to two years in getting the correct diagnosis. Also, it is difficult to diagnose because the symptoms can be mild and not easily noticed, making it difficult to distinguish between normal varients or another type of neurological disorder. To diagnose myasthenia gravis, the doctor will need to perform a complete physical and neurological exam. A complete and accurate medical history is also essential. If the doctor suspects myasthenia gravis there are certain blood tests that can be done to confirm the diagnosis.
Myasthenia gravis is one of those disorders for which there is no currently known cure. However, today it can be better controlled. There are improved medications such as neostigmine and pyridostigmine that improve neuromuscular transmission. Immunosuppressive medications like prednisone or cyclosporine are frequently used to improve muscle strength because the suppress the production of abnormal antibodies. Other things you can do to improve your quality of life with myasthenia gravis include a well balanced diet high in fresh fruits and vegetables. Exercise is also important, but it is important to acheive a good balance between rest and activity.
Increased knowledge and technilogical advances have improved diagnosis and treatment of myasthenia gravis as well as long term management of the disease. With early diagnosis and treatment most patients with myasthenia gravis can lead close to normal lives.
Kimberly Allen is a registered nurse with an AND in nursing. She has worked in ACF, LCF and psychiatric facilities, although she spent most of her career as a home health expert. She is now a regular contributor to HealthAndFitnessTalk.com, dispensing advice and knowledge about medical issues and questions. You can reach her with any comments or questions at firstname.lastname@example.org.