字幕表 動画を再生する 英語字幕をプリント Hello fellow classmates! My name is Sheila Arciaga and I am doing a presentation about the Guillian-Barré syndrome. Guillian-Barré syndrome or GBS is a rare autoimmune disease in which the immune system attacks the peripheral nervous system which causes muscle weakness and in severe cases, paralysis. GBS usually last a few weeks up to several months. It is so rare that it only occurs in about one person in 100,000. According to the CDC website, in the United States, the rate is about 80 to 160 cases each week. Signs and symptoms include myoparesis and paresthesia in the legs and progress towards the arms and upper body. Absence of patellar reflex may also be a sign. In severe cases, it is considered as a medical emergency because it can result in total paralysis which can interfere with ventilation, blood pressure, and heart rate. Guillian-Barré syndrome is an idiopathic disease which means there is no known cause. However, the most common risk factor is infection with the bacterium Campylobacter jejuni. It also may develop after having the flu or viral infection such as cytomegalovirus, Epstein-Barr virus, and Zika virus. In very rare occasions, it is triggered after having flu vaccination. Now, I'm going to discuss the pathophysiology of Guillian-Barré syndrome. The cells of the immune system damage the myelin sheath surrounding the axons of the peripheral nerves, or sometimes the axon itself. The myelin sheath is a special type of plasma membrane that protects and insulates the axon. It speeds up the electrical conduction between neurons over long distances. The axon is the long, thin part of a nerve cell that acts like a passageway which carries nerve impulses. At the top, you can see a picture of a perfect healthy peripheral neuron surrounded by a yellow substance composed with protein and adipose tissue called the myelin sheath. At the bottom, the demyelinated neuron is damaged exposing the axon beneath. So what happens when the myelin sheath is damaged? You can see in this picture the comparison of the electrical impulses between normal and damage nerve. In a healthy nerve, it speeds up the electrical impulses to and from the brain. Texture, heat, pain and other sensations are relayed to the brain and the brain sends appropriate commands back to the muscle. However, with GBS, the signal transmission is interrupted between neurons. The signal slows down. The brain might receive inappropriate signals which results to tingling sensations. In addition to that, the reason why the paralysis begins with the hands and legs is because the signals in these areas take the longest distances to travel to and from the brain. Unfortunately, there is no cure of the disease but there are therapies to treat severe symptoms and speed up the recovery time of GBS. One example is plasmapheresis. It involves taking out the whole blood from the patient; removing the liquid portion of the blood, also called the plasma; and the blood without plasma is then returned to the body so the body can replace the plasma. Scientists think that it works because it can remove antibodies and immune cells that could further damage the nerve cells. Another example is high-dose immunoglobulin therapy. It is administered through IV injections and works by reducing the chances of the immune system attacking the nervous system. Steroid hormones have been used to reduce severe symptoms of GBS. However, it is not as effective as the ones I mentioned before because it may produce harmful effects. And lastly, the most important treatment is the use of mechanical ventilator assistance, heart monitor, and other machines that aid in body function.