0:03 [Music]
0:05 myasthenia gravis is an autoimmune
0:07 disorder that causes weakness in
0:09 skeletal muscles it occurs when the body
0:11 mistakenly produces antibodies that
0:13 attack the neuromuscular Junction which
0:15 is the meeting point between nerve
0:21 fibers typically when the brain sends a
0:23 signal to move a muscle it travels down
0:25 motor nerves until it reaches the
0:28 neuromuscular Junction at this Junction
0:30 nerve cells release a chemical mess
0:32 called acetylcholine a neurotransmitter
0:35 that crosses a small Gap and binds to
0:37 receptors on the surface of muscle cells
0:43 contraction with myasthenia gravis
0:45 antibodies bind to these receptors
0:46 blocking their interaction with
0:48 acetylcholine and weakening muscle
0:51 contraction over time these antibodies
0:53 can damage and reduce the amount of
0:55 receptors on the muscle cell surface
0:57 further leading to weak and easily fatigued
0:58 fatigued
1:01 muscles although it's unclear why
1:03 myasthenic gravis tends to affect young
1:06 females in their 20s and 30s and older
1:09 males in their 60s and 7s it's also more
1:11 common in people who have a thymoma
1:13 which is a type of tumor that develops
1:15 in the thymus
1:17 gland the Hallmark of myasthenia gravis
1:19 is muscle weakness that worsens after
1:22 activity and improves with rest
1:24 initially myasthenia gravis may only
1:26 affect the muscles that control movement
1:28 of the eye and eyelids causing symptoms
1:31 like double vision or drooping eyelids
1:32 when the arm and leg muscles are
1:34 involved people might experience severe
1:36 fatigue and difficulties with walking or
1:39 climbing stairs weakness in the muscles
1:41 responsible for swallowing and speech
1:42 production can cause symptoms like a
1:45 change in voice and slur speech as well
1:47 as difficulty
1:49 swallowing finally if the muscles that
1:51 control breathing are affected people
1:53 can develop a myasthenic crisis which is
1:55 a life-threatening manifestation of the
1:57 disorder that causes muscle weakness of
1:59 the respiratory muscles leading to
2:01 difficulty breathing which rapidly
2:03 results in respiratory failure if not
2:05 treated some factors that may trigger a
2:08 myasthenic crisis include infections
2:15 stress diagnosis is usually based on
2:17 suggestive symptoms and the presence of
2:18 anti-acetylcholine receptor antibodies
2:22 in the blood a simple bedside test that
2:24 can assist in the diagnosis is the ice
2:26 pack test which involves placing an ice
2:28 cube over the person's eyelids for a
2:29 couple of minutes and then checking if
2:31 they is an improvement in muscle
2:33 strength the cooling effect of the ice
2:35 pack temporarily slows the breakdown of
2:37 acetylcholine which can improve muscle
2:39 weakness in people with myasthenia
2:42 gravis additional tests may include
2:44 electromyography and nerve conduction
2:46 studies which typically show decreased
2:48 muscle activity with repetitive
2:51 stimulation once mythia gravis is
2:54 diagnosed a CT scan or MRI of the thorax
2:57 may be done to check for
3:00 thymoma treatment of myasthenia gravis
3:01 consists of medications that increase
3:03 the amount of acetylcholine available to
3:06 muscle cells like neostigmine or paridos
3:08 stigmine severe cases can also be
3:10 treated with immunosuppressive
3:12 medications like prazone which reduce
3:15 the production of harmful antibodies
3:17 finally many individuals with myasthenia
3:19 gravis undergo surgical removal of the
3:21 thymus which can improve symptoms even
3:23 to those who don't appear to have any
3:25 issue with the thymus gland
3:28 itself all right as a quick recap
3:30 myasthenia gravis is an autoimmune
3:32 disorder caused by antibodies against
3:34 the neuromuscular Junction it's
3:36 clinically characterized by muscle
3:38 weakness that worsens with activity and
3:41 improves with rest the purpose of
3:42 treatment is to reduce the immune
3:44 systems attack on the muscles and
3:46 improve muscle strength by increasing
3:48 the amount of acetylcholine available
4:13 helping current and future clinicians
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