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8 Cards in this Set
- Front
- Back
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What is the main clinical feature of myasthenia gravis?
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Muscle weakness
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What muscles are involved in the early stages of myasthenia gravis?
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-Proximal limb muscles
-Extraocular muscles -Muscles of mastication, speech and facial expression |
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What causes the disease?
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IgG antibodies complex with the acetylcholine receptor protein.
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What is the aetiology of myasthenia gravis?
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-Twice as common in women
-Average age of incidence is 30 -Prevalence is 4 in 100,000 |
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Link with other diseases?
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Thymic hyperplasia is found in 70% of myasthenic patients below the age of 40.
In 10% a thymic tumour is found (thymoma). Antibodies against striated muscle are found in these patients. |
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What happens with a Tensilon test?
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The anticholinesterase edrophonium is injected. If improvement of weakness occurs, patient has myasthenia.
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How do anticholinesterases work?
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They inhibit the enzyme cholinesterase and so prolong the action of acetylcholine in neuromuscular junctions.
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What is neostigmine?
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It is an anticholinesterase drug.
Used to alleviate muscle weakness in myasthenia gravis. Also used in general anaesthesia to reverse the effects of non-depolarising muscle relaxants. |
