mohamed.ali
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20. A 72-year-old man comes to the physician because of a 7-month history of leg weakness and dry eyes and mouth. He also has had a 10.4-kg (23-lb) weight loss over the past 4 months despite no change in appetite. He has smoked one and a half packs of cigarettes daily for 50 years. He drinks 4 oz of alcohol daily. He has peptic ulcer disease and emphysema. Medications include cimetidine, theophylline, and low-dose prednisone. Examination shows mild ptosis. He has a barrel-shaped chest. Breath sounds are distant. There is moderate weakness of the proximal muscles of the lower extremities. Reflexes are absent. He has difficulty rising from a chair. Sensory examination shows no abnormalities. An x-ray film shows a hyperinflated chest and a 3 x 4-cm mass in the right hilum. His neurologic findings are most likely due to a lesion involving which of the following?
A
) Muscle membrane
B
) Parasympathetic nervous system
C
) Peripheral nerve
D
) Presynaptic neuromuscular junction
E
) Sympathetic nervous system
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Is it A or D ..plz reply
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| farnsworth
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D - Eaton Lambert Syndrome (affects pre-synaptic calcium channels, Ca++ is required for release of acetylcholine from the pre-synaptic membrane).
Myasthenia gravis: antibodies against post-synaptic acetylcholine receptor (neuromuscular junction - A)
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| mohamed.ali
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okay I got it now .thnx for ur explanation .
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| Miradautas Vras
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No answer is muscle membrane. It's from UW. I don't remember the explanation except that it was vague and not much informative.
It's myopathy of malignancy, if i remember correct and affect proximal group more frequently. In eaton lambert syndrome patient has weakness n rest which improves with activity [opp of MG] , no such description here. Plus patient most likely has Small cell Ca --> PTHrp secretion -->Hypercalcemia so presynaptic membranes won't have trouble procuring calcium
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| farnsworth
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A rare disease showing similar symptoms is idiopathic inflammatory myopathy (annual incidence 1:100,000), which can be associated w/ malignancies (cause or effect? The relation between myopathy and malignancy is controversial). Most inflammatory myopathies show as idiopathic polymyositis or dermatomyositis.
But you may be right: the key hints are dry mouth (xerostomia) and eyes (xerophthalmia), as inflammatory myopathies can be associated w/ Sjoegrens syndrome!
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| dr.wad
Forum Senior
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Eaton Lambert Syndrome.....is associated with dry mouth and dry eye .
so it is D .
tx : diaminopyridine, tx the malignancy.
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| Miradautas Vras
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It's muscle membrane. check with UW fellas! it was one of those typically anal UW questions which makes me feel like a douchebag.
ELS may be associated with dry mouth and dry eyes , but it's secondary. Primary s/s of ELS are not present here.
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Man who fights too long against the dragons becomes a dragon himself.
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| dr.wad
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Miradautas Vras ......in myopathies the defect is in the muscle proteins ,not in the muscle membrane......so u havnt any choice goes with myopathy.
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| mohamed.ali
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hey guys it's reaching its peak here .. good!
I just would like to highlight that in CXR there is lung mass in the hilar region ..
so if we arrange info again ..
hilar lung mass,weight loss (10 Kg) despite of no change of appetite, history of smoking, leg weakness and dry eyes and mouth, ........ those all pointing to para neaplastic syndrome [ small cell carcinoma plus Eaton Lambert ]
so it would be DDDDDD
to Midradauatas , if we think that it's myophathy so what's the explanation of the weight loss and the CXR finding
..
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| farnsworth
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I am not sure if we can trust every answer those UW guys give us, especially when the explanation is kind of vague.
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