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موضوع مهم عن التروبونين

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موضوع مهم عن التروبونين

مُساهمة من طرف marwa في الأربعاء 09 ديسمبر 2009, 6:29 pm

Cardiac troponins
- troponins are regulatory proteins in cardiac muscle that modulate the interaction between actin and myosin, functioning as a "calcium switch"
- two forms – cardiac troponin T (cTnT) and cardiac troponin I (cTnI)
(cTnT testing is only available from one vendor, while cTnI testing is available from many vendors and the test may be more highly specific with less false positives)
- the rise in serum level of cTnT parallels the rise in serum level of cTnI after myocardial injury, and both tests parallel the rise in serum CK-MB levels in a patient with an AMI; with a similar sensitivity at 4 - 6 hours (~ 50%) and at 12 hours (> 95%) for an AMI
(troponin testing may be more sensitive because troponin is found only in cardiac tissue and ambient serum levels are extremely low in healthy individuals, while the serum CK-MB has to exceed a broad reference range before it is regarded as positive - small rises due to minor cardiac damage may be "invisible" to standard testing procedures)
- the serum troponin levels remain elevated for 10 - 14 days and cTnT/cTnI testing is useful for detecting an AMI many days after an episode of chest pain (wide diagnostic window)
- a repeat qualitative serum troponin test cannot be used to detect a recurrent AMI/ACI a few days after admission if the initial serum troponin test was positive => serial quantitative serum troponin levels need to be measured
- a false-positive serum cTnT test may very rarely occur in a wide range of traumatic, inflammatory and congenital myopathies and in chronic renal failure
- a false positive serum cTnI test occurs even more rarely - near-zero incidence - in skeletal muscle disorders and renal failure and occurs mainly in other conditions causing myocardial damage eg. myocarditis, cardiac contusion, recent cardiac surgery or catheterization
(all serum cardiac enzyme markers may be positive in rhabdomyolysis - however, the serum cTnI is usually only slightly elevated, despite signficant elevations in both the CK and CK-MB)
- a positive serum troponin test may occur in a patient with unstable angina and probably reflects a micro-infarct (infarctlet) not detectable by CK-MB testing
- a positive serum troponin test in a patient with a history suggestive of cardiac ischemia (and who has a non-diagnostic ECG and a normal CK-MB level) defines a subset of high-risk acute coronary syndrome (ACS) patients = Acute cardiac insult (ACI)
- an elevated serum troponin has been found to be an independent predictor of 30 day mortality in patients with non-Q wave infarctions and ACI, and a positive serum troponin test helps in risk stratification and ED triage => an ACS patient with a positive serum troponin test should definitely be admitted to the CCU for aggressive ACS therapy eg. anti-thrombotic agents +/- anti-platelet agents +/- early cardiac catheterization
- the increased risk of adverse cardiac events in troponin-positive patients may also directly correlate with the degree of increase of the serum troponin
- repeat serum troponin testing should be performed if the serum troponin at presentation is negative => repeat at 4 hours and again at 8 hours => ? whether early detection of increased serum troponin may allow for earlier institution of advanced ACS therapies in these "extra" (CK-MB-negative) patients identified by serum troponin testing
(serum troponin testing may also produce a cost benefit if future studies suggest that only troponin positive patients benefit from aggressive ACS therapy
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marwa
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رد: موضوع مهم عن التروبونين

مُساهمة من طرف ahmed abdelrahim في الأربعاء 09 ديسمبر 2009, 6:38 pm

so beautiful Dr\ Marwa
and we need more and more
thanks
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ahmed abdelrahim
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رد: موضوع مهم عن التروبونين

مُساهمة من طرف welfarin في السبت 12 ديسمبر 2009, 12:56 pm

الكلام ده في المنهج ولا ايه اصلي انا مدرستش الكلام ده
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welfarin
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