WBR0354
| Author | PageAuthor::Neeraja Danda M.B.B.S |
|---|---|
| Exam Type | ExamType::USMLE Step 2 CK |
| Main Category | MainCategory::Internal medicine |
| Sub Category | SubCategory::Cardiovascular |
| Prompt | [[Prompt::A 55 year old male presented to the emergency room with acute chest pain and diaphoresis . Electrocardiogram revealed ST segment elevation in leads V2 – V4 . Aspirin was administered and the patient was sent for coronary angiography, which revealed a 75% stenosis in the left main coronary artery . Angioplasty was performed immediately thereafter. On the fourth day following angioplasty, the patient began to experience chest pain again .Which of the following would be helpful in diagnosing a reinfarction?]] |
| Answer A | AnswerA::Troponin |
| Answer A Explanation | AnswerAExp::'''Incorrect''' Troponin starts to rise at 4-6 hours and remains elevated for 10-14 days. Therefore, elevated troponin within this window would not be specific for reinfarction. |
| Answer B | AnswerB::Myoglobin |
| Answer B Explanation | AnswerBExp::'''Incorrect''' Myoglobin can be used to detect reinfarction but it is less specific than CK-MB |
| Answer C | AnswerC::Electrocardiogram |
| Answer C Explanation | AnswerCExp::'''incorrect''' Electrocardiogram also helps in diagnosing reinfarction , however CK-MB along with Electrocardiogram is the better option |
| Answer D | AnswerD::Cardiac auscultation |
| Answer D Explanation | AnswerDExp::'''Incorrect''' Cardiac auscultation can help in diagnosing pericarditis when pericardial rub is appreciated but it has no value in diagnosing infarction. |
| Answer E | AnswerE::Electrocardiogram and CK-MB levels |
| Answer E Explanation | [[AnswerEExp::CK MB returns to normal level 2 days after infarction Therefore, it is a useful diagnostic criterion for a second MI outside of a 2 day window.Electrocardiogram will help to confirm the diagnosis by showings new changes, particularly in the ST segments]] |
| Right Answer | RightAnswer::E |
| Explanation | [[Explanation::Electrocardiogram demonstrates an up to date image of the heart electrical activity. . Cardiac enzymes Troponin, Myoglobin and CK-MB start to rise after infarction of cardiac muscle with various kinetics.The first cardiac injury marker to rise is myoglobin at 1-4 hours and reaches baseline in 1-2 days. CK MB rises at 4-6 hours and becomes normal in 1-2 days. Finally,Troponin starts to rise at 4-6 hours and remains elevated for 10-14 days. Therefore, to diagnose a reinfarction, perform an electrocardiogram and measure CK-MB as the raised levels from previous infarction become normal on the second day.
Educational Objective:CK-MB returns to normal levels 2 days after infarction. Therefore, its is a useful diagnostic criterion for a second MI outside of a 2 day window. Electrocardiogram will help to confirm the diagnosis by showing new changes, particularly in the ST segments . References: 66 Master the boards Step 2 Ck second edition |
| Approved | Approved::Yes |
| Keyword | |
| Linked Question | Linked:: |
| Order in Linked Questions | LinkedOrder:: |