The nurse is reviewing the chart of a client with an indication of myocardial infarction or unstable angina. Which laboratory test result(s) should the nurse recognize as an indication of myocardial injury? (Select all that apply)
Elevated troponins
Decreased homocysteine levels
Elevated CK-MB
Decreased alkaline phosphatase (ALP)
Increased platelet count
Correct Answer : A,C
Choice A: Elevated troponins. This is a correct answer. Troponins are proteins that regulate the myocardial contractile process². They are released into the bloodstream when the myocardial cells are damaged by ischemia or infarction². Troponins are highly specific and sensitive indicators of myocardial injury². The normal range for troponin I is less than 0.03 ng/mL and for troponin T is less than 0.01 ng/mL².
Choice B: Decreased homocysteine levels. This is not a correct answer. Homocysteine is an amino acid that is involved in the metabolism of methionine². Elevated homocysteine levels are associated with an increased risk of cardiovascular disease, but they are not a direct marker of myocardial injury². The normal range for homocysteine is 5 to 15 micromol/L².
Choice C: Elevated CK-MB. This is a correct answer. CK-MB is one of the isoenzymes of creatine kinase, an enzyme that catalyzes the conversion of creatine to phosphocreatine, which is used for energy storage in the muscles². CK-MB is found mainly in the myocardium and is released into the blood when the myocardial cells are injured². CK-MB is a specific and sensitive marker of myocardial injury, but it is less specific than troponins². The normal range for CK-MB is 0 to 3 ng/mL².
Choice D: Decreased alkaline phosphatase (ALP).This is not a correct answer. ALP is an enzyme that is found in various tissues, such as the liver, bone, intestine, and placenta². ALP is not a marker of myocardial injury, and its levels are not affected by ischemia or infarction². The normal range for ALP is 30 to 120 U/L².
Choice E: Increased platelet count.This is not a correct answer. Platelets are blood cells that are involved in hemostasis and clot formation². Increased platelet count, or thrombocytosis, can be a sign of inflammation, infection, malignancy, or other conditions². Platelet count is not a marker of myocardial injury, and it does not reflect the extent of ischemia or infarction². The normal range for platelet count is 150,000 to 450,000 per microliter of blood².
Nursing Test Bank
Naxlex Comprehensive Predictor Exams
Related Questions
Correct Answer is B
Explanation
Choice A reason: While gaining weight and having pink buccal mucosa can be signs of overall improved health, they are not specific indicators of effective treatment for vitamin B12 deficiency¹².
Choice B reason: Paresthesia (a sensation of tingling, tickling, pricking, or burning of a person's skin) of the hands and feet is a common symptom of vitamin B12 deficiency¹². If the client no longer has this symptom, it could indicate that the treatment for vitamin B12 deficiency has been effective¹².
Choice C reason: Eating more iron-fortified cereals can contribute to overall nutritional health, but it's not directly related to the treatment of vitamin B12 deficiency¹².
Choice D reason: While stopping alcohol consumption can improve overall health, it's not a specific indicator of effective treatment for vitamin B12 deficiency¹²..
Correct Answer is D
Explanation
Choice A reason: This is not a correct interpretation. An occlusion of the right coronary artery is a blockage of the blood flow to the right side of the heart, which can cause a heart attack or ischemia. This condition does not produce a systolic murmur, but rather chest pain, shortness of breath, sweating, or nausea. A systolic murmur is a sound that occurs during the contraction of the heart, when the blood flows through a narrowed or leaky valve.
Choice B reason: This is not a correct interpretation. An aneurysm of the descending aorta is a bulging or weakening of the wall of the large artery that carries blood from the heart to the lower body. This condition does not produce a systolic murmur, but rather a pulsating mass in the abdomen, back pain, or abdominal pain. A systolic murmur is a sound that occurs during the contraction of the heart, when the blood flows through a narrowed or leaky valve.
Choice C reason: This is not a correct interpretation. Decreased fluid in the pericardial sac is a condition where the amount of fluid that surrounds and cushions the heart is reduced. This can be caused by dehydration, infection, or inflammation. This condition does not produce a systolic murmur, but rather a pericardial friction rub, which is a scratching or grating sound that occurs when the layers of the pericardium rub against each other. A systolic murmur is a sound that occurs during the contraction of the heart, when the blood flows through a narrowed or leaky valve.
Choice D reason: This is the correct interpretation. Distortion of one or more heart valves is a condition where the shape or function of the valves that regulate the blood flow through the heart is altered. This can be caused by congenital defects, rheumatic fever, endocarditis, or aging. This condition can produce a systolic murmur, which is a sound that occurs during the contraction of the heart, when the blood flows through a narrowed or leaky valve. The location and the intensity of the murmur can help identify which valve is affected. A systolic murmur in the second intercostal space to the right of the sternum can indicate a problem with the aortic valve.
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