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[The enzymatic and electrocardiographic changes falsely indicative of an acute myocardial infarct during
1Divisione di Cardiologia, Presidio Ospedaliero di Camerino, Regione Marche, USL 20, Marcerata.
Insights
Diagnosing myocardial infarction requires careful interpretation of enzyme levels. This case highlights hypothyroidism mimicking heart attack symptoms, emphasizing cautious analysis of enzyme profiles alongside clinical findings.
Area of Science:
- Cardiology
- Clinical enzymology
- Endocrinology
Background:
- Cardiac enzyme testing, including creatine phosphokinase (CPK) and lactate dehydrogenase (LDH) isoenzymes, is crucial for diagnosing myocardial infarction (MI).
- Elevated levels of specific isoenzymes like CPK-MB and LDH1 can indicate cardiac muscle damage.
- However, these enzyme elevations are not exclusive to MI and can occur in other conditions.
Observation:
- A case of hypothyroidism presented with elevated CPK-MB and LDH1 levels.
- The patient experienced an altered electrocardiogram and localized chest discomfort, initially suggesting acute myocardial infarction.
- Diagnostic challenges arose due to the non-specific nature of the enzyme elevations and presenting symptoms.
Findings:
- The elevated CPK-MB and LDH1 levels in this case were attributed to hypothyroidism, not acute myocardial infarction.
- Hypothyroidism can mimic cardiac ischemia, leading to potential misdiagnosis if enzyme levels are considered in isolation.
- The study underscores that conditions like hypothyroidism, muscular dystrophy, polymyositis, and malignant diseases can cause false positives for MI based on enzyme markers.
Implications:
- Plasma enzyme and isoenzyme profiles must be interpreted cautiously, especially when clinical and instrumental findings (e.g., 2D echocardiography) are not fully consistent with myocardial infarction.
- This case emphasizes the importance of a comprehensive diagnostic approach, integrating clinical presentation, instrumental data, and biochemical markers.
- Accurate diagnosis relies on considering the full clinical picture to avoid misattributing enzyme elevations to MI when other underlying conditions are present.
Abstract:
Estimation of the enzymes CPK and LDH, with their isoenzymes, is useful in diagnosing myocardial infarction and monitoring its progress. However, increases of CPK-MB and LDH1, may be not associated with acute myocardial infarction, as in hypothyroidism, muscular dystrophy, polymyositis, malignant disease. We report a case of hypothyroidism with increased CPK-MB and LDH1. At the beginning the diagnosis was difficult because of altered electrocardiogram associated with one event of "burning" localized altered at the anterior thorax. This case illustrates that plasma enzyme activity and isoenzyme profiles should be interpreted with caution when clinical and instrumental (eco 2D) findings are not entirely associated with myocardial infarction.