Cellular Damage

• Elevated LDH is seen with myocardial infarction, liver injury, hemolysis, and muscle damage.

Malignancies

• High LDH is often noted in certain cancers (e.g., lymphomas, leukemias) as a sign of rapid cell turnover.

Infections/Autoimmune Conditions

• Widespread inflammation or autoimmune tissue destruction can lead to cell lysis, thereby raising LDH levels.

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Usually Not Pathologic

• Low LDH is rare and not commonly used as a disease marker.

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Children

• May naturally have higher LDH levels due to rapid growth and cellular turnover.

Adults

• In adults, high LDH is more concerning for acute injury or disease processes.

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Markers of Muscle and Tissue Damage

Enzymatic Markers:

Common Creatinphosphokinase (CPK), Common Lactadehydrogenase (LDH), and Serum Aspartaminotransferase (AST) are enzymes released when muscle, heart, or other tissues are damaged. Their elevation indicates cell injury and, in combination, helps differentiate the source and extent of tissue damage.

Protein Markers:

Myoglobin and Troponin are proteins specific to muscle tissue. Troponin is highly specific for cardiac muscle injury, while myoglobin rises quickly after muscle damage but is less specific, offering early insights into muscle breakdown.

Metabolic Marker:

Lactic Acid levels increase during anaerobic metabolism when tissues experience hypoxia, indicating metabolic stress or injury.

Additional Enzymatic Marker:

Acid Phosphatase is another enzyme released with tissue cell breakdown, sometimes used for broader assessments of tissue damage.

Together, these markers provide a comprehensive view of tissue and muscle injury, supporting the diagnosis and management of conditions like myocardial infarction, muscle damage, and systemic tissue hypoxia.

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