From the Guidelines
Lactate dehydrogenase (LDH) can be elevated due to various conditions that cause tissue damage or cell death, including osteosarcoma, as elevated serum LDH level is associated with a worse prognosis in patients with osteosarcoma 1.
Common Causes of Elevated LDH
- Myocardial infarction (heart attack), where damaged heart muscle releases LDH into the bloodstream
- Liver diseases such as hepatitis, cirrhosis, or liver cancer, which can elevate LDH as liver cells are injured
- Muscle damage from trauma, rhabdomyolysis, or muscular dystrophies, which also increases LDH levels
- Various cancers, particularly lymphomas, leukemias, and solid tumors, can raise LDH through rapid cell turnover and tissue invasion
- Hemolytic anemias cause LDH elevation when red blood cells rupture prematurely
- Other causes include pulmonary embolism, pneumonia, kidney disease, pancreatitis, seizures, and strenuous exercise
- Certain medications and treatments like chemotherapy can also damage tissues and elevate LDH
Importance of Interpreting Elevated LDH
When interpreting elevated LDH, it's essential to consider it alongside other clinical findings and laboratory tests to determine the specific underlying cause. The enzyme exists in five different isoenzymes distributed throughout the body's tissues, which is why damage to various organs can result in increased serum LDH levels.
Clinical Relevance
In the context of osteosarcoma, elevated LDH levels are associated with a worse prognosis, with 5-year disease-free survival rates of 39.5% for patients with high LDH levels and 60% for those with normal values 1. Similarly, in septic shock, increased lactate levels are associated with worse outcomes, and lactate-guided resuscitation has been shown to reduce mortality 1.
Key Considerations
- Elevated LDH levels can be caused by various conditions, and it's crucial to consider the clinical context and other laboratory findings to determine the underlying cause
- In certain conditions, such as osteosarcoma and septic shock, elevated LDH or lactate levels are associated with worse outcomes and can guide treatment decisions
- Lactate-guided resuscitation has been shown to reduce mortality in septic shock patients 1
From the Research
Causes of Elevated Lactate Dehydrogenase
- Benign etiology, such as various non-malignant diseases or conditions, can cause elevated lactate dehydrogenase (LDH) levels in 60% of cases 2
- Malignant etiology, such as cancer, can cause elevated LDH levels in 36% of cases 2
- Cardiac insufficiency, particularly in elderly patients with acute myocardial infarction, can be predicted by high serum LDH levels 3
- Cardiac remodeling, including early cardiac remodeling after myocardial infarction, can be associated with elevated LDH levels 4
- Hemodynamic stress, such as high blood pressure, can lead to elevated lactate dehydrogenase A (LDHA) levels, which governs cardiac hypertrophic growth 5
Disease-Specific Elevations
- Myocardial infarction, including ST-elevation myocardial infarction (STEMI) and non-ST-elevation myocardial infarction (NSTEMI), can cause elevated LDH levels 3, 4
- Neoplasia and malignant hemopathy can cause elevated LDH levels, and LDH level elevations can be associated with therapeutic failure 2
- Cardiac hypertrophy and heart failure can be associated with elevated LDHA levels 5
Clinical Significance
- Elevated LDH levels, particularly those superior to 10-fold the normal rate, can be a pejorative predictive criterion, indicating a higher mortality rate 2
- LDH level elevations can be associated with a higher risk of cardiac insufficiency and cardiac remodeling 3, 4
- LDH levels can be used as a biomarker to predict future cardiac dysfunction after acute myocardial infarction, especially in the elderly 3