Lactate Dehydrogenase: pathophysiologic marker

Sara Pape-Salmon NP(F)

Mental Health and Addictions Service, VIHA

What is Lactate Dehydrogenase?Lactate Dehydrogenase (LDH)

Intracellular enzymeFound in the cells of many body tissues: Heart, liver, RBC, kidneys, skeletal muscle brain, and lungs.

When these cells become injured, they lyse & LDH enters the blood stream.

LDH Fractions:

LDH - although nearly ubiquitous body distribution, five separate fractions exist: LDH 1LDH 2LDH 3LDH 4LDH 5

LDH Tissue Distribution:

• LDH - Total LDH

• LDH 1 - Found in HEART predominantly

• LDH 2 - RETICULOENDOTHELIAL system

• LDH 3 - LUNGS (predominantly)

• LDH 4 - KIDNEY, PLACENTA, PANCREAS

• LDH 5 - mainly LIVER and STRIATED MUSCLE

LDH & certain diseases:

LDH 1 - indicates MI (> LDH 2). Testicular tumors.

LDH 2 & 3 - Pulmonary disease: CHF, embolism, infarct, pneumonia, lymphoma & other reticuloendothelial tumors. AIDS - histoplasmosis.

LDH 4 - Pancreatitis, kidney diseaseLDH 5 - liver disease (hepatitis, cirrhosis, neoplasm) ischemic bowel disease, striated muscle disease (muscular dystrophy, strenuous exercise)

Should we be ordering LDH?Although certain LDH patterns are classic for certain diseases, it is non-specific.

There are other tests/enzymes that are more specific

Can it be an important adjunct - yes…? e.g. declining transaminases in context of liver disease

e.g. differentiating angina from heart attack e.g. differentiate hepatic disease from benign condition (Gilbert’s disease vs. hemolytic disease)