Lactic Acidosis
We have become a culture where, as soon as a person even hints at being sick, we check a stat lactate/lactic acid. If we understand our enemy, we won’t be frightened by it - Eddy J. Gutierrez MD
image by: National Human Genome Research Institute
HWN Suggests
Morning Report: Lactic Acidosis – A Misnomer
Lactic acid is a normal metabolite that exists as a link between aerobic and anerobic metabolism. During normal (aerobic) metabolism the majority of pyruvate enters the citric acid cycle via the thiamine dependent enzyme pyruvate dehydrogenase. However, when a state of relative oxygen deficiency exists based on cellular demands, increased amounts of pyruvate will be converted to lactate. Lactate can enter the systemic circulation and ultimately be converted back to pyruvate and eventually glucose in the liver via the Cori Cycle (however this is an energy requiring process and will not occur to a significant degree if there is ongoing oxygen deficiency, anerobic metabolism, and relative excess…
Featured
Lactic Acid/Lactate in Sepsis & the Critically Ill: The Ultimate Guide
Elevated Lactate/lactic acid in sepsis does not mean give more fluids: Diminishing returns.
The World of Complexity Behind Lactic Acidosis
Figuring out the underlying cause of a lactic acidosis often boils down to two choices... But other toxic-related etiologies are less appreciated, and these are the more obscure etiologies of metabolic acidosis with increased lactate levels.
Articles of Interest
Differential Diagnosis of Elevated Serum Lactate
Type A and Type B.
Demystifying Lactate in the Emergency Department
Lactate measurement in the emergency department (ED) is a source of both guidance and confusion. Although lactate can be a useful tool when interpreted correctly, improper interpretation can mislead clinicians and result in inappropriate care and unnecessary therapies.
Gasping for Air: Albuterol-Induced Lactic Acidosis
Lactic acidosis is a commonly encountered phenomenon within the emergency department (ED). In the setting of sepsis, elevated lactate levels can be an indicator of hypoxia or decreased perfusion. Its clearance can be a sign of increased perfusion. However, lactic acidosis is much more encompassing and can be the result of many other pathophysiologic processes.
Lactate and Lactic Acidosis
Lactate ≥ 4 is associated with poorer outcome regardless of whether it is from sepsis or not (some exceptions e.g. salbutamol toxicity, seizure)
Lactic Acidosis... is it really that bad? Oh yeah. It is bad!
Lactic acid is often associated with badness, and the higher the number the worse the patient is. However, producing lactate is an appropriate stress response, and when it accumulates due to poor utilization, it indicates serious cellular function problems.
Metformin and Fatal Lactic Acidosis
Metformin is a useful anti-hyperglycaemic agent but significant mortality is associated with drug-induced lactic acidosis. Significant renal and hepatic disease, alcoholism and conditions associated with hypoxia (eg. cardiac and pulmonary disease, surgery) are contraindications to the use of metformin. Other risk factors for metformin-induced lactic acidosis are sepsis, dehydration, high dosages and increasing age.
Metformin-Associated Lactic Acidosis
Suspect MALA in any patient on metformin who presents with abdominal pain, nausea and vomiting and/or AMS.
Utility of Obtaining a Lactate Measurement in the ED
In a patient with a lactate >4 mmol/L or even >2 mmol/L, this should raise your concern for a potentially dangerous condition. If this patient is clinically stable and without deranged vital signs, it is reasonable to judiciously resuscitate them with fluids and recheck a lactate level in 2 hours. If the patient is unstable or has vital sign abnormalities suggestive of shock, this patient is likely critically ill and in need of emergent intervention.
