Lactic Acidosis Causes and Management

Classification and Causes

The American College of Physicians suggests that circulatory disorders, such as shock and cardiac failure, can cause Type A Lactic Acidosis, characterized by tissue hypoxia 1
Severe infections are a common cause of lactic acidosis, particularly in patients with underlying diseases such as diabetes mellitus 2
The American Academy of HIV Medicine recommends that nucleoside reverse transcriptase inhibitors (NRTIs) in HIV treatment, especially stavudine and didanosine, can cause lactic acidosis 4, 5, 1
Metformin, especially with renal impairment, can cause lactic acidosis, with a rare but serious incidence of 2-9/100,000 patients/year 3, 2

Mitochondrial toxicity, such as from NRTIs, can inhibit DNA polymerase γ, responsible for mitochondrial DNA synthesis, leading to increased production of lactic acid 4, 1

The American College of Internal Medicine recommends that laboratory findings for lactic acidosis include arterial pH <7.3, blood lactate >2 mEq/L, and increased anion gap (Na - [Cl+CO2] >16) 1
Clinical symptoms of lactic acidosis often include nausea, vomiting, abdominal pain, dyspnea, tachypnea, generalized weakness, and myalgias 1

Proper lactate measurement requires prechilled fluoride-oxalate tubes, transport on ice to laboratory, processing within 4 hours of collection, and collection without tourniquet or fist-clenching 1
The American College of Internal Medicine suggests that interpretation of serum lactate levels includes: 2-5 mmol/L (elevated), >5 mmol/L (abnormal), and >10 mmol/L (serious/life-threatening) 1

The American College of Internal Medicine recommends that treatment of lactic acidosis includes discontinuing offending medications, such as metformin, and providing supportive care, including bicarbonate infusions, hemodialysis, and mechanical ventilation 1
Consider thiamine and riboflavin supplementation in specific cases of lactic acidosis 1
The American Geriatrics Society suggests that advanced age (>65 years) and congestive heart failure are risk factors for metformin-associated lactic acidosis 6