Lactic AcidosisJ. Ryan Altman, MD
6 October 2009 Lactic AcidosisMost common cause of metabolic acidosis in hospitalized patients
Associated with elev anion gap and plasma [lactate] > 4mEq/L
Result of both overproduction and underuse of lacate
Normal plasma [lactate] is 0.5 to 1.5 mEq/L
Impaired tissue oxygenation (Type A)
Systemic impairment in oxygenation is not apparent (Type B) Lactic AcidosisType A
Impairment of tissue oxygenation
Circulatory or respiratory failure, sepsis, ischemic bowl, carbon monoxide, marked tissue hypoperfusion (shock), hypovolemia
No impairment of tissue oxygenation (toxin-induced impairment of cellular metabolism or regional areas of ischemia)
Malignancy, alcoholism, NRTIs, salicylates, metformin
Predisposing conditions to metformin toxicity: renal insufficiency (Cr>1.5mg/dl), concurrent HF req pharmacologic therapy, liver disease or EtOH abuse
Malignancy: pathogenesis unclear, but removal of tumor (chemo, irradiation, or surgery) leads to correction of acidosis
Alcoholism: lactate production is nl, but utilization is diminished b/c of impaired hepatic gluconeogenesis.
HIV infection: may be from serious infections leading to sepsis induced lactic acidosis (Type A) or drug induced mitochondrial dysfunction in absence of sepsis or hypoperfusion (Type B) ...