Lactic Acidosis

Question 1

what is it?

Answer 1

lactate is end product of the anaerobic metabolism of glucose - comes from red cells e.g. skeletal muscle, brain and renal medulla
for lactate to be cleared there needs to be hepatic uptake and aerobic conversion to pyruvate

Question 2

what is Type A?

Answer 2

associated with tissue hypoxaemia (infarcted tissue, cardiogenic or hypovolaemic shock, sepsis - endotoxic shock or haemorrhage)

Question 3

what is Type B?

Answer 3

may occur with liver disease or leukaemic states, associated with diabetes (10% DKA lactate >5mmol/L) also associated with metformin usually in severe illness or renal failure
consider rare inherited conditions if well and non-diabetic

Question 4

The ion gap

Answer 4

= [Na + K] - [HCO3 + Cl]
the normal range is 10-18 mmol/L
negatively charged proteins, sulphate and phosphate and some organic acids make up the difference
ion gap is a way to help determine the cause of the acidosis

Question 5

how does lactic acidosis present?

Answer 5

hyperventilation
mental confusion
stupor or coma if severe

Question 6

what are the biochemical results of lactic acidosis?

Answer 6

reduced bicarbonate 
raised anion gap 
glucose variable often raised 
absence of ketonemia 
raised phosphate

Question 7

how is it managed?

Answer 7

treat underlying condition
fluids
antibiotics
withdraw offering medication