lactic acidosis Flashcards
lactic acid is the
normal endpoint for the anaerobic metabolism of glucose in tissues, the lactate exits the cells and is transported to the liver where it is oxidised back to pyruvate and is converted into glucose via the cori cycle (lactic acid cycle)
lactate is predominantly metabolised
in the liver (60%) but 30% also occurs in the kidneys, half of the lactate gets converted to glucose while the other hand gets converted to CO2 and H20 via the TCA cycle which prevents the net production of hydrogen ions
lactic acidosis can occur due to
- excessive tissue lactate production
- impaired metabolism of lactate in the liver or the kidneys
classification of lactic acidosis
type A or type B
which type of lactic acidosis is more common
type A
lactic acidosis type A occurs due to
tissue hypoxaemia:
- infarcted tissue (e.g ischaemic bowel)
- cariogenic shock
- hypovolaemic shock (sepsis and haemorrhage)
lactic acidosis type B occurs due to
- liver disease
- metformin usage in people with severe renal or hepatic impairment or have sepsis
clinical features of lactic acidosis
- hyperventilation
- mental confusion
- in severe cases causes a coma
lab findings
- reduced bicarbonate
- high anion gap
- raised phosphates
- high serum lactate (greater than 5)
- no ketonuria
what is the anion gap
measure of the gap between the cations (positively charged ions) and anions (negatively charged ions)
ion gap calculation
(Na+ + K+)- (HCO3- + CL-)
normal range of anion gap
10 to 18 mol/l
what should the anion gap technically be
0 but because many anions are not measured e,g albumin, phosphate, sulphate
what is anion gap used for
to determine the cause of a metabolic acidosis
high anion gap metabolic acidosis is caused by
increased production of organic acid
