BOF: 113
A 74-year-old male who is known to have ischaemic heart
disease and has had a myocardial infarction presents with breathlessness. His
extremities are cold and clammy; his pulse rate is 120 beats per minute, blood
pressure 80/40. JVP elevated, heart sounds triple rhythm, crepitations are
heard in both bases.
Investigations show:
pH 7.24
Pa O2 8.5 kPa
Pa CO2 4.4 kPa
Blood lactate 5.9 mmol/l
Urine pH 5.2
Urine osmolarity 320mmol/l
Blood glucose 8.6 mmol/l
In this patient the abnormal acid-base balance is due to:
a)
Aspirin overdose
b)
D-lactic acidosis
c)
Type A L-lactic acidosis
d)
Type B L-lactic acidosis
e)
Diabetic ketoacidosis
Answer:
c)
Type A L-lactic acidosis occurs when excess lactic acid
is formed by anaerobic metabolism.
Type B L-lactic acidosis is due to decreased hepatic
lactate metabolism caused by insulin deficiency, drugs such as biguanides,
haematological malignancies, enzyme deficiencies.
D-lactic acidosis is caused by bacterial fermentation in
the gut in the short bowel syndrome
