BOF: 11
A
46 year old homeless male is brought in to casualty. No formal history can be
taken as the patient is drowsy.
On examination he is drowsy but responds to pain, pulse 110 beats per minute
BP 140 /80
Heart sounds were normal no murmurs, lungs were clear
Investigations reveal normal arterial oxygen saturation, blood glucose within
normal range and a metabolic acidosis with and increased anion gap
Which one of the following conditions would account for this:
a)
Renal tubular acidosis
b)
Severe diarrhoea
c)
Pancreatic fistula
d)
Methanol ingestion
e)
Pyelonephritis
Answer: d)
Elevated anion-gap metabolic acidosis
CVS
ü
Hypoperfusion
Lactic
acidosis (L-lactate)
RS
ü
Carbon
monoxide/cyanide poisoning
L-lactate
GIT
ü
Short
bowel syndrome
D-Lactataemia
E&M
ü
Diabetic ketoacidosis
Acetoacetate/beta-hydroxybutyrate
ü
Maple
syrup urine disease
KUS
ü
Renal
failure
Urate,
hippurate, sulphate and phosphate
LMS
ü
Rhabdomyolysis
Direct
proton release from lysed muscle cells
Toxins
ü
Alcoholic ketoacidosis
Acetoacetate/beta-hydroxybutyrate
ü
Methanol or formaldehyde poisoning
Formate
ü
Ethylene glycol poisoning
Glycolate and oxalate
ü
Paraldehyde poisoning
Variety of organic acids
ü
Sulphur poisoning
ü
Sulphate.
ü
Pyroglutamic acidaemia
5-oxoprolate
Drugs
ü
Biguanide toxicity (lactic acid )
ü
Salicylate poisoning
Normal
anion-gap metabolic acidosis (hyperchloraemic acidosis)
GIT
ü
Gastrointestinal bicarbonate loss
Diarrhoea, pancreatic or intestinal fistulae, ureterosigmoidostomy
ü
Parenteral or hyperalimentation feeding
KUS
ü
Renal
tubular acidosis
ü
Pyelonephritis
Drugs
and Toxins
ü
Ammonium chloride
ü
Carbonic anhydrase inhibitors
