Unexplained acidosis of malnutrition: a study by ion-exchange chromatography/mass spectrometry

Keto-acidosis is usually associated with uncontrolled diabetes and typically poses few diagnostic problems when presenting as hyperglycaemia, metabolic acidosis and a high anion gap. An emaciated patient suffering from Duchenne Muscular Dystrophy and volume depletion presented with acidosis of unknown origin. Preliminary investigations appeared to rule out lactic acidosis, diabetic keto-acidosis and acidosis due to base loss. We have previously reported a technique utilizing liquid chromatography coupled to mass spectrometry (LC-MS) which can be used to characterize the underlying aetiology of acidosis and applied it to ultrafiltrate derived from a blood sample taken from this patient. The anion profile obtained on the chromatogram showed elevated levels of acetoacetate and hydroxybutyrate but no evidence of lactic acidosis, nor was the profile typical of that seen in 'unexplained' acidosis. We concluded that the patient was suffering from keto-acidosis associated with starvation and dehydration, the biochemical features being obscured by both the patient's chronic malnutrition and minimal muscle mass. A combination of enteral feeding and rehydration led to prompt resolution of the patient's metabolic acidosis.