Lab Case 161 – Interpretation

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2 year old male BIB mother with a 24 hour history of fever, diarrhoea and vomiting

Metabolic acidosis

Expected PCO2 =(1.5xHCO3)+8 = 23.75. Actual 41, therefore uncompensated or underlying respiratory acidosis

AG = Na- (Cl+HCO3)=16 therefore HAGMA

Delta Gap = (AG-12)/(24-HCO3)=0.3 Therefore the disturbance is a pure NAGMA

Lactate of 10.1, renal dysfunction with an elevated urea and creatinine, hypoglycaemia

Interpretation – This is a critically unwell child, showing signs of shock clinically as well on lab investigations. The delta gap shows a pure NAGMA. The NAGMA is likely secondary to the profuse diarrhoea in this case. Other differentials for the NAGMA would be Addisons – low normal sodium and low glucose , however the potassium is low(corrected for acidosis).  Other contributing causes of the acidosis would be high lactate (secondary to shock), renal failure, and/or starvation ketosis. The actual CO2 is higher than expected, therefore the acidosis is not adequately compensated for, or there is an underlying respiratory acidosis – underlying pneumonia, ARDS. The renal failure could be pre renal secondary to dehydration and shock, however in this case of gastroenteritis HUS needs to be excluded.

The hypoglycaemia is likely related to sepsis. Other causes to be considered starvation ketosis, adrenal insufficiency, liver failure, metabolic disorders

Resuscitation – resuscitation area, with most senior doctor and nursing staff, PPE, cardiac monitoring and ivi access, monitoring of input and output

  • Fluid bolus 20ml/kg normal saline – repeat, if needed depending on response. Child likely markedly intravascularly depleted, so might require repeated boluses, but if not responding diagnosis of septic shock needs to be made and need for inotropes considered
  • 2ml/kg 10 % dextrose to address hypoglycaemia – repeat if required
  • Continue IV fluids: 0.9% saline + 5 % glucose (maintenance + deficit+ losses over 24 hours)
  • Antibiotics – see local guidelines – ceftriaxone 50mg/kg and vancomycin 15mg/kg (ChAMP guidelines)
  • Early paeds input