This is a 3 month old (weight 5kg) critically unwell child who requires resuscitation with concomitant assessment to determine the cause of her illness.
Her clinical picture is one of severe dehydration (at least 7%)
Severe life threatening metabolic acidosis ( BE -25, HCO3 4) with maximum compensation ( CO2 very rarely decreases to less than 10)
Anion gap = 15, high side of normal – accounted for by high lactate, severe peripheral circulatory compromise and tissue hypoperfusion. Consider severe dehydration,sepsis, toxins (glucose normal and creatinine normal). The anion gap is not large enough to explain the very low pH.
Delta ratio = 0.15 , consistent with normal anion gap metabolic acidosis
Causes – intestinal catatstrophies, diarrhoea
Osmolality = 331.5, high urea, pre renal cause ie. fluid loss and dehydartion, hypoperfusion
Mild hypokalaemia – secondary to diarrhoea and likely to reflect critically low total body potassium due to acidosis and shift. Requires careful monitoring and replacement, particularly as acidosis corrects and potassium shifts to intracellular compartment.
High sodium and chloride – pure water loss from diarrhoea, consider whether these blood tests were taken after a fluid bolus of normal saline
Normal glucose – not DKA, ketones not given
Creatinine normal – normal renal function
Venous sample so cannot interpret Aa gradient or pO2
An unwell 3 month old with a mixed anion gap and normal anion gap metabolic acidosis (hyperchloraemic), severe dehydration. She requires immediate iv access with 10ml/kg normal saline fluid bolus and re assessment, assessment of cause and specific treatment as indicated.
Gastroenteritis – infective (viral, bacterial, parasitic)
Inborn errors of metabolism
Fluid Calculation in children:
Degree of dehydration (deficit) – weight X % dehydration X 10
Maintenance fluid requirements (4;2;1 rule)
Ongoing losses – best measured
Aim to replace over 48 hours, in severe cases subtract the bolus doses given from the total.