7 year old male presents unwell

Answer

Metabolic acidosis with ph 7.080 and HCO3 of 6.8

Compensation  Expected PCO2 = 1.5X HCO3 +8 (+/-2) =18.2

AG = NA- (CL+HCO3)= 27.2

Corrected Na =Na +(glucose -5)/3 =141

Delta Gap =AG-12/24-HCO3=0.88

Description and Interpretation

There is a high anion gap metabolic acidosis with no other underlying acid base disturbance shown by adequate compensation and a delta gap of 0.8. The AG is raised and the corrected Na given the high glucose is within normal limits. The patients lactate is moderately raised, and potassium is within normal limits however at the lower end.  The patients glucose is markedly raised, and he has a normal Cr.

This patient is severely unwell.  In this clinical context, the likely cause for the patients HAGMA is a ketoacidosis as well as a lactic acidosis. The ketoacidosis is the child’s first presentation of DKA. The lactic acidosis is likely secondary to intravascular volume depletion from the vomiting and polyuria. Clinically the patient is likely to be 5% dehydrated.  The  low normal potassium is from the vomiting and osmotic diuresis.

Management

Resuscitation:

-10ml/kg normal saline stat to replace intravascular losses. Endpoints being decrease in HR, decrease in CPR. This bolus can be repeated, but the patient is unlikely to require further boluses.

Specific Management (estimated weight 28KG)

–fluid : Normal Saline over 24 hours. Change to 0.9%normalsaline +5%dextrose when BSL <15mmol/l

Deficit =%dehydration x 10 x weight =1400ml

plus

Maintenance = 1500ml(100ml/kg first 10kg+50ml/kg 11-20kg) +20ml/kg over 20KG = 1660mls

Minus

bolus already given

-potassium replacement – if the child has passed urine and potassium <5mmol/l – add 20mmol/l to 500ml normal saline

–Insulin –pH<7.2 an insulin infusion is indicated at 0.1units/kg/hr

-underlying precipitant– look for and treat underlying precipitant eg infection, pancreatitis, other abdominal pathology

–monitor for signs of raised intracranial

Supportive Management

-hourly observations, fluid balance, hourly glucose and BSL measurement, check K 2 hourly (correction of the acidosis and the insulin infusion will drop the potassium levels)

-analgesia and antiemetics.

-support and explanation to parents and child

Disposition

-early consult with an endocrinologist and transfer to tertiary facility.