Well, there are no hidden tricks with this case. This is not a fancy diagnosis, rather a very common one. I feel that if you are in a department that sees children, then you need to know Paediatric DKA back to front & be able to manage it with a certain level of finesse, particularly as there is certainly the potential to do more harm than good.

Management of Paediatric DKA.

I wanted to use this case as a vignette to bring the following paper to your attention….

To my knowledge it is the most concise paper that summarises the management of Paediatric DKA. Below are what I consider the pertinent points to take from this guideline…

Diagnosis:

• * Hyperglycaemia 
       - Blood glucose > 11mmol/L (200mg/dL)
  * Venous pH < 7.3 or HCO3 < 15mmol/L
  * Ketonaemia / Ketonuria.

Severity:

• * Mild
       - pH < 7.3  or  HCO3 < 15 mmol/L
  * Moderate
       - pH < 7.2  or  HCO3 < 10 mmol/L
  * Severe  
       - pH < 7.1  or  HCO3 < 5 mmol/L

Goals of Therapy:

• * Correct dehydration.
  * Correct acidosis & reverse ketosis.
  * Restore blood glucose to near normal.
  * Avoid complications of therapy.
  * Identify & treat any precipitating causes.

Fluid Management:

• * Severe volume depletion w/out shock.
       - Volume resuscitation begins immediately w/ 0.9% saline.
       - Aim for 10mL/kg/hr over 1-2 hours
            ~ repeat if necessary.
       - Do not exceed 30mL/kg in first 4 hours.
  
  * DKA w/ shock (rare).
       - 20mL/kg bolus (0.9% Saline or Hartman's) 
       - reassess after each bolus
       - don't forget the intraosseous route !
  
  * Subsequent fluid management (deficit replacement).
       - 0.9% Saline or Hartman's for at least 4-6 hours.
            ~ Thereafter; tonicity > 0.45% (w/ added K+)
       - Calculate fluid deficit (ie. 5 vs 7 vs 10% dehydration).
            ~ Rehydrate evenly over 48 hours
            ~ Avoid rates of > 1.5-2x usual daily maintenance requirements.
            ~ click here for fluid calculation example
       - No need to add urinary losses to fluid calculations.
       - Sodium content may need to be increased 
         (if Na+ not increasing w/ appropriate therapy).

Insulin Therapy:

• * Start insulin infusion 1-2 hours after commencing fluid replacement.
       - ie. after initial volume expansion.
  * Dose = 0.1 units / kg / hour (via infusion).
       - reduce to 0.05 units/kg/hr in those w/ exquisite insulin sensitivity.
       - do not use boluses !!
  * Continue insulin until DKA resolves [ Target BSL ~ 11mmol/L ].
       - ie. pH > 7.3, HCO3 > 15 mmol/ or anion gap is closed.
  * Add 5% Dextrose to IV fluid when glucose ~ 14-17mmol/L
       - consider adding earlier w/ rapid glucose drop (>5mmol/hr).
       - up to 10-12.5% may be required to correct acidosis.

Potassium Replacement:

• * Children w/ DKA have total body deficits of up to 3-6 mmol/kg.
  * Replacement is required regardless of serum K+ concentration.
       - If hypokalaemic;
            ~ start K+ replacement w/ initial volume expansions.
            ~ concentration of 20mmol/L should be used.
       - If normal K+;
            ~ start K+ replacement after expansion, before insulin therapy.
       - If hyperkalaemic;
            ~ defer K+ replacement until urine output is documented.
  
  * Maintenance therapy;
       - Potassium concentration of 40mmol/L.
  * Maximum replacement is ~ 0.5mmol/kg/hr.
  

Phosphate Replacement:

• * No clinical benefit from routine replacement.
  * Severe hypophosphataemia w/ unexplained weakness should be treated.
  * Potassium phosphate can be used with KCl to replace both.
       - Beware inducing hypocalcaemia.

Acidosis:

• * Severe acidosis is reversible by fluid & insulin therapy.
       - Insulin stops further ketoacid production & generates bicarbonate.
  * No clinical benefit from bicarbonate administration.
       - May cause paradoxical CNS acidosis.
  * Consider bicarbonate use in;
       - severe acidosis (pH < 6.9) w/ decreased cardiac contractility 
         & vasodilatation 
       - life threatening hyperkalaemia.

Cerebral Oedema:

• * Responsible for 60-90% of all DKA-related deaths.
  * Incidence ~ 0.5-0.9% of DKA cases.
  * Mortality ~ 21-24%.
  
  * Risk Factors:
       - younger age / New onset diabetes / longer duration of symptoms
       - greater hypocapnia (adjusted for severity of acidosis)
       - more severe acidosis
       - increased serum urea
       - bicarbonate therapy (to correct acidosis)
       - greater volumes of fluid given in first 4 hours
       - attenuated rise in serum sodium concentration (despite therapy)
       - administration of insulin in first hour of fluid therapy
  
  * Signs & Symptoms:
       - Headache / progressive bradycardia or hypertension
       - Altered neurological status
            ~ restlessness
            ~ irritability
            ~ drowsiness
            ~ incontinence 
       - Focal neurological signs (eg. cranial nerve palsies)
       - Decreased oxygen saturations.
  
  * Treatment:
       - Elevate head of bed
       - Reduce IV fluids to 1/3 the rate
       - Mannitol:
            ~ 0.5-1.0 grams/kg over 20 minutes.
            ~ repeat if no response in 30-120 minutes.
       - Hypertonic (3%) saline.
            ~ an alternative to mannitol
            ~ 5-10mL/kg over 30 minutes.
       - Intubation. Avoid aggressive hyperventilation.
       - CNS imaging (CT-Brain); 
            ~ confirming diagnosis/assessing for alternate diagnoses.

Reference.

1. Wolfsdorf, J. et al. Diabetic ketoacidosis in children and adolescents with diabetes. Pediatric Diabetes. 2009. 10 Suppl 12: 118–133.