Paediatric Diabetic Ketoacidosis

Last Updated on by FRCEM Intermediate

Overview

  • potentially life-threatening complication of diabetes melitus resulting from the consequences of insulin deficiency

Diagnostic feature

  • Hyperglycaemia (blood glucose >11 mmol/L)
  • Acidosis (pH < 7.3, bicarbonate <15 mmol/L)
  • Ketosis (presence of ketones in the blood (3mmol/L) and/or urine (++))

Pathogenesis

increased glucagon, cortisol, catcholamines, GH decreased insulin -> hyperglycaemia
-> hyperosmolality + glycosuria
-> electrolyte loss
-> ketone production from metabolism of TG
-> acidosi

Clinical Features

  • Dehydration
  • Kussmaul respiration (deep, rapid, sighing)
  • Nausea and vomiting
  • Abdominal pain (can mimic an acute abdomen) (r/o ileus )
  • Progressive clouding of consciousness and coma (cerebral edema)
  • Increased leukocyte count with left shift (does not necessarily indicate sepsis)
  • Non-specific elevation of serum amylase

Investigations

  • ABG
  • electrolytes
  • osmolality
  • urinalysis: ketones
  • standard investigations to rule out the cause: FBC, ECG, CXR

Management

  • establish precipitant and treat
  • assess the severity of metabolic derangement
  • cautious fluid resuscitation with the replacement of body H2O
  • provision of insulin
  • replacement of electrolytes

The volume of Fluid Required

Fluid deficit

Fluid deficit (ml) = % dehydration x weight (kg) x 10

Assessment of dehydration in young people with DKA

Mild dehydration
(~ 3%)
  • Only just clinically detectable
Moderate dehydration
(~ 5%)
  • Dry mucous membranes
  • Reduced skin turgor
Severe dehydration
(~ 8%)
  • As above PLUS
  • Sunken eyes
  • Prolonged CRT
Clinical shock (rare)
  • Poor perfusion
  • Weak pulses
  • Hypotension (very late sign)

 

Maintenance fluid

Calculations are based upon body weight:

0 – 12.9 kg = 80 ml / kg / 24hrs
13 – 19.9 kg = 65 ml / kg / 24hrs
20 – 34.9 kg = 55 ml / kg / 24hrs
35 – 59.9 kg = 45 ml / kg / 24hrs
Adult (>60 kg) = 35 ml / kg / 24hrs

 

For DKA fluid calculations these volume needs be doubled as correction occurs over 48 hours

 

Total requirement

Requirement =  maintenance + deficit – fluid already given Correction should occur over 48 hours.

 

Example

What is the fluid requirement for a 20 kg boy who is 8% dehydrated and has already received a 20 ml/kg fluid bolus?

48 hour maintenance = 55 ml/kg x 20 kg x 2 = 2200 ml

8% deficit = 20 kg x 8% dehydration x 10 = 1600 ml

Minus fluid already given = 20 ml/kg x 20 kg = 400 ml

Total requirement = 2200 ml + 1600 ml – 400 ml = 3400 ml

Hence, 71 ml/hour over 48 hours

 

For at least the first 12 hours

  • N/Saline (0.9% sodium chloride without added glucose) for both rehydration and maintenance fluid until the [glucose] < 14 mmol/litre
  • Glucose can be added once blood sugar <14 mmol/L (Add 5% glucose to fluids (i.e. 500 ml bag of 0.9% saline and 5% glucose with 20 mmol potassium))
  • Ensure that all fluids (except any initial bolus) contain 40 mmol/litre potassium chloride, (except in renal failure) – Always ensure every 500 ml bag contains 20 mmol potassium (40 mmol/L) – Check electrolytes 2 hours after the start of fluid management and then at least 4 hourly

Insulin

  • 50 units Actrapid® in 50 ml 0.9% saline (1 unit/ml)
  • Run at 0.1 unit/kg/hour = 1 ml/hour
  • Start one hour after fluids commenced., do NOT start insulin until intravenous fluids have been running for at least an hour risk of cerebral odeama

Complications

hypoglycaemia
hyponatraemia
hyperchloraemic acidosis
cerebral oedema
arrhythmias
venous thrombosis
infection
hyperchloraemia

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