DKA - paediatric



Background

  • Always admit children in suspected DKA
  • Consult with a more senior doctor on call as soon as you suspect DKA, even if you feel confident of your management

Remember : children can die from DKA

  • Cerebral oedema (unpredictable, younger children, mortality rate 25%).Minimised by slow correction of electrolytes. No Insulin in the 1st hour.
  • Hypokalaemia
  • Aspiration pneumonia (avoid NG tube if possible)

Recent changes in practice

  • Use capillary bld ketone measurement during treatment
  • ↓ in degree of dehydration to be used to calculate fluids
  • ↓ in maintenance fluid rates
  • Continuation of normal saline for the first 12 hours of rehydration
  • Delay insulin until fluids have been running for an hour
  • Option to continue insulin glargine during treatment
  • Consider anticoagulant prophylaxis in young children, esp. those with femoral lines
  • Interpretation of blood ketone measurements if pH not improving

Diagnosis

↑glucose (plasma glucose >11 mmol/l)

Ketonaemia >3mmol/L

pH < 7.3

and

  • > 3% dehydrated
  • ± vomiting
  • ± drowsy
  • ± clinically acidotic

Children <5% dehydrated and not clinically unwell usually tolerate oral rehydration and subcutaneous insulin. Blood ketone levels are generally over 3.0 mmol/l but some well children who do not fulfil the criteria above for IV fluids may have ketone levels of up to 6.0 mmol/l.


Initial Management

Resuscitation

Airway

  • Ensure that the airway is patent (± insert airway)
  • If ↓consciousness or recurrent vomiting, insert NGT, aspirate and leave on open drainage

Breathing

  • Give 100% oxygen by face-mask

Circulation

  • Insert IV cannula and take blood samples (see below)
  • Cardiac monitor for T waves (peaked in hyperkalaemia)
  • Only if shocked (poor peripheral pulses, ↑cap. filling with ↑HR, ±↓BP) give 10 ml/kg 0.9% (normal) saline as a bolus, and repeat up to twice as necessary

Confirm the diagnosis

  • History: polydipsis, polyuria
  • Clinical: acidotic respiration, dehydration, drowsy, abdo. pain/vomiting
  • Biochemical:
    • ↑ blood glucose (>11mmol/L) on finger prick test
    • Blood pH <7.3 and/or HCO3 <15 mmol/L
    • Finger prick blood ketones >3.0 mmol/L
    • Glucose and ketones in urine

Initial investigations

  • Blood glucose
  • U&E (calculate corrected Na+ and effective osmolality)
  • VBG (not arterial)
  • Near patient blood ketones
  • ± other investigations only if indicated e.g. FBC count (leucocytosis is common in DKA and does not necessarily indicate sepsis), CXR, CSF, throat swab, blood culture, urinalysis, C&S etc.

1st presentation

If this is a first presentation of DKA, send samples for:

  • HbA1C
  • TFT and anti-TPO
  • Anti-GAD, ZnT8 and anti-IA2 antibodies
  • IgA and TTG

Full clinical assessment and observations

1 Degree of dehydration

Mild, 3% is only just clinically detectable
Moderate, 5% dry mucous membranes, ↓skin turgor
Severe, 8% above with sunken eyes, poor capillary return
± shock may be severely ill with poor perfusion, thready rapid pulse
(↓BP is not likely and is a very late sign)

Over-estimation of degree of dehydration is dangerous
Do not use more than 8% dehydration in calculations.

2. Conscious level

Institute hourly neurological observations including GCS whether or not drowsy on admission.

If in coma on admission, or there is any subsequent deterioration:

  • consider transfer to PICU/HDU if available
  • consider instituting cerebral oedema management (if high level of suspicion, start treatment prior to transfer)
  • coma is directly related to degree of acidosis, but signs of ↑ICP suggest cerebral oedema

3. Full Examination

Look particularly for evidence of -

  • cerebral oedema: headache, irritability, ↓ pulse, ↑ BP, ↓ conscious level N.B. papilloedema is a late sign
  • infection
  • ileus

WEIGH THE CHILD

4. Consider PICU or HDU for the following, and discuss with a paediatric consultant.

  • severe acidosis pH<7.1 with marked hyperventilation
  • severe dehydration with shock
  • ↓ sensorium with risk of aspiration from vomiting
  • very young (under 2 years)
  • staffing levels on the wards are insufficient to allow adequate monitoring

Where PICU or HDU do not exist within the admitting hospital, transfer to another hospital for such care (unless ventilatory support becomes necessary) may not be appropriate. However, ALL children with DKA are high-dependency patients and require a high level of nursing care, usually 1:1 even if on general paediatric wards.

5. Observations to be carried out

Ensure full instructions are given to the senior nursing staff emphasising the need for:

  • strict fluid balance (urinary catheterisation may be required in young/sick children)
  • measurement of volume of every urine sample
  • hourly capillary blood glucose measurements (these may be inaccurate with severe dehydration/acidosis but useful in documenting the trends. Do not rely on any sudden changes but check with a venous laboratory glucose measurement)
  • capillary blood ketone levels every 1-2 hours
  • hourly BP and basic observations
  • twice daily weight; can be helpful in assessing fluid balance
  • hourly or more frequent neurological observations initially
  • reporting immediately to the medical staff, even at night, symptoms of headache, or slowing of pulse rate, or any change in either conscious level or behaviour
  • reporting any changes in the ECG trace, especially T wave changes suggesting hyper- or hypokalaemia

Start recording all results and clinical signs on a flow chart.


Key points

  • Don't treat with insulin in the first hour of maintenance fluids
  • Add or increase Dextrose concentration of the IV fluid if the glucose is falling too fast (>5mmol/l) or going to low (<17mmol/l add 5%, <8mmol/l increase to 10%). Insulin infusion remains the same unless serum glucose continuing to fall despite 10% dextrose
  • Add KCL 20mmol/l in 500ml 0.9% Saline when K <5.5mol/l and recent history of urination
  • Give 0.9% saline boluses of 10ml/kg if clinically shocked

Approach


Continue management

Fluids

A. Volume of fluid

By this stage, the circulating volume should have been restored and the child no longer in shock. If not, give a further 10 ml/kg 0.9% saline (to a maximum of 30 ml/kg) over 30 minutes. (discuss with a consultant if the child has already received 30 ml/kg).

Otherwise, once circulating blood volume has been restored, calculate fluid requirements as follows:

Requirement = Maintenance + Deficit – fluid already given.

Deficit (litres) = % dehydration x body weight (kg)
Ensure this result is then converted to ml.

For most children, use 5% to 8% dehydration to calculate fluids.

Maintenance requirements:

Maintenance requirements
Weight Fluid
0-12.9kg 80 ml/kg/24 hrs
13-19.9kg 65 ml/kg/24 hrs
20-34.9kg 55 ml/kg/24 hrs
35-59.9kg 45 ml/kg/24 hrs
>60kg 35 ml/kg/24 hrs

Neonatal DKA will require special consideration and larger volumes of fluid than those quoted may be required, usually 100-150 ml/kg/24 hours).

APLS maintenance fluid rates over-estimate requirement, particularly at younger ages. Add calculated maintenance (for 48 hrs) and estimated deficit, subtract the amount already given as resuscitation fluid, and give the total volume evenly over the next 48 hours. i.e.

Hourly rate = 48 hr maintenance + deficit – resuscitation fluid already given / 48.


Example:

A 20 kg 6 year old boy who is 8% dehydrated, and who has already had 20ml/kg saline, will require:71mls/hr.

Do not include continuing urinary losses in the calculations at this stage.

For a method of calculating fluid rates which can be printed out for the child's medical record.

Example fluid req.
8% x 20kg = 1600 mls deficit
plus 55 mls x 20kg = 1100 mls maintenance (each day)
= 3800 mls
minus 20kg x 20ml 400mls resusc. fluid
= 3400mls over 48 hrs = 71 mls/hr

Calculator

Please feel free to check your calculations on the below.

Result:

National (2021) guideline

National 2021 Guideline

B. Type of fluid

Initially use 0.9% saline with 20 mmol KCl in 500 ml, and continue this NaCl for at least 12 hours.

Once the blood glucose has fallen to 14 mmol/l add glucose to the fluid.

A bag of 500 ml 0.9% saline with 5% glucose and 20 mmol KCl should be available from Pharmacy. If not, make up a solution as follows - withdraw 50ml 0.9% sodium chloride/KCl from 500ml bag, and add 50ml of 50% glucose (this makes a solution which is approximately 5% glucose with 0.9% saline with potassium).

After 12 hours, if the plasma sodium level is stable or increasing, change to 500ml bags of 0.45% saline/5% glucose/20 mmol KCl.

If the plasma sodium is falling, continue with Normal saline (with or without glucose depending on blood glucose levels). Some have suggested that Corrected Sodium levels give an indication of the risk of cerebral oedema. If you wish to calculate this, go to: http://www.strs.nhs.uk/resources/pdf/guidelines/correctedNA.pdf.

Corrected sodium levels should rise as blood glucose levels fall during treatment. If they do not, then continue with Normal saline and do not change to 0.45% saline.

Check U&E's 2 hours after resuscitation is begun and then at least 4 hourly.

Oral fluids

  • In severe dehydration, impaired consciousness & acidosis do not allow fluids by mouth. A N/G tube may be necessary in the case of gastric paresis
  • Oral fluids (eg fruit juice/oral rehydration solution) should only be offered after substantial clinical improvement and no vomiting
  • When good clinical improvement occurs before the 48hr rehydration period is completed, oral intake may proceed and the need for IV infusions reduced to take account of the oral intake

Potassium

Once the child has been resuscitated, potassium should be commenced immediately with rehydration fluid unless anuria is suspected.

Ensure that every 500 ml bag of fluid contains 20 mmol KCl (40 mmol per litre).

Check U&E's 2 hours after resuscitation is begun and then at least 4 hourly, and alter potassium replacements accordingly. More potassium than 40 mmol/l is occasionally required.

Use a cardiac monitor and observe frequently for T wave changes.

Insulin

Once rehydration fluids and potassium are running, blood glucose levels will start to fall. Do not start insulin until intravenous fluids have been running for at least an hour.

Continuous low-dose intravenous infusion is the preferred method. There is no need for an initial bolus.

Make up a solution of 1 unit per ml. of human soluble insulin (e.g. Actrapid) by adding 50 units (0.5 ml) insulin to 50 ml 0.9% saline in a syringe pump. Attach this using a Y-connector to the IV fluids already running. Do not add insulin directly to the fluid bags.

The solution should then run at 0.1 units/kg/hour (0.1ml/kg/hour).

  • Once the blood glucose level falls to 14mmol/l, change the fluid to contain 5% glucose (generally 0.9% saline with glucose and potassium). Do not ↓ the insulin. The insulin dose needs to be maintained at 0.1 units/kg/hour to switch off ketogenesis
  • Do not stop the insulin infusion while glucose is being infused
  • If the blood glucose falls below 4 mmol/l, give a bolus of 2 ml/kg of 10% glucose and increase the glucose concentration of the infusion. Insulin can temporarily be reduced for 1 hour
  • If needed, a solution of 10% glucose with 0.45% saline can be made up by adding 50ml 50% glucose to a 500 ml bag of 0.45% saline/5% glucose with 20 mmol KCl
  • Once the pH is above 7.3, the blood glucose is down to 14 mmol/l, and a glucose-containing fluid has been started, consider reducing the insulin infusion rate, but to no less than 0.05 units/kg/hour
  • If the blood glucose rises out of control, or the pH level is not improving after 4-6 hours consult senior medical staff and re-evaluate (possible sepsis, insulin errors or other condition), and consider starting the whole protocol again

For children who are already on long-acting insulin (especially Glargine (Lantus)), your local consultant may want this to continue at the usual dose and time throughout the DKA treatment, in addition to the IV insulin infusion, in order to shorten length of stay after recovery from DKA.

For children on continuous subcutaneous insulin infusion (CSII) pump therapy, stop the pump when starting DKA treatment.

Bicarbonate

This is rarely, if ever, necessary. Discuss with senior staff.

Phosphate

There is always depletion of phosphate, another predominantly intracellular ion. There is no evidence to support replacement therapy.

Anticoagualtion prophylaxis

There is a significant risk of femoral vein thrombosis in young and very sick children with DKA who have femoral lines inserted. Therefore consideration should be given to anticoagulating these children with 100 units/kg/day as a single daily dose of Fragmin.

Children who are significantly hyperosmolar might also require anticoagulant prophylaxis (discuss with your consultant).


Monitoring

Monitoring during therapy
Continuous
  • ECG monitoring
½ hourly
  • Neuro obs, including consciousness (using modified GCS) and heart rate, in children under age 12
  • Or in children and young people with a pH <7.1 (↑ risk cerebral oedema)
1 hourly
  • Vital signs (or more frequently if indicated)
  • Neuro obs (escalate immediately if headache or change in conscious level or behaviour)
  • Blood glucose and blood ketone levels
2 hourly
  • Electrolytes (x2) (and calculate corrected sodium)/VBG/Lab glucose until acidosis reversed
  • Review fluid composition and rate following each result
  • May be able to check 4 hourly after substantial clinical improvement
Accurate
  • Documentation of fluid input and output
Twice daily
  • Weights

Consider ITU admission

If severe DKA (pH <7.1, Shock, decreased GCS, age <2 years of age) or if staffing on the ward is insufficient to allow adequate monitoring.

Where PICU or HDU do not exist within the admitting hospital, transfer to another hospital for such care (unless ventilatory support becomes necessary) may not be appropriate. However, ALL children with DKA are high-dependency patients and require a high level of nursing care, usually 1:1 even if on general paediatric wards.


Sodium and Osmolality:

A rapid fall in effective plasma osmolality and/or sodium during therapy may be associated with cerebral oedema. Aim for slow correction of no more than 0.5mmol/hr.

Where effective osmolality = 2 X (Na+K) + Glucose.

Hyperglycaemia causes falsely low plasma sodium levels. Sodium falls 2mmol/l for every 5.5mmol/l rise in glucose.

Corrected Sodium = Measured Na + (2X (glucose – 5.5) / 5.5).

If the initial corrected sodium is >150mmol/l, a slower rehydration rate should be considered.

If actual serum sodium falls during treatment consider slowing the rehydration rate or increasing the sodium concentration and increase vigilance for signs of cerebral oedema.


Continuing management

Urinary catheterisation should be avoided but may be useful in the child with impaired consciousness.

  • Documentation of fluid balance is of paramount importance. All urine needs to be measured accurately. All fluid input must be recorded (even oral fluids)
  • If a massive diuresis continues fluid input may need to be increased. If large volumes of gastric aspirate continue, these will need to be replaced with 0.9% saline with KCl
  • Check biochemistry, blood pH, and lab. blood glucose 2 hours after the start of resuscitation, and then at least 4 hourly. Review the fluid composition and rate according to each set of electrolyte results

If acidosis is not correcting, consider the following:

  • insufficient insulin to switch off ketones
  • inadequate resuscitation
  • sepsis
  • hyperchloraemic acidosis
  • salicylate or other prescription or recreational drugs

Use near-patient ketone testing to confirm that ketone levels are falling adequately. If blood ketones are not falling, then check infusion lines, the calculation and dose of insulin and consider giving more insulin.

Consider sepsis, inadequate fluid input and other causes if sufficient insulin is being given.

Insulin management once ketoacidosis resolved

Continue with IV fluids until the child is drinking well and able to tolerate food. Only change to subcutaneous insulin once blood ketone levels are below 1.0 mmol/l, although urinary ketones may not have disappeared completely.

Discontinue the insulin infusion 60 minutes (if using soluble or long-acting insulin) or 10 minutes (if using Novorapid or Humalog) after the first subcutaneous injection to avoid rebound hyperglycaemia. Subcutaneous insulin should be started according to local protocols for the child with newly diagnosed diabetes, or the child should be started back onto their usual insulin regimen at an appropriate time (discuss with senior staff).


Cerebral oedema

  • Cause unclear
  • Possible association with early insulin so it is recommended that children receive fluids only in the first hour of treatment
  • Incidence 0.5-0.9% episodes of D.K.A. with 21-24 % mortality
  • Most commonly occurs in first 24 hours, usually 4-12 hours after treatment begins but may occur at 24-48 hours

Signs/symptoms (cerebral oedema):

  • Headache, irritability, restlessness, drowsiness, incontinence (in a previously continent child) or specific neurological signs
  • Cushings triad: ↑BP, ↓HR, irregular resps.
  • Late signs: Seizures, papilloedema, unequal pupils, respiratory arrest

Risk factors cerebral oedema

  • Younger (< 5 years old), 1st presentation
  • Dehydration (↑urea), Hypernatraemia
  • Na+ fails to rise with treatment, pH < 7.0

Management (cerebral oedema):

  • Exclude hypoglycaemia
  • Nurse at 45° head up
  • Contact Consultant immediately
  • Hypertonic saline 3% 3ml/kg over 10 minutes
  • Doses may need to be repeated if no response
  • Reduce maintenance fluid by a third and deliver rehydration fluid over 72 hours (rather than 48hours)
  • Transfer to ICU and consider need for transfer to a tertiary PICU
  • Arrange Neuroimaging (CTB or MRI) in discussion with PICU and neurosurgical team as other intracerebral pathology can present in the same way (e.g. cerebral venous thrombosis)

Other complications

  • Hypoglycaemia and hypokalaemia – avoid by careful monitoring and adjustment of infusion rates. Consideration should be given to adding more glucose if BG falling quickly even if still above 4 mmol/l
  • Systemic Infections – Antibiotics are not given as a routine unless a severe bacterial infection is suspected
  • Aspiration pneumonia – avoid by nasogastric tube in vomiting child with impaired consciousness

Continuing abdominal pain is common and may be due to liver swelling, gastritis, bladder retention, ileus. However, beware of appendicitis and ask for a surgical opinion once DKA is stable. A raised amylase is common in DKA.

Other problems are pneumothorax ± pneumo-mediastinum, interstitial pulmonary oedema, unusual infections (e.g. TB, fungal infections), hyperosmolar hyperglycaemic non–ketotic coma, ketosis in type 2 diabetes. Discuss these with the consultant on-call.


Guide for increasing the percentage glucose in a bag:

Glucose 50% is used to increase the glucose concentration.

These calculations are based on adding glucose to a 5% dextrose / 0.9% Saline 500ml bag.

Guide for increasing % glucose in a bag
%w/v glucose required  Vol to be withdrawn from infusion bag Vol of glucose 50% to be added to infusion bag
7.5% 28ml 28ml
10% 55ml 55ml
12.5% 82.5ml 82.5ml


Content by Dr Rory O'Brien, Dr Emmanuelle Fauteux-L, Dr Íomhar O' Sullivan. Last review Dr ÍOS 16/04/22.