Diabetic ketoacidosis in children


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Diabetic ketoacidosis in children

  1. 1. DIABETIC KETOACIDOSIS (DKA) Severe DKA is a grave illness and is the commonest cause of diabetes-related deaths in children and adolescentsMost deaths in DKA occur in young people as a result of cerebral oedemaTreatment is distinctly different from adults because of the threat ofcerebral oedemaDeaths should be avoidable by(a) Reducing the incidence of DKA by- earlier diagnosis at onset, immediate referral and urgent treatment- appropriate management of diabetes during intercurrent illness- recognition that recurrent DKA is often caused by insulin omission(b) Optimal management of DKA.
  2. 2. DefinitionThese DKA guidelines are recommended for children with• Heavy glycosuria (> 55mmol/l) and ketonuria• Hyperglycemia (BG >11 mmol/l)• pH < 7.3• Bicarbonate < 15 mmol/l and who are5% or more dehydrated± vomiting± drowsy
  3. 3. Confirm the diagnosis• Characteristic history – polydipsia, polyuria, nocturia, enuresis• Biochemical confirmation – glycosuria, ketonuria, Blood Glucose (BG >11),pH <7.3 and Bicarbonate <15• Clinical assessment – full examination◊ Severity of dehydration 3 % just detectable5 % dry mucous membranes, reduced skin turgor8 % capillary return 3 seconds or more, sunken eyes10 %+ shock, poor peripheral pulses
  4. 4. NB Clinical assessment of dehydration may be difficult especially inyoung children.Severity of dehydration is often overestimated.◊ Evidence of moderately severe acidosis – hyperventilation, pH <7.2, HCO3 <10or severe acidosis – hyperventilation, pH <7.1, HC03 <5◊ Assessment of conscious level, GCS score ( and examine pupils & retinal fundi)Consider admitting direct to CICU if there is(a) severe acidosis pH<7.1 with marked hyperventilation(b) severe dehydration with shock(c) depressed sensorium with risk of aspiration fromvomiting
  5. 5. Immediate investigations• Weigh child whenever possible• Capillary BG• Capillary, venous or arterial blood gases• Venous BG, electrolytes and urea, FBC (leucocytosis is a common featureof DKA), blood culture• take blood for HbA1c, thyroid function, thyroid antibodies, coeliac screen,GAD antibodies, Islet cell antibodies, and insulin antibodies if newlydiagnosed.• As indicated: urine culture, throat swab, chest X-ray.Height measurementor estimation is of value if calculation of Body Surface Area is required.Retrospectively a fluid input of > 4 litre/m²/24h has been suggested as arisk factor in cerebral oedema
  6. 6. ResuscitationAirway• Ensure airway patent; in coma or severe vomiting - insert airway and drainstomach with NG tubeBreathing• Oxygen 100% by face maskCirculation• Insert Cannula and take blood samplesNormal Saline 0.9% 10ml/kg as a bolus usually over 10-15mins and maybe repeated if still inshock to a total of 30 mls/kg (further resuscitation fluid may berequired if peripheral pulses remainpoor but additional rapid fluid input should be discussed with consultant).(There is no evidence to support the use of colloids or other volumeexpanders inpreference to crystalloids)• Attach ECG monitor to assess T-wavesNB: In most DKA protocols the fluid for resuscitation up to 20 mls/kgis not included in the calculations for later deficit dehydration
  7. 7. Fluid ReplacementTo be commenced if resuscitation is not required or has beencompleted.IV fluid administration alone results in substantial falls in bloodglucose, ECF o osmolality and improves GFR before insulin is given
  8. 8. Fluid calculationRequirements = Deficit + 48hr Maintenance• Calculate DEFICIT = estimated % dehydration x body weight (kg ) X 10( amount inmls)• Calculate MAINTENANCE :Age (years) Weight (kg) Maintenance Fluid (ml/kg/24 hrs )<1 3 – 9 801 – 5 10 – 19 706 – 9 20 – 29 6010 – 14 30 – 50 50>15 >50 35• Then add DEFICIT to 48 HOURS MAINTENANCE and replace this volume evenlyover 48 hours as NormalSaline 0.9% initiallyExample: 20 kg child 10% dehydrated.Deficit = 10 x 20kg x10 = 2000mlsMaintenance = 20 x 60 = 1200 mls/24 or 2400 mls/48hTotal fluid steadily over 48 h = 2000 + 2400 = 4400 mls or 4400/48 = 91 mls per hourThese calculations will usually cover ongoing losses which in most cases do not needadditional replacement butexcessive continuing fluid losses in urine and /or vomitingmight need replacing if the severity of dehydration is not improving
  9. 9. Potassium◊ Total body potassium is always depleted in DKA◊ Initial serum potassium may be low, normal or high◊ If serum potassium is not available before the completion of resuscitation,check ECG monitor to before potassium isadded to the infusion fluid• Potassium replacement should not be started until shock has beensuccessfully reversed, the ECG does not showelevated T waves (or if serum potassium is not elevated) but is bestcommenced before the insulin infusion is started• Potassium chloride 40 mmol is usually added to each litre of Salineinfusion(Rate is approximately 3 mmol / kg / 24h )
  10. 10. InsulinDKA is caused by insulin deficiency, either relative or absolute.• Insulin should only be given when shock has been successfully reversed byemergency resuscitation andSaline/potassium rehydration regimen has already begun (this avoids suddeninflux of potassium from plasma intocells with danger of cardiac arrhythmia). Commence 1-2 hours after starting fluidreplacement therapy.• Insulin by continuous low-dose intravenous infusion is the optimalmethod[There is evidence that bolus insulin is unnecessary, but may be used whentreatment is very delayed]• A solution of Soluble (Actrapid) Insulin 1.0 unit / ml made up in NormalSaline should be given by electronicsyringe pump(make up solution by drawing up 50mls Normal saline into a 50ml syringe andthen injecting exactly 50 units of Actrapid insulin into the saline in the syringe,mix well and use syringe pump via extension tubing to 3-way tap and into themain infusion line)• Recommended initial insulin dose = 0.1 units / kg / hour (to the nearestround figure )
  11. 11. BG monitoring and further IV infusionDuring rehydration the typical rate of fall of BG is 4 –5 mmol /hour• If the BG does not fall by at least 3mmol/l/hr over the first 4hours of insulin administration, increase the insulininfusion to 0.125 units/kg/hr and increase to 0.15units/kg/hr if the fall is less than 3mmol/hr in thesubsequent 4hours• When BG falls below 15 mmol/l or falls at more than 5mmol/hr change to a glucose solution namely Half NormalSaline 0.45% + Glucose 5% infusion to maintain BG in thedesired range of 8 – 15 mmol/l• From now on if the BG rises again above 15 mmol/l., increaseinsulin infusion by 0.025units/kg/hr (ie from 0.1u/kg/hrTo o.125u/kg/hr).Do not revert back to 0.9%saline
  12. 12. If BG falls to < 8 mmol/l or falls more rapidly than 5 mmol/hr., increasethe concentration ofGlucose infusion to 10% with added Saline 0.45%*. If BG should thencontinue to fall at more than 5mmol/hr reduceinsulin infusion by0.025u/kg/hr, and again by 0.025u/kg/hr if BG is still <8 mmol/l, or stillfalling more than 5 mmol/l/hr.NB only decrease the insulin infusion if acidosis improving with ph> 7.3,bicarbonate > 15mmol/l and serum ketones decreasing – otherwisediscuss with consultant to increase glucose concentration to 12.5% - alsore-evaluate fluidquantities.(*this solution is supplied as special DKA fluid in glass bottles on theward. If unavailable mix 250ml 20% glucose with 250ml N.Saline bywithdrawing 250ml from each 500ml bag & mixing the residual amountswith each other)
  13. 13. Do not stop insulin infusion during the rehydration process because acontinuous supply of both insulin andglucose substrate is needed topromote anabolism and reduce ketosis. The insulin infusion rateshould only be decreasedto less than 0.05 units/kg/hr if the BG levelremains below 5 mmol/l despite glucose supplementation.• If sufficient clinical and biochemical improvement occurs in the first24 hours, the need for IV infusions should bereviewed with consideration of starting s/c insulin and oral fluids
  14. 14. Clinical observations and monitoringCareful frequent documented clinicalmonitoring to detectwarning signs of complications is of paramountimportance• Hourly pulse rate, respiratory rate, BPaccurate fluid input and output (when level of consciousness isimpaired a urinarycatheter may be necessary). Test urine for glucose and ketones• Hourly or more frequent neurological observations• ECG monitoring may be helpful in the initial assessment ofsevere DKA for T-wave measurement(There is no evidence but it would seem logical after resuscitation tonurse patients with the head of the bed raised in an attempt to reduce csfpressure
  15. 15. Bicarbonate in DKAThere is evidence that BICARBONATE confers no clinical benefit and itmay be unsafe in childhood onset DKA.Acute resuscitation protocols no longer include bolus bicarbonateadministration.Fluid and insulin replacement without bicarbonate correctsketoacidosis.• Potential hazards of bicarbonate therapy◊ Exacerbation of CNS acidosis◊ Hypokalaemia and altered calcium ionisation◊ Excessive osmolar load◊ Tissue hypoxia• Persistent acidosis is likely to be caused by inadequate resuscitation,inadequate insulin effect or sepsis. If you aresure the calculated volume of fluid replacement is correct, consider increasinginsulin to 0.125 units/kg/hr.Bicarbonate should only be considered for treatment of impaired cardiaccontractility in persistent severe shock butalways discuss this with a member of the Consultant staff(If bicarbonate is considered, proceed with caution giving 1-2 mmol / kgbicarbonate over 60 minutes. A 4.2% Bicarbonate solution contains0.5mmol /ml
  16. 16. Oral fluids• In severe dehydration, impaired consciousness & acidosis, only allow sipsof cold water or ice to suck.• Oral fluids (eg fruit juice/oral rehydration solution) should only be offeredafter substantial clinical improvement and novomiting• When good clinical improvement occurs before the 48hr rehydrationcalculations have been completed, oral intake mayproceed and the need for IV infusions reduced to take account of the oralintake.• If oral intake includes carbohydrate and the BG rises DO NOT stop theoral intake but increase the insulin infusion or insulindoses to improve anabolism and further reduce ketone production
  17. 17. sodium and Osmolality - despite the depletion of total bodysodium in DKA, the elevated osmolality in thehyperglycaemic state results in a dilutional effect on the measured sodium (ieartefactual hyponatraemia exaggerated byhyper triglyceridaemia)◊ Serum sodium often rises as the blood glucose falls. Theoretically sodiumshould rise by2 mmol for every 5.5 mmol fall in BG, resulting in a slower fall in osmolalityA fall in serum sodium has been noted in a number of studies as one ofthe laboratory correlates of impendingcerebral oedema• If serum sodium fails to rise and particularly if it falls, a careful re-evaluationof the fluid replacement is required. Considerincreasing the concentration of sodium chloride and observe with increasedvigilance for signs of cerebral oedema (seelater)• An initial serum sodium >150 mmol/l might prompt slower rehydration ratethan 48 hour
  18. 18. ComplicationsCerebral oedema◊ Approximately 0.4-1% of children with DKA develop cerebral oedema with a highmortality/morbidity◊ Cerebral oedema most commonly occurs in the first 24 hours, often secondary tovigorous rehydration. It is advisableto avoid more than 30 mls/kg fluid bolus. Vigilant observations throughout the 24hours must not diminish◊ In many cases warning signs/symptoms occur which should prompt the emergencyadministration of MannitolWarning signs/symptoms of cerebral oedema• Headache & slowing of heart rate• Change in neurological status (restlessness, irritability, increaseddrowsiness, incontinence) specificneurological signs (eg. cranial nerve palsies)• Rising BP, decreased O2 saturation◊ More dramatic changes such as convulsions, papilloedema, respiratory arrest arelate signs associated withextremely poor prognosisAction – These children should be transferred to CICU as soon as possible forfurther management. Pleaseinform the General Paediatric Consultant on call and CICU team
  19. 19. • Exclude hypoglycaemia• If warning signs occur at any time day or night, giveImmediate IV Mannitol 1 g/kg over 20minutes (ie. 5ml / kg 20% solution) or 2-4 mls/kg of Hypertonic (3%) Sodium Chloride tomaintain serum Na > 150 mmol/l• Halve rehydration infusion rate until situation is improved but it is important to maintaininsulin infusion to switch off ketotic process• Nurse with child’s head elevated• Avoid intubation unless absolutely necessary. Decision for intubation and advice onoptimal pCO2 levels if intubated should be discussed with CICU consultant. pCO2 shouldbe kept >3.5kPa – very poor outcome associated when pCO2 falls <2.9 kPa• Consider continuation of Mannitol infusion 0.25 g/kg/hour to prevent rebound increasein intracranial pressure (orrepeat bolus doses every 4-6 hours).Hypertonic 3% saline may be an alternative to mannitol• Cranial imaging should only be considered after child has been stabilised. Intracranialevents other than oedema mayoccur e.g.haemorrhage, thrombosis, infarction
  20. 20. OTHER COMPLICATIONS : Hypoglycaemia and hypokalaemia – avoid by carefulmonitoring and adjustment of infusion rates. Consideration should begiven to adding more glucose if BG falling quickly even if still above 4mmol/l. Systemic Infections – Antibiotics are not given as a routineunless a severe bacterial infection is suspected Aspiration pneumonia – avoid by nasogastric tube in vomitingchild with impaired consciousness Continuing abdominal pain ( may be due to liver swelling,gastritis, bladder retention, ileus. However, beware ofappendicitis and ask for a surgical opinion ). A raised amylase iscommon in DKA. Other problems are pneumothorax ± pneumo-mediastinum,interstitial pulmonary oedema, unusual infections (eg TB,fungal infections), hyperosmolar hyperglycaemic non–ketotic coma, ketosis in type 2 diabetes. Discuss these with the consultant on-call
  21. 21. Transition to subcutaneous insulin injections• Oral fluids should be introduced only when substantial clinical improvementhas occurred (mild acidosis / ketosismay still be present)• Insulin infusion may be continued with adjustments to cover carbohydrate intake.Do not restrict carbohydrateintake at this stage. If BG rises increase insulininfusion.• Insulin by subcutaneous injection may be started when oral intake is tolerated• Stop both the IV fluid and insulin infusion simultaneously 30 minutes afterthe first subcutaneous injection is givenand child has had a meal.Give their normal dose of subcutaneous insulin.If newly diagnosed:Weight < 30kg - 0.2 u/kg/dose Insulatard am, 0.1 u/kg/dose Insulatard pmWeight > 30kg – 0.4 u/kg/dose Mixtard 30/70 am, 0.2 u/kg/dose Mixtard 30/70 pmsubcutaneously and let the child have a meal. Wait for 30 minutes and then stop theIV insulin and IV fluids simultaneously
  22. 22. Diet• The dietitian will advise on this according to the child’s usual foodintake. In the recovery period the child’s appetite is likelyto be enormous. Do not restrict this. The child must however receivestarchy carbohydrate food every 2-3 hours withemphasis given to bedtime snack to avoid nocturnal hypoglycaemia.RECURRENT DKA◊ Associated with inadequate insulin levels◊ Commonly due to insulin omission