Clinical Guidelines (Nursing)

Ketogenic diet acute illness management


  • Introduction

    The Ketogenic Diet (KD) is a recognised treatment option for some children with refractory epilepsy.  The diet has few side effects and is generally well tolerated.   Many childhood illnesses can be managed at home.

    When a child on a KD becomes unwell and presents to hospital, the illness and it’s effect on the diet require assessment.  Children on a KD will usually require hospital review if they present with the following: 

    • vomiting and diarrhoea (often caused by gastroenteritis),
    • febrile illness,
    • increased seizures.

      Aim

    The aim of this guideline is to provide a medical, nursing and allied health framework for decision making in relation to the management of the unwell child on KD therapy. 

    Definition of terms 

    • Ketogenic Diet (KD): A very high fat, low carbohydrate, medically supervised diet often used as a treatment option for some children with refractory epilepsy.  It is calculated for each child on an individual basis and so dietary prescriptions for fat, protein and carbohydrate are specific for each child.  
    • Ketone bodies: Are water-soluble compounds that are produced when excessive amounts of fat are broken down for energy.  In some circumstances they are used as a source of energy in the heart and brain.   

    Assessment 

    There are four key factors to the assessment of a child on KD therapy who is acutely unwell presenting to hospital for management.  

    1)            Establish child’s medical status

    • What is causing the child to be unwell?
    • Note: Any child who is septic, vomiting blood or bile or has severe abdominal pain needs IMMEDIATE assessment by the senior paediatric medical officer of the Emergency Department or Unit. 

    2)            Establish patient’s level of hydration.

    • Assess degree of dehydration on clinical signs and change in body weight (if recent weight available) as per Dehydration guidelines.
    • With mild dehydration (< 4%) no clinical signs. They may have increased thirst.
    • Moderate dehydration (4-6%) delayed CRT (capillary refill time) >2 secs, increased respiratory rate, mild decreased skin turgor
    • Severely dehydrated (>7%) signs of dehydration more pronounced: very delayed CRT >3 seconds, mottled skin, decreased skin turgor, signs of shock.

    3)            Establish if patient is ketoacidotic

    • Take capillary gases, electrolytes, calcium, magnesium, phosphate, urea and glucose   
    • Based on our local/institutional experience, well children on KD treatment should not normally have serum HCO3 level below 17mmol/L.
    • excessive fatigue or lethargy,
    • nausea,
    • vomiting,
    • very strong fruity smell on breath,
    • rapid panting/breathing,
    • an increased heart rate.

    4)            Establish if patient has experienced change in usual level of ketosis 

    • Measure serum ketone level (beta-hydroxybutyrate) by finger prick: usually maintained between 2.4-5mmol/L. 
    • Measure urine ketone level if possible (Ketodiastix®): usually maintained between 8-16mmol/L.  (Parents/caregivers may report Ketodiastix® has turned instantly black if level is too high).
    • Note that serum ketone levels above 5mmol/L are not necessarily concerning provided the child is not demonstrating clinical signs of excessive ketosis.
    • Lower than usual levels of ketones are not dangerous.
    • Families usually have a routine for measuring ketones when a child is well and will be able to report any changes.

    Management of  dehydration 

    Mildly Dehydrated

    • Oral Rehydration
      • Increase frequency of usual fluids. 
      • No regular soft drinks, milk, cordial, juices, are allowed. 
      • Usual KD fluids are allowed (These may include water, Ketocal® and others, check with dietitian if suitable fluids are being provided).
      • If child not drinking monitor hydration status and consider moderate dehydration management.

    Moderately dehydrated and still drinking  

    • Oral Rehydration 

      • Oral rehydration solutions may be used, these include Repalyte® (1.8gm glucose/100ml) and Hydralyte® (1.5gm glucose/100ml). 
      • Aim for additional fluid with each loose bowel action or vomit.  Rehydration is more important than any loss of ketosis the child may experience.

      Moderately dehydrated and not drinking 

    • Nasogastric Rehydration
      • Used to rehydrate most children with moderate to severe dehydration.  In many cases it may be used when the child continues to vomit. 
      • Replace deficit over 6 hours, give daily maintenance over the next 18 hours.  To calculate the hourly rate see recommended as per “RCH Dehydration guidelines” (Ref 4).
      • Suitable fluids may include: Hydralyte® Repalyte®, Ross Carbohydrate Free formula (RCF) + additives (Polyjoule®, Calogen®, Liquigen ®), Ketocal®, SHS CHO free mix + additives.

    Severely Dehydrated

    • Intravenous Rehydration

      • Any child with severe dehydration requires immediate boluses normal saline (10-20ml/kg) and then maintenance fluids adjusted according to clinical situation.
      • No IV glucose should be given (provided true BSL ≥2.6mmol/L) unless ordered by the on-call Neurology Consultant.
      • Urgent investigations:
        • Urea & electrolytes,
        • glucose,
        • FBE
        • Capillary blood gas
        • Urinalysis
      • Consider need for septic work up or surgical consult.

    If serum Na+ between 135mmol/L and 145mmol/L:

    • once circulation has been restored aim to replace deficit and maintenance over 24 hours
    • re-assess clinically 4 hourly
    • re-weigh at 6 and 12 hours.  

    Contact General Medical Consultant:

    • if patient haemodynamically unstable,
    • a past history of gut surgery,
    • a past history of other significant disease,
    • if serum Na+ < 135mmol/L or > 145mmol/L, correct deficit carefully over 48-72 hours

    Management of excessive katoacidosis 

    Excessive ketoacidosis needs to be managed by the administration of extra carbohydrate.  

    Orally and Nasogastrically 

    • Administer child 30ml regular lemonade. 
    • Retest serum ketones using finger prick 15 minutes after administration. 
    • If serum ketone level  ≥6mmol/L and/or patient showing clinical symptoms of acidosis, administer another 30ml regular lemonade and monitor clinical symptoms. 
    • If second dose of regular lemonade does not result in improvement the child will require IV glucose maintenance.
    • Serum ketones will need to be monitored 6 hourly whilst ketone levels are high or unstable.  
    • Blood glucose levels will need to be monitored. Aim for ≥2.6mmol/L. Contact Neurology Consultant before any treatment.

    Intravenously 

    Administer Maintenance 5% Dextrose and Normal Saline if continuing ketoacidosis.

    General Guidelines 

    • High ketosis and well – no concern
    • High ketosis & drowsy – assess for other medical factors contributing
    • High ketosis & acidosis – maintenance 5% Dextrose & Normal Saline
    • High ketosis & hypoglycaemia – follow hypoglycaemia protocol 

    Contact General Medical or Endocrinology Consultant if high ketosis and child unwell.

    Links

    Evidence table

    Please remember to read the disclaimer. 


    References

    1. Thammongkol et al. (2012) Efficacy of the ketogenic diet: Which epilepsies respond? Epilepsia, 53(3):e55-e59.
    2. Kossoff et al. (2009) Optimal clinical management of children receiving the ketogenic diet: recommendations of the International Ketogenic Diet Study Group. Epilepsia 50:304-317.
    3. Neal et all. (2008) The ketogenic diet for the treatment of childhood epilepsy: a randomised controlled trial. Lancet Neurol 7:500-506.
    4. Clinical Practice Guidelines; Royal Children's Hospital (2012) Dehydration. Melbourne, Australia.
    5. Kossoff EH, Freeman JM, Turner Z & Rubinstein JE. (2011) Ketogenic Diets: Treatments for Epilepsy and Other Disorders. Fifth Edition  New York:Demos Medical Publishing


    The development of this nursing guideline was coordinated by Jill Bicknell-Royle, Epilepsy Nurse Specialist, Neurology, and approved by the Nursing Clinical Effectiveness Committee. Updated November 2015.