Guidelines_for_the_management_of_patients_on_the_ketogenic…

Guidelines for the Management of Patients on the Ketogenic Diet

Introduction

The ketogenic diet (KD) is an established, effective nonpharmacologic treatment for
intractable childhood epilepsy (Freeman et al., 2007). It is a high fat, restricted
carbohydrate regimen that was first used to treat epilepsy in the 1920s (Wilder RM,
1921). It was observed that fasting decreased seizure frequency and the KD was
designed to mimic a similar metabolic response. By providing a large quantity of fat
and a small quantity of carbohydrate in the diet, the body is induced to switch its
energy metabolism to the ketogenesis pathway producing the ketone bodies ß-
hydroxybutyrate and acetoacetate which become the primary source of energy for
the brain. Additional benefits also observed on the KD include increased alertness,
increased awareness and increased responsiveness (Neal et al 2008)
Until recently there have been no standardised protocols or management
recommendations for the clinical use of the KD with significant differences in the
administration of the diet in centres across the world. In December 2006, The Charlie
Foundation commissioned a panel comprised of 26 paediatric epileptologists and
dietitians from nine countries with particular expertise using the KD to create a
consensus statement regarding the clinical management of the KD (Kossoff et al,
2008). Their recommendations are the main framework for these guidelines.
Patient Selection for the Ketogenic Diet
Indications for KD

Although anti-epileptic medication can be used to control seizure activity in most
cases, approximately 20-30% do not respond to drug therapy and go on to develop
refractory epilepsy (Sillanpää & Schmidt, 2006). For these patients, the KD may be
very effective and should be given due consideration. The efficacy of the KD in the
treatment of intractable epilepsy has become more evident over recent years from
the number of publications and the increasing number of centres offering the KD as a
treatment option across the world (Kossoff & McGrogan, 2005; Freeman et al.,
2007).
Regardless of age, seizure type or aetiology, the KD appears to provide a third of
patients >90% reduction in their seizure frequency (Henderson et al., 2006). Given its
efficacy, the KD should be considered as a therapeutic option early in the treatment
of more difficult to control epilepsy regardless of age or gender after two to three
anticonvulsant therapies fail to work adequately (Kossoff et al., 2008).
Specific conditions where the KD should be considered even earlier are:

Probable benefit (min 2 publications)
• glucose transporter protein I (GLUT-I) deficiency (KD is treatment of choice) • pyruvate dehydrogenase deficiency (PDHD) (KD is treatment of choice) • myoclonic-astatic epilepsy (Doose syndrome) • severe myoclonic epilepsy of infancy (Dravet Syndrome) • children receiving only formula (infants or enterally fed patients)
Suggestion of benefit:
• subacute sclerosing panencephalitis (SSPE)
Contraindications for KD

The KD is contraindicated in several specific disorders. As the KD involves a shift in
energy metabolism to using lipids in the form of ketones as the primary energy
source, patients with an underlying disorder of fatty acid metabolism placed on the
KD could potentially develop a devastating catabolic crisis. It is essential to screen
for the disorders listed below to avoid the possible exacerbation of an underlying
metabolic defect (Kossoff et al., 2008).
Absolute contraindication for KD:
• carnitine palmitoyltransferase (CPT) I or II deficiency • short-chain acyl dehydrogenase deficiency (SCAD) • medium-chain acyl dehydrogenase deficiency (MCAD) • long-chain acyl dehydrogenase deficiency (LCAD) • medium-chain 3-hydroxyacyl-CoA deficiency • long-chain 3-hydroxyacyl-CoA deficiency
Relative contraindication for KD
• inability to maintain adequate nutrition (e.g., very fussy eater) • surgical focus identified by neuro-imaging and video EEG monitoring
The success of the KD requires a high level of commitment by the parent/carer(s)
and willingness to adapt to the requirements of full compliance of the dietary
prescription. A reasonable level of literacy and mathematical ability is required to
understand and implement the menus and the parent/carer must also be capable of
monitoring and recording ketone levels, seizure activity and fluid intake.


Pre-Diet Evaluation & Counselling

Implementation of the KD is difficult and success depends on a number of core staff
with a multidisciplinary approach to the care of the child. Suggested core team
members are a neurologist with experience of the diet, a skilled paediatric dietitian
and a specialist nurse. The team must be able to assist and advise patients when
they encounter possible complications that are either caused or exacerbated by
being on the diet (Neal & Mc Grath, 2007).
A minimum of one clinic visit prior to initiation of the KD is essential to identify the
seizure type, rule out metabolic disorders that are contraindications for the diet and
evaluate for complicating factors i.e. presence of kidney stones, dyslipidaemia, liver
disease, faltering growth, gastroesophageal reflux, poor oral intake, constipation,
cardiomyopathy and chronic metabolic acidosis (Kossoff et al., 2008). All medications
should be reviewed at this initial consult to calculate carbohydrate content and if
possible switch to lower carbohydrate alternatives.
It is essential that the psychosocial issues related to the KD are discussed at this
early stage. Adequate information should be provided including:
• the importance of strict adherence to the diet both at home, school and social • the need for vitamin and mineral supplementation • tolerability including potential side effects of the diet • what to expect during the hospital admission • the requirement for ongoing ketone monitoring and regular outpatient follow- • minimum trial length on the diet and expected duration on the diet if effective. Parental expectations should also be assessed prior to diet commencement to ensure realistic expectations for the individual child. Recommendations for Pre-KD Evaluation—adapted (Kossoff et al., 2008)
(including suggested member of team responsible for the action where
N = Neurologist, D = Dietitian, C = Clinical Nurse Specialist )
Counselling
• discuss seizure reduction, medication, and cognitive expectations (N)
• identify potential psychosocial barriers to the use of KD (N)
• review anticonvulsants and other medications for carbohydrate content – must be <500-100mg of carbohydrate per day from medications (N plus C
to assist)
• recommend family read parent-oriented KD information (C)
Nutritional Evaluation
• baseline weight, height/length, and ideal weight for stature (D)
• body mass index (BMI) where appropriate (D)
• diet history min 3-5 day food record, food preferences, allergies, aversions, and intolerances (D)
• establishes diet formulation: infant, oral, enteral, or a combination (D)
• decision on which diet to begin (classical, MCT, modified Atkins, low glycaemic index)-note currently only classical is offered at MCH (D)
• calculation of calories, protein, fluid, and ketogenic ratio as appropriate • establish nutritional supplementation products based on dietary reference intake (D)
Laboratory Evaluation
• complete blood count with platelets (N)
• electrolytes to include serum bicarbonate, total protein, calcium, zinc, selenium, magnesium, and phosphate (N)
• serum liver and kidney tests (including albumin, AST, ALT, blood urea nitrogen, creatinine) (N)
• fasting lipid profile (N)
• serum acylcarnitine profile (N)
• urinalysis (N)
• urine calcium and creatinine (N)
• anticonvulsant drug levels (if applicable) (N)
• urine organic acids (N)
• serum amino acids (N)
Ancillary Testing (optional) to be ordered by N if required
• renal ultrasound and nephrology consultation (if a Hx of kidney stones) • cerebrospinal fluid (CSF) (If no clear aetiology has been identified) • EKG (echocardiogram) if history of heart disease Medications & the KD
The KD is traditionally used in patients who have not responded to anticonvulsant
therapies and patients starting the KD are often concurrently on one or more
anticonvulsants. There is currently no data regarding particular drugs and KD and
greater or less efficacy of seizure control. The KD may have synergistic effects when
used in combination with vagus nerve stimulation (Kosskoff et al., 2007). Historically
it was widely held that valproic acid should not be used together with the KD due to
concerns that valproic acid in combination with KD might increase the risk of
hepatotoxicity. Recent clinical evidence supports the safe use of valproic acid and
the KD (Lyczkowski et al., 2005).
If a patient is on a regimen of carbonic anhydrase inhibitors—such as topiramate—
adding the KD may worsen a pre-existing metabolic acidosis, particularly early in diet
initiation. It is recommended that bicarbonate levels are monitored and, if the patient
is symptomatic with vomiting or lethargy, bicarbonate supplements should be
commenced. It is also recommended that this sub-group of patients are also closely
observed for the increased risk of kidney stones (Kossoff et al., 2002). Oral citrates
may also be required (Kossoff et al., 2008).
If the KD is found to be successful, anticonvulsant medications may be weaned
within the first few months. Caution is advised, particularly when reducing
phenobarbital and benzodiazepines, as seizure exacerbations are more common
with these medications (Kossoff et al., 2008)

Specific diet selection & provision

There is no evidence of increased efficacy of the MCT KD versus the Classical KD,
therefore the KD that is chosen should be based on the dietary needs and habits of
the individual child, although it may be influenced by the experience of the team
involved (Kossoff et al., 2008). There is preliminary evidence for the use of the less-
restrictive modified Atkins Diet and Low Glycaemic Index Treatment (LGIT), but the
optimal patient populations (possibly adolescents and adults) for these diets have not
yet been identified (Kossoff et al., 2008)
Currently, due to the time constraints and team experience at MCH only the classical
KD is offered as a therapeutic diet. It is hoped that with increased funding this may
expand to include the option for MCT KD, and possibly the modified Atkins KD, and
the LGIT for suitable patients as more evidence becomes available.
Diet Initiation

Fasting has traditionally been used to initiate the KD, however, in recent years this
has shown to be unnecessary (Kim et al., 2004). Fasting may be appropriate when a
quicker time to response is desired, but is not necessary for long-term efficacy and
may have more immediate side effects (Kossoff et al., 2008). At MCH the patient is
admitted for KD initiation to enable close monitoring of the patient for adequate
ketosis, safe blood glucose levels, diet tolerance and also to allow time for the
necessary intensive teaching of the parent(s)/caregiver(s).
At MCH the diet is currently introduced gradually over a period of several days to
optimise tolerance of the introduction of large quantities of fat. The patient consumes
their usual dinner or supper the evening before admission (with the omission of very
sugary foods such as soft drink or cordial) and they then fast until lunchtime on the
day of admission or until the pre-diet bloods are taken. The patient is encouraged to
drink plenty of water from the onset of the fast to prevent dehydration. A urine
specific gravity test performed at the bedside can quickly determine urine
concentration. The first ketogenic meal which comprises approximately one third of
the full final recipes is given at approximately 12 noon, followed by two more similar
meals on day one of the admission. The diet then advances daily in one-third caloric
intervals until full calorie meals are tolerated (typically day three), while keeping the
KD ratio constant. Gradual introduction protocols similar to the MCH protocol have
been found to offer the same seizure control at three months, with significantly lower
frequency and severity of side effects (Bergqvist et al., 2005).
Prior to consideration for discharge home, the child must be able to tolerate full
ketogenic diet, have blood glucose levels within normal limits and have adequate
ketosis. The child will also need to be weighed on the scales that will be used for
follow up prior to discharge. Note that it is usual to expect weight loss on initiation of
the diet due to the diuretic effect of a low carbohydrate diet. The parents must also
be fully educated on the KD and able to recognise the signs of dehydration,
hyperketosis and hypoglycaemia and be able to treat accordingly. Discharge letters
to the child’s local paediatrician or GP and school or school nurse are essential.
Contact numbers for the keto team should also be supplied to allow the parent or
carer to access advice as required on the KD in between clinic visits.
Diet Supplementation
Due to the restricted nature of the KD, sufficient intake of vitamins and minerals
cannot be achieved and full daily vitamin and mineral supplementation is required.
Separate calcium, magnesium and phosphorus supplementation is also usually
required particularly on the classical KD. All vitamin and mineral supplements should
be assessed for carbohydrate content as many paediatric preparations contain
added sucrose and/or lactose.
Fluids are also an important part of the KD. Previously fluids were restricted on the
classical KD but in recent years relaxing of the fluid restriction to provide
maintenance fluids has not shown adverse effects on ketosis (Vaisleib et al., 2004).
Low carbohydrate diets have a diuretic effect and the food allowed on the KD do not
provide a significant contribution of fluid. Adequate daily fluid intake through water
and carbohydrate and caffeine-free fluids is essential to prevent possible side effects
such as renal stones and constipation. Excessive fluid intake however, should be
discouraged as it may reduce ketosis.
The KD may also require the addition of suitable laxatives such as Movicol to assist
in the prevention of constipation which could potentially lead to the recurrence of
seizure activity. As previously discussed oral citrates appear to be preventative for
kidney stones, but its empiric use has not yet been established as beneficial (Kossoff
et al., 2008).
Maintenance of Children receiving the KD

The child on KD needs regular review by both the dietitian and the neurologist for the
evaluation of growth parameters, seizure activity and assessment of possible side
effects of the diet, fluid intake and tolerance of the KD. The child should be seen
initially at least every three months after discharge, with follow-up in the interim—
especially if expected urinary ketosis is not maintained. A child under 12 months
should be reviewed two to four weeks after discharge and will require more frequent
contacts with the Keto team. After one year on the KD, visits may be extended to
every six months with interim phone contacts as required (Kossoff et al., 2008).
The majority of centres offering the KD advocate routine monitoring of urinary
ketones several times per week. Only some centres provide blood ketone monitors.
At MCH blood ketone monitoring is recommended for the initial period post discharge
when fine-tuning of the diet is required. After this period, regular urine ketone measurements are less invasive and are usually adequate for diet monitoring. Recommendations for Aspects of a Follow up KD Clinic Visit-adapted
(Kossoff et al., 2008)
(including suggested member of team responsible for the action where
N = Neurologist, D = Dietitian, C = Clinical Nurse Specialist )

Nutritional Assessment (D)
• obtain height/length, weight, ideal weight for height, growth velocity, BMI as • review appropriateness of diet prescription (calories, protein, fluid) • review vitamin and mineral supplementation based on dietary reference • adjust therapy if necessary to improve compliance and optimise seizure
Medical Evaluation (N)
• efficacy of the diet (is the KD meeting parental expectations) • anticonvulsant reduction (if applicable)
Laboratory Assessment (N)
• electrolytes (including serum bicarbonate, total protein, calcium, phosphate, • serum liver and kidney profile (including albumin, AST, ALT, blood urea • anticonvulsant levels (if applicable)
Optional (N)
• serum ß-hydroxybutyrate (BOH) level Visits should be at least every three months for the first year of the KD Management of Illness
When the child is unwell, the KD should take second place to the necessary
treatment needed (Neal & Mc Grath, 2007). Wherever possible however, sugar-free
medications should be used and avoidance of loss of ketosis should be the goal.
Vomiting & Diarrhoea
The KD should be stopped and clear fluids that are low in carbohydrate (water, sugar
free cordial and flat sugar free lemonade) should be offered to ensure adequate
hydration. Low glucose oral rehydration fluids (e.g., ORS ®, Paedialyte ®) may be
used but should be diluted 2:1 to prevent an upset in ketosis. If intravenous fluids are
required, saline at an appropriate strength to the child’s age and requirements should
be used. It may, however, become necessary to add dextrose to the solution if there
are concerns regarding hypoglycaemia or intravenous fluids are required for a
prolonged length of time (Neal & Mc Grath, 2007). Blood glucose measurements
should be taken throughout the day (if monitors available) and the child should be
observed for signs of hypoglycaemia. Regular ketone monitoring should also be
performed to pre-empt the possibility of hyperketosis. Measurements should be done
at any time of fasting e.g. on waking in the morning or if meals are missed or are not
completed due to poor appetite. Hyperketosis or hypoglycaemia should be treated
quickly by administering a 20-30mls of a 10% carbohydrate containing drink. The
offending level should be rechecked 20-30 minutes post administration of
carbohydrate and the drink administration should be repeated if necessary.
When vomiting has subsided the KD should be reintroduced gradually with half the
usual meal quantities for the first 24-48 hours or as per tolerance. If the child is
unable to complete the meals, the meal ingredients should be mixed together e.g.
scrambled egg recipe/custard recipe so that each mouthful will be in the correct
ketogenic ratio. If fat tolerance is a problem, the amount of fat in the diet may be
reduced temporarily (24-48 hours) and increased gradually as tolerated. For the
tube-fed patient, half strength feeds may be given for 24-48 hours and gradually built
up to full strength as tolerated over a few days (Neal & Mc Grath, 2007).

Other illness
Infection may cause a drop in ketones but once the child has recovered from the
offending illness, ketosis should gradually return. For colds and influenza, the diet
should be continued if possible and cold medications should be avoided as very few
are sugar free. Sugar free paracetamol may be used if required.

Adverse Effects of KD
Like all medical therapies, the KD has potential adverse effects. Overall the risk is
low and the KD does not need to be discontinued for these reasons for most children
(Kossoff et al., 2008). The keto team should be aware of the potential risks involved
with the diet so that they can monitor children on the KD appropriately for the
possible development of these complications.
Possible side effects include hyperuricaemia (2-26%), hypocalcaemia (2%),
hypomagnesemia (5%), decreased amino acid levels and acidosis (2-5%) (Chesney
et al., 1999; Kang et al., 2004). Hypercholesterolaemia has been reported in 14-59%
of patients on the KD (Chesney et al., 1999; Kwiterovich et al., 2003; Kang et al.,
2004).
Gastrointestinal symptoms including vomiting, constipation, diarrhoea and abdominal
pain occur in 12-50% of patients (Kang et al., 2004). Renal calculi occur in 3-7% of
children on the KD (Sampath et al., 2007). They typically do not require diet
discontinuation and lithotripsy is only rarely necessary.
In some studies the linear growth of children on the KD has been shown to be
slowed (Williams et al., 2002) however not all studies concur. Other reported possible
complications include cardiomyopathy and prolonged QT interval, decreased bone
density and pancreatitis.

KD Discontinuation
Patient response to the KD largely influences the timing and method of KD
discontinuation. At MCH the diet is introduced for a minimum of three months to
adequately assess a patient’s response to the diet. The KD works rapidly when
effective with the majority of patients (75%) respond to the KD within 14 days
(Kossoff et al., 2008b); however some patients can take up to 8-10 weeks to
respond. Consideration should be given to discontinue the KD after three months if
unsuccessful, and at two years if completely successful or in children with >50%
seizure reduction. The two year timeframe is similar to the time period used for
anticonvulsant drugs which are often discontinued after that time if the child has
become seizure free. Longer diet durations are necessary for GLUT-1 and PDHD
and may also be appropriate based on individual responses for intractable epilepsy,
particularly where seizure control is almost complete and side effects are low
(Kossoff et al, 2008).
It is recommended that prior to diet discontinuation in seizure-free children, a routine
EEG and review of clinical data should be performed to enable counselling of families
regarding recurrence risk which is 20% overall. For those who have been seizure
free on KD, 80% will remain seizure free post diet discontinuation (Martinez et al.,
2007). Children with epileptiform EEG, structural abnormalities on neuro-imaging and
tuberous sclerosis complex are at a higher risk of seizure recurrence (Martinez et al.,
2007).
A gradual tapering off the KD is recommended to mimic weaning off anti-seizure
medications. If the diet is withdrawn too quickly there is a risk of an increase in the
number and intensity of seizures. The diet should be discontinued over a period of
two to three months unless an urgent discontinuation of the diet is required.
Indication for a more urgent wean off the KD are worsening seizures for more than a
few days post diet initiation. Weaning off the diet should be performed by gradually
lowering the ketogenic ration from 4:1 to 3:1 to 2:1, then ketogenic foods are
continued, but calories and fluids are increased ad libitum. When urinary ketosis is
lost, high carbohydrate foods can be introduced (Freeman et al., 2006). If seizures
worsen, the KD can be increased to the previously effective formulation (Kossoff et
al., 2008).In the majority of cases, seizure control can be attained again with either
KD or anticonvulsants (Martinez et al., 2007).


References

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