Ketogenic Diets for Epilepsy PDF

KETOGENIC DIETS  Introduction  Epilepsy is the most prevalent of the serious neurological disorders, the highest incidence occurring in early childhood and old age.  Seizure activity is caused by abnormal and excessive discharge from the neurons in the brain, which can present in...

KETOGENIC DIETS  Introduction  Epilepsy is the most prevalent of the serious neurological disorders, the highest incidence occurring in early childhood and old age.  Seizure activity is caused by abnormal and excessive discharge from the neurons in the brain, which can present in a range of different seizure types.  Although anti-epileptic medication can be used to control seizures in most cases, a minority do not respond to drug therapy.  The ketogenic diet is a high fat, restricted carbohydrate with sufficient protein regimen that was first used to treat epilepsy in 1920 before the appearance of anti-epileptic medication in 1950  It is reserved now for those resistant to the drug therapy  How the ketogenic diet works  One of the theories:  Fasting may decrease seizure frequency→ ketogenic diet induce formation of ketone bodies (acetoacetate and β-hydroxybutyrate) because of the absence of adequate glucose supply and thus producing an anticonvulsant effects  Types of ketogenic diet  4 types of ketogenic diet.  Classical diet: based on a ratio of fat to carbohydrate and protein.  The fat component is long chain triglycerides (LCT) (recently we are using MCT) , mainly provided from foods.  Protein is based on minimum requirements for growth.  Carbohydrate is very restricted.  Ex: 4:1 ratio  Types of ketogenic diet  4 types of ketogenic diet.  MCT diet: yield more ketones per kilocalorie of energy; they are absorbed more efficiently and carried directly to the liver in the portal blood.  This increased ketogenic potential means less total fat is needed in the MCT diet, thus allowing inclusion of more carbohydrate and protein.  Types of KD  Modified KD or modified Atkins KD:  Free intake of protein  Very low in CHO  Liberal fat intake (app. 75% of total calories)  Frequently used in older children and ados who may not cope with the dietary restrictions of the classical or MCT diets.  Types of KD  Low glycemic index treatment LGIT:  Designed to limit increases in post prandial BG levels by restricting the quantity of CHO to 10% total calorie and using only low GI CHO.  Fat: 60% of calories  Protein: 30% of calories  Possible side effects  Raised lipid levels: less in MCT. No risk of CVD later in adulthood  Delayed growth: +++ in the first 6 months therefore the ht and wt should be monitored regularly and the diet prescription changed if needed  Cardiac complications due to Se deficiency  Pancreatitis  Hypoproteinemia  Hematological disturbances (impaired neutrophil and platelet functions with increased tendency to bleeding and bruising) Considerations before commencing the diet  Epilespy diagnosis should be made and the child referred by a pediatric neurologist  Other contraindications:  Feeding difficulties should be first identified  Dysphagia and significant gastroesophageal reflux /might require a EN)  Dietary restrictions and food allergy  Medical history (renal stones, hyperlipidemia, those taking diuretics or medications which increase the risk of acidosis may be unsuitable for dietary treatment and must be well assessed by their physician).  Commitment of the family  Families are required to monitor and record the child’s weight, test and record twice daily urine and blood ketones, keep a seizure diary, communicate frequently with the dietitian and attend regular clinic appointments Lab test and urinalysis.  Dietetic assessment  3-4 days food diary → test suitability of the type of diet chosen, child’s preferences and eating patterns.  Factors to consider:  Nutritional factors, allergies, swallowing pbs, food textures…  Anthropometric tests: W, H, HC  Level of mobility and activity  Vitamin and mineral sup  Bowel habits  Others involved in child care  Seizures type and frequency  Medications (CHO content, side effects). Deciding which KD to use Duration of dietary treatment: - 3 months trial period  Discontinuing the diet in case:  Child or family finds the diet very difficult  Diet is not effective in controlling seizures  Side effects outweigh benefits (poor growth)  Non compliance  Review the diet every 6 months if it continues  Trial off diet is suggested at 2 years to determine the efficacy of the treatment  Initiating the KD  Calculating the diet  Prescription adjusted over time depending on the child’s weight, level of ketosis, seizure control and activity.  If seizure activity decreases, mobility may increase and with it energy requirements.  Fasting is not necessary as initiation.  Calorie requirements:  Excess or limited calories may compromise ketosis and seizure control.  Daily intake is based on the EAR for energy.  Requirements individualized  Initiating the KD  Protein requirements:  Based on safe levels of growth  Minimum 1-1.2 g/kg/d  Higher for younger children to ensure optimal growth.  Diet prescription for the classical diet  Diet prescription for the classical diet  Calculation based on:  Calorie requirements  Protein requirements  Ratio of fat: (protein+CHO)  Diet prescription for the classical diet  Each meal and snack must be in the correct ketogenic ratio.  Actual amounts may need to be rationalized so that the diet prescription can be translated into food.  The quantity of protein should not be reduced in order to do this.  Meal replacements  If child is unwell with cough/cold… and not wanting to complete their usual meals, a drink can be given as a meal replacement.  Ketocal LQ (4:1 ratio)  Ratio should be kept the same as the child’s usual prescription so glc polymer can be added to the ketocal LQ to achieve the required ratio.  Initiating the classical diet  Start with 2:1 ratio and build up to 3:1 or 4:1 over a period of days or weeks depending on the child’s tolerance and level of seizure control at each step.  Managing the KD  Fluid:  Children are encouraged to take adequate fluids to meet normal requirements.  Vitamins and mineral supplements:  Full vit and min sup free of CHO  Phlexy-vits or Fruitivits  Forceval Adult (7-10 y)  Calcium sup may be required (not always necessary with MCT diet)  Vitamin D:  Levels should be checked at baseline and 6 months thereafter.  1000 IU/d  Managing the KD  Other supplements:  K citrate: alkalize urine and reduce risk of renal stones  Carnitine: transport LCT into mitochondria for oxidation and requirements increase on a high fat diet.  If deficiency → 50-100 mg/kg/d  Children at risk are the younger age groups and those on valproate medication.  Minimizing CHO content of medications:  Sugar derivatives with “ol” or “ose” are converted to glc (except cellulose)  Sorbitol contributes to some CHO and should be considered if used.  Adding interest to the diet  MCT oil can be used for frying and roasting  Liquigen can be used for making deserts, potatoes, sauces, drinks, mixed with semi skimmed milk…  Add fat to the diet as butter, margarine, oil, cream, mayonnaise…  Free foods  Water  Up to 1000 ml of low CHO squash  Diet fizzy drinks  Sweeteners free of CHO  Powdered sweeteners with maltodextrin should be avoided.  Spices.  Monitoring the diet  Blood and urine sample taken at baseline and throughout the course of this treatment.  Seizures: seizure diary with frequency, type  Ketones: in urine or blood; measured twice per day (in the morning before breakfast and before bed)→ less frequently once the diet is stabilized  Focus on seizures control more than achieving a certain level of ketones  Ketones are lower in the morning reflecting the overnight fast  Monitoring the diet  Urine ketones: aim: 4-16 mmol/l  Blood ketones: B-hydroxybutyrate (finger pricked twice daily) → aim: minimum 2 mmol/l  Hyperketosis or acidosis: blood ketones > 5 mmol/l or urine ketones > 16 mmol/l should be monitored carefully.  W and H checks: weekly or fortnightly checks are used to assess if E intake is appropriate.  Troubleshooting (short term complications)  Short term complications during the first few days of diet initiation can include dehydration, drowsiness, hypoglycemia, nausea, vomiting and diarrhea (resolve after a few days).  Troubleshooting (short term complications)  Hypoglycemia can occur and some centers recommend blood sugar levels should be checked regularly during diet initiation.  Many children on the diet have lower blood sugars than normal this is not a problem unless symptoms develop.  Symptoms of low BG include sweating, pallor, dizziness, becoming cold and clammy, jittery, confused or aggressive.  Such symptoms are treated immediately by giving a drink that contains CHO ( 15-30 ml fruit juice).  Excess ketosis  The signs of this are rapid, panting breathing; increased heart rate; facial flushing; irritability; vomiting; unexpected lethargy.  This should be treated by giving 1–2 tablespoons of fresh fruit juice or alternative carbohydrate containing drink.  If symptoms have not improved after 15–20 minutes, this should be repeated.  It will be necessary to alter the diet ratio if excessive ketone levels persist  Possible causes of low ketones:  Extra CHO given  Excess E given in diet prescription  The child developing an intercurrent illness  After exercise  Starting steroid medication  Change in ketone levels or seizure control should prompt these questions:  Are ketones and seizures being tested and monitored closely and regularly?  Do all carers understand the diet?  Is extra food being taken  Is the child completing all the fat in the meals?  Is the child unwell  Has a new medication been added that contains extra CHO  Is weight gain appropriate?  Correct composition of any food/recipe  Accurate measurement of foods/ CHO in drinks…  Discontinuing the diet  The longer the child have been on the diet, the more successfully it has controlled seizures, the more gradual should be the change back to normal diet.  Seizures should be monitored throughout the weaning period.  If at any time the seizures increase during weaning the diet is kept at the same level for a time or the child reverts to the previous step of the wean.  If the diet is successfully discontinued but seizures recur some time later, patients may wish to return to using the diet again or opt for medication.  Discontinuing the diet  Classical diet:  Reduce the diet ratio stepwise from 4:1 to 3:1 (for 6 months) to 2:1 (for 6 month) to 1:1 over a period of weeks depending on seizure activity.  MCT:  MCT reduced slowly (5 g per meal/d)  More protein and CHO choices should be added to the diet with same Cal content.  Fluid requirements  On both classical and MCT diets normal amounts of fluids are allowed.  However, excessive fluid intake should be discouraged as it may reduce ketosis.  Adequate fluid intake is essential wherever possible as renal stones may be one of the side effects of the diet.  Fine tuning the diet  Regular W checks will enable calorie modifications as needed.  If weight is being gained too quickly, E intake should be decreased by 100 kcal/day initially.  If W gain is judged to be too slow, E intake should be increased by 100 kcal/day initially.  Fine tuning the diet  As a child grows, the diet may need recalculating to increase protein intake in line with increases in body weight.  Meal and/or snack distribution may also need changing to fit with changes in a child’s lifestyle (e.g. the start of a new school).  Vitamin and mineral intakes should always be checked if they are likely to be altered by dietary modifications and supplementation reviewed as necessary.  Monitoring the diet Daily monitoring:  Seizure diary recording number and type of seizures.  Urine test for ketones (acetoacetate) using a dipstick, initially at least twice daily, in the morning before breakfast and before another meal later in the day (then once daily).  The aim is to have moderate to high ketones in the urine in the range of 4–16 mmol/L. Urinary ketones are typically lower in the morning reflecting the overnight fast.  Finger prick blood ketones (easier and more accurate than urinary ketone) (twice daily at the beginning then once daily before meals).  Monitoring the diet 3 monthly monitoring:  Growth monitoring using height, weight and mid arm circumference measures.  Head circumference can be included in younger children.  Biochemical nutritional screening including plasma lipids, nutritional indices and carnitine.  Urine testing for hematuria; calcium:creatinine ratio for renal stones.  Monitoring the diet 6 monthly monitoring:  Nutritional assessment carried out by the dietitian to ensure the diet remains nutritionally adequate  A complete biochemical nutritional screening.  Electroencephalogram (EEG) examination  Renal ultrasound scan (may be necessary sooner if problems are detected in 3-monthly urine tests)  Adverse effects  Hematological disturbances have been reported in children on the diet, both impaired neutrophil function and alterations in platelet function, with increased tendency to bruising and bleeding  Raised serum cholesterol and triglyceride levels are common (less problematic on MCT diet).  There is no evidence from case reports that the diet causes any adverse effects on cardiovascular function later in adulthood  Adverse effects  To minimize hyperlipidemia PUFA are recommended.  Renal stones +++ in children undergoing concomitant topiramate (anti-epileptic) treatment.  Other reported problems including cardiac complications, pancreatitis, hypoproteinemia.  Constipation can be caused by the high fat, low CHO nature of the diet → increase fluid intake; use a small amount of MCT oil to replace some LCT in the classical diet; prescribe a sugar free laxative if problems continue.  Adverse effects  W gain may be slower than prior to the diet, +++ during the first 6 months, and the weight centile may gradually drop.  A reduction in bone density can occur without adequate calcium supplementation.  Serum carnitine levels (both free and total) should be regularly monitored.  If deficiency → supplement: 50–100 mg/kg/day given to children  Although most children do not require supplementation those most at risk of deficiency are in the younger age groups and those on valproate (anti-epileptic drug) medication.  Duration and discontinuation of the diet  Generally, a trial of 3 months on the ketogenic diet is recommended.  If no improvement → it should be discontinued.  When the diet is successful the usual recommendation is that the child remains on it for at least 2 years or until they have been seizure free without medication for 1 year.  Discontinuation must be carried out cautiously.  The longer the child has been on the diet and the more successfully it has controlled seizures, the more gradual should be the change back to a normal diet.  Duration and discontinuation of the diet  When coming off the classical diet, a gradual increase of protein and carbohydrate and lowering of fat may be achieved by lowering the diet ratios slowly until normal diet is achieved.  Recommendations: ratio should be reduced from 4 : 1 to 3 : 1 for 6 months and then to 2 : 1 for another 6 months, followed by a gradual normalization of the diet.  If the diet is withdrawn too quickly there is the risk of an increase in the number and intensity of seizures.  If at any point the seizures return or worsen then the diet must revert to the previous ratio.  Duration and discontinuation of the diet  Discontinuing the MCT diet should also follow a stepwise, gradual process.  The amount of MCT fat should be slowly reduced (5 g/d).  Alongside this reduction, protein is increased by one exchange daily until normal size protein portions are achieved, then the carbohydrate is increased by one carbohydrate exchange daily until normal size portions are reached.  Ketone levels should continue to be monitored until a normal diet is achieved.