DiMauro on illness protocol

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Question:

In a patient with mitochondrial disease, does giving extra calories, in

the form of glucose, extra tube feeds or uncooked cornstarch have any

effect on decompensation due to illness? Can it prevent decompensation

if started at the first sign of illness, before any noticeable

decompensation? D.L.

Answer:

If by "mitochondrial disease", we refer, as it is now customary, to

disorders due to defects of the mitochondrial respiratory chain, then

unfortunately provision of extra calories does not help because the

problem is not in the metabolism of foodstuff (glycogen, lipids), but

in the generation of energy from their terminal product,

acetylcarnitine. However, many patients with mitochondrial diseases

have gastrointestinal problems, making adequate nutrition difficult. In

these patients, nasogastric feeding or percutaneous endoscopic

gastrostomy (PEG) may be of great benefit.

Responder: Salvatore DiMauro MD

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There is no single answer to this question.

The

stomach and small intestine break food down into fats, carbohydrates

(sugars) and amino acids (protein). In a healthy person, any food eaten

that is needed immediately is stored in the liver as glycogen (a

complex form of sugar) or as fat. Protein cannot be stored and is

converted into sugar and urea. The urea is excreted in the urine. The

liver can store enough sugar to run the body for about 12 hours. The

ability to store fat is enormous. During times of starvation, whether

this is voluntary or due to an inability to eat because of illness, we

live off our stored sugars and fats. In the healthy person, the ability

to survive starvation depends on how much fat is stored, and given a

supply of water, people can live for months. The fat can be mobilized

and quickly converted into fatty acids and ketones, which can run the

body. During periods of fasting the blood sugar levels can drop to very

low levels, but the body can still survive as long as it can produce

and use those fatty acids and ketones.

In many mitochondrial

patients there is an inability to store or access any stored sugar, and

an inability to convert fat into ketones, or an inability to use the

fatty acids and ketones. Because there is a relative block in

metabolism, the ability to process (the speed at which food can be

turned into energy) calories is reduced. During an illness, giving

supplemental sugar is usually necessary. This can be given as food, a

beverage (Gatoraid for example), or as an IV. Cornstarch is a complex

carbohydrate, which is slowly digested and releases the sugar over 6-8

hours.

In a healthy child, starvation during a one or two day

illness rarely causes any problems. In a child with a mitochondrial

disease, where the caloric reserves are low and the ability to

compensate for any stress is reduced, the risk of energy failure with

resultant serious effects is heightened. This is a relative risk, and

some patients are more susceptible to problems than other patients.

Early fluids and sugar is helpful as a general rule. In children with

fatty acid oxidation disorders, such as medium chain acylCoA

dehydrogenase deficiency, each illness needs to be treated as a crisis.

These children must have IV fluids and glucose. I tell parents "do

not

pass GO, do not collect $200,,,,,go to the ER with the first sniffle."

In other children, everything can be handled at home. The protocol for

this problem should be discussed with your physician beforehand.