Friday, August 19, 2011

#AskDrKK: What is re-feeding syndrome?

#DrKKAnswers: The basic aim of breaking any fast is to prevent occurrence of re-feeding syndrome, a metabolic complication that occurs when nutritional support is given to severely malnourished patients or to someone recovering from prolonged fast or hunger strike.

During prolonged fasting the body conserve muscle and protein breakdown by switching to ketone bodies derived from fatty acids as the main energy source. The liver decreases its rate of gluconeogenesis thus conserving muscle and protein. Many intracellular minerals become severely depleted during this period, although serum levels may remain normal. Insulin secretion is suppressed and glucagon secretion is increased.

During re-feeding the metabolism shifts from a catabolic to an anabolic state. Insulin is released on carbohydrate intake resulting in increased glycogen, fat and protein synthesis. Insulin release triggers cellular uptake of potassium, phosphate, and magnesium which are already depleted and the stores rapidly become used up.

When the serum concentrations of these electrolytes are reduced, serious complications, such as irregular heart beat can occur. Patients can also develop fluid and electrolyte imbalance, low phosphate levels, neurologic, lung, heart, neuromuscular, and blood related complications. Irregular heart rhythm is the most common cause of death with other significant risks including confusion, coma and convulsions and cardiac failure.

The diagnostic feature is presence of low phosphate, potassium, magnesium, vitamin B1 levels and fluid overload with edema feet. Low phosphate levels are the essential criteria for diagnosis.

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