Energy metabolism

• With reduced energy intake, a decrease in physical activity occurs along with a slower and ultimately, lack of growth.  Weight loss occurs by a decrease in fat mass, then a decrease in muscle mass, as clinically measured by changes in arm circumference.  Muscle mass loss results in a decrease of energy expenditure.  Reduced energy metabolism can impair the response of children with marasmus to changes in environmental temperature, resulting in an increased risk of hypothermia.

Protein metabolism

• Intestinal absorption of amino acids is maintained, despite the atrophy of the intestinal mucosa.  Protein turnover is decreased (up to 40% in severe forms), and protein-sparing mechanisms regulated by complex hormonal controls redirect amino acids to vital organs.  Amino acids liberated from the loss of muscle mass are recycled in priority to the liver for the synthesis of essential protein.  Total plasma proteins, including albumin, are decreased, whereas gamma globulins are often increased by the associated infections.

Albumin

• An albumin concentration lower than 30g/L, is often considered as the threshold below which edema develops from decreased oncotic pressure.  However, in marasmus, albumin concentration can occasionally be below this value without edema

Carbohydrate metabolism

• This has mainly been studied in order to explain the serious and often fatal hypoglycemia occurring in the initial renutrition phase of marasmic children.  Glucose level is often low initially, and the glycogen stores are depleted.  Also, a certain degree of floccose intolerance of unclear etiology exists, possibly associated with a peripheral resistance to insulin or with hypokalemia.  In the initiation of renutrition or in association with diarrhea or infection, a significant risk of profound and even fatal hypoglycemia occurs.

Fat metabolism