Protein-energy malnutrition

Protein-energy malnutrition (PEM), or also known as protein-calorie malnutrition is a malnutrition and deficiency syndrome in organisms, especially humans caused by the inadequate intake of macronutrients through food in their diet. more...

It is characterized not only by an energy deficit due to a reduction in all macronutrients but also by a deficit in many micronutrients. Cells in an organism require these sources of nutrients to perform cellular respiration in order to produce adenosine triphosphate, which is the energy currency of most cellular functions.

When energy or carbohydrate intake is lacking, the organism's body must break down its own proteins which form the major building components of the cells in the organism in order to continue to provide energy for itself. This syndrome is one example of the various levels of inadequate protein or energy intake between starvation and adequate nourishment. Although infants and children of some developing nations dramatically exemplify this type of malnutrition, it can occur in persons of any age in any country.

Classification and etiology

Clinically, protein-energy malnutrition has three forms: dry (thin, desiccated), wet (edematous, swollen), and a combined form between the two extremes. The form depends on the balance of protein or nonprotein sources of energy, such as carbohydrates or milk respectively. Each of the three forms can be graded as mild, moderate, or severe. Grade is determined by calculating weight as a percentage of expected weight for length using international standards (normal, 90 to 110%; mild protein-energy malnutrition, 85 to 90%; moderate, 75 to 85%; severe, < 75%).

The dry form, marasmus, results from near starvation with deficiency of protein and nonprotein nutrients. The marasmic child consumes very little food often because his mother is unable to breastfeed and is very thin from loss of muscle and body fat.

The wet form is called kwashiorkor, an African word literally meaning first child-second child. It refers to the observation that the first child develops protein-energy malnutrition when the second child is born and replaces the first child at the breast of the mother. The weaned child is fed a thin gruel of poor nutritional quality (compared with breastmilk) and fails to thrive. The protein deficiency is usually more marked than the energy deficiency, and edema results. Children with kwashiorkor tend to be older than those with marasmus and tend to develop the disease after they are weaned.

The combined form of protein-energy malnutrition is called marasmic kwashiorkor. Children with this form have some edema and more body fat than those with marasmus.

Epidemiology

Marasmus is the predominant form of protein-energy malnutrition in most developing countries. It is associated with the early abandonment or failure of breastfeeding and with consequent infections, most notably those causing infantile gastroenteritis. These infections result from improper hygiene and inadequate knowledge of infant rearing that are prevalent in the rapidly growing slums of developing countries.

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