Protein-Calorie Malnutrition: Overview and Treatment
Protein-calorie malnutrition results in 2 similar but distinct diseases, marasmus and kwashiorkor.
Marasmus is defined simply as chronic deprivation of energy needed to maintain body weight. Its extreme form is characterized by severe weight loss and cachexia.1 Marasmus is further characterized by subnormal body temperature, decreased pulse and metabolic rate, loss of skin turgor, constipation, and starvation diarrhea, consisting of frequent, small, mucus-containing stools.2
Kwashiorkor is a somewhat more complex disease. It is characterized by edema, low capillary-filtration rate, hypoalbuminemia, and dermatitis.
Derived from an African term meaning "the disease that occurs when the next baby is born", kwashiorkor was initially thought to result from a diet high in calories (mainly carbohydrates, such as maize), yet deficient in protein. However, infection, aflatoxin poisoning, and oxidative stress may also play causative roles.1,3 Edema, a defining characteristic of kwashiorkor, resolves with treatment, despite continuing hypoalbuminemia, suggesting that the edema is due to leaky cell membranes, low capillary filtration rates, high concentrations of free iron, and free radicals that increase capillary permeability.4 Kwashiorkor is further distinguished from marasmus by the following findings:
Kwashiorkor may also involve severe, life-threatening hypophosphatemia (<1.0 mg/dL), which has been found to triple the mortality rate when compared with children who have normal phosphorus levels.7
Overall, in impoverished regions of Africa, marasmus is more prevalent than kwashiorkor.8 These conditions are most commonly seen in areas that are both impoverished and affected by human immunodeficiency virus (HIV) infection. Evidence indicates that HIV-infected children in Africa have more than twice the incidence of marasmus, compared with uninfected children (16% vs. 7%).
Protein-calorie malnutrition is also found in developed countries under unusual circumstances, including anorexia nervosa and cancer. The condition has also been found in infants placed on severely restricted diets,9,10 and in 5% of a population of patients who requested Roux-en-Y gastric bypass surgery to control obesity.11
Both marasmus and kwashiorkor can lead to impaired immune responses; cell-mediated immunity is particularly affected.2 The result is greater susceptibility to and mortality from infectious disease. Immune function can be normalized by refeeding.5 The same cannot always be said for the extensive physical and mental retardation that may occur.2
Individuals treated for protein-energy malnutrition are at risk for refeeding syndrome, in which hypophosphatemia, hypokalemia, and hypomagnesemia may lead to disturbances in the cardiac, neurologic, gastrointestinal, respiratory, hematologic, skeletal, and endocrine systems. Guidelines have been developed to help prevent these complications and to establish a transition to normalcy. Treatment consists of 2 phases: stabilization and rehabilitation.
The initial (stabilization) phase proceeds from days 1 through 7. It consists of treatment and prevention of hypoglycemia, hypothermia, dehydration, and infection; correction of electrolyte imbalance and micronutrient deficiencies; and a cautious feeding regimen.
A rehabilitation phase proceeds from weeks 2 through 6. It consists of achievement of catch-up growth; provision of sensory stimulation and emotional support; and preparation for follow-up after recovery.
These initial 2 steps are followed by protocols for the treatment of shock and anemia; management of associated conditions; and guidelines for individuals who fail to respond.12
Protein-Calorie Malnutrition: References >>