Recognition and Management of Malnutrition

Protein-energy malnutrition (PEM) is a general term describing a state of deficiency involving multiple nutrients. Usually malnutrition in children results from a combination of energy and protein deficiency, often with associated micronutrient deficiency. Frequent infections causing anorexia and decreased food intake play an important contributing role. The pathophysiology of severe PEM is very complex, affecting the cellular function of many organ systems, including heart and bowel. In the heart, redistribution of muscle proteins increases the risk for cardiovascular collapse, and damage to the intestinal villi leads to malabsorption. The edema associated with malnutrition results from a combination of hypoalbuminemia and deficiencies in copper, zinc, selenium, thiamine and vitamins A, E, and C.

There are two major clinical presentations of severe PEM: marasmus and kwashiorkor. Marasmus is the most common form of PEM and is caused by deprivation of both energy/calories and protein that leads to weight loss of more that 20% of initial body weight. It is characterized by profound wasting, fatigue, apathy, and irritability. A person of normal weight (10% to 12% body fat) would develop marasmus after approximately 60 days of total starvation. Marasmus is most common in infants under 1 year of age, and these children maintain their hunger despite appearing irritable.

Kwashiorkor usually occurs when a previously malnourished patient is exposed to the catabolic stress of infection (measles, tuberculosis, pertussis, and others), diarrhea, or trauma. Studies suggest that there is no difference in diets of children who develop marasmus or kwashiorkor. The generation of free radicals and depletion of anti-oxidants associated with inflammation appears to be linked to the development of edema in kwashiorkor. Nutritional edema is associated with an increased secretion of an anti-diuretic substance (probably antidiuretic hormone) which prevents the normal excretion of free water. Low-protein, low-calorie diets may affect the inactivation of anti-diuretic hormone.

In Latin America, kwashiorkor is estimated to occur in only 2% of malnourished individuals, although in some regions in the world, such as Africa, this proportion is much higher, up to 30%. It is more commonly found in children 1 to 3 years of age and is more prevalent in regions where the majority of nutrition is obtained from starchy vegetables that may be contaminated with aflatoxin (a fungal toxin that commonly attacks plants in wet regions). Kwashiorkor is characterized by abdominal distension, peripheral edema, flaking skin lesions, hair changes, including decoloration, and hepatomegaly. Children with kwashiorkor are often anorexic, which poses additional challenges to their management. A subset of these children may present with marasmic kwashiorkor, typically with edema, significant subcutaneous fat and muscle wasting, stunting, and mild hepatomegaly. Children with marasmic kwashiorkor show high mortality rates; thus, highly cautious rehydration and refeeding are critical.