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The etiology of malnutrition can be primary, as when the otherwise healthy
individual’s needs for protein, energy, or both are not
met by an adequate diet, or secondary, as a result of disease states
that may lead to suboptimal intake, inadequate nutrient absorption
or use, and/or increased requirements because of nutrient
losses or increased energy expenditure. Protein-energy malnutrition
is the most important nutritional disease in developing countries
and one of the leading causes of morbidity and mortality in childhood
worldwide.1,2 In the Western world primary malnutrition
continues to occur with alarming frequency because of neglect or
poverty. Secondary malnutrition exists as a result of chronic or acute
illness.
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In primary protein-energy malnutrition, calorie inadequacies
generally are linked to conditions of war, social disruption, poverty,
ignorance, infectious diseases, and food distribution inequalities.
Therefore, socioeconomic, political, and other environmental deprivations
can be considered to be the most global cause for childhood starvation with
its deleterious effects on growth and development.
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In the clinical setting, acute and/or chronic illness
may lead to malnutrition and, if prolonged, result in failure to
thrive. Although the etiology of malnutrition can be traced to an
underlying pathology (ie, increased energy needs secondary to respiratory
distress, fever, wound healing, or a malabsorptive state), the common
pathway to a malnourished state is still a net deficiency of the
nutrients required for an individual. Although dietary energy and
protein deficiencies typically occur in concert, one may predominate,
resulting in either kwashiorkor (primarily a protein-deficient state)
or marasmus (primarily an energy-deficient state). Marasmic kwashiorkor
also can occur and is the combination of chronic energy deprivation
with a superimposed chronic or acute protein deficit. In both pathologic states,
apathy, indifference, fatigue, and irritability are common.
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There are several different criteria using weight and height
to classify malnutrition, and all must be judiciously applied. The
most useful and widely employed are the Waterlow classification2 and
the Gomez criteria,3 which are used to distinguish
a chronically malnourished or “stunted” child
from an acutely malnourished or “wasted” child.
An expected (or predicted) weight-for-height index is employed.
This assessment allows classification of the degree of stunting
(ie, decreased height-for-age, an indicator of chronic malnutrition) and
wasting (ie, decreased weight-for-height, an indicator of acute
malnutrition). The severity of an individual’s wasting
and/or stunting is calculated as a percentage of the reference
median value. The 50th percentile weight for that age and height-for-age
are taken as the denominator, and the actual weight or height as
the numerator. Gomez criteria assess the degree of malnutrition
based on weight-for-age. The actual weight is compared to the median
value (50th percentile for age) for the patient’s actual age.
This criterion aids in the recognition of acute malnutrition. The
Waterlow revised grading index for height-for-age and weight-for-height
and the Gomez criteria can be found in Table 29-1.3,4
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