Etiopathogenesis

Undernutrition is a result of complex interplay bet­ween: (a) inadequate dietary intake, due to various dietary, socioeconomic and cultural factors, and (b) increased nutritional requirements, due to infections or illnesses.

• Child-relatedfactors:

- Low birth weight

- Absence or early cessation of breastfeeding

- Delayed or inappropriate complementary feeding

- Incorrect dietary habits, e.g. food fads and junkfoods.

- Recurrent infections, e.g. diarrhea, respiratory infections, measles, helminthiasis, etc.

• Maternalfactors:

- Lactation failure

- Maternal malnutrition/illnesses

- Ignorance about child-feeding practices

- Separation, e.g. dead, single or working mother

• Socioeconomic factors:

- Poverty and unemployment

- Large family size

- Unhygienic living conditions

- Inequitable food distribution in family, with mothers and infants being last priority

- Disadvantaged children, e.g. girls, orphans, etc.

• Cultural factors:

- Wrong beliefs, e.g. colostrum is harmful, hot/cold foods to be avoided in children, milk aggravates diarrhea, etc.

- Wrong customs, e.g. delayed introduction of comple­mentary feeds, waiting for religious ceremonies (annaprashan).

- Wrong cooking practices, e.g. peeling of vegetables before cooking, use of polished food, draining away the water after cooking, etc.

• Community factors:

- Natural/man-made disasters with food shortage, e.g. famines, wars, civil unrests.

- Inappropriate agricultural practices, production and distribution of food grains.

- Generalized economic depression.

- Inadequate primary health care.

It is not yet clear, why some malnourished children clinically present differently from others (marasmus vs kwashiorkor).Various theories have been suggested to explain different clinical presentations in PEM, of which two are important and deserve mention here

a. Adaptation theory suggests that during early stages of nutritional deficiency, human body tries to adapt by: (a) curtailing energy expenditure by reduced physical activity and growth, (b) efficient utilization of available calories by enhanced glucose uptake by cells, and (c) utilizing endogenous stores, e.g.

Children with gradual nutritional deprivation, e.g. delayed or inappropriate complementary feeding adapt better and develop marasmus-like illness with growth failure, muscle wasting and loss of subcutaneous tissue. Lack of urgency for endogenous catabolism as well as limited muscle mass and hepatic stores in them prevent development of edema and hepatomegaly.

Conversely children with sudden nutritional deprivation, e.g. those with acute illnesses or infections get less time is available to adjust for lower energy intake, necessitating rapid mobilization of endogenous stores (neoglucogenesis), leading to kwashiorkor-like state with edema (due to protein utilization) and fatty hepatomegaly (due to lipolysis).

b. Role of infections: Infections and nutrition are closely linked to each other (Fig. 6.1) and infections, e.g. diarrhea, acute respiratory infections or measles, are common preceding events to precipitate malnutrition in sub-clinically undernourished children, due to sudden widening of demand-supply gap. Kwashiorkor is relatively more common following infections than marasmus, due to inadequate adaptation.

6.1.2