Protein-Energy Malnutrition: Kwashiorkor and Marasmus
Low body weight, edema in the abdomen and lower extremities, and dermatitis with depigmentation of the skin are characteristic of kwashiorkor. In addition to the signs and symptoms noted in this child, kwashiorkor also manifests with anorexia, irritability, hepatomegaly (enlarged liver), resulting from fatty infiltrates in the liver, and an inability to produce antibodies when challenged with an infection, or a vaccine. From the Ga language of the Ghana coast, the name Kwashiorkor was introduced to western medicine by Cicely Williams, a Jamaican pediatrician and means something along the lines of "a disease that develops in a child after a new baby is born". This refers to weaning of an older child from breast milk to allow a baby sibling to nurse. At this point, the older child is put on a diet that is both reduced in calories and almost entirely carbohydrates, or has a protein source that is incomplete (does not include all of the essential amino acids).
Kwashiorkor and marasmus are different types of protein-energy malnutrition (PEM), which affects children in south Asia and sub-Saharan Africa with an incidence of more than 50 percent and 30 percent, respectively, with notable rises in Africa since 1990, though globally the incidence of PEM has decreased. Marasmus, which tends to develop in dryer climates, is characterized by emaciation resulting from a deficiency in total calories, which is to say in all nutrients. Kwashiorkor initially was thought to result mostly from protein deficiency in particular. However, it now is thought that deficiencies of certain antioxidants such as glutathione, vitamin E, selenium, and polyunsaturated fatty acids must play a role, along with deficiencies in other micronutrients such as vitamin C, folic acid, iodine, and iron. Thus, several of the symptoms noted in PEM overlap with symptoms exhibited in deficiencies of individual micronutrients. For instance, niacin (vitamin B3) deficiency alone leads to pellagra which manifests as aggression, dermatitis, weakness, mental confusion, insomnia, and diarrhea. Ultimately, dementia and death can result. Thus, symptoms can be remembered in terms of the "four Ds" which are diarrhea, dermatitis, dementia, and death. Deficiency of pyridoxine, which is vitamin B6, results in microcytic anemia due to a deficiency in heme synthesis, while deficiency of vitamin C causes scurvy. Once known as the sailor's disease in the past, scurvy presents with spongy gums, bleeding from all mucous membranes, and frequent bruising and results from disruption of the manufacture of collagen.