Protein-energy malnutrition (PEM), also referred to as protein-calorie malnutrition, is a potentially fatal body-depletion disorder. It is a leading cause of death in children in developing countries.
Although PEM is not prevalent among the general population of the United States, one governmental study estimated that up to half of elderly patients in nursing home are suffering from PEM. Additionally, PEM seen in children in the United States is often a sign of child abuse or severe neglect. Other groups who may suffer from PEM in industrialized nations such as the United States are cancer patients, those with anorexia nervosa, and patients who have had gastric bypass surgery in order to control obesity.
Outside industrialized nations, PEM is common in areas with high rates of impoverishment, especially in Africa. It is also prevalent after large natural disasters, such as drought, or during political unrest, which leads to a shortage of food in an area.
PEM develops in children and adults whose consumption of protein and energy (measured by calories) is insufficient to satisfy the body's nutritional needs. Whereas pure protein deficiency can occur when a person's diet provides enough energy but lacks the protein minimum, in most cases the deficiency will be dual. PEM may also occur in persons who are unable to absorb vital nutrients or convert them to energy essential for healthy tissue formation and organ function.
Primary PEM results from a diet that lacks sufficient sources of protein and/or energy. Secondary PEM is more common in the United States, where it usually occurs as a complication of AIDS, cancer, chronic kidney failure, inflammatory bowel disease, or other illnesses that impair the body's ability to absorb or use nutrients or to compensate for nutrient losses. PEM can develop gradually in a patient who has a chronic illness or who experiences chronic semistarvation. It may appear suddenly in a patient who has an acute illness.
Kwashiorkor, also called wet protein-energy malnutrition, is a form of PEM characterized primarily by protein deficiency. This condition usually appears at the age of about 12 months when breastfeeding is discontinued, but it can develop at any time during a child's formative years. It causes fluid retention (edema); dry, peeling skin; and hair discoloration.
Primarily caused by energy deficiency, marasmus is characterized by stunted growth and wasting of muscle and tissue. Marasmus usually develops between the ages of six months and one year in children who have been weaned from breast milk or who suffer from weakening conditions such as chronic diarrhea.
Secondary PEM symptoms range from mild to severe and can alter the form or function of almost every organ in the body. The type and intensity of symptoms depend on the patient's prior nutritional status, the nature of the underlying disease, and the speed at which it is progressing.
Losing 20% of body weight or more is generally classified as severe PEM. People with this condition cannot eat normal-sized meals. They have slow heart rates and low blood pressure and body temperatures. Other symptoms of severe secondary PEM are baggy, wrinkled skin; constipation; dry, thin, brittle hair; lethargy; and pressure sores or other skin lesions.
People who have kwashiorkor often have extremely thin arms and legs, but liver enlargement and ascites (abnormal accumulation of fluid) can distend the abdomen and disguise weight loss. Hair may turn red or yellow. Anemia, diarrhea, and fluid and electrolyte disorders are common. The body's immune system is often weakened, behavioral development is slow, and mental retardation may occur. Children may grow to normal height but are abnormally thin.
Kwashiorkor-like secondary PEM usually develops in patients who have been severely burned, suffered trauma, or had sepsis (tissue-destroying infection) or another life-threatening illness. The condition's onset is so sudden that body fat and muscle mass of normal-weight people may not change. Some obese patients even gain weight.
Profound weakness accompanies severe marasmus. Since the body breaks down its own tissue to use as calories, people with this condition lose all their body fat and muscle strength, and acquire a skeletal appearance most noticeable in the hands and in the temporal muscle in front of and above each ear. Children with marasmus are small for their age. Since their immune systems are weakened, they experience frequent infections. Other symptoms include loss of appetite, diarrhea, skin that is dry and baggy, sparse hair that is dull brown or reddish yellow, mental retardation, behavioral retardation, low body temperature (hypothermia), and slow pulse and breathing rates.
The absence of edema distinguishes marasmuslike secondary PEM, a gradual wasting process that begins with weight loss and progresses to mild, moderate, or severe malnutrition (cachexia). It is usually associated with cancer, chronic obstructive pulmonary disease (COPD), or another chronic disease that is inactive or progressing very slowly.
Some individuals have kwashiorkor and marasmus at the same time. This situation most often occurs when a person who has a chronic, inactive condition develops symptoms of an acute illness.
Difficulty chewing, swallowing, and digesting food, as well as pain, nausea, and lack of appetite are among the most common reasons that many hospital patients do not consume enough nutrients. Nutrient loss can be accelerated by bleeding, diarrhea, abnormally high sugar levels (glycosuria), kidney disease, malabsorption disorders, and other factors. Fever, infection, surgery, and benign or malignant tumors increase the amount of nutrients hospitalized patients need. So do trauma, burns, and some medications.
A thorough physical examination and a health history that probes eating habits and weight changes, checks body-fat composition and muscle strength, and assesses gastrointestinal symptoms, underlying illness, and nutritional status is often as accurate as blood tests and urinalyses used to detect and document abnormalities.
Some doctors further quantify a patient's nutritional status by the following:
Treatment is designed to provide adequate nutrition, restore normal body composition, and cure the condition that caused the deficiency. Tube feeding or intravenous feeding is used to supply nutrients to patients who cannot or will not eat protein-rich foods.
Most people can lose up to 10% of their body weight without side effects, but losing more than 40% is almost always fatal. Death usually results from heart failure, an electrolyte imbalance, or low body temperature. Patients with certain symptoms, including semiconsciousness, persistent diarrhea, jaundice, and low blood sodium levels, have a poorer prognosis than other patients. Recovery from marasmus usually takes longer than recovery from kwashiorkor. The long-term effects of childhood malnutrition are uncertain. Some children recover completely, whereas others may have a variety of lifelong impairments, including an inability to properly absorb nutrients in the intestines and mental retardation. The outcome appears to be related to the length and severity of the malnutrition, as well as to the age of the child when the malnutrition occurred.
Breastfeeding a baby for at least six months is considered the best way to prevent early childhood malnutrition. Preventing malnutrition in developing countries is a complicated and challenging problem. Providing food directly during famine can help in the short term, but more long-term solutions are needed, including agricultural development, public health programs (especially programs that monitor growth and development, as well as programs that provide nutritional information and supplements), and improved food distribution systems. Programs that distribute infant formula and discourage breastfeeding are believed to hurt the reduction of PEM cases, and many believe these programs should be discontinued, except in areas where many mothers are infected with HIV.
Every patient being admitted to a hospital should be screened for the presence of illnesses and conditions that could lead to PEM. The nutritional status of patients at higher-than-average risk should be more thoroughly assessed and periodically reevaluated during extended hospital stays or nursing home residence.
See also Drought ; Famine ; HIV/AIDS .
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American Academy of Pediatrics (AAP), 141 Northwest Point Blvd., Elk Grove, IL, 60007-1098, (847) 434-8000, http://www.aap.org .
American College of Nutrition, 300 S. Duncan Ave., Ste. 225, Clearwater, FL, 33755, (727) 446-6086, Fax: (727) 446-6202, office@AmericanCollegeofNutrition.org, http://www.americancollegeofnutrition.org .
American Society for Nutrition, 9650 Rockville Pike, Bethesda, MD, 20814, (301) 634-7050, Fax: (301) 634-7894, http://www.nutrition.org .
National Institute of Child Health and Human Development (NICHD), PO Box 3006, Rockville, MD, 20847, (800) 370-2943, Fax: (866) 760-5947, NICHDInformation ResourceCenter@mail.nih.gov, http://www.nichd.nih.gov .
World Health Organization, Avenue Appia 20, 1211 Geneva 27, Switzerland, +2241 791 21 11, Fax: +2241 791 31 11, firstname.lastname@example.org, http://www.who.int .
Revised by Tish Davidson, AM