Protein-energy malnutrition (PEM) is a potentially fatal body-depletion disorder. It is the leading cause of death in children in developing countries.
PEM is also referred to as protein-calorie malnutrition. It develops in children whose consumption of protein and energy (measured by calories) is insufficient to satisfy their nutritional needs. While pure protein deficiency can occur when a person's diet provides enough energy but lacks an adequate amount of protein, in most cases deficiency will exist in both total calorie and protein intake. PEM may also occur in children with illnesses that leave them unable to absorb vital nutrients or convert them to the energy essential for healthy tissue formation and organ function.
Types of PEM
Primary PEM results from a diet that lacks sufficient sources of protein. 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, and 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 child who has a chronic illness or experiences chronic semi-starvation. 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 about the age of 12 months when breast-feeding 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.
Marasmus, a PEM disorder, is caused by total calorie/energy depletion rather than primarily protein calorie/energy depletion. 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.
It is not entirely clear how common PEM is in the United States. Primary PEM is common in impoverished areas of developing countries. In the United States, secondary PEM is more common. Children at particular risk for secondary PEM are those who have diseases that involve diarrhea or that otherwise interfere with nutrient absorption. Children with chronic illnesses that require frequent hospitalization are more likely to develop PEM.
Causes and symptoms
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 the PEM is progressing.
Mild, moderate, and severe classifications for PEM have not been precisely defined, but patients who lose 10–20 percent of their body weight without trying may have moderate PEM. Some of the cause is replacement dependent (i.e. patients do not take in adequate protein during recovery from illness). This level of PEM is
Losing 20 percent of body weight or more is generally classified as severe PEM. Children 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 include baggy, wrinkled skin; constipation; dry, thin, or brittle hair; lethargy; pressure sores, and other skin lesions.
Children suffering from 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 children who have been severely burned, suffered trauma, or had sepsis (massive 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 patients even gain weight because of fluid retention.
Profound weakness accompanies severe marasmus. Since the body breaks down its own tissue to use for energy, children 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 suffer from 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 (fluid retention) distinguishes marasmus-like 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 progresses very slowly.
Difficulty chewing, swallowing, and digesting food, 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 blood sugar levels (glycosuria), kidney disease, malabsorption disorders, and other factors. Fever, infection, surgery, and benign or malignant tumors increase the amount of nutrients that hospitalized patients need. Trauma, burns, and some medications also increase caloric requirements.
When to call the doctor
The doctor should be consulted if a child has lost a significant amount of weight without trying, has persistent diarrhea, or has any other signs of PEM.
- eating habits and weight changes
- body-fat composition and muscle strength
- gastrointestinal symptoms
- presence of underlying illness
- developmental delays and loss of acquired milestones in children
- nutritional status
Doctors further quantify a patient's nutritional status by:
- comparing height and weight to standardized norms
- calculating body mass index (BMI)
- measuring skinfold thickness or the circumference of the upper arm
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.
In patients with severe PEM, the first stage of treatment consists of correcting fluid and electrolyte imbalances, treating infection with antibiotics that do not affect protein synthesis, and addressing related medical problems. The second phase involves replenishing essential nutrients slowly to prevent taxing the patient's weakened system with more food than it can handle. Physical therapy may benefit patients whose muscles have deteriorated significantly.
Most children can lose some of their body weight without side effects, but losing more than 40 percent is usually fatal. Death usually results from heart failure, an
Breastfeeding a baby for at least six months is considered the best way to prevent early-childhood malnutrition. Talking to a doctor before putting a child on any kind of diet, such as vegan, vegetarian, or low-carbohydrate, can help assure that the child gets the full supply of nutrients that he or she needs.
Every child 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.
Protein-energy malnutrition is fairly easily treated. If, however, it occurs for a prolonged period, it can have very serious and permanent health consequences. It is important to ensure that children are getting a healthy and balanced diet. Children should not be put on weight loss or other special diets without first consulting a pediatrician.
Electrolytes—Salts and minerals that produce electrically charged particles (ions) in body fluids. Common human electrolytes are sodium chloride, potassium, calcium, and sodium bicarbonate. Electrolytes control the fluid balance of the body and are important in muscle contraction, energy generation, and almost all major biochemical reactions in the body.
Kessler, Daniel B. and Peter Dawson, eds. Failure to Thrive and Pediatric Undernutrition: a Transdisciplinary Approach. Baltimore: P.H. Brookes, 1999.
Gonzalez-Barranco, et al. "Early Malnutrition and Metabolic Abnormalities Later in Life." Nutrition Reviews 62, no.7 (July 2004): 134–40.
Hamer, C. et al. "Detection of Severe Protein-Energy Malnutrition by Nurses in the Gambia." Archives of Disease in Childhood (Feb. 2004): 181–5.
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