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For further information, see CMDT Part 29–03: Protein-Energy Malnutrition

Key Features

Essentials of Diagnosis

  • Decreased intake of energy or protein, increased nutrient losses, or increased nutrient requirements

  • Kwashiorkor: caused by protein deficiency

  • Marasmus: caused by combined protein and energy deficiency

  • Protein loss correlates with weight loss: 35–40% total body weight loss can be fatal

General Considerations

  • Results from a relative or absolute deficiency of energy and protein

  • May be primary, due to inadequate food intake, or secondary, as a result of other illness

  • For many developing nations, primary protein–energy malnutrition remains a significant health problem

  • It occurs in two distinct syndromes

    • Kwashiorkor

      • Caused by a deficiency of protein in the presence of adequate energy

      • Typically seen in weaning infants at the birth of a sibling where foods containing protein are insufficient

    • Marasmus

      • Caused by combined protein and energy deficiency

      • Seen where adequate quantities of food are not available

      • In industrialized societies, protein–energy malnutrition is most often secondary to other diseases

    • Kwashiorkor-like secondary protein–energy malnutrition occurs primarily in hypermetabolic acute illnesses such as

      • Trauma

      • Burns

      • Sepsis

    • Marasmus-like secondary protein–energy malnutrition typically results from chronic diseases such as

      • Chronic obstructive pulmonary disease (COPD)

      • Heart failure

      • Cancer

      • AIDS

    • In both syndromes, protein–energy malnutrition is caused either by decreased intake of energy and protein or by increased nutrient losses related to the underlying illness

Clinical Findings

  • Every organ system affected

  • Loss of body weight, adipose stores, and skeletal muscle mass

  • Loss of protein from skeletal muscle and internal organs is usually proportionate to weight loss

  • Hepatic synthesis of serum proteins decreases, and depressed levels of circulating proteins are observed

  • Cardiac output and contractility are decreased

  • Respiratory function

    • Affected primarily by weakness and atrophy of the muscles of respiration

    • Vital capacity and tidal volume are depressed

    • Mucociliary clearance is abnormal

  • Gastrointestinal tract

    • Affected by mucosal atrophy and loss of villi of the small intestine, resulting in malabsorption

    • Intestinal disaccharidase deficiency and mild pancreatic insufficiency also occur

  • Changes in immunologic function are among the most important changes

    • T lymphocyte number and function are depressed

    • Changes in B cell function are more variable

    • Impaired complement activity, granulocyte function, and anatomic barriers to infection are noted

    • Wound healing is poor

  • Dependent edema, ascites, or anasarca may develop


  • Serum albumin may be normal or slightly decreased, but rarely to < 2.8 g/dL (28 g/L)

  • The serum protein level, however, typically declines and the serum albumin is often < 2.8 g/dL (28 g/L)

  • ECG may show decreased voltage and a rightward axis shift


  • Severe protein–energy undernutrition

    • Initial efforts

      • Should be directed at correcting fluid and electrolyte abnormalities and infections

      • Of particular concern are depletion of potassium, magnesium, and calcium as well as acid-base abnormalities

    • Second phase of treatment

      • Directed at ...

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