Protein-energy malnutrition

Malnutrition is a significant cause of morbidity and mortality worldwide, leading to ∼ 45% of all deaths in children under the age of five. Approximately 52 million children have wasting with one-third (17 million) suffering from severe acute malnutrition. Even more children (∼ 154.8 million) have stunted growth, indicating widespread chronic malnutrition. In severe cases, primary protein-energy malnutrition (PEM) can develop, which has two major clinical forms: kwashiorkor and marasmus. Kwashiorkor is characterized by muscle atrophy, pitting edema, and distended abdomen with an enlarged fatty liver. It is caused by a deficiency of dietary protein despite sufficient calorie intake (e.g., from carbohydrates). Marasmus is the diffuse loss of muscle and fat tissue (without edema or distended abdomen) due to a severe state of total calorie deficiency of all macronutrients. Secondary PEM occurs due to illnesses affecting appetite, digestion, absorption, metabolism, and/or increased energy/protein demand. In addition to muscle atrophy, it is possible for patients to have clinical features of either marasmus or kwashiorkor. All forms of PEM are primarily clinical diagnoses; for primary PEM, WHO diagnostic criteria involve a child's weight-for-length/height and mid-upper arm circumference. Thorough laboratory testing should also be conducted to evaluate for severity and complications. Treatment involves managing complications, rehydration, and careful nutritional rehabilitation to avoid refeeding syndrome. In the case of secondary PEM, underlying conditions should also be treated, as well.

• Protein-energy malnutrition (PEM) describes pathological conditions resulting from a deficiency of dietary protein and/or total calories.
• Primary PEM: due to inadequate macronutrient intake
  • Marasmus: due to deficiency of all macronutrients and total calories
  • Kwashiorkor: due to protein deficiency
  • Marasmic kwashiorkor: a severe form with features of both marasmus and kwashiorkor
• Secondary PEM: due to chronic illnesses or drugs disrupting appetite, digestion, absorption, metabolism, and/or increased energy/protein demand

Protein-deficient KWick MEALS lead to Kwashiorkor: Malnutrition, Edema, Anemia, fatty Liver, Skin lesions.

Marasmus causes Muscle wasting but no edema.

• Description: A form of PEM caused by illnesses affecting appetite, digestion, absorption, metabolism, and/or increased energy/protein demand rather than a lack of calorie intake.
• Epidemiology: usually observed in
  • Chronically ill, hospitalized patients
  • Elderly
  • Chronic alcoholics
• Etiology: decreased appetite/food intake, increased energy and protein demand, and/or malabsorption due to illnesses and medications
  • Cachexia/wasting syndrome: a form of secondary PEM caused by an underlying illness that causes chronic muscle breakdown despite nutritional supplementation
    • Neoplasm (cancer cachexia)
    • AIDS (HIV wasting syndrome)
    • Chronic renal failure
    • Congestive heart failure
    • COPD
    • Less common
      • Neuromuscular disorders
      • Cystic fibrosis
      • Crohn disease
  • Gastrointestinal dysfunction
    • Chronic liver disease
    • Pancreatic insufficiency
    • Enteropathy (e.g., celiac disease, HIV enteropathy)
    • Retroperitoneal fibrosis
  • Increased metabolic demands
    • Chronic infection
    • Endocrine disorders (hyperthyroidism, pheochromocytoma)
    • Trauma, surgery, or burns
• Clinical features
  • Depleted subcutaneous fat and skeletal muscle (as seen in marasmus)
  • Lower extremity edema
  • Bradycardia, hypotension, and hypothermia
  • Delayed wound healing, increased risk of decubitus
  • Susceptibility to infections

PEM is primarily a clinical diagnosis. Laboratory testing should be conducted to assess the severity and complications. Additional testing may be required to determine the underlying condition for secondary PEM.

Clinical diagnosis ^[6]

Primary PEM

• H&P: Take a thorough history and physical exam, focusing on nutrition/potential child maltreatment and typical clinical features.
• Anthropometrics: to assess the degree of malnutrition
  • Height/length
  • Weight
  • Weight-for-length/height (WFL/H) represented as a Z-score or a percentile
  • Height/length-for-age (HFA) represented as a Z-score or a percentile
  • Mid-upper arm circumference (MUAC)
  • BMI
• WHO diagnostic criteria: for primary PEM in children aged 6–60 months ^[7]
  • Marasmus
    • WFL/H z-score < -3 OR
    • MUAC < 11.5 cm
  • Kwashiorkor
    • WFL/H z-score < -2 OR
    • MUAC < 12.5 cm WITH
    • Bilateral pitting edema

Secondary PEM

• Clinical diagnosis based on history, body composition (e.g., low BMI), and underlying condition
• If etiology is unclear, determine the cause, e.g.:
  • HIV testing
  • Cytokine excess: measure cytokines
  • Hyperthyroidism: measure thyroid function tests

Laboratory tests

• Thorough laboratory testing (CBC, electrolyte panel, inflammatory markers, organ function tests) should be conducted to evaluate for severity and any complications.
• Typical findings
  • Anemia
  • ↓ Total lymphocyte count, ↓ CD4+ count
  • Electrolyte abnormalities, especially:
    • Hypokalemia
    • Hyponatremia
    • Hypophosphatemia
    • Also: hypocalcemia, hypomagnesemia
  • ↓ Serum albumin and transferrin (especially in Kwashiorkor)
  • ↓ Blood glucose
  • ↓ BUN and creatinine (unless concurrent renal failure)
  • ↑ CRP if associated with an inflammatory condition
• Test for ova and parasites in stool culture.

• Hydration (typically oral)
• Nutritional rehabilitation: must occur slowly to prevent refeeding syndrome
  • Should be initiated slowly at ∼ 20% above the child's recent intake.
  • Slowly increase calorie intake while monitoring lab values daily.
  • For kwashiorkor, protein should slowly be introduced into the diet to avoid acute liver injury.
• Treat complications (e.g., infection)
• For secondary PEM
  • Treat the underlying condition
  • Nutritional counseling
  • In anorexia-cachexia syndrome: consider corticosteroids (e.g., prednisolone) and cannabinoids (e.g., dronabinol)

Refeeding syndrome is a frequent complication if nutritional rehabilitation occurs too rapidly (sudden shift from a catabolic to an anabolic state): It is characterized by fluid retention, hypophosphatemia, hypomagnesemia, and hypokalemia.

• Approx. 50 million children < 5 years of age are malnourished. The fatality rate of severely malnourished children brought to the hospital still is 30–50%. With the right management, this rate can be reduced to approx. 5%. The following 10 steps (conditions to treat) are an attempt to drastically reduce the fatality rate. ^[8]
• The first 9 steps usually take at least 1–3 weeks depending on the child's general status and recovery. ^[9]

• Infections (e.g., pneumonia, gastroenteritis, urinary tract infection, sepsis)
• Delayed wound healing
• Growth retardation
• Micronutrient deficiencies (e.g., vitamin deficiencies, iron deficiency, zinc deficiency)
• Dehydration
• Multiorgan failure and death if left untreated

We list the most important complications. The selection is not exhaustive.