Protein-energy malnutrition

Feature	Kwashiorkor	Marasmus
Deficiency	Protein	Total Calories
Edema	Present (↓ oncotic pressure)	Absent
Liver	Fatty Change (↓ ApoB-100)	Normal
Appearance	”Potbelly”, “Flaky paint” skin	”Old man” facies, muscle wasting
Key Diff	Swollen belly	Starved appearance

• Kwashiorkor
  • Pathophysiology
    • Severe protein deficiency with relatively sufficient caloric intake.
    • ↓ Protein intake $\to$ ↓ Synthesis of visceral proteins (e.g., albumin) $\to$ ↓ plasma oncotic pressure $\to$ Edema.
    • ↓ Synthesis of apolipoproteins (specifically ApoB-100) $\to$ inability to export VLDL from liver $\to$ Hepatic Steatosis (Fatty Liver).
  • Clinical Features
    • “MEALS” Mnemonic:
      • Malnutrition
      • Edema (Pitting, bilateral)
      • Anemia
      • Liver (Fatty change/Hepatomegaly)
      • Skin lesions (Hyperkeratosis, dyspigmentation/“flaky paint” dermatitis)
    • Abdominal distension (“Potbelly”) due to ascites and fatty liver.
    • Hair changes: Depigmentation, reddish tint, loss of curl, “flag sign” (alternating bands of color).
    • Emotional: Apathy, irritability.
• Marasmus
  • Pathophysiology
    • Severe deficiency of total calories (energy) and nutrients.
    • Muscle wasting + loss of subcutaneous fat.
    • No edema (albumin levels remain relatively normal due to synthesis prioritization).
  • Clinical Features
    • “Marasmus results in Muscle wasting.”
    • Significant weight loss (<60% expected weight for age).
    • “Old man” appearance: Loss of buccal fat pads, wrinkled skin.
    • Muscle atrophy with preserved alertness (unlike the lethargy in Kwashiorkor).
    • Normal hair texture (though may be thin).
• Complications & Management
  • Refeeding Syndrome (High Yield)
    • Potentially fatal shift in fluids and electrolytes that occurs when feeding is reintroduced too rapidly.
    • Mechanism: Sudden food intake $\to$ ↑ Insulin secretion $\to$ drives Phosphate, Potassium, and Magnesium intracellularly.
    • Result: Hypophosphatemia (hallmark) $\to$ ATP depletion $\to$ cardiac arrhythmias, rhabdomyolysis, respiratory failure.
  • Treatment Approach
    • Phase 1 (Resuscitation): Correct dehydration (cautiously), treat infections, correct electrolyte imbalances. Start low and go slow with calories to prevent refeeding syndrome.
    • Phase 2 (Rehabilitation): Catch-up growth, gradual increase in calories/protein.
  • Immune Dysfunction: Cell-mediated immunity is impaired (T-cell dysfunction) $\to$ false-negative PPD (anergy) and increased susceptibility to infections.