Protein-Energy Malnutrition - Empty Plate Problems
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A spectrum of diseases from inadequate protein and calorie intake, primarily affecting somatic (skeletal muscle) and visceral (organ) protein compartments.
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Marasmus (Total Calorie Deficiency)
- Adaptation to starvation; "to waste away."
- Clinical: Severe muscle wasting (emaciation), loss of subcutaneous fat, prominent bones, "old man" face.
- Labs: Serum albumin is near-normal.
- Somatic protein compartment depleted.
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Kwashiorkor (Protein Deficiency > Calorie Deficiency)
- Maladaptive response; "sickness of the weaned child."
- Clinical: Pitting edema, ascites, hepatomegaly (fatty liver), "flaky-paint" dermatosis, alternating hair color (flag sign).
- Labs: Markedly ↓ serum albumin.
- Visceral protein compartment depleted.
⭐ High-Yield: The fatty liver in Kwashiorkor is due to decreased apolipoprotein synthesis, which impairs the export of VLDL from the liver.
Fat-Soluble Vitamins - ADEK's Fat Stash
- Absorbed with lipids; deficiencies seen in malabsorption (celiac, cystic fibrosis) and with mineral oil intake. 📌 All Dogs Eat Kibble.
| Vitamin | Core Function(s) | Deficiency Manifestations | Excess Manifestations |
|---|---|---|---|
| A (Retinol) | Vision, antioxidant, epithelial cell differentiation | Night blindness, xerophthalmia, Bitot spots | Teratogenic, hepatotoxicity, alopecia |
| D (Calciferol) | ↑ Ca²⁺ & PO₄³⁻ absorption | Rickets (kids), osteomalacia (adults) | Hypercalcemia, confusion |
| E (Tocopherol) | Antioxidant (protects RBCs) | Hemolytic anemia, spinocerebellar tract demyelination | ↑ Warfarin effect, bleeding |
| K (Phytonadione) | Coagulation factors (II, VII, IX, X, C, S) | Hemorrhage, ↑ PT/PTT | Hemolytic anemia (high doses) |
Water-Soluble Vitamins - B & C's Washout
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General: Absorbed in the small intestine; excess excreted in urine. Not stored in the body (except B12, B9), requiring consistent dietary intake. Act as crucial coenzymes in metabolic pathways.
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Vitamin C (Ascorbic Acid)
- Function: Antioxidant; essential for collagen synthesis (hydroxylation of proline/lysine).
- Deficiency (Scurvy): Impaired wound healing, bleeding gums, perifollicular hemorrhage.
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B-Complex Vitamins
- Function: Coenzymes in energy metabolism (e.g., Thiamine in PDH complex).
- 📌 Mnemonic: B vitamins are coenzymes for "Burning" fuel.
⭐ Thiamine (B1) Deficiency: In alcoholics, can lead to Wernicke-Korsakoff syndrome. Always give thiamine before glucose to prevent precipitating encephalopathy.
Essential Minerals - Tiny But Mighty
- Iron (Fe): O₂ transport (Hb, myoglobin); cytochrome function.
- Deficiency: Microcytic, hypochromic anemia; koilonychia.
- Excess: Hemochromatosis (organ damage from iron deposition).
- Iodine (I): Synthesis of thyroid hormones ($T_3, T_4$).
- Deficiency: Goiter, hypothyroidism, cretinism.
- Copper (Cu): Cofactor for lysyl oxidase, tyrosinase, cytochrome c oxidase.
- Deficiency (Menkes): Brittle, "kinky" hair, growth retardation.
- Excess (Wilson's): Kayser-Fleischer rings, liver disease.
- Zinc (Zn): Cofactor for >100 enzymes (e.g., carbonic anhydrase).
- Deficiency: Delayed wound healing, hypogonadism, dysgeusia.
⭐ Acrodermatitis enteropathica, a rash around body orifices, is a classic sign of severe Zinc deficiency, often tested alongside delayed wound healing and anosmia/dysgeusia.
High‑Yield Points - ⚡ Biggest Takeaways
- Marasmus results from total calorie malnutrition, leading to severe muscle wasting and loss of subcutaneous fat.
- Kwashiorkor is primarily a protein deficiency, characterized by pitting edema, fatty liver, and skin lesions.
- Vitamin A deficiency classically presents with night blindness (nyctalopia) and Bitot's spots on the conjunctiva.
- Vitamin C deficiency impairs collagen synthesis, causing scurvy (bleeding gums, poor wound healing).
- Vitamin D deficiency leads to Rickets in children and Osteomalacia in adults.
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