Nutritional Diseases

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Protein-Energy Malnutrition - Hunger Games Saga

  • Spectrum: Inadequate protein & calorie intake.
  • Kwashiorkor: Predominant protein deficiency.
    • Age: 1-3 years.
    • Features: Edema, "flaky paint" dermatosis, hair changes (flag sign), fatty liver, ↓ serum albumin.
    • 📌 Mnemonic: FLAME (Fatty Liver, Anemia, Malabsorption/Moon facies, Edema).
  • Marasmus: Predominant calorie deficiency.
    • Age: Infants (<1 year).
    • Features: Severe muscle wasting ("wizened" face), growth retardation, no edema, serum albumin near normal.
  • Marasmic-Kwashiorkor: Mixed features of both.

⭐ "Flag sign" in hair (alternating bands of depigmentation) is highly suggestive of Kwashiorkor due to periods of poor and adequate protein intake. Kwashiorkor vs Marasmus Comparison

Fat-Soluble Vitamin Deficiencies - ADEK's Missing Acts

  • General causes: Malabsorption (e.g., celiac disease, cystic fibrosis), biliary obstruction, mineral oil abuse. 📌 "DEKA" are fat-soluble.
  • Vitamin A (Retinol)
    • Deficiency: Night blindness (nyctalopia), xerophthalmia (Bitot's spots, corneal ulcers), keratomalacia, squamous metaplasia, impaired immunity (↑ infections).
  • Vitamin D (Calciferol)
    • Deficiency: Rickets (children - craniotabes, rachitic rosary, leg bowing), osteomalacia (adults - bone pain, fractures). Results in ↓ Ca²⁺, ↓ PO₄³⁻, ↑ PTH, ↑ ALP.
  • Vitamin E (Tocopherol)
    • Deficiency: Rare. Hemolytic anemia (especially in premature infants), spinocerebellar degeneration (ataxia, peripheral neuropathy), muscle weakness. Potent antioxidant.
  • Vitamin K (Phylloquinone, Menaquinones)
    • Deficiency: Bleeding diathesis (↑ PT/INR, ↑ aPTT, normal bleeding time). Hemorrhagic disease of the newborn. Impaired synthesis of clotting factors II, VII, IX, X, protein C & S.

    ⭐ Warfarin (Coumadin) acts by inhibiting Vitamin K epoxide reductase, leading to a functional Vitamin K deficiency. Vitamin A Metabolism

Water-Soluble Vitamin Deficiencies - B&C's Empty Seats

Rapid turnover; minimal storage (except B12). Deficiency manifests relatively quickly.

  • B1 (Thiamine): Beriberi (polyneuropathy, edema, heart failure); Wernicke-Korsakoff (ataxia, confusion, ophthalmoplegia).
  • B2 (Riboflavin): Ariboflavinosis (cheilosis, glossitis, seborrheic dermatitis).
  • B3 (Niacin): Pellagra (3Ds: Dermatitis, Diarrhea, Dementia; +Death).
  • B6 (Pyridoxine): Peripheral neuropathy, sideroblastic anemia, cheilosis. Isoniazid ↑risk.
  • B9 (Folate): Megaloblastic anemia, ↑homocysteine, neural tube defects.
  • B12 (Cobalamin): Megaloblastic anemia, neurological sx (subacute combined degeneration).
  • C (Ascorbic Acid): Scurvy (impaired collagen synthesis: poor wound healing, bleeding gums, petechiae).

⭐ Wernicke encephalopathy is a medical emergency; treat with IV thiamine before glucose administration to prevent precipitation or worsening of symptoms.

Mineral Deficiencies & Obesity - Imbalance Issues

  • Iron: Microcytic hypochromic anemia, koilonychia, pica. Plummer-Vinson syndrome (IDA, esophageal webs, glossitis).
  • Iodine: Goiter, hypothyroidism. Cretinism (childhood).
  • Zinc: Acrodermatitis enteropathica, ↓wound healing, alopecia, diarrhea, anosmia. 📌 "Zinc for Zmell (smell) and Zaste (taste)".
  • Copper: Menkes disease (XLR, ↓ATP7A, kinky hair, neurodegeneration), Wilson's disease (AR, ↓ATP7B, Kayser-Fleischer rings).
  • Selenium: Keshan disease (cardiomyopathy), Kashin-Beck disease (osteoarthropathy).
  • Fluoride: Deficiency → dental caries. Excess → fluorosis.
  • Obesity:
    • Body Mass Index (BMI) ≥ 30 kg/m² ($BMI = \frac{weight(kg)}{height(m)^2}$).
    • ↑Risk: Type 2 DM, cardiovascular disease, hypertension, dyslipidemia, NAFLD, certain cancers.
    • Hormones: Leptin (adipocytes, ↓appetite), Ghrelin (stomach, ↑appetite).
    • Metabolic Syndrome: Central obesity + ≥2 of: ↑Triglycerides (≥150 mg/dL), ↓HDL (<40 mg/dL men, <50 mg/dL women), ↑BP (≥130/85 mmHg), ↑Fasting glucose (≥100 mg/dL). Obesity-related conditions

⭐ Acrodermatitis enteropathica, due to zinc deficiency, classically presents with periorificial and acral dermatitis, alopecia, and diarrhea, often after weaning in infants with inherited defects in zinc absorption or in acquired deficiency states (e.g., TPN without zinc).

High‑Yield Points - ⚡ Biggest Takeaways

  • Kwashiorkor: Severe protein deficiency with edema, fatty liver, skin lesions (flaky paint).
  • Marasmus: Overall calorie/protein deficiency causing severe muscle wasting, loss of fat, no edema.
  • Vitamin A deficiency: Leads to night blindness (nyctalopia), xerophthalmia, Bitot's spots, keratomalacia.
  • Vitamin D deficiency: Causes Rickets in children (e.g., bowed legs) and Osteomalacia in adults.
  • Vitamin C deficiency (Scurvy): Results in defective collagen synthesis, bleeding gums, petechiae, poor wound healing.
  • Thiamine (B1) deficiency: Manifests as Beriberi (wet/dry) and Wernicke-Korsakoff syndrome.
  • Niacin (B3) deficiency (Pellagra): Characterized by the 3 Ds: Dermatitis, Diarrhea, Dementia.

Practice Questions: Nutritional Diseases

Test your understanding with these related questions

Dermatitis may be a clinical manifestation of deficiency states of all of the following nutrients except -

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Flashcards: Nutritional Diseases

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_____ is an iron-dependent pathway of cell death induced by lipid peroxidation.

TAP TO REVEAL ANSWER

_____ is an iron-dependent pathway of cell death induced by lipid peroxidation.

Ferroptosis

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