Micronutrient deficiencies

Iron Deficiency - The Pale Story

• Etiology: Most common nutritional anemia worldwide.
  • Causes: Inadequate intake, prematurity, exclusive breastfeeding >6mo, malabsorption (celiac disease), chronic blood loss (hookworm).
• Clinical Features:
  • Pallor, fatigue, irritability.
  • Pica (pagophagia: ice), koilonychia (spoon nails), glossitis.
  • Plummer-Vinson syndrome: triad of dysphagia, esophageal webs, and IDA.
• Labs & Diagnosis:
  • Microcytic hypochromic anemia (↓ MCV, ↓ MCH).
  • ↓ Serum Ferritin (<15 ng/mL), ↓ Serum Iron, ↑ TIBC.
• Treatment: Oral elemental iron (3-6 mg/kg/day).

⭐ High-Yield: The earliest biochemical marker to decrease in iron deficiency is serum ferritin, reflecting depleted iron stores before anemia is apparent.

Vitamin A - See The Light

• Function: Essential for vision (retinal pigment), immune function, and epithelial cell integrity.
• Ocular Manifestations (Xerophthalmia):
  • XN: Night blindness (earliest symptom).
  • X1A/B: Conjunctival xerosis & Bitot’s spots.
  • X2/X3: Corneal xerosis, ulceration & keratomalacia.
  • XS/XF: Corneal scarring & xerophthalmic fundus.
• Systemic: Follicular hyperkeratosis (phrynoderma), impaired immunity.
• Diagnosis: Serum retinol < 20 µg/dL.
• Treatment (WHO Schedule): Oral Vitamin A on days 0, 1, and 14.
  • <6 mo: 50,000 IU
  • 6-12 mo: 100,000 IU

  • 1 yr: 200,000 IU

⭐ Bitot's Spots (X1B): Pathognomonic. Triangular, pearly-white/yellowish, foamy plaques of keratinized epithelium, classically on the temporal bulbar conjunctiva.

Vitamin D & Calcium - Rickets Rules

• Biochemistry: ↓ Ca²⁺, ↓ PO₄³⁻, ↑ Alkaline Phosphatase (ALP), ↑ PTH.
  • ALP is the earliest marker to ↑.
• Clinical Features:
  • Early: Craniotabes, wrist widening.
  • Late: Rachitic rosary, Harrison's sulcus, delayed fontanelle closure, genu varum/valgum.
• X-Ray Findings (Metaphysis): Cupping, fraying, splaying.
  • Looser's zones (pseudofractures) in osteomalacia.

• Treatment (Nutritional Rickets):
  • Stoss Therapy: 600,000 IU Vitamin D₃ single dose.
  • Daily: 3000-5000 IU for 6 weeks, then 400 IU prophylaxis.
  • Always supplement with Calcium.

⭐ First radiological sign of healing is the appearance of the line of provisional calcification (usually within 2-4 weeks).

• VDDR-II: Features rickets + alopecia + very high 1,25(OH)₂D levels due to receptor defect.

Iodine & Zinc - The Essential Trace

• Iodine Deficiency Disorders (IDD)

  • Manifestations: Goiter, hypothyroidism, and cretinism (neurologic/myxedematous).
  • Pathophysiology: ↓ Thyroid hormone synthesis → ↑ TSH.
  • Diagnosis: Median urinary iodine < 100 µg/L.
  • Prevention: Iodized salt (>15 ppm at consumer level).

• Zinc Deficiency

  • Classic Triad: Acrodermatitis enteropathica (periorificial/acral rash), alopecia, diarrhea.
  • Other signs: Growth retardation, immune dysfunction.

  ⭐ High-Yield: Zinc supplementation (10-20 mg/day for 10-14 days) is crucial in acute diarrhea, reducing duration and severity.

High‑Yield Points - ⚡ Biggest Takeaways

• Vitamin A deficiency presents with Bitot's spots and keratomalacia; the first dose is given at 9 months with the measles vaccine.
• Rickets (Vitamin D deficiency) shows cupping, fraying, and splaying of metaphysis on X-ray, with rachitic rosary clinically.
• Scurvy (Vitamin C deficiency) is marked by bleeding gums, corkscrew hair, and subperiosteal hemorrhages.
• Iron deficiency, the most common nutritional disorder, causes microcytic hypochromic anemia; serum ferritin is the best screening test.
• Iodine deficiency is the most common preventable cause of intellectual disability (cretinism).
• Zinc deficiency classically presents as acrodermatitis enteropathica with periorificial dermatitis.