USMLE

Vitamin C (Ascorbic Acid) Deficiency and Excess

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Vitamins
  1. Vitamin B1 (Thiamine) Biochemistry
  2. Vitamin B1 (Thiamine) Deficiency
  3. Vitamin B2 (Riboflavin)
  4. Vitamin B3 (Niacin) Biochemistry
  5. Vitamin B3 (Niacin) Deficiency and Excess
  6. Hartnup Disease
  7. Vitamin B5 (Pantothenic Acid)
  8. Vitamin B6 (Pyridoxine)
  9. Vitamin B7 (Biotin)
  10. Vitamin B9 (Folate)
  11. Vitamin B12 (Cobalamin) Biochemistry
  12. Vitamins B9 and B12 Deficiencies
  13. Vitamin A (Retinol) Biochemistry
  14. Vitamin A (Retinol) Deficiency and Excess
  15. Vitamin C (Ascorbic Acid) Biochemistry
  16. Vitamin C (Ascorbic Acid) Deficiency and Excess
  17. Vitamin D Biochemistry
  18. Vitamin D Deficiency and Excess
  19. Vitamin E (Tocopherol/Tocotrienol)
  20. Vitamin K Biochemistry
  21. Vitamin K Deficiency
  22. Zinc
  23. Kwashiorkor and Marasmus

Summary

Vitamin C (Ascorbic Acid) imbalances can occur as either deficiency or excess. Deficiency of Vitamin C results in the clinical syndrome of scurvy. Symptoms include easy bleeding, swollen gums, weakened immune response, anemia, and coiled or “corkscrew” hairs. The bleeding abnormalities can manifest as bruising, petechiae, hemarthrosis, subperiosteal and perifollicular hemorrhages. Vitamin C excess is rare and presents clinically with fatigue, nausea/vomiting, calcium oxalate kidney stones, and increased risk for iron toxicity (hemochromatosis).

Key Points

  • Ascorbic Acid (Vitamin C) Deficiency
    • Rare in developed countries, but seen in malnourished (elderly, alcoholics, poor/homeless)
    • Clinical syndrome of scurvy
      • impaired collagen synthesis weakens vascular beds
        • subperiosteal hemorrhages
        • hemarthrosis (bleeding into joint spaces)
        • swollen, painful gums
        • bruising, petechiae, and perifollicular hemorrhages
      • poor wound healing
      • weakened immune response
      • anemia, coiled “corkscrew” hair also seen
  • Ascorbic Acid (Vitamin C) Excess (low-yield)
    • diarrhea, abdominal bloating, nausea/vomiting, fatigue
    • increased risk of iron toxicity (transfusions, hemochromatosis)
    • may predispose to calcium oxalate nephrolithiasis


Find Vitamin C Deficiency and other Vitamins among Pixorize's visual mnemonics for the USMLE Step 1 and NBME shelf exams.