Epidemiology

Etiology

severe malnutrition (e.g., due to alcoholism, illicit drug use, and/or psychiatric illness)

Pathophysiology

Vitamin C functions

• Hydrophilic antioxidant
• Conversion of dopamine to norepinephrine: coenzyme in dopamine β-hydroxylase
• collagen synthesis: coenzyme in hydroxylation reaction of proline and lysine
• Facilitates iron absorption (keeps iron in Fe2+ reduced state)

Clinical features

• Scurvy: clinical manifestation of vitamin C deficiency, which leads to impaired collagen synthesis and easily damaged connective tissue
  • Follicular hyperkeratosis, perifollicular hemorrhage, coiled “corkscrew” hair
  • Intramuscular or subperiosteal hemorrhages, especially in the lower extremities due to increased hydrostatic pressure. This results in pain and difficulty with ambulation, which may be the presenting symptoms in children.
  • Gingivitis, swollen gums
  • Mucosal bleeding, easy bruising, petechiae
  • Impaired wound healing
  • Arthralgia, hemarthrosis
  • Signs of anemia (fatigue, paleness)
    • Normocytic anemia: decreased iron absorption in the small intestine
    • Macrocytic anemia: decreased conversion of folate into its active metabolite
• Poor immune response

Diagnostics

Treatment

Vitamin C toxicity

• Nausea, vomiting
• Diarrhea, bloating
• Fatigue
• ↑ Risk of iron toxicity in transfusion patients and hereditary hemochromatosis due to increased absorption of dietary iron
• Nephrolithiasis due to ↑ calcium oxalate formation
  • excess oxalate from vitamin C metabolism