Epidemiology

Etiology

• Malnutrition
• Heavy drinking
• Chronic renal failure
• Chronic hepatitis
• Drug interactions
  • Isoniazid
  • Oral contraceptives

Pathophysiology

Active form: pyridoxal phosphate (PLP)

Vitamin B6 functions

• PLP is a coenzyme for the following reactions:
  • Transamination (e.g., AST and ALT)
  • Decarboxylation
  • Amino acid metabolism
  • Glycogenolysis (glycogen phosphorylase)
• Involved in the synthesis of:
  • Heme, see Heme synthesis
  • Histamine
  • Niacin
  • Gluthathione
  • Cystathionine
  • Neurotransmitters, including:
    • Serotonin
    • Dopamine
    • Epinephrine
    • Norepinephrine
    • GABA

Clinical features

• Cheilosis, glossitis, stomatitis
• Sideroblastic anemia: Vitamin B6 deficiency causes heme synthesis dysfunction with impaired transfer of iron to hemoglobin, which ultimately leads to iron accumulation in RBCs.
• Irritability, seizures, peripheral neuropathy
  • Because involved in the synthesis of neurotransmitters
• Seborrheic dermatitis
  

Diagnostics

Treatment