Learn with Med Nuggets: Vitamin B Overview

Introduction

• Discussion on Vitamin B types, deficiencies, symptoms, and mnemonics.

Types of Vitamin B

• Vitamin B1: Thiamine
• Vitamin B2: Riboflavin
• Vitamin B3: Niacin
• Vitamin B5: Pantothenic Acid
• Vitamin B6: Pyridoxine
• Vitamin B7: Biotin
• Vitamin B9: Folic Acid
• Vitamin B12: Cobalamin

Functions of Vitamin B

• Convert carbohydrates to glucose for energy.
• Metabolize fats and proteins.
• Essential for healthy skin, hair, eyes, liver.
• Important for brain and nervous system functioning.

Vitamin B Deficiencies and Symptoms

Vitamin B1 (Thiamine)

• Causes: Alcoholism, malabsorption, diarrhea, vomiting, bariatric surgery.
• Important Note: Give thiamine before dextrose in malnourished/alcohol-dependent patients to prevent Wernicke encephalopathy.
• Symptoms:
  • Beriberi:
    • Dry Beriberi: Symmetrical peripheral neuropathy.
    • Wet Beriberi: High output heart failure.
  • Wernicke Encephalopathy: Confusion, ataxia, ophthalmoplegia.
  • Korsakoff Syndrome: Personality changes, amnesia, confabulations.

Vitamin B2 (Riboflavin)

• Mnemonic: "Flavin" sounds like "flavors"; B2 is "two flavors" like chocolate and vanilla.
• Symptoms: Chelitis, corneal vascularization (Mnemonic: The two C's of B2).

Vitamin B3 (Niacin)

• Causes: Alcoholism, tryptophan deficiency (Hartnup disease, carcinoid syndrome).
• Requirement: Vitamin B6 for niacin synthesis from tryptophan.
• Symptoms: Diarrhea, dementia, dermatitis (Mnemonic: The 3D's of B3).

Vitamin B5 (Pantothenic Acid)

• Mnemonic: "Pentagon" for "Pentothenic" and B5 has five sides.
• Symptoms: Rare, includes adrenal insufficiency, enteritis, alopecia, dermatitis.

Vitamin B6 (Pyridoxine)

• Causes: Drugs like isoniacin, oral contraceptives.
• Symptoms: Sideroblastic anemia, peripheral neuropathy (can be irreversible).
• Important Note: Administer pyridoxine with isoniacin to prevent neuropathy.

Vitamin B7 (Biotin)

• Causes: Excessive raw egg whites (avidine), prolonged antibiotic use.
• Symptoms: Various symptoms (not critical for exams).

Vitamin B9 (Folate)

• Causes: Poor diet, malabsorption (celiac disease, inflammatory bowel disease).
• Drugs: Methotrexate, phenytoin, trimethoprim, sulfonamides.
• Symptoms: Megaloblastic anemia, neural tube defects in babies.

Vitamin B12 (Cobalamin)

• Found In: Animal products; deficiency risk in vegetarians.
• Functions: Myelination of nervous system, red blood cell formation.
• Symptoms: Megaloblastic anemia, Subacute combined degeneration (spinal cord issues).
• Causes: Malabsorption, vegan diet, anorexia, increased demand, drugs like metformin.
• Differentiation: From B9; B12 has neurological symptoms and high methyl malonic acid levels, develops over years due to large body stores.

Conclusion

• Summary of Vitamin B types and their importance.
• Emphasis on recognizing deficiency symptoms for clinical and board examinations.