2025 – PAGE 223 – VITAMIN AND NUTRITIONAL DISORDERS
PYRIDOXINE (B6) DEFICIENCY
Pyridoxine (Vitamin B6) deficiency can result in neuropathy, rashes, seizures, and tongue swelling. Isoniazid (INH) can lead to pyridoxine deficiency. This is why your medical school probably taught you that patients on isoniazid therapy for tuberculosis should always be placed on pyridoxine supplements.
PEARL: Know that pyridoxine is the same thing as B6 (higher yield than others).
MNEMONIC: pyridoXine = vitamin b siX
(DOUBLE TAKE) BIOTIN/BIOTINIDASE (B7) DEFICIENCY
Biotin and biotinidase deficiencies may present with a RASH + ALOPECIA + NEUROLOGIC SIGNS (ataxia, coma, etc.). Patients may also have lactic acidosis. Treat with biotin.
MNEMONICS: Imagine the bio-TIN MAN from The Wizard of Oz walking with an ATAXIC gait as he SCRATCHES his bare arm (NO HAIR)! Also, think of biotin as bio7in to remember that this is vitamin B7.
(DOUBLE TAKE) FOLATE (B9) DEFICIENCY
Folate (Vitamin B9) deficiency results in a macrocytic anemia and glossitis (red, swollen tongue). In pregnant women, deficiency can lead to neural tube defects (such as spina bifida) in the unborn fetus.
PEARLS: Look for a diet poor in veggies or a history of goat milk ingestion.
PEARL: Both B12 and Folate deficiency can lead to hypersegmented neutrophils and neural tube defects. Deficiency of either can be masked by treatment with the other. Use the symptoms, diet history, and blood testing to get the diagnosis right the first time!
MNEMONIC: FOLATE deficiency form FOLIAGE (veggies) deficiency!
IMAGE: www.pbrlinks.com/FOLATE1 (hypersegmented neutrophils)
(DOUBLE TAKE) B12 DEFICIENCY (AKA CYANOCOBALAMIN DEFICIENCY)
Cyanocobalamin (Vitamin B12) deficiency can present as a macrocytic anemia in a patient with neurologic issues (paresthesias, ataxia, and decreased reflexes). This anemia may be called pernicious anemia. Maternal B12 deficiency can result in neural tube defects (e.g., spina bifida) in the unborn fetus. Common causes of B12 deficiency include diet (VEGANS) and an inability to absorb B12. Intrinsic factor is made by parietal cells in the stomach and is needed to absorb B12. If a child is born with INTRINSIC FACTOR DEFICIENCY, or if there are autoantibodies to intrinsic factor, or if gastric surgery results in a lack of parietal cells, then the child can develop B12 deficiency. B12 is absorbed in the terminal ileum, which means B12 deficiency can also result from bacterial overgrowth, inflammatory bowel disease (IBD), or short bowel syndrome. Treat with IM B12 injections.
PEARLS: B12 will likely be seen on the exam. KNOW that B12 = cyanocobalamin. In a B12-deficient patient, if the macrocytic anemia mistakenly treated with folate supplements, the B12 deficiency will be MASKED as the megaloblastic anemia improves. This can eventually lead to irreversible neurologic damage.
VITAMIN C DEFICIENCY AND EXCESS
- VITAMIN C DEFICIENCY can lead to SCURVY and OSTEOPENIA.
- SCURVY: Look for poor wound healing, skin spots, spongy/bleeding gums, or bone pain.
- OSTEOPENIA: In infants, osteopenia related to Vitamin C deficiency can lead to brittle bones and fractures.
- PEARL: If you encounter a patient with bone issues and bleeding gums, look for Vitamin C deficiency as the etiology.
- VITAMIN C EXCESS may result in nephrolithiasis. In G6PD patients, it may result in hemolysis.