Pathophysiology
Clinical meaning
the clinician manages nutritional pharmacology and micronutrient deficiency states through understanding of nutrient biochemistry, absorption mechanisms, and evidence-based supplementation. Micronutrient deficiencies manifest with specific clinical syndromes: iron deficiency (microcytic anemia, koilonychia, pica, angular cheilitis -- serum ferritin less than 30 mcg/L is most sensitive indicator; oral iron therapy with ferrous sulfate 300 mg daily taken on empty stomach with vitamin C to enhance absorption, or IV iron for intolerance or malabsorption), vitamin B12 deficiency (megaloblastic anemia, subacute combined degeneration of the spinal cord with peripheral neuropathy and posterior column dysfunction, glossitis -- serum B12, methylmalonic acid and homocysteine elevation; caused by pernicious anemia, metformin use, PPI use, vegan diet; treatment IM cyanocobalamin 1000 mcg daily for 7 days then weekly then monthly, or high-dose oral 1000-2000 mcg daily), vitamin D deficiency (osteomalacia, secondary hyperparathyroidism, increased fracture risk -- 25-hydroxyvitamin D level; treatment vitamin D3 at doses based on severity), and folate deficiency (megaloblastic anemia without neurological findings -- distinguished from B12 deficiency by normal methylmalonic acid; critical to supplement before conception to prevent neural tube defects). The clinician evaluates nutritional...