Contents

Search

folate deficiency

Etiology: 1) alcoholism (90%) 2) malabsorption 3) pregnancy 4) desquamatory skin diseases (psoriasis) 5) hemolytic anemia (sickle cell disease) 6) pharmaceutical agents a) methotrexate b) trimethoprim is a weak folate antagonist & rarely causes folate deficiency without coexisting causes c) sulfasalazine inhibits folate absorption [4] Clinical manifestations: - megalobastic anemia* - paresthesia* [1] - glossitis* [3] - angular stomatitis [3] - GI symptoms of nausea, vomiting, abdominal pain, & diarrhea, especially after meals with anorexia & weight loss may be due to underlying malabsorption that may be causing the folate depletion - neuropsychiatric symptoms of cognitive impairment & depression* * may be due to concurrent vitamin B12 deficiency Laboratory: 1) serum folate is generally low - but may be normal after a single folate-containing meal in patients with chronic folate deficiency [1] 2) erythrocyte folate is a better indicator of folate status [1] 3) complete blood count (CBC) may show macrocytic anemia 4) peripheral smear may show macrocytes & hypersegmented neutrophils 5) elevated serum homocysteine - sensitivity & specificity of >90& for folate deficiency [1] - useful for low normal serum folate [1] 6) exclude vitamin B12 deficiency a) serum methylmalonic acid - NOT sensitive to folate deficiency b) serum vitamin B12 7) deoxyuridine suppression test (dUST) {rarely done} 8) bone marrow biopsy unnecessary [1] Differential diagnosis: - vitamin B12 deficiency Management: 1) treat etiology - exclude & treat vitamin B12 deficiency prior to treatment of folate deficiency 2) folate supplementation 1-5 mg/day [1] - oral therapy is effective even in malabsorption syndrome - a therapeutic trial of folate supplementation is indicated after vitamin B12 deficiency is excluded prior to workup for folate deficiency [1] 3) folate can improve anemia in patients with vitamin B12 deficiency but will not improve, slow or prevent neuropathology prevention: - fortification of foods with folic acid [2] - FDA approves fortification of corn masa flour with folic acid, up to 0.7 mg per pound, similar to what is found in other fortified flours & grains [2]

Related

folate in serum/plasma folic acid; folate; vitamin B9 megaloblastic anemia vitamin B12 deficiency

General

vitamin B deficiency

References

  1. Medical Knowledge Self Assessment Program (MKSAP) 11, 15, 16, 17. 18, 19. American College of Physicians, Philadelphia 1998, 2009, 2012, 2015, 2018, 2022. - Medical Knowledge Self Assessment Program (MKSAP) 19 Board Basics. An Enhancement to MKSAP19. American College of Physicians, Philadelphia 2022
  2. Kelley KJ, Sofair A, Chavey WE Folic Acid Fortification Approved for Corn Masa Flour Physician's First Watch, April 15, 2016 David G. Fairchild, MD, MPH, Editor-in-Chief Massachusetts Medical Society http://www.jwatch.org - FDA News Release. April 14, 2016 FDA approves folic acid fortification of corn masa flour http://www.fda.gov/NewsEvents/Newsroom/PressAnnouncements/ucm496104.htm
  3. Besa EC Fast Five Quiz: Vitamin B9 (Folate) Medscape. Nov7, 2022 https://reference.medscape.com/viewarticle/983190
  4. NEJM Knowledge+ Gastroenterology