Updated: 4/5/2021

Folic Acid Deficiency

0%
Topic
Review Topic
0
0
N/A
N/A
Questions
5
0
0
100%
0%
Evidence
6
0
0
Topic
Snapshot
  • A 50-year-old alcoholic man presents to the hospital in a florid alcohol withdrawal. He confabulates and trembles uncontrollably. He is started on supportive therapy for now. An alcohowal withdrawal score is done regularly to assess for the need for medical therapy. In the meantime, bloodwork comes back with megaloblastic anemia and increased homocysteine and normal methylmalonic acid. He is immediately started on folic acid supplementation.
Introduction

  • Folic acid (or vitamin B9) is found in leafy green vegetables
  • Pathogenesis
    • folic acid is absorbed in jejunum and ileum
      • used in tetrahydrofolate (THF) as coenzyme
      • important for DNA and RNA synthesis
      • small reserve pool in liver
    • causes megaloblastic anemia due to impaired DNA synthesis
  • Epidemiology
    • most common vitamin deficiency in the US
    • most common cause of megaloblastic anemia
    • can manifest after 4 months (depleted storage from liver) 
  • Associated conditions
    • chronic hemolytic anemias
    • malnutrition
      • alcoholism
      • elderly
      • psychiatric comorbidity
    • pregnancy
      • increased folate requirement
    • malabsorption
      • celiac disease
      • tropical sprue
    • pregnancy
      • risk of neural tube defects in infant
    • certain drugs (anti-folates)
      • phenytoin
      • methotrexate
      • trimethoprim
Presentation
  • Symptoms
    • no neurological symptoms (unlike in B12 deficiency)
    • anemia 
      • fatigue
      • weakness
      • shortness of breath
  • Physical exam
    • glossitis
    • pallor
Evaluation
  • Peripheral blood smear 
    • hypersegmented lobes seen in neutrophils
    • macrocytosis
    • basophilic stippling
  • Serum 
    • ↓ folic acid
    • ↑ homocysteine
    • NORMAL methylmalonic acid (MMA)
      • unlike in vitamin B12 deficiency, which has ↑MMA
    • ↓ reticulocyte count
    • may see pancytopenia due to destruction of abnormal cells
    • increased MCV
      • folate is more readily depleted than B12
  • Also test for B12 deficiency and TSH (to rule out hypothyroidism)
Differential
  • Vitamin B12 deficiency
  • Pernicious anemia
  • Other causes of macrocytic anemia
    • alcoholism
    • hypothyroidism
    • liver dysfunction
    • drugs 
Treatment
  • Folic acid supplementation
  • Eat a more balanced diet
    • fruits and vegetables
Prognosis, Prevention, and Complications
  • Prognosis
    • good with supplementation
  • Prevention
    • folic or folinic acid supplementation, especially if chronically on drugs such as methotrexate
  • Complications
    • neural tube defects in infant if deficient during pregnancy
    • in the setting of a B12 deficiency, the anemia can correct with aggressive folate supplementation but the patient will still be at risk for neurological complications of B12 deficiency including peripheral neuropathy and posterior column defects due to deficiencies in myelin production

Please rate topic.

Average 5.0 of 5 Ratings

Questions (5)
Question locked
Sorry, this question is for
PEAK Premium Subscribers only
Upgrade to PEAK

(M2.HE.16.4692) A 29-year-old woman, who is 16 weeks into her pregnancy, comes to your office with symptoms of fatigue and dizziness. She has been taking iron, but no other vitamins or minerals. She denies any medical history and states all her physician visits before pregnancy were normal. She also denies taking any supplements or medications. On exam, she has no neurological deficits, but her complete blood count (CBC) is significant for hemoglobin of 10.2 g/dL. The mean corpuscular volume (MCV) of her red blood cells (RBCs) is 105 fl, and Figure A illustrates the peripheral blood smear of the patient. Her methylmalonic acid level is normal. What is the most likely cause of her condition?

QID: 107667
FIGURES:
1

Iron deficiency

0%

(0/0)

2

Thalassemia

0%

(0/0)

3

Vitamin B12 deficiency

0%

(0/0)

4

Folate deficiency

0%

(0/0)

5

Anemia of chronic disease

0%

(0/0)

M 6 B

Select Answer to see Preferred Response

(M3.HE.16.112) A 52-year-old female presents to her rheumatologist with complaints of fatigue, a sore mouth, and occasional nausea and abdominal pain over the past several months. Her medical history is significant for 'pre-diabetes' treated with diet and exercise, hypertension managed with lisinopril, and rheumatoid arthritis well-controlled with methotrexate. Her vital signs are within normal limits. Physical examination is significant for an overweight female with the findings as shown in Figures A and B. The physician orders laboratory work-up including complete blood count with peripheral blood smear as well as basic metabolic panel and serum methylmalonic acid and homocysteine levels. These tests are significant for a hematocrit of 29.5, a decreased reticulocyte count, normal serum methylmalonic acid level, increased homocysteine level, as well as the peripheral smear shown in Figure C. Which of the following could have reduced this patient's risk of developing their presenting condition?

QID: 103475
FIGURES:
1

Discontinuation of lisinopril and initiation of triamterene for blood pressure control

0%

(0/0)

2

Administration of daily, high-dose PO vitamin B12

0%

(0/0)

3

Monthly injection of vitamin B12 supplementation

0%

(0/0)

4

Initiation of folinic acid

0%

(0/0)

5

Addition of metformin

0%

(0/0)

M 11 B

Select Answer to see Preferred Response

(M2.HE.15.96) A 34-year-old female with a past medical history of a gastric sleeve operation for morbid obesity presents for pre-surgical clearance prior to a knee arthroplasty. Work-up reveals a hemoglobin of 8.7 g/dL, hematocrit of 26.1%, and MCV of 106 fL. With concern for folate deficiency, she is started on high dose folate supplementation, and her follow-up labs are as follows: hemoglobin of 10.1 g/dL, hematocrit of 28.5%, and MCV of 96 fL. She is at risk for which long-term complication?

QID: 104736
1

Neural tube defects

10%

(3/30)

2

Macular degeneration

3%

(1/30)

3

Peripheral neuropathy

73%

(22/30)

4

Hypothyroidism

7%

(2/30)

5

Microcytic anemia

3%

(1/30)

M 8 C

Select Answer to see Preferred Response

(M2.HE.14.12) An 82-year-old woman is brought to the emergency room after her neighbor saw her fall in the hallway. She lives alone and remarks that she has been feeling weak lately. Her diet consists of packaged foods and canned meats. Her temperature is 97.6°F (36.4°C), blood pressure is 133/83 mmHg, pulse is 95/min, respirations are 16/min, and oxygen saturation is 98% on room air. Physical exam is notable for a weak, frail, and pale elderly woman. Laboratory studies are ordered as seen below.

Hemoglobin: 9.1 g/dL
Hematocrit: 30%
Leukocyte count: 6,700/mm^3 with normal differential
Platelet count: 199,500/mm^3
MCV: 110 fL

Which of the following is the most likely deficiency?

QID: 104652
1

Folate

25%

(2/8)

2

Niacin

0%

(0/8)

3

Thiamine

62%

(5/8)

4

Vitamin B12

0%

(0/8)

5

Zinc

12%

(1/8)

M 6 E

Select Answer to see Preferred Response

Evidence (6)
EXPERT COMMENTS (5)
Private Note