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'''For patient information click [[Folate deficiency (patient information)|here]]'''
'''For patient information click [[Folate deficiency (patient information)|here]]'''


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{{CMG}} '''Editor''' : [https://www.wikidoc.org/index.php?title=L.Farrukh&action=edit&redlink=1 L.Farrukh]​


{{SK}} Folic acid deficiency
{{SK}} Folic acid deficiency
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==[[Folate deficiency pathophysiology|Pathophysiology]]==
==[[Folate deficiency pathophysiology|Pathophysiology]]==
Folate deficiency can occur when the body's need for folate is increased, when dietary intake or absorption of folate is inadequate, or when the body loses more folate than it acquires from the diet. Certain medications (e.g Anticonvuslants, Methotrexate, Sulfasalazine) can also interfere with the folate metabolism in our body. The deficiency is more common among pregnant women, infants, children, and adolescents. Poor diet and chronic alcoholism is also an important cause of folate deficiency.
==[[Folate deficiency differential diagnosis|Differentiating Folate deficiency from other Diseases]]==
==[[Folate deficiency epidemiology and demographics|Epidemiology and Demographics]]==
==[[Folate deficiency risk factors|Risk Factors]]==
==[[Folate deficiency screening|Screening]]==
==[[Folate deficiency natural history, complications and prognosis|Natural History, Complications and Prognosis]]==
==Treatment==


Moreover, a defect in homocysteine methyltransferase or a deficiency of cobalamine (B-12) may lead to "folate trap". In vitamin B12 deficiency, the utilization of Methyl THF in the B-12 dependent methylation of homocysteine to methionine is impaired. THF is converted to methyl-THF which cannot be further metabolized, and serves as a sink of THF that leads to a subsequent deficiency in folate. Thus, a deficiency in B-12 can generate a large pool of methyl-THF that is unable to undergo reactions and resembles folate deficiency. Folate is absorbed in the small intestine, mainly in the Jejunum, after binding to specific receptor proteins. Inflammatory or degenerative changes in the small intestine, such as [[Crohn's disease]], chronic enteritis, [[Celiac disease]], may reduce the folate uptake, which gives rise to folate deficiency.
==[[Folate deficiency cost-effectiveness of therapy|Cost-Effectiveness of Therapy]]==
According to a study, the greatest benefits from fortification were predicted in MI prevention, with 16,862 and 88,172 cases averted per year in steady state for the 140-mcg and 700-mcg fortification levels, respectively. These projections were 6,261 and 38,805 for colon cancer and 182 and 1,423 for Neural tube defects , while 15 to 820 additional B-12 cases were predicted. Compared with no fortification, all post-fortification strategies provided QALY gains and cost savings for all subgroups, with predicted population benefits of 266,649 QALYs gained and $3.6 billion saved in the long run by changing the fortification level from 140-mcg/100-g enriched grain to 700-mcg/100-g.


=== Physiology ===
This study indicates that the health and economic gains of folic acid fortification far outweigh the losses for the U.S. population, and that increasing the level of fortification deserves further consideration to maximize net gains.
In human body folic acid serves a lot of functions such as :
* Production and maintenance of new cells
* DNA and RNA synthesis
* Carrying one-carbon groups for various methylation reactions
* Preventing changes to DNA, therefore, for preventing cancer
In adults, normal total body folate is between 10,000–30,000 micrograms (µg) with blood levels of greater than 7 nmol/L (3 ng/mL).


=== Dietary sources ===
==[[Folate deficiency future or investigational therapies|Future or Investigational Therapies]]==
Folate naturally occurs in a variety of foods, including dark green leaf vegetables, fruits , nuts, soybeans, dairy products, poultry, eggs, seafood, grains, and some beers. Avocado, beetroot, spinach, liver, yeast, asparagus, kale, and Brussels sprouts are among the foods that contain the highest levels of folate. Folate found in food is susceptible to high heat, UV light and may also be susceptible to damage by oxidation. Folic acid is also added to grain products and these fortified products make up a significant source of the population's folate intake. For example enriched flour and fortified rice typically contain folate.
Reticulocytosis can be assessed at the end of the first week of therapy. It is important to determine completeness of response after 8 weeks of therapy, when blood counts should have normalized. Homocysteine levels can be used to monitor response. Inadequate response indicates a coexisting cause of anemia, such as iron deficiency or vitamin B12 (cobalamin) deficiency.                                                                                    


=== Absorption and Bioavailability ===
==Case Studies==
Folates exist as polyglutamates in the diet and need to be enzymatically converted into monoglutamate forms by folate reductase. This takes place in the jejunum where the absorption of folate also occurs. Natural folates are quite unstable and they lose their vitamin activity during food processing. In vegetables the folates can be destroyed by cooking and in grains/cereals folates can be broken down during milling and baking.
[[Folate deficiency case study one|Case #1]]


Folate itself is not biologically active, but is converted into dihydrofolate, by the enzyme dihydrofolate synthetase, in the liver. This is then converted into tetrahydrofolate (THF) by dihydrofolate reductase.Tetrahydrofolate is converted into 5,10-methylenetetrahydrofolate by serine hydroxymethyltransferase. Tetrahydrofolate and its methylated forms then play a crucial role as methyl donors in different reactions that occurthroughout the body.  
===Case presentation===
A year 30 year old woman (gravida 4, para 3) was admitted at 33 weeks gestation with worsening fatigue and shortness of breath on exertion over a month. Recently she noticed occasional gum bleeding and easy bruising. She reported that her appetite had decreased and attributed this to pregnancy related nausea. She denied any fever or night sweats. There was no history of alcohol abuse or dietary restriction. She had no history of any medication and all her previous pregnancies had been uneventful.


Absolute folate deficiency is usually associated with dietary insufficiency but may it also be caused by impairment in the folate absorption. This can occur due to gastrointestinal diseases or certain genetic defects that impair the absorption in the gastrointestinal tract. Other causes may include mutations causing impaired activity of the enzymes involved in folate metabolism. Low levels of blood folate can lead to increased plasma homocysteine, impaired DNA synthesis and DNA repair and may promote the development of some forms of cancers as well.
=====Examination=====
She was pale with few petechiae seen on the buccal mucosa. Her blood pressure was 120/80 mm Hg with a trace of protein detected on urine dipstick. There was no lymphadenopathy or splenomegaly palpable. The remainder of the clinical examination was unremarkable.


==[[Folate deficiency causes|Causes]]==
===Investigations===
A full blood count revealed a macrocytosis with a severe pancytopenia. Haemoglobin of 70 g/L with a MCV of 105 fL , platelets were decreased 14×109/L and neutrophils were also low 0.5×109/L (1.7–7.5×109). Her last recorded haematological profile 5 months ago was within normal limits. Reticulocyte count was decreased 8×109/L. RFTs, LFTs and coagulation screen were normal. A blood film showed  macrocytes. Hypersegmented neutrophils and thrombocytopenia were also seen. Ferritin and vitamin B12 level were normal. Serum folate was subtherapeutic at 2.5 ng/mL (4.6–18.7 ng/mL). An autoimmune screen was unremarkable. Antitransglutaminase antibodies were also negative.A bone marrow aspirate was hypercellular with megaloblastoid features. Early erythroid precursors and giant metamyelocytes were seen.


==[[Folate deficiency differential diagnosis|Differentiating Folate deficiency from other Diseases]]==
===Treatment===
She was transfused with two units packed red cells and one adult dose of platelets. She was then started on folic acid 5 mg daily. A single dose of 1 mg hydroxycobalamin  was also administered. A week later, the neutrophil count had recovered (1.5×109/L) with an increase in platelet count (25×109/L)


==[[Folate deficiency epidemiology and demographics|Epidemiology and Demographics]]==
===Outcome and follow-up===
Her counts normalized and she gave birth to a healthy male baby. His full blood count was normal and there were no signs of neurological compromise.


==[[Folate deficiency risk factors|Risk Factors]]==
===Discussion===
Folate deficiency is a cause of macrocytosis in pregnancy. If left untreated, it could progress to severe megaloblastic anaemia with pancytopenia. Peripheral blood film may reveal macrocytic anaemia and hyper-segmented neutrophils. Bone marrow examination could demonstrate megaloblastic changes reflecting ineffective haematopoiesis and resultant bone marrow failure.


==[[Folate deficiency screening|Screening]]==
In the majority of developed countries, folic acid supplementation (at least 400 µg) is recommended for 2–3 months prior to conception and throughout pregnancy into the postpartum period. This been adopted as a worldwide strategy to reduce the incidence of fetal neural tube defects (NTD) such as anencephaly, spina bifida and meningomyelocele. This may also lower the risk of other congenital anomalies and adverse pregnancy outcomes such as pontaneous abortions, placental abruption and low birth weight.


==[[Folate deficiency natural history, complications and prognosis|Natural History, Complications and Prognosis]]==
Folate deficiency is most often a result of poor dietary intake either alone or in combination with malabsorption or increased utilisation. Excess cell turnover may be physiological such as in pregnancy and lactation or pathological such as in haemolysis or chronic inflammatory disorders. Other causes of folate deficiency include excess urinary loss, drugs, long-term dialysis and alcoholism. While there is no requirement to measure serum folate routinely in pregnancy, testing should be sought in those with a history of poor or inadequate diet, any symptoms of malabsorption and those with an unexplained macrocytic anaemia. Hyperemesis during pregnancy and multiparity are also recognised as risk factors prompting investigation.
 
==Diagnosis==
[[Folate deficiency history and symptoms|History and Symptoms]] | [[Folate deficiency physical examination|Physical Examination]] | [[Folate deficiency laboratory findings|Laboratory Findings]] | [[Folate deficiency imaging findings|Imaging Findings]] | [[Folate deficiency other diagnostic studies|Other Diagnostic Studies]]
 
==Treatment==
[[Folate deficiency medical therapy|Medical Therapy]] | [[Folate deficiency primary prevention|Primary Prevention]] | [[Folate deficiency secondary prevention|Secondary Prevention]] | [[Folate deficiency cost-effectiveness of therapy|Cost-Effectiveness of Therapy]] | [[Folate deficiency future or investigational therapies|Future or Investigational Therapies]]
 
==Case Studies==
[[Folate deficiency case study one|Case #1]]





Latest revision as of 15:16, 6 September 2020

Folate deficiency
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Folic acid (B9)
ICD-10 D52 E53.8
ICD-9 266.2
DiseasesDB 4894
MedlinePlus 000354
MeSH D005494

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Editor-In-Chief: C. Michael Gibson, M.S., M.D. [1] Editor : L.Farrukh

Synonyms and keywords: Folic acid deficiency

Overview

Historical Perspective

Classification

Pathophysiology

Differentiating Folate deficiency from other Diseases

Epidemiology and Demographics

Risk Factors

Screening

Natural History, Complications and Prognosis

Treatment

Cost-Effectiveness of Therapy

According to a study, the greatest benefits from fortification were predicted in MI prevention, with 16,862 and 88,172 cases averted per year in steady state for the 140-mcg and 700-mcg fortification levels, respectively. These projections were 6,261 and 38,805 for colon cancer and 182 and 1,423 for Neural tube defects , while 15 to 820 additional B-12 cases were predicted. Compared with no fortification, all post-fortification strategies provided QALY gains and cost savings for all subgroups, with predicted population benefits of 266,649 QALYs gained and $3.6 billion saved in the long run by changing the fortification level from 140-mcg/100-g enriched grain to 700-mcg/100-g.

This study indicates that the health and economic gains of folic acid fortification far outweigh the losses for the U.S. population, and that increasing the level of fortification deserves further consideration to maximize net gains.

Future or Investigational Therapies

Reticulocytosis can be assessed at the end of the first week of therapy. It is important to determine completeness of response after 8 weeks of therapy, when blood counts should have normalized. Homocysteine levels can be used to monitor response. Inadequate response indicates a coexisting cause of anemia, such as iron deficiency or vitamin B12 (cobalamin) deficiency.                                                                                    

Case Studies

Case #1

Case presentation

A year 30 year old woman (gravida 4, para 3) was admitted at 33 weeks gestation with worsening fatigue and shortness of breath on exertion over a month. Recently she noticed occasional gum bleeding and easy bruising. She reported that her appetite had decreased and attributed this to pregnancy related nausea. She denied any fever or night sweats. There was no history of alcohol abuse or dietary restriction. She had no history of any medication and all her previous pregnancies had been uneventful.

Examination

She was pale with few petechiae seen on the buccal mucosa. Her blood pressure was 120/80 mm Hg with a trace of protein detected on urine dipstick. There was no lymphadenopathy or splenomegaly palpable. The remainder of the clinical examination was unremarkable.

Investigations

A full blood count revealed a macrocytosis with a severe pancytopenia. Haemoglobin of 70 g/L with a MCV of 105 fL , platelets were decreased 14×109/L and neutrophils were also low 0.5×109/L (1.7–7.5×109). Her last recorded haematological profile 5 months ago was within normal limits. Reticulocyte count was decreased 8×109/L. RFTs, LFTs and coagulation screen were normal. A blood film showed macrocytes. Hypersegmented neutrophils and thrombocytopenia were also seen. Ferritin and vitamin B12 level were normal. Serum folate was subtherapeutic at 2.5 ng/mL (4.6–18.7 ng/mL). An autoimmune screen was unremarkable. Antitransglutaminase antibodies were also negative.A bone marrow aspirate was hypercellular with megaloblastoid features. Early erythroid precursors and giant metamyelocytes were seen.

Treatment

She was transfused with two units packed red cells and one adult dose of platelets. She was then started on folic acid 5 mg daily. A single dose of 1 mg hydroxycobalamin was also administered. A week later, the neutrophil count had recovered (1.5×109/L) with an increase in platelet count (25×109/L)

Outcome and follow-up

Her counts normalized and she gave birth to a healthy male baby. His full blood count was normal and there were no signs of neurological compromise.

Discussion

Folate deficiency is a cause of macrocytosis in pregnancy. If left untreated, it could progress to severe megaloblastic anaemia with pancytopenia. Peripheral blood film may reveal macrocytic anaemia and hyper-segmented neutrophils. Bone marrow examination could demonstrate megaloblastic changes reflecting ineffective haematopoiesis and resultant bone marrow failure.

In the majority of developed countries, folic acid supplementation (at least 400 µg) is recommended for 2–3 months prior to conception and throughout pregnancy into the postpartum period. This been adopted as a worldwide strategy to reduce the incidence of fetal neural tube defects (NTD) such as anencephaly, spina bifida and meningomyelocele. This may also lower the risk of other congenital anomalies and adverse pregnancy outcomes such as pontaneous abortions, placental abruption and low birth weight.

Folate deficiency is most often a result of poor dietary intake either alone or in combination with malabsorption or increased utilisation. Excess cell turnover may be physiological such as in pregnancy and lactation or pathological such as in haemolysis or chronic inflammatory disorders. Other causes of folate deficiency include excess urinary loss, drugs, long-term dialysis and alcoholism. While there is no requirement to measure serum folate routinely in pregnancy, testing should be sought in those with a history of poor or inadequate diet, any symptoms of malabsorption and those with an unexplained macrocytic anaemia. Hyperemesis during pregnancy and multiparity are also recognised as risk factors prompting investigation.


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