Macrocytic anemia causes
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Editor-In-Chief: C. Michael Gibson, M.S., M.D. [1]
Overview
Causes
Normal B12 absorption and action are dependent of 5 things: dietary intake, acid in the stomach, pancreatic secretions, secretion of IF by Gastric parietal cells, an ileum that can absorb the IF-B12 complex
- Deficient intake
- Deficient intrinsic factor (pernicious anaemia or gastrectomy)
- Bilogical competition for B12 by diverticulosis, fistula, intestinal anastomosis, achlorhydria and infection by the marine parasite Diphyllobothrium latum
- Selective B12 malabsorption (congenital and drug-induced)
- Chronic pancreatitis
- Ileal resection and bypass
- Folate Deficiency:
- Deficient intake.
- Increased needs: pregnancy, infant, rapid cellular proliferation, and cirrhosis
- Malabsorption (congenital and drug-induced)
- Intestinal and jejunal resection
- Combined Dieficiency (Tropical Sprue): Vitamin B12 & Folate.
- Inherited DNA Synthesis Disorders: Deficient thiamine and factors (e.g. enzymes) responsible for folate metabolism.
- Toxins and Drugs:
- Amobarbital sodium
- Cycloserine
- Cytarabine
- Ethotoin
- Folic acid antagonists (methotrexate)
- Pergolide
- Purine antagonists (6-mercaptopurine)
- Pyrimidine antagonists (cytosine arabinoside)
- Phenobarbital
- Pyrimethamine
- Secobarbital sodium
- Erythroleukemia.
- In general:
- Nutritional defects (folic acid or vitamin B12 which is mainly from animal sources; vegans may require supplementation)
- Chronic liver diseases
- Alcoholism
- Pregnancy
- Decreased production of intrinsic factor (this disease entity is called pernicious anemia)
- Intestinal malabsorption (due to an enteritis, celiac disease or other causes).
- Fish tapeworm infestation (Diphyllobothrium latum)
- Failure to replicate chromosomes due to lack of thymidine.
- Lesch-Nyhan Syndrome
- Cytotoxic drugs interfering with DNA synthesis
- intestinal flora disruption due to antibiotic use
Causes
Life-threatening Causes
- Life-threatening causes include conditions which may result in death or permanent disability within 24 hours if left untreated. There are no life-threatening causes of disease name, however complications resulting from untreated disease name is common.
- Life-threatening causes of [symptom/manifestation] include [cause1], [cause2], and [cause3].
- [Cause] is a life-threatening cause of [disease].
Common Causes
Common causes of [disease name] may include:
- [Cause1]
- [Cause2]
- [Cause3]
OR
- [Disease name] is caused by an infection with [pathogen name].
- [Pathogen name] is caused by [pathogen name].
Less Common Causes
Less common causes of [disease name] include:
- [Cause1]
- [Cause2]
- [Cause3]
Genetic Causes
- [Disease name] is caused by a mutation in the [gene name] gene.
Causes by Organ System
Cardiovascular | No underlying causes |
Chemical/Poisoning | No underlying causes |
Dental | No underlying causes |
Dermatologic | No underlying causes |
Drug Side Effect | No underlying causes |
Ear Nose Throat | No underlying causes |
Endocrine | No underlying causes |
Environmental | No underlying causes |
Gastroenterologic | No underlying causes |
Genetic | No underlying causes |
Hematologic | No underlying causes |
Iatrogenic | No underlying causes |
Infectious Disease | No underlying causes |
Musculoskeletal/Orthopedic | No underlying causes |
Neurologic | No underlying causes |
Nutritional/Metabolic | No underlying causes |
Obstetric/Gynecologic | No underlying causes |
Oncologic | No underlying causes |
Ophthalmologic | No underlying causes |
Overdose/Toxicity | No underlying causes |
Psychiatric | No underlying causes |
Pulmonary | No underlying causes |
Renal/Electrolyte | No underlying causes |
Rheumatology/Immunology/Allergy | No underlying causes |
Sexual | No underlying causes |
Trauma | No underlying causes |
Urologic | No underlying causes |
Miscellaneous | No underlying causes |
Causes in Alphabetical Order
List the causes of the disease in alphabetical order:
- Caus