eMedicine Specialties > Hematology > Red Blood Cells and Disorders

Macrocytosis: Treatment & Medication

Author: Wendy Brick, MD, Consulting Staff, Department of Internal Medicine, Division of Hematology and Oncology, Mecklenburg Medical Group
Coauthor(s): Russell Burgess, MD, Department of Internal Medicine, Division of Hematology/Oncology, East Carolina Internal Medicine
Contributor Information and Disclosures

Updated: Aug 29, 2009

Treatment

Medical Care

  • Evaluation usually can be performed on an outpatient basis.
  • Medical treatment depends on the etiology of the macrocytosis, the presence and severity of an anemia, and the symptoms of the patient.
    • After the appropriate laboratory studies are obtained, the symptomatic anemic patient may be transfused with packed RBCs.
    • If a drug is thought to be the cause of the macrocytic anemia, especially if hemolysis is occurring, discontinue administration of the offending drug.
    • Patients deficient in vitamin B-12 or folate should receive replacement therapy.
    • Counsel patients suspected of abusing alcohol to abstain.
    • Treat malignancies, granulomatous diseases, and COPD according to standards for each.
  • Hospitalization may be required to treat some causes of macrocytosis, especially acute leukemias.

Consultations

  • Hematology
  • Oncology

Diet

If folate or vitamin B-12 deficiency is the cause of the macrocytosis, modify the diet to include foods rich in these vitamins. Red meat is a good source of vitamin B-12, and green leafy vegetables are excellent sources of folate. Do not provide folate supplementation without vitamin B-12 replacement therapy in any patient with vitamin B-12 deficiency or with suspected vitamin B-12 deficiency, since this may precipitate subacute combined degeneration of the spinal cord.

Medication

The goals of pharmacotherapy are to reduce morbidity and to prevent complications.

Vitamins

In macrocytosis associated with vitamin deficiencies, the deficient vitamin is replaced.5


Folic acid (Folvite)

Important cofactor for enzymes used in production of RBCs.

Adult

1 mg/d PO

Pediatric

Not established

Increase in seizure frequency and a decrease in subtherapeutic levels of phenytoin reported when used concurrently

Pregnancy

A - Safe in pregnancy

Precautions

Benzyl alcohol may be contained in some products as a preservative (associated with a fatal gasping syndrome in premature infants); resistance to treatment may occur in patients with alcoholism and deficiencies of other vitamins


Vitamin B-12 (Crystamine, Crysti 1000, Cyomin)

Deoxyadenosylcobalamin and hydroxocobalamin are active forms of vitamin B-12 in humans. Vitamin B-12 is synthesized by microbes but not by humans or plants. Vitamin B-12 deficiency may result from intrinsic factor deficiency (pernicious anemia), partial or total gastrectomy, or diseases of the distal ileum.

Adult

100-1000 mcg IM qmo

Pediatric

Not established

Documented hypersensitivity; hereditary optic nerve atrophy

Pregnancy

A - Safe in pregnancy

Precautions

Severe hypokalemia may result in vitamin B-12 megaloblastic anemia (may be fatal) because of increased cellular potassium requirements when anemia corrects


Multiple vitamins (M.V.I.-12, Cernevit-12)

Used as dietary supplement.

Adult

M.V.I.-12: 10 mL/d IV
Cernevit: 5 mL/d IV

Pediatric

M.V.I.-12:
<12 years: 5 mL/d IV
>12 years: Administer as in adults
Cernevit:
<12 years: 2.5 mL/d IV
>12 years: Administer as in adults

Hydralazine and isoniazid may decrease effect of pyridoxine; pyridoxine may decrease effect of levodopa

Pregnancy

A - Fetal risk not revealed in controlled studies in humans

C - Fetal risk revealed in studies in animals but not established or not studied in humans; may use if benefits outweigh risk to fetus

Precautions

Caution in severe renal or liver failure; additional vitamin A may be required in pediatric patients

More on Macrocytosis

Overview: Macrocytosis
Differential Diagnoses & Workup: Macrocytosis
Treatment & Medication: Macrocytosis
Follow-up: Macrocytosis
References
Further Reading
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References

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  2. Rumsey SE, Hokin B, Magin PJ, Pond D. Macrocytosis--an Australian general practice perspective. Aust Fam Physician. Jul 2007;36(7):571-2. [Medline]. [Full Text].

  3. Sternfeld T, Lorenz A, Schmid M, et al. Increased red cell corpuscular volume and hepatic mitochondrial function in NRTI-treated HIV infected patients. Curr HIV Res. May 2009;7(3):336-9. [Medline].

  4. Argento V, Roylance J, Skudlarska B, et al. Anemia prevalence in a home visit geriatric population. J Am Med Dir Assoc. Jul 2008;9(6):422-6. [Medline].

  5. Ganji V, Kafai MR. Hemoglobin and hematocrit values are higher and prevalence of anemia is lower in the post-folic acid fortification period than in the pre-folic acid fortification period in US adults. Am J Clin Nutr. Jan 2009;89(1):363-71. [Medline]. [Full Text].

  6. Ali G, Pecoud A, Decrey H, Verdon F. [Vitamin B 12 deficiency: early diagnosis in ambulatory care medicine]. Schweiz Med Wochenschr. Nov 7 1998;128(45):1763-71. [Medline].

  7. Atony AC. Megaloblasctic anemias. Hematology Basic Principles and Practice. 1995;2nd ed:552-581.

  8. Bessman JD, Banks D. Spurious macrocytosis, a common clue to erythrocyte cold agglutinins. Am J Clin Pathol. Dec 1980;74(6):797-800. [Medline].

  9. Breedveld FC, Bieger R, van Wermeskerken RK. The clinical significance of macrocytosis. Acta Med Scand. 1981;209(4):319-22. [Medline].

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  11. Curtis D, Sparrow R, Brennan L, Van der Weyden MB. Elevated serum homocysteine as a predictor for vitamin B12 or folate deficiency. Eur J Haematol. Apr 1994;52(4):227-32. [Medline].

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  16. Grgic I, Kaistha BP, Paschen S, et al. Disruption of the Gardos channel (KCa3.1) in mice causes subtle erythrocyte macrocytosis and progressive splenomegaly. Pflugers Arch. Jun 2009;458(2):291-302. [Medline].

  17. Karnad AB, Krozser-Hamati A. Pernicious anemia. Early identification to prevent permanent sequelae. Postgrad Med. Feb 1 1992;91(2):231-4, 237. [Medline].

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  19. Lindenbaum J, Savage DG, Stabler SP, Allen RH. Diagnosis of cobalamin deficiency: II. Relative sensitivities of serum cobalamin, methylmalonic acid, and total homocysteine concentrations. Am J Hematol. Jun 1990;34(2):99-107. [Medline].

  20. Phekoo K, Williams Y, Schey SA, et al. Folate assays: serum or red cell?. J R Coll Physicians Lond. May-Jun 1997;31(3):291-5. [Medline].

  21. Rizeq M, Sinha SK, Zaman MN. Macrocytosis in elderly patients [letter; comment]. Age Ageing. May 1997;26(3):237-8. [Medline].

  22. Sechi LA, De Carli S, Catena C, et al. Benign familial macrocytosis. Clin Lab Haematol. Mar 1996;18(1):41-3. [Medline].

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  24. Swain RA, St Clair L. The role of folic acid in deficiency states and prevention of disease. J Fam Pract. Feb 1997;44(2):138-44. [Medline].

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Keywords

macrocytosis, macrocytes, megaloblasts, anemia, megaloblastic anemia, myelodysplastic anemia, myelophthisic anemia, aplastic anemia, acquired sideroblastic anemia, vitamin B-12 deficiency, folate deficiency, chronic alcoholism, alcoholism, accelerated erythropoiesis, chronic obstructive pulmonary disease, COPD, Lesch-Nyhan syndrome, deficient enzymes for folate metabolism, homocystinuria, liver disease, hypothyroidism

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Contributor Information and Disclosures

Author

Wendy Brick, MD, Consulting Staff, Department of Internal Medicine, Division of Hematology and Oncology, Mecklenburg Medical Group
Wendy Brick, MD is a member of the following medical societies: Alpha Omega Alpha, American College of Physicians, American Medical Association, and American Society of Hematology
Disclosure: Nothing to disclose.

Coauthor(s)

Russell Burgess, MD, Department of Internal Medicine, Division of Hematology/Oncology, East Carolina Internal Medicine
Russell Burgess, MD is a member of the following medical societies: American College of Physicians and American Medical Association
Disclosure: Nothing to disclose.

Medical Editor

Paul Schick, MD, Emeritus Professor, Department of Internal Medicine, Thomas Jefferson University Medical College; Research Professor, Department of Internal Medicine, Drexel University College of Medicine; Adjunct Professor of Medicine, Lankenau Hospital, Wynnewood, PA
Paul Schick, MD is a member of the following medical societies: American College of Physicians, American Heart Association, American Society of Hematology, International Society on Thrombosis and Haemostasis, and New York Academy of Sciences
Disclosure: Nothing to disclose.

Pharmacy Editor

Francisco Talavera, PharmD, PhD, Senior Pharmacy Editor, eMedicine
Disclosure: eMedicine Salary Employment

Managing Editor

Ronald A Sacher, MB, BCh, MD, FRCPC, Professor, Internal Medicine and Pathology, Director, Hoxworth Blood Center, University of Cincinnati Academic Health Center
Ronald A Sacher, MB, BCh, MD, FRCPC is a member of the following medical societies: American Society of Hematology
Disclosure: Glaxo Smith Kline Honoraria Speaking and teaching; Talecris Honoraria Board membership

CME Editor

Rajalaxmi McKenna, MD, FACP, Consulting Staff, Department of Medicine, Southwest Medical Consultants, SC, Good Samaritan Hospital, Advocate Health Systems
Rajalaxmi McKenna, MD, FACP is a member of the following medical societies: American Society of Clinical Oncology, American Society of Hematology, and International Society on Thrombosis and Haemostasis
Disclosure: Nothing to disclose.

Chief Editor

Emmanuel C Besa, MD, Professor, Department of Medicine, Division of Hematologic Malignancies, Kimmel Cancer Center, Thomas Jefferson University
Emmanuel C Besa, MD is a member of the following medical societies: American Association for Cancer Education, American College of Clinical Pharmacology, American Federation for Medical Research, American Society of Hematology, and New York Academy of Sciences
Disclosure: Nothing to disclose.

 
 
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