Approach Considerations

Evaluation usually can be performed on an outpatient basis. Medical treatment depends on the etiology of the macrocytosis, the presence and severity of anemia, and the symptoms and physical findings. Hematologic and oncologic consultation should be obtained as necessary. After the appropriate laboratory studies are obtained, the symptomatic anemic patient may undergo transfusion with packed red blood cells (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. If the patient is suspected of abusing alcohol, counsel abstention.

Patients deficient in vitamin B12 or folate should receive replacement therapy.^[30]Folate 1 mg/day may be prescribed in patients with folate deficiency. Intramuscular vitamin B12 injections (100-1000 mcg/mo), continued indefinitely, may be prescribed.

Treat malignancies, granulomatous diseases, and chronic obstructive pulmonary disease (COPD) according to the standards appropriate for each. Hospitalization may be required to treat some causes of macrocytosis, especially acute leukemias. Outpatient follow-up depends on the cause of the macrocytosis.

Diet

If folate or vitamin B12 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 B12, and green leafy vegetables are excellent sources of folate. Do not provide folate supplementation without vitamin B12 replacement therapy in any patient with vitamin B12 deficiency or with suspected vitamin B12 deficiency; doing so may precipitate subacute combined degeneration of the spinal cord.

Medication

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Author

Vincent E Herrin, MD, FACP Professor of Medicine, Division of Hematology and Medical Oncology, Director, Medicine Residency Program, University of Mississippi School of Medicine

Vincent E Herrin, MD, FACP is a member of the following medical societies: American College of Physicians, American College of Physicians-American Society of Internal Medicine, American Society of Clinical Oncology, Southern Society for Clinical Investigation, American Society of Hematology

Disclosure: Nothing to disclose.

Chief Editor

Emmanuel C Besa, MD Professor Emeritus, Department of Medicine, Division of Hematologic Malignancies and Hematopoietic Stem Cell Transplantation, Kimmel Cancer Center, Jefferson Medical College of Thomas Jefferson University

Emmanuel C Besa, MD is a member of the following medical societies: American Association for Cancer Education, American Society of Clinical Oncology, American College of Clinical Pharmacology, American Federation for Medical Research, American Society of Hematology, New York Academy of Sciences

Disclosure: Nothing to disclose.

Acknowledgements

Russell Burgess, MD (Retired) Chief, Division of Hematology/Oncology, Eastern Carolina Internal Medicine, PA

Russell Burgess, MD is a member of the following medical societies: American College of Physicians and American Medical Association

Disclosure: Nothing to disclose.

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 Association for the Advancement of Science, American Association of Blood Banks, American Clinical and Climatological Association, American Society for Clinical Pathology, American Society of Hematology, College of American Pathologists, International Society of Blood Transfusion, International Society on Thrombosis and Haemostasis, and Royal College of Physicians and Surgeons of Canada

Disclosure: Glaxo Smith Kline Honoraria Speaking and teaching; Talecris Honoraria Board membership

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.

Francisco Talavera, PharmD, PhD, Adjunct Assistant Professor, University of Nebraska Medical Center College of Pharmacy; Editor-in-Chief, Medscape Drug Reference

Disclosure: Medscape Reference Salary Employment

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