5.2: Non-Megaloblastic Macrocytic Anemia

Last updated
Save as PDF

Page ID: 38799

\( \newcommand{\vecs}[1]{\overset { \scriptstyle \rightharpoonup} {\mathbf{#1}} } \) \( \newcommand{\vecd}[1]{\overset{-\!-\!\rightharpoonup}{\vphantom{a}\smash {#1}}} \)\(\newcommand{\id}{\mathrm{id}}\) \( \newcommand{\Span}{\mathrm{span}}\) \( \newcommand{\kernel}{\mathrm{null}\,}\) \( \newcommand{\range}{\mathrm{range}\,}\) \( \newcommand{\RealPart}{\mathrm{Re}}\) \( \newcommand{\ImaginaryPart}{\mathrm{Im}}\) \( \newcommand{\Argument}{\mathrm{Arg}}\) \( \newcommand{\norm}[1]{\| #1 \|}\) \( \newcommand{\inner}[2]{\langle #1, #2 \rangle}\) \( \newcommand{\Span}{\mathrm{span}}\) \(\newcommand{\id}{\mathrm{id}}\) \( \newcommand{\Span}{\mathrm{span}}\) \( \newcommand{\kernel}{\mathrm{null}\,}\) \( \newcommand{\range}{\mathrm{range}\,}\) \( \newcommand{\RealPart}{\mathrm{Re}}\) \( \newcommand{\ImaginaryPart}{\mathrm{Im}}\) \( \newcommand{\Argument}{\mathrm{Arg}}\) \( \newcommand{\norm}[1]{\| #1 \|}\) \( \newcommand{\inner}[2]{\langle #1, #2 \rangle}\) \( \newcommand{\Span}{\mathrm{span}}\)\(\newcommand{\AA}{\unicode[.8,0]{x212B}}\)

: An image from a peripheral blood smear demonstrating round macrocytes and poikilocytosis in liver disease. 100x oil immersion. From MLS Collection, University of Alberta, https://doi.org/10.7939/R3MP4W32X

Cause(s):

A group of anemias that present with macrocytes without megaloblastic features. Most often, non-megaloblastic macrocytic anemias are caused by: alcoholism, liver disease, bone marrow failure, and myelodysplastic syndromes (MDS).^1,2

Chronic and heavy consumption of alcohol can lead to macrocytosis due to a variety of effects it has in erythrocyte development. Alcohol can not only interfere with folate metabolism but also is also directly toxic on bone marrow precursors. ^1,3

Liver disease is commonly associated with alcoholism and it is thought that macrocytosis is caused by an increase in cholesterol and lipids in the red blood cell membrane.³

Note: Additional information about bone marrow failure and MDS will be discussed in later chapters.

Laboratory Features: ^1-4

CBC:

PLT: Decreased

*MCV: usually 100-110 fL

(MCV is rarely >110 fL)

*RETIC: Increased (if hemolytic anemia is present)

PBS:

*Round Macrocytes

Target cells

*NO hypersegmented neutrophils

BM:

Nomorcellular or hypercellular

Erythroid hyperplasia

*Megaloblastic features are absent in precursors

Iron Studies (Liver Disease):

Serum Iron: Decreased to Normal

Ferritin: Increased

Transferrin: Normal

Transferrin Saturation: Normal to Increased

Other Tests:

Liver enzyme tests

*Features that differentiate megaloblastic from non-megaloblastic anemias

References:

1. Hubbard J, Robinson S. Megaloblastic and nonmegaloblastic macrocytic anemias. In: Clinical laboratory hematology. 3rd ed. New Jersey: Pearson; 2015. p. 277-301.

2. Nagao T, Hirokawa M. Diagnosis and treatment of macrocytic anemias in adults. J Gen Fam Med [Internet]. 2017 Oct 13 [cited 2018 Jun 25];18(5):200–4. Available from: http://doi.wiley.com/10.1002/jgf2.31

3. Taghizadeh M. Megaloblastic anemias. In: Clinical hematology and fundamentals of hemostasis. 5th ed. Philadelphia: F.A. Davis Company; 2009. p. 138-55.

4. Goossen LH. Anemias caused by defects of DNA metabolism. In: Rodak’s hematology clinical applications and principles. 5th ed. St. Louis, Missouri: Saunders; 2015. p. 314-30.