Normal newborn peripheral blood morphology

Published on 04/03/2015 by admin

Filed under Hematology, Oncology and Palliative Medicine

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23 Normal newborn peripheral blood morphology

In the healthy, full-term newborn, peripheral blood collected within the first 12 hours of birth has distinctive morphology. Some morphological changes persist for up to 3 to 5 days after birth. These changes should be recognized as physiological and not pathological. For a fuller discussion of hematology in the newborn, refer to a hematology textbook such as Hematology: Clinical Principles and Applications* or a pediatric hematology text such as Nathan and Oski’s Hematology of Infancy and Childhood.†

Entire books have been written to address abnormal hematology in neonates and especially in the premature infant. This chapter does not attempt to address those disorders but rather depicts morphological changes commonly seen in the healthy newborn.

Erythrocyte morphology demonstrates macrocytes, with a mean cell volume of 110 ± 15 fL, which declines dramatically after the first 12 hours. Up to 3 to 10 orthochromic normoblasts (nucleated red blood cells) may be seen per 100 white blood cells and should disappear by day 5. Polychromasia reflects the erythropoietic activity of the newborn. Anisocytosis is reflected in the red blood cell distribution width index, which ranges from 15.2% to 18.0%.

Occasional spherocytes are common, varying from one every two fields to one or more in every field.

Newborn total leukocyte counts are higher than for adults, and newborns have more segmented and band neutrophils than at any other time in childhood.‡ An occasional metamyelocyte may be seen without evidence of infection. Monocyte morphology is similar to that of the adult.

Lymphocyte morphology is pleomorphic, spanning the range from reactive to mature. The presence of a nucleolus is not uncommon; however, the chromatin pattern is coarse and not as fine as seen in blasts. Hematogones (immature B cells) are occasionally seen in bone marrow and peripheral blood of newborns. Caution must be exercised to correctly differentiate hematogones from blasts that may indicate a pathologic condition.

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FIGURE 23–1 Peripheral blood from a neonate demonstrating macrocytes, polychromasia, nucleated red blood cell, Howell-Jolly body, and one spherocyte (arrow) (PB ×1000).

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FIGURE 23–2 Peripheral blood from a neonate demonstrating polychromasia, anisocytosis, echinocytes, and spherocytes (PB ×1000).

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FIGURE 23–3 Lymphocyte from neonate blood. Although there appears to be a nucleolus, the chromatin pattern is coarse (PB × 1000).

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FIGURE 23–4 Bone marrow from neonate with acute lymphoblastic leukemia, demonstrating hematogones and lymphoblasts. Hematogones vary in size. Nucleus is round to oval with condensed, smudged chromatin. Nucleoli are absent or indistinct. Cytoplasm is indiscernible to scant. Arrows point to hematogones. Most of the other cells are blasts (BM ×1000). See chapter 16 for comparison with blasts.

* Rodak BF, Fritsma GA, Keohane EM, editors: Hematology: clinical principles and applications, ed 4, St. Louis, 2012, Saunders.

† Orkin SH, Nathan DG, Ginsburg D et al: Nathan and Oski’s hematology of infancy and childhood, ed 7, St. Louis, 2009, Saunders.

‡ Quinn CT, Buchanan GR: Hematopoiesis and hematologic diseases. In McMillan JA, Feigin RD, DeAngelis C, Jones MD, editors: Oski’s pediatrics, Philadelphia, 2006, Lippincott Williams & Wilkins.

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