APIH243885241 - CME/CMLE - Blood Cell ID #1: A Patient Infected with Malaria-APIH243885241

APIH243885241 - Educational Activity

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This educational commentary by Karen A. Brown focuses on the morphologic examination of peripheral blood cells in a patient diagnosed with malaria, highlighting key features to aid laboratory professionals in diagnosis.<br /><br />The case involves a 23-year-old female recently returned from overseas, presenting with fatigue and tachycardia. Her CBC showed mild leukopenia and thrombocytopenia. The blood smear reveals various cells: reactive lymphocytes, normal erythrocytes (RBCs), a malarial parasite within an RBC, segmented neutrophils, and normal platelets.<br /><br />Reactive lymphocytes, stimulated in response to antigenic challenges (commonly viral infections), appear large with abundant cytoplasm often pale to deep blue, with cytoplasmic molding around adjacent RBCs and azurophilic granules. Their nuclei vary in shape and chromatin texture.<br /><br />A key diagnostic feature is the presence of malarial parasites inside RBCs, specifically ring trophozoites that exhibit a distinctive blue cytoplasmic ring and a red chromatin dot, while the infected RBC retains normal size and shape. Careful microscopic examination distinguishes intracellular parasites from artifacts like precipitated stain or platelets, which differ in focus and morphology.<br /><br />Normal RBCs are assessed for size (similar to small resting lymphocyte nuclei), shape, pallor area (~1/3 cell diameter), staining (pink due to hemoglobin), and absence of inclusions. Segmented neutrophils have multi-lobed nuclei (2-5 segments) connected by chromatin strands and granulated pink cytoplasm. Platelets, small cytoplasmic fragments from megakaryocytes, stain light purple/blue-gray and may show granular cores.<br /><br />Malaria, caused by Plasmodium species (P. falciparum, P. vivax, P. malariae, and P. ovale), is transmitted by female Anopheles mosquitoes and involves complex life cycles with asexual stages (ring trophozoites) visible in peripheral blood. P. falciparum is notably associated with leukopenia and thrombocytopenia.<br /><br />In summary, recognizing morphological features of blood cells and malaria parasites in stained peripheral blood smears is vital for accurate diagnosis and patient care in malaria infections.

Keywords

malaria diagnosis

peripheral blood smear

morphologic examination

ring trophozoites

Plasmodium species

reactive lymphocytes

leukopenia

thrombocytopenia

segmented neutrophils

blood cell morphology