MLT GlobeHematology: RBC morphology & inclusions – page 5
89 Hematology MCQs on RBC morphology & inclusions with answers and explanations.
A man has hemolytic anemia with marked coarse basophilic stippling. His blood lead level is normal. The most likely inherited enzyme defect is:
Pyrimidine 5'-nucleotidase normally breaks down ribosomal RNA; its deficiency leaves aggregated ribosomes visible as stippling. Lead also inhibits this enzyme, which explains stippling in lead poisoning.
According to ICSH recommendations, schistocytes in an adult smear provide strong morphological support for thrombotic microangiopathy when they exceed:
ICSH suggests that a schistocyte count above 1% in adults is a robust indicator of TMA when the clinical picture fits. Small numbers (under about 0.5%) can be seen in healthy people and many other conditions.
A family has mild hemolysis, raised MCHC and red cells in which hemoglobin appears pushed to one side, with a clear area at the other. Osmotic fragility is decreased. This is most consistent with:
Xerocytes are dehydrated cells, often due to PIEZO1 mutations, with raised MCHC and decreased osmotic fragility. Hereditary spherocytosis also raises MCHC but shows increased, not decreased, osmotic fragility.
A child has severe hemolysis, MCV about 55 fL and bizarre micropoikilocytes and fragments. The red cells fragment when heated to about 45 °C, compared with about 49 °C for normal cells. The diagnosis is:
Hereditary pyropoikilosis is a severe spectrin disorder related to hereditary elliptocytosis; its cells are unusually heat-sensitive and fragment at a lower temperature. Burns damage normal cells only when the patient is heated, with no inherited heat sensitivity.
A family has mild hemolysis with many stomatocytes, MCV 110 fL, MCHC 29 g/dL (290 g/L) and increased osmotic fragility. B12 and folate are normal. The most likely diagnosis is:
In overhydrated stomatocytosis, cells gain sodium and water, so they are large with low MCHC and lyse easily in hypotonic saline. Xerocytosis is the dehydrated form, with high MCHC and decreased osmotic fragility.
By WHO criteria, a ring sideroblast is an erythroblast with at least 5 iron granules encircling at least:
WHO defines a ring sideroblast as an erythroblast with 5 or more Prussian blue–positive granules covering at least one-third of the nuclear circumference. These iron-loaded mitochondria are typical of sideroblastic anemias and some MDS.
A traveler from the Andes of Peru has fever and severe hemolytic anemia. The smear shows small red-violet rods and coccobacilli on the surface of many red cells. The most likely organism is:
Bartonella bacilliformis causes Oroya fever in Andean valleys and attaches to red cells as small rods, causing hemolysis. Anaplasma forms morulae in neutrophils, and Babesia forms intracellular rings.
An adult has chorea, raised creatine kinase, normal plasma lipids and normal Kell antigens. The smear shows many acanthocytes. The most likely diagnosis is:
Neuroacanthocytosis syndromes combine movement disorders, muscle damage and acanthocytes with normal lipids. Normal Kell antigens argue against McLeod syndrome, and normal lipids argue against abetalipoproteinemia.
During a hemolytic crisis in G6PD deficiency, the smear shows cells whose hemoglobin is pulled to one side, leaving a clear membrane 'bubble' at the edge. These are called:
Oxidant damage causes hemoglobin to retract from part of the membrane, creating a clear blister-like area; these cells are called blister cells or hemighosts. Stomatocytes have a slit-like central pallor instead.