Ch. 18 - Anemias: Red Blood Cell Morphology and Approach to Diagnosis (RVSP) Flashcards
2 classical symptoms of anemia
- fatigue
- shortness of breath
2 important components in making clinical diagnosis of anemia
- history
- physical examination
Condition having a symptom of pica
Iron deficiency
Having cravings for unusual substances
Pica
Craving for ice
Pagophagia
Shift in the oxygen dissociation curve caused by 2,3-bisphosphoglycerate
Shift to the right (decreased oxygen affinity of Hb)
Percent of RBCs removed per day due to senescence
1%
Marrow erythroid proliferative activity
Erythropoiesis
Production of erythroid progenitor cells that are defective
Ineffective erythropoiesis
3 examples of conditions for ineffective erythropoiesis
- megaloblastic anemia
- thalassemia
- sideroblastic anemia
A decrease in the number of erythroid precursors in the bone marrow
Insufficient erythropoiesis
Measure of the average RBC volume in femtoliters (fL)
MCV
Most important RBC indice to detect anemia
MCV
Unit for MCV
Femtoliters (fL)
An RBC volume frequency distribution curve
RBC histogram
With normal population of RBCs, the distribution of the RBC histogram is approximately ___________
Gaussian
Shift in the RBC histogram due to microcytosis
Left shift
Shift in the RBC histogram due to macrocytosis
Right shift
Causes widening of the curve of the RBC histogram
Anisocytosis
The coefficient of variation of RBC volume expressed as a percentageq
RDW
Indicates the variation in RBC volume within th epopulation measured
RDW
Important tool to assess the bone marrow’s ability to increase RBC production in response to an anemia
Reticulocyte count
Young RBCs lacking a nucleus but still containing residual RNA
Reticulocytes
Adult reference range for reticulocyte count
0.5 - 1.5%
Newborn reference range for retic count
1.5 - 5.8%
Reference range for absolute retic count
25-75 x 10^9/L
Average normal hematocrit
45
Abnormal variation in RBC volume or diameterq
Anisocytosis
Large RBC (>8 um in diameter), MCV >100 fL
Macrocyte
Large oval RBC
Oval macrocyte
Small RBC (MCV <6 um in diameter)
Microcyte
Abnormal variation in RBC shape
Poikilocytosis
Small, round, dense RBC with no central pallow
Spherocyte
Elliptical (cigar-shaped)/oval (egg-shaped) RBC
Elliptocyte/ovalocyte
RBC with slitlike area of central pallor
Stomatocyte
Thin, dense, elongated RBC pointed at each end
Sickle cell (drepanocyte)
Hexagonal crystal of dense Hb formed within the RBC membrane
Hb C crystal
Fingerlike or quartzlike crystal of dense Hb protruding from the RBC membrane
Hb SC crystal
RBC with Hb concentrated in the center and around the periphery resembling a target
Codocyte (target cell)
Fragmented RBC due to rupture in the peripheral circulation
Schistocyte (schizocyte)
RBC fragment in the shape of a helmet
Keratocyte (bite cell/helmet cell)
RBC with membrane folded over
Folded cell
Small, dense RBC with few irregularly spaced projections of varying length
Acanthocyte (spur cell)
RBC with blunt or pointed, short projections that are usually evenly spaced over the surface of the cell
Burr cell (echinocyte)
RBC with a single pointed extension resembling a teardrop or pear
Dacryocyte (teardrop cell)
Diffuse basophilia composed of
RNA
Basophilic stippling (punctate basophilia) composed of
Precipitated RNA
Howell-Jolly body composed of
DNA (nuclear fragment)
Heinz body composed of
Denatured Hb
Pappenheimer bodies composed of
Non-heme iron
Cabot ring composed of
Mitotic spindle remnants
Hb H composed of
Precipitated ß chains of Hb
Used to investigate the presence of inappropriately low retic count and a microcytic anemia
Iron studies
2 assays helpful in investigsting a low retic count with a macrocytic anemia
- vitamin B12 assay
- serum folate assay
Test used to differentiate autoimmune hemolytic anemias from hemolytic anemias of othe causes
Direct antiglobulin test
Anemia characterized by an MCV of less than 80 fL with small RBCs
Microcytic anemia
Most common cause of microcytic anemia
Iron deficiency
Anemia characterized by an MCV greater than 100 fL with large RBCs
Macrocytic anemia
2 types of macrocytic anemias
Megaloblastic
Nonmegaloblastic
Type of macrocytic anemia caused by impairment of DNA synthesis
Megaloblastic anemia
3 causes of megaloblastic anemia
- vitamin B12 deficiency
- folate deficiency
- myelodysolasia
Type of macrocytic anemia where the nuclear maturation lags behind cytoplasmic development
Megaloblastic anemia
Anemia that causes vitamin B12 deficiency
Pernicious anemia
Causes folate deficiency
Malabsorption secondary to inflammatory bowel disease
2 characteristics of megaloblastic anemia in peripheral blood
- oval macrocytes
- hypersegmented neutrophils
Characteristic of megaloblastic anemia in bone marrow
megaloblasts
Type of macrocytic anemia where there ae membrane changes due to disruption of the cholesterol-to-phospholipid ratio
Nonmegaloblastic anemia
2 conditions where nonmegaloblastic anemia is commonly seen
- chronic liver disease
- bone marrow failure
Anemia with MCV in the range of 80-100 fL
Normocytic anemia