Erythrocyte Disorders Flashcards
derived from the Greek word βanaimiaβ meaning βwithout bloodβ
Anemia
- is a decrease in the oxygen carrying capacity of the blood (functional definition)
- is defined operationally as a reduction in the hemoglobin content of blood that can be caused by a decrease in RBCs, hemoglobin, and hematocrit
- should not be thought of as a disease but rather as a manifestation of an underlying disease or deficiency
Anemia
1.Increase in heart rate, respiratory rate, and cardiac output
- Redistribution of blood flow from skin and viscera to heart, brain, and muscle
Anemia caused by sudden loss of blood volume:
- Decrease in hemoglobin-oxygen affinity by increasing the production of 2,3-biphosphoglycerate
- Increase in EPO production by kidneys
Anemia caused by slow loss of blood:
-refers to the production of erythroid precursor cells that are defective
- these defective precursors often undergo apoptosis
Ineffective erythropoiesis
megaloblastic anemia, thalassemia, sideroblastic anemia
Ineffective erythropoiesis
-refers to the decrease in the number of erythroid precursor in the bone marrow
- iron deficiency anemia, renal disease, aplastic anemia, acquired pure red cell aplasia, infection
Insufficient erythropoiesis
- most important among the RBC indices
- a measure of the average RBC volume in fL
- key in the morphologic classification of anemia
Mcv
- index of variation of cell volume in a red blood cell population
- the coefficient of variation of RBC volume expressed in percentage
Rdw
- an important tool to assess the bone marrowβs ability to increase RBC production in response to anemia
- determines whether an anemia is due to an RBC production defect or to a shortened survival defect
Reticulocyte count
- serves as a quality control to verify the results produced by automated analyzers
Peripheral Blood Smear/film
- may help in establishing the cause of anemia
Bone marrow aspiration and biopsy
valuable if an inappropriately low reticulocyte count and a microcytic anemia are present
Iron studies
helpful in investigating a macrocytic anemia with a low reticulocyte count
Serum vitamin B12 and serum folate assays
can differentiate autoimmune hemolytic anemias from hemolytic anemias due to other causes
DAT direct antiglobulin test (
Degree of hemoglobinization
Normochromia
Hypochromia
Hyperchromia
Central pallor is 1/3 of the red cell diameter
Normochromia
Central pallor is >1/3 of the red cell diameter
Hypochromia 1+
Central pallor is >2/3 of the red cell diameter
Hypochromia 2+
Central pallor is 3 quarter of the red cell volume
Hypochromia 3+
Thin rim of hemoglobin is left
Hypochromia 4+
Decreased or absent central pallor
Hyperchromia
variation in red cell size
Anisocytosis
-characterized by an MCV of less than 80 fL with small RBCs (less than 6ΞΌm)
-are caused by conditions that result in reduced hemoglobin synthesis
Microcytic anemia
IDA, chronic inflammatory states, sideroblastic anemia, lead poisoning
Defective heme synthesis : microcytic anemia
Thalassemia, Hb E disease
Defective globin synthesis: microcytic anemia
TAILS
Microcytic anemia
-characterized by an MCV in the range of 80-100 fL
- develop due to premature destruction and shortened survival of RBCs
Normocytic anemia
Immune and nonimmune RBC injury
Extrinsic causes
- characterized by an MCV greater than 100 fL with large RBCs (greater than 8 ΞΌm)
- arise from conditions that result in megaloblastic and nonmegaloblastic red cell development
Macrocytic anemia
are caused by conditions that impair synthesis of DNA
Megaloblastic anemia
are related to membrane changes owing to disruption of the cholesterol-phospholipid ratio
Nonmegaloblastic anemia
measures red cell immaturity; correlates with reticulocyte count (%)
Polychromasia
RBC/ 10 hpf
0-1
1-3
4-6
>6
Normal
Slight
Moderate
Marked
% retic
1-2%
2-4%
4-6%
>6%
Normal
Slight
Moderate
Marked
1% 3% 5% 10% 11%
Grade
Slight
1+
2+
3+
4+
variation in red cell shape
Poikilocytosis
Acanthocyte synonym
Spur cell
2-10 pointed projections of various lengths and irregular spacing
Acanthocyte
Spur cell
Abetalipoproteinemia
Pyruvate kinase deficiency
Alcohol intoxication
Post-splenectomy
Acanthocyte
Spur cell
Contains one or more vacuoles that resemble a blister on the skin
Blister cell
Burr cell synonym
Echinocyte Crenated RBC
10-30 pointed projections evenly distributed around the cell
Burr cell
Echinocyte Crenated RBC
Post-splenectomy patients with enzyme anomalies
Artificial drying
Burr cell
Echinocyte Crenated RBC
Narrow and elongated,
resembling a rod or cigar shape
Elliptocyte
Pencil cell
IDA
Hereditary elliptocytosis
Elliptocyte
Pencil cell
Fragment in which the volume is close to normal
Keratocyte
Horned cell or Helmet cell
G6PD deficiency
Keratocyte
Horned cell Helmet cell
Narrow band of hemoglobin across the center of the cell
Knizocyte
Pinch bottle cell
Oval or egg-like appearance
Ovalocyte
Elliptocyte
Thalassemia syndromes
Myelodysplastic syndromes
Ovalocyte
Elliptocyte
Fragment in which cellular volume is reduced
Schistocyte
Schizocyte
MAHA Microangiopathic hemolytic anemia
Schistocyte
Schizocyte
Crescent-shaped with at least one end that is pointed
Sickle cell
Drepanocyte
Sickle cell anemia
Sickle cell
Drepanocyte
Compact and round: has lost its area of central pallor
Spherocyte
Hereditary spherocytosis
Spherocyte
Central slit-like opening resembling a mouth
Stomatocyte
Stomatocytosis
Stomatocyte
Contains a central bullβs eye surrounded by a clear ring and then an outer red ring
Target cell
Codocyte
LCAT deficiency
Thalassemia
Target cell
Codocyte
Resembles a tear
Teardrop cell
Dacryocyte
Myelofibrosis
Teardrop cell
Dacryocyte
Red blood cell inclusions
Howell-Jolly body
Pappenheimer body
Basophilic stipplings
Cabot ring
Heinz body
DNA: nuclear or chromosomal remnant
Howell-Jolly body
Non-heme iron
Pappenheimer body
Altered RNA
Basophilic stipplings
Mitotic spindle remnant
Cabot ring
Not visible
Heinz body
Denatured hemoglobin
Heinz body
Multiple, uniform, dark dots distributed evenly throughout the cell
Basophilic stipplings
Clusters or small blue coccoid bodies located at the periphery of the cell
Pappenheimer body
Single, occasionally double, rarely multiple red purple coccoid bodies
Howell-Jolly body
QUALITATIVE RED CELL ABNORMALITIES
- Degree of hemoglobinization
- Anisocytosis - variation in red cell size
- Polychromasia - measures red cell immaturity; correlates with reticulocyte count (%)
- Poikilocytosis - variation in red cell shape
- Red blood cell inclusions
- Red blood cell indices