After examining the peripheral smear and calculating the reticulocyte index
We measure
LDH Bilirubin
– The unconjugated bilirubin is elevated with extravascular hemolysis
RBC
Globin
Hemoglobin Dimer
Red Cell Destruction by the Reticuloendothelial System
CO (expired)
RBC
Transferrin
Amino Acid Pool
Fe Hb Globin
RE Cell
Bilirubin
Liver
Urobilinogen
Intravascular Red Cell Hemolysis
Marrow/Circulating Red Cell Relationships In Disturbances Of The Erythron
Marrow
Normal Hypoproliferative
Maturation abnormality
Hemolytic
Red cell life span – 120 days
The distinguishing feature of the hemolytic anemias is the increased rate of destruction of circulating red cells.
Hemolytic anemias are recognized by anemia with signs of increased red cell production which occurs as the normal bone
Hemolysis
Learning Objectives
Distinguish extravascular from intravascular hemolysis Recognize hemolytic anemia by its clinical and laboratory features Diagnose the common types of hemolytic anemias
Hale Waihona Puke SplenomegalyOne of the most constant features of extravascular hemolysis It is caused by accelerated destruction of red cells, mediated by macrophages in the spleen, and sometimes the liver
marrow attempts to compensate for the accelerated loss of RBC’s.
Peripheral smear – polychromasia
Reticulocytosis with an elevated RPI
Changes in RBC morphology
>3 (with 1 being baseline)
We search for hemoglobin breakdown pigments indicative of hemolysis
Scleral Icterus
Jaundice due to increased bili pigment – best seen in the sclerae
anemia?
We start with the history and physical exam We do a careful examination of the peripheral smear We measure the reticulocyte count and calculate the reticulocyte production index (RPI).
Elevated LDH from red cell breakdown
Increase in hemoglobin breakdown pigments
Accompanied by intense erythroid hyperplasia of the marrow
How do we diagnose hemolytic
Intravascular – within blood vessels
Plays little or no role in normal red cell destruction, but plays a major role in certain types of hemolytic anemia Causes hemoglobinuria and/or hemosiderinuria
What is the predominant site of red cell breakdown in hemolysis?
Extravascular – outside the blood vessels
Within macrophages in the
– Spleen – Liver
Causes hyperbilirubinemia
Pigmented Gall Stones
From increased bilirubin content of the bile, if the process is chronic.
Polychromasia
Reticulocytes contain a large amount of RNA which stains bluish red on a standard blood smear. Because there is a shift of marrow retics into the PB, there is polychromasia. Also look for shape changes.