Hematology |QUESTIONS      Case contributor:  Dr. Dennis DeNicola, Purdue University

HERSHEY

Question 1:  This calf has recurrent hypoproteinemia.  What are the common causes of this alteration?
Answer:
Low plasma protein concentration is generally associated with decreased production of proteins or increased loss of protein via gastrointestinal system, renal/urinary system, marked exudation, or a third compartment shift phenomenon.

Question 2: Given the history, physical examination findings and the hemograms depicted above, what is the most probable cause of the recurrent hypoproteinemia?
Answer:
Increased loss of protein in the gut due to chronic parasitism/ malabsorption.

Question 3:  Using succinct medical terminology, describe the erythron on Day 1.
Answer:
There is a nonregenerative microcytic anemia.  Although the MCHC is within reference range, there is morphologic support for hypochromasia.

Question 4:  What is your interpretation of the erythrogram on Day1?
Answer:
Although the MCHC is within reference range, the anemia should be classified as a microcytic hypochromic anemia because of the decreased MCV and the observed 4+ hypochromasia detected when examining the peripheral blood film.  This type of anemia is results from a limited number of causes.  Iron deficiency secondary to chronic hemorrhage is the most frequent cause of this type of anemia in domestic mammals.  Other causes of microcytic, hypochromic anemia include copper deficiency and pyridoxine deficiency.  Thalassemia and sideroblastic anemia cause these characteristic changes in the erythrocyte indices but these diseases are rarely encountered in domestic mammals.The most common cause of measured/calculated normal MCHC in the face of microscopically observed hypochromasia is the presence of cell-free hemoglobin in the specimen being analyzed due to either in vivo or in vitro hemolysis.  The calculation of MCHC is ([hemoglobin concentration x100] / hematocrit).  If extracellular hemoglobin is present, this will be included in the measurement of hemoglobin and therefore, falsely increase the actual corpuscular hemoglobin concentration.  In this case the artifactual increased MCHC prevents the recognition of hypochromasia based solely upon evaluation of the erythrocyte indices.

Question 5:  What is the most logical explanation for the poikilocytosis and shistocyte formation noted in the comments section of the erythrogram?
poikilocytosis

Answer:
Erythrocytes from animals which are iron deficient have fragile membranes that tend to fragment and deform easily.

Question 6:   Comparing the erythrogram from Day 1 to that of Day 22, would you say that this calf is improving or declining in health–why?
Answer:
The erythrograms indicate slow but steady regeneration.  Note the rise in RBC, Hct, Hgb, NRBC, and reticulocytosis.

Question 7:   On Days 2 and 5, 11 and 16 nucleated erythrocytes were seen/100 leukocytes on the respective differential counts.  Why is it important to note the number of nucleated erythrocytes in the comments section of the hematology report?
Answer:
Nucleated erythrocytes may be counted as leukocytes by many types of automated cell counters as well as during manual leukocyte counting.  The formula for a manual correction of the leukocyte counts is as follows:
             
CWBC = WBC X 100/ (#NRBC+ 100)

Question 8:   With this information in mind, what was the original uncorrected nucleated cell count on Days 2 and 5?
Answer: 

Day 2

Day 5

7,500  = x (100)/(11+100) 

7,600  = x (100)/(16+100)

7,500 = 100x/111 

 7,600 = 100x/116

832,500 = 100x  

881,600 = 100x

8,325 = x  

 8,816 = x

Question 9: What is the significance of the serial reticulocyte counts in this case?  What stain is used to count reticulocytes in most manual methods?
Answer:
 The number of reticulocytes is used as an objective measure of regenerative capacity of the bone marrow.  Reticulocytes are recognized using New Methylene Blue stain. Residual RNA in the im-mature erythrocytes will precipitate with New Methylene Blue and these cells are identified as pale blue-green non-nucleated erythrocytes with aggregates of dark blue staining precipitates of RNA.

Question 10:  How is the mean corpuscular volume calculated?
Answer:
        
MCV (fL) = Hematocrit X 10/RBC (millions)

However, the instrument used to make the determination of MCV in this case actually measures the MCV and the hematocrit is calculated.  Most automated hematology analyzers used in commercial reference  laboratories measure MCV and calculate hematocrits.

Question 11:  How is the mean corpuscular hemoglobin concentration calculated?
Answer:
  
  MCHC (g/dL) = Hemoglobin X 100/ Hematocrit

Question 12:  What are some common signs of erythroid regeneration in the bovids?
Answer:
The signs of regeneration in bovine species are similar to that of other domestic mammals and include: polychromasia, macrocytosis, reticulocytosis, and presence of increased number of nucleated erythrocytes.  In addition,  basophilic stippling is often seen during moderate to marked regenerative responses in bovids.

Question 13:  Using succinct medical terminology, describe the leukon on
 Day 1.
Answer:
The leukocyte count was within the reference intervals and was characterized by neutrophilia with a mild left shift, lymphopenia and eosinopenia.

Question 14:  What is your interpretation of the leukogram on Day 1?
Answer:
The neutrophilia with  left shift indicates inflammation.  Lymphopenia and eosinopenia support concurrent stress/release of endogenous corticosteroids.  Corticosteroids may also contribute to the increase in the number of segmented neutrophils.

Question 15:  Is the left shift demonstrated in these hemograms typical of that seen in most adult bovid?  If not, what differences would you expect in an adult cow?
Answer:
Young calves (less than 3-4 months of age) may develop a neutrophilia with a mild to moderate left shift during inflammation.  The leukogram changes are similar to that of dogs and cats.  However, adult cattle often develop a left shift and neutropenia during acute inflammation.  Adult cattle have a small storage pool of neutrophils in the bone marrow and a low number of circulating neutrophils in the peripheral blood.  Sudden demands for phagocytes in the tissues can quickly overwhelm the bone marrow and a  left shift occurs when immature neutrophils are released from the marrow.  A potential dramatic left shift to even metamyelocyte and myelocyte stages can occur.  It may take 1-2 days before the neutrophil count can normalize after the initial insult.

Question 16:  What is the significance of the fibrinogen concentration on
Day 2?
Answer:
The hyperfibrinogenemia with a plasma protein / fibrinogen ratio of less than 10 supports an  interpretation of inflammation.

Question 17: Reactive lymphocytes were noted in the blood smear on Day 5.  What is the significance of this notation?
Answer:
When stimulated by antigens, these lymphocytes undergo morphologic alterations that indicate stimulation of the lymphoid cells to produce cytokines (T-cells) or differentiate further to plasma cells (B-cells) and eventually produce antibody.

Question 18:  What are the morphologic criteria used to recognize reactive lymphocytes?
Answer:
Reactive lymphocytes appear as a slightly larger lymphocyte with condensed chromatin, pale perinuclear Golgi zone and deeply basophilic cytoplasm.  The nucleus may be slightly eccentric in some cells
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