Lecture 8

Question 1

What are the individual variation challenges with birds and reptiles in terms of clin. path.?

Answer 1

-more extensive variability
-seasonal changes
-sexual dimorphism
-reproductive status
-environment and husbandry impacts

Question 2

Why is determining “normal” for non-mammalian species difficult?

Answer 2

-individual labs often have insufficient patient numbers or funds for quality RI establishment
-published RIs often have widely variable sample sizes and analytical methods
-defining health in wild animals can be difficult
-data simply non-existent for many species

Question 3

What is important to remember when interpreting blood work results in non-mammals?

Answer 3

-use published reference intervals or values with caution
-rely on “first principles” and anchors
-do serial monitoring of changes with uncertain significance
-wellness testing can help to establish “normals” for a patient

Question 4

What are the guidelines for blood sample collection in non-mammals?

Answer 4

-can be a limiting factor
-do not want to remove more than 1% body weight in healthy animals
-should limit collection to 0.5% body weight in sick animals

Question 5

How much blood is need to run a full CBC/chem at specialized labs?

Answer 5

0.2 to 0.3 mL of blood

Question 6

What are the pros of using lithium heparin tubes for non-mammalians?

Answer 6

-can be used for both hematology and chemistry
-avoids EDTA-mediated cell lysis
-generates higher volume of plasma versus volume of serum from clotted blood

Question 7

What are the cons of using lithium heparin tubes for non-mammalians?

Answer 7

-inferior cell preservation vs. EDTA
-thrombocytes clump more vs EDTA
-gives a blue “tinge” to stained blood smears

Question 8

What are the components of a hemogram in non-mammals?

Answer 8

-spun PCV
-manual WBC count (all cells are nucleated; cannot automate)
-total protein via refractometry
-blood smear evaluation and manual leukocyte differential count

Question 9

How is a manual WBC count done?

Answer 9

phloxine dye stains granules in heterophils and eosinophils

Question 10

What are the characteristics of total protein via refractometer?

Answer 10

-estimation of protein in plasma
-expressed as conc. in g/dL
-light refraction proportional to solids in solution
-refractometers are calibrated for mammals; accuracy in non-mammals is questionable

Question 11

What is the opinion on fasting prior to blood work in non-mammals?

Answer 11

fasting not recommended, especially for smaller species

Question 12

What are the characteristics of normal erythrocyte evaluation in birds?

Answer 12

-PCV of 35-55%
-up to 5% polychromatophils
-RBC half-life of 28 to 45 days

Question 13

What are the characteristics of normal erythrocyte evaluation in reptiles?

Answer 13

-PCV of 20-45%
-0-1% polychromatophils
-RBC half-life of 600 to 800 days

Question 14

What are the characteristics of regenerative vs. non-regenerative anemia?

Answer 14

Regenerative:
-decreased PCV
-increased polychromasia
-mechanisms include hemorrhage or hemolysis

Non-Regenerative:
-decreased PCV
-absent or normal percent of polychromasia
-mechanism includes reduced erythropoiesis

Question 15

What are other erythrocyte morphologic changes that might be seen on a blood smear?

Answer 15

-anisocytosis (variable size)
-hypochromasia
-poikilocytosis (variable shape)
-hemoparasites

Question 16

What are the characteristics of heterophils?

Answer 16

-rod-shaped brown-pink granules; may have a refractile core
-functionally similar to a neutrophil
-predominant leukocyte in most birds and some reptiles
-morphologic variability between species
-lobulated nucleus in most species except chelonians and snakes
-cytoplasm is clear

Question 17

What are the characteristics of left shift and toxic change?

Answer 17

-left shift and toxic change indicate acute inflammation
-nuclear shape changes for left shift are similar to mammals but more difficult to visualize
-toxic change characterized by increasing cytoplasmic basophilia, degranulation, and visible primary granules

Question 18

What are the characteristics of eosinophils?

Answer 18

-usually have rounder, brighter pink granules than heterophils
-usually have light blue cytoplasm
-present in low numbers in birds and lizards
-up to 20% of leukocytes in other reptiles
-psittacines and iguanas have blue to lavender granules

Question 19

What are the characteristics of basophils?

Answer 19

-intensely staining dark purple granules
-granules can obscure nucleus
-low numbers in birds
-higher proportions in reptiles
-can be predominant leukocyte in some chelonians

Question 20

What are the characteristics of monocytes?

Answer 20

-resemble mammalian counterpart with similar function
-monocytosis seen frequently with chronic disease in birds and reptiles

Question 21

What are the characteristics of azurophils?

Answer 21

-only found in reptiles
-resembles monocyte with pink hue and/or discrete pink granules in cytoplasm
-functionally similar to monocytes
-azurophilia associated with infection

Question 22

What are the characteristics of lymphocytes?

Answer 22

-resemble mammalian counterparts
-can be the predominant leukocyte in some birds and reptiles
-increased cytoplasmic basophilia with antigenic stimulation

Question 23

What are the characteristics of thrombocytes?

Answer 23

-frequently clumped in blood smear
-condensed chromatin
-clear to pale blue cytoplasm
-cytoplasm often vacuolated
-round or oval shape
-thrombocyte conc. lower than in mammals

Question 24

How can a leukogram be determined to be inflammation vs corticosteroid-induced?

Answer 24

*inflammation:
-increased segmented heterophils
-normal to increased bands
-normal or increased monocytes
-normal lymphocytes

*corticosteroid-induced:
-increased segmented heterophils
-normal bands
-normal or increased monocytes
-decreased lymphocytes

Question 25

What are the characteristics of acute leukemia?

Answer 25

-uncommon -persistent, unexplained increase in large, immature cells

Question 26

What are the characteristics of chronic lymphocytic leukemia?

Answer 26

-uncommon -persistent, unexplained increase in small lymphocytes -can be associated with avian leukosis virus in poultry

Question 27

What are the characteristics of hemoproteus?

Answer 27

-intraerythrocytic gametocytes -occupy approx. 1/2 of RBC cytoplasm -wrap around nucleus without displacement -contain refractile, yellowish-brown pigment -common in wild birds -transmitted by louse fly -infected birds usually asymptomatic -hemolytic anemia rare

Question 28

What are the characteristics of plasmodium?

Answer 28

-intraerythrocytic -may be seen in thrombocytes and leukocytes -may displace RBC nucleus -often refractile, yellow-brown pigment -most common in passerines -transmitted by mosquitoes -many birds asymptomatic carriers -can cause hemolytic anemia -need PCR to differentiate from hemoproteus

Question 29

What are the characteristics of Leukocytozoon?

Answer 29

-intraerythrocytic -gross distortion of host cell -does not contain pigment -transmitted by black flies -seen in raptors and waterfowl -low pathogenicity -hemolytic anemia rare

Question 30

What are the characteristics of hemogregarines?

Answer 30

-common hemoparasite of reptiles -sausage-shaped intraerythrocytic gametocytes -usually only one per cell -parasite displaces nucleus to cell margin -organism lacks refractile pigment -transmitted by various biting insects -usually do not cause clinical disease

Question 31

What are the characteristics of microfilaria?

Answer 31

-many different species based on host and geography -usually considered an incidental, non-pathogenic finding

Question 32

What other inclusions can be seen on blood smears?

Answer 32

*degrading organelles: -small basophilic intraerythrocytic inclusions in reptiles *inclusions of unknown origin: -small clear round to polygonal intraerythrocytic inclusions in reptiles *inclusion body disease: -smooth pale blue viral inclusions -seen in lymphocytes, heterophils, and erythrocytes

Question 33

What is the Biuret method?

Answer 33

reliable method for total protein quantification in non-mammalian species

Question 34

What are the characteristics of bromocresol green dye-binding?

Answer 34

-preferentially binds to albumin -causes color change -read spectrophotometrically

Question 35

What are the cons to bromocresol green dye-binding?

Answer 35

-will bind to some globulins, esp. if albumin is low -hemolysis can cause interference -unreliable in most mammalian species

Question 36

What are the characteristics of protein electrophoresis?

Answer 36

-plasma is applied to agarose gel and proteins migrate towards positive anode or negative cathode -separates proteins based on size, shape, and charge -densitometer translates bands into peaks -area under each peak is proportional to % of fraction in serum -highly variable between species in birds and reptiles

Question 37

What are the characteristics of AST in non-mammalians?

Answer 37

-most sensitive indicator of hepatocellular injury -not liver-specific -evaluate AST and CK in tandem

Question 38

What are the characteristics of GLDH in non-mammalians?

Answer 38

-most specific indicator of hepatocellular injury -not available at every lab

Question 39

What are the characteristics of ALT in non-mammalian species?

Answer 39

not clinically useful

Question 40

What are the characteristics of ALKP in non-mammalian species?

Answer 40

-associated with osteoblastic activity, bone remodeling, or egg-shell deposition -may indicate hepatobiliary dz

Question 41

What are the characteristics of GGT in non-mammalian species?

Answer 41

not clinically useful

Question 42

What are the characteristics of the liver function tests in non-mammalian species?

Answer 42

*albumin: -routine method of measurement not likely accurate *BUN: -utility as liver function marker not clear *cholesterol: -may be markedly inc. during vitellogenesis and egg formation *glucose: -may be decreased in birds with liver insufficiency but rarely reported *bilirubin: -not synthesized in appreciable quantities -biliverdin is end product of hemoglobin catabolism

Question 43

What are the characteristics of bile acids?

Answer 43

-increased conc. of BAs associated with hepatic insufficiency in birds -use of paired fasting and postprandial samples in birds is complicated by anatomy and physiology -fasted sample preferred but contraindicated in sick birds or small species

Question 44

What are the characteristics of uric acid?

Answer 44

-primarily excreted by renal tubules and utilized to detect kidney dz -insensitive; must have > 75% loss before increase is seen -nonspecific; affected by species, age, diet, and other disease -dehydration only causes changes if severe -main clinical use is monitoring progression or response to therapy

Question 45

What are the characteristics of BUN and creatinine?

Answer 45

-poor markers of renal disease -BUN may be better than uric acid as a marker of prerenal azotemia in birds -BUN may be of some value as a marker in some aquatic reptiles

Question 46

What are the characteristics of glucose?

Answer 46

-normally higher in birds than mammals -highly species-dependent -pathologic processes causing glucose imbalances in birds are similar to those in mammals

Question 47

What are the characteristics of calcium and phosphorus?

Answer 47

-total calcium may be markedly inc. in oviparous birds and reptiles -calcium is bound to vitellogenic proteins -hypocalcemia associated with malnutrition and chronic egg laying -other disorders that cause Ca and/or P imbalances in birds and reptiles are similar to those in mammals -secondary nutritional hyperparathyroidism seen in herbivorous reptiles on low Ca:P diets