Clinical Pathology Considerations for Wildlife

1
Clinical Pathology Considerations for Wildlife

• Mark A. Mitchell DVM, MS, PhD
• University of Illinois
• College of Veterinary Medicine

2
Introduction

• Wildlife
• stoic
• evolved to mask illness
• Treat n run?
• Diagnostic Tests
• to identify physiologic anomalies

3
How much blood can you collect???
4
Blood Collection

• Blood volume
• 8-10 of body weight of birds
• General rule of thumb
• 0.8-1.0 ml/100 g (avian and mammal)
• 0.5-0.8 ml/100 g (reptiles)

Where do you collect it from????
5
Venipuncture sites
6
Venipuncture sites
7
Venipuncture sites
8
Venipuncture Sites Lizards
Ventral tail vein
9
Venipuncture sites Lizards
Jugular vein

• Ventral coccygeal/tail vein
• Ventral abdominal vein
• Cardiac- euthanasia
• Toe nail- never

10
(No Transcript)
11
Ventral abdominal vein
12
Venipuncture sites Snakes
Venipuncture Sites Snakes

• Cardiac
• Ventral tail vein
• Palatine
• Jugular

Cardiac
13
Ventral tail vein
14
Jugular vein
15
Palatine vein
16
Venipuncture sites Chelonians

• Jugular
• Dorsal coccygeal
• Brachial
• Subcarapacial

17
(No Transcript)
18
(No Transcript)
19
Blood collection tubes

• CBC
• EDTA or lithium heparin
• Plasma chemistry
• Lithium heparin

EDTA
LH
20
Hematology

• Evaluating the packed cell volume
• Reference ranges
• Birds40-55
• Mammals 30-55
• Reptiles 20-40
• Low values?
• Chronic inflammation
• Trauma blood loss
• Immune mediated
• Not making
• When are you concerned?
• Transfusion??

21
Hematology

• Evaluating the packed cell volume
• Buffy coat
• anecdotal used to estimate WBC (mammals)
• limited samples suggest not useful
• Lawton and Divers, 1999
• Serum
• appearance

22
Hematology Slide Preparation

• Techniques
• Standard slide technique
• cell destruction in avian and reptile patients
• 1 drop 22 bovine albumin 5 drops blood

23
(No Transcript)
24
Hematology Slide Preparation
25
Hematology Evaluating the erythron

• Total Red Blood Cell Count
• Manual techniques
• Erythrocyte Unopette system
• Natt and Herricks solution

26
Hematology

• Erythrocytes
• mature cells
• ellipsoid with central nucleus
• cytoplasm- orange-pink
• immature cells
• small, round cells increased NC ratio
• basophilic cytoplasm

Mature
Immature
27
Hematology

• Erythrocytes
• abnormal shapes and sizes
• regeneration
• basophilic stippling
• anemia, iron deficiency
• hypochromatosis-
• iron deficiency anemia, chronic blood loss

28
Hematology

• Blood parasites
• common wild caught specimens
• evaluate overall health
• evaluate erythron
• anemia?
• regenerative

29
Hematology Leukocytes

• Birds and Reptiles
• Manual counts necessary because of nucleated RBCs
  and thrombocytes
• Natt Herricks technique
• Stains blue
• Small lymphocytes and thrombocytes appear similar
• Phloxine B solution
• Stains heterophils and eosinophils red
• Total WBC count determined after differential

30
Hematology Leukocytes

• Counting white blood cells
• Hemocytometer
• mammals recommend count all 64 squares
• Doxley, 1989
• avian count 4 large squares
• Hawkey and Samour, 1988

31
(No Transcript)
32
Hematology Leukocytes

• Counting white blood cells
• Hemocytometer
• mammals recommend count all 64 squares
• Doxley, 1989
• avian count 4 large squares
• Hawkey and Samour, 1988
• reptiles count 9 large squares
• Campbell, 1996
• reptiles no difference between counting 10 or 40
  large squares
• Lawton and Divers, 1999

33
Complete blood counts

• Cell types
• Heterophils-Neutrophils
• Eosinophils
• Basophils
• Lymphocytes
• Monocytes
• Measures current status
• Elevated?
• Time frame?
• Iguana study

34
Hematology Leukocytes

• Circulating pool very large
• Reptile study
• Salmonella SQ
• 12 hr 45.0-76.0 x 103
• 24-48 h returned to normal

35
Clinical pathology

• Complete blood count
• Methods
• Eosinophil unopette estimate and differential
• Misclassification
• Sample quality
• Volume
• Transport
• Lab/Technician
• Sensitivity and specificity variable with
  application

36
Effect of sampling site??
37
Clinical pathology

• Normal ranges?????
• WBC
• Mean 4.8 x 103
• SD 2.5
• gt 2 SD WBC0?
• Best measure central tendency?

38
Clinical pathology

• Data presentation Percentages
• White blood cell count 4.8-15.6 x 103
• Heterophils 48-75
• 2.3 x 103 (48 of 4.8)
• 11.7 x 103 (75 of 15.6)
• Prefer to use absolutes

39
Mitchells Rules

• WBC 5-15,000 cells/ml
• Heterophil Lymphocyte ratio
• 11-31
• Raptors- heterophil predominant cell
• Lymphocytes
• lt1,500 cells/ml absolute lymphopenia
• Monocytes
• lt 500 cells/ml normal
• 500-1,000 cells/ml stress
• gt1,500 cells/ml chronic inflammation
• Eosinophils and basophils
• lt 500 cells/ml

40
Hematology Granulocytes

• Heterophils
• fusiform granules
• large round, acentric nucleus
• function-
• phagocytosis
• heterophilia
• inflammation, stress
• seasonal
• increase summer

41
(No Transcript)
42
Hematology Granulocytes

• Toxic heterophils
• suggestive of infectious cause
• indicative of severity
• changes
• degranulation
• cell swelling
• cytoplasmic vacuolization

43
Hematology Granulocytes

• Eosinophil
• large, round cells
• spherical granules
• nucleus centrally located
• function-
• parasitemia
• seasonal variation
• increased winter

44
Hematology Granulocytes
45
Hematology Granulocytes

• Basophils
• small, spherical cells
• basophilic meta-chromatic granules
• function
• histamine release

46
Hematology Lymphocyte

• Lymphocytes
• small, basophilic staining
• acentric nucleus
• function
• B cells- Ab production
• T cells moderate immune function
• seasonal variation
• decreased in winter

47
Hematology Monocyte

• Largest WBC
• cytoplasm- blue-gray
• function
• granuloma formation
• antigenic processing
• chronic inflammation

48
(No Transcript)
49
Hematology

• Thrombocytes
• central nucleus
• confused with lymphocytes
• functions- thrombus formation, clot, wound
  healing
• gt200,000 cells/ml

50
Plasma Chemistries

• Reference material limited
• Affected by seasonal, environmental, gender and
  nutritional changes
• Sample size considerations

51
Equipment

• Abaxis VetScan
• Small sample volumes required
• Whole blood or plasma
• Portable
• Rapid
• No calibration time

52
Plasma Chemistries

• Glucose
• reference range highly variable
• avian 100-400 mg/dl
• hypoglycemia
• starvation, septicemia, hepatopathies, high
  protein diets,
• hyperglycemia
• rare

53
Plasma Chemistries

• Protein
• avian 2.5-6.0 mg/dl
• Mammal and reptile 4-8 mg/dl
• Hyperproteinemia
• dehydration
• elevated globulins- serum electrophoresis
• alpha 1, alpha 2, beta 1, beta 2, gamma
• Hypoproteinemia
• malnutrition, malabsorption, blood loss, hepatic
  or renal failure

54
Plasma Chemistries

• Uric Acid
• primary catabolic end-product of protein
• reference range lt 10-15 mg/dl
• hyperuricemia
• renal disease, dehydration, gout
• affected by diet carnivores
• not specific to renal function

55
Plasma Chemistries

• Sodium (140-160 mg/dl)
• hypernatremia- dehydration, renal disease,
  re-feeding syndrome
• hyponatremia- diarrhea, diet
• Chloride (90-120 mg/dl)
• hyperchloremia- dehydration, renal disease
• Potassium (2-6 mg/dl)
• hypokalemia diet, diarrhea
• re-feeding syndrome- shift extra- to intracellular

56
Plasma Chemistries

• Aspartate aminotransferase (AST)
• present in all body tissues
• elevated levels in liver and muscle
• Alanine aminotransferase (ALT)
• Hepatocytes- mammals
• Unreliable- birds and reptiles
• Creatine kinase (CK)
• skeletal muscle
• rule-out liver disease with AST

57
Plasma Chemistries

• Calcium
• measures total calcium
• ionized biologically active
• unionized bound to protein or complexed
• reduced pH increases ionic form
• e.g., apnea- anesthesia
• increased likelihood for calcification

58
Plasma Chemistries

• Calcium
• reference ranges 8-12 mg/dl
• calcium to phosphorus ratio
• calcium-phosphorus product

59
Plasma Chemistries

• Calcium
• hypocalcemia
• renal compromise
• nutritional imbalance
• certain speciesAfrican Grey
• hypercalcemia
• primary hyperparathyroidism
• folliculogenesis

60
Plasma Chemistries

• Phosphorus
• reference range 2-6 mg/dl
• hyperphosphatemia
• renal disease, hypervitaminosis D, excessive
  dietary phosphorus, folliculogenesis
• hypophosphatemia
• starvation (re-feeding syndrome), dietary
  imbalance

61
Plasma Chemistries

• Bile Acids
• sensitive indicator of liver function in birds
• elevations in bile acid- liver biopsy
• Pre-prandial and post-prandial levels identified
  in some species of psittacines

62
Questions?
Questions??