Veterinary Necropsy Guide

Preface xv

List of Contributors xvii

Acknowledgments xix

About the Companion Website xxi

Part I Necropsy Fundamentals 1

1 Introduction to the Necropsy 3

1.1 What Is a Necropsy? 3

1.2 Why Do a Necropsy? 3

1.3 What Information Can and Cannot Be Gained from a Necropsy 3

1.4 When to Refer a Necropsy 4

2 Necropsy Basics 6

2.1 Necropsy Facilities 6

2.2 Necropsy Equipment 6

2.3 Safety Considerations 10

2.3.1 Cuts and Punctures 10

2.3.2 Slips and Falls 11

2.3.3 Zoonotic Disease 11

2.3.4 Formalin 12

2.4 The Importance of a Good History 12

2.5 The Necropsy Report 12

2.5.1 Gross Description 12

2.5.2 Gross Findings 13

2.5.2.1 Inflammatory Lesion 13

2.5.2.2 Fluid in a Body Cavity 13

2.5.2.3 Hemorrhage in an Organ 13

2.5.2.4 Neoplasm, Congenital Defect 13

2.5.3 Gross Diagnosis 13

2.5.4 Comment 13

2.6 Postmortem Changes 14

Part II The Mammalian Necropsy 17

3 The Necropsy 19

3.1 Introduction 19

3.2 Small Animal Necropsy Technique 19

3.2.1 Weigh the Body 19

3.2.2 External Examination 19

3.2.3 Reflect the Skin and Right Limbs 20

3.2.4 Open the Abdominal Cavity 23

3.2.5 Puncture the Diaphragm 23

3.2.6 Open the Thoracic Cavity 24

3.2.7 Open the Pericardium 25

3.2.8 In Situ Examination of Organs 25

3.2.9 Remove the Adrenal Glands 25

3.2.10 Remove the Pluck 26

3.2.11 Remove the Gastrointestinal Tract, Liver, and Spleen 27

3.2.12 Remove the Urogenital Organs 29

3.2.13 Remove the Head 29

3.2.14 Take Out the Eyes 29

3.2.15 Remove the Brain 30

3.2.16 Remove the Pituitary Gland 32

3.3 Modifications for Large Animals 32

3.4 Modifications for Pocket Pets 37

4 The Integumentary System 39

4.1 Anatomy Review and Species Differences 39

4.1.1 Dermis and Epidermis 39

4.1.2 Hair 39

4.1.3 Sweat Glands 41

4.1.4 Sebaceous Glands 41

4.1.5 Mammary Glands 41

4.1.6 Claws 42

4.1.7 Horns 42

4.2 Organ Examination and Sampling 42

4.2.1 Primary Lesions 43

4.2.2 Lesions That May Be Primary or Secondary 44

4.2.3 Secondary Skin Lesions 44

4.2.4 Sampling the Skin 45

4.3 Special Techniques 46

4.3.1 Cytology 47

4.3.2 Skin Scrapes 47

4.3.3 Hair Examination (Trichogram) 47

4.3.4 Hoof/Claw/Nail 47

4.4 Common Artifacts, Incidental Findings, and Postmortem Changes 47

4.5 Common, Classic, and Pathognomonic Lesions 48

5 The Musculoskeletal System 49

5.1 Anatomy Review and Species Differences 49

5.1.1 Bones and Joints 49

5.1.2 Teeth 52

5.1.3 Skeletal Muscle 53

5.2 Organ Examination and Sampling 55

5.2.1 Bones 55

5.2.2 Joints, Tendons, and Ligaments 56

5.2.3 Skeletal Muscle 56

5.3 Special Techniques 56

5.4 Common Artifacts, Incidental Findings, and Postmortem Changes 58

5.5 Classic or Pathognomonic Lesions 58

6 The Cardiovascular System 60

6.1 Anatomy Review and Species Differences 60

6.1.1 Right Heart 60

6.1.2 Left Heart 63

6.1.3 Vessels: Great and Small 63

6.1.4 Embryology, Fetal Circulation, and Congenital Defects 63

6.2 Organ Examination and Sampling 66

6.3 Special Techniques 68

6.4 Common Artifacts, Incidental Findings, and Postmortem Changes 69

6.5 Common, Classic, or Pathognomonic Lesions 71

7 The Respiratory System 72

7.1 Anatomy Review and Species Differences 72

7.2 Organ Examination and Sampling 77

7.2.1 Larynx and Trachea 77

7.2.2 Lungs 78

7.2.3 Nasal Cavity and Sinuses 79

7.3 Special Techniques 79

7.4 Common Artifacts, Incidental Findings, and Postmortem Changes 80

7.5 Common, Classic, and Pathognomonic Lesions 81

8 The Alimentary System 82

8.1 Anatomy Review and Species Differences 82

8.1.1 The Oropharyngeal Cavity 82

8.1.2 The Salivary Glands 82

8.1.3 The Esophagus 82

8.1.4 The Mesentery and Omentum 85

8.1.5 The Stomach 85

8.1.6 The Small Intestine 86

8.1.7 The Large Intestine 87

8.1.8 The Intestinal Vasculature and Nervous System 88

8.2 Organ Examination and Sampling 88

8.2.1 The Esophagus 88

8.2.2 The Gastrointestinal Tract 89

8.3 Special Techniques 90

8.4 Common Artifacts, Incidental Findings, and Postmortem Changes 90

8.5 Common, Classic, and Pathognomonic Lesions 91

9 The Liver and Pancreas 93

9.1 Anatomy Review and Species Differences 93

9.1.1 The Liver 93

9.1.2 The Pancreas 96

9.2 Organ Examination and Sampling 97

9.2.1 The Liver 97

9.2.2 The Pancreas 98

9.3 Special Techniques 99

9.4 Common Artifacts and Postmortem Changes 99

9.4.1 The Liver 99

9.4.2 The Pancreas 99

9.5 Common, Classic, and Pathognomonic Lesions 100

10 The Urogenital System 101

10.1 Anatomy Review and Species Differences 101

10.1.1 Urinary Tract 101

10.1.2 Reproductive Tract 103

10.1.3 Fetal Membranes and Placenta 103

10.1.4 Umbilical Cord 106

10.2 Organ Examination and Sampling 108

10.2.1 Kidneys 109

10.2.2 Ureters 109

10.2.3 Bladder and Urethra 109

10.2.4 Ovaries 109

10.2.5 Oviduct/Uterus/Cervix/Vagina 110

10.2.6 Testes/Epididymides/Ductus Deferens 110

10.2.7 Accessory Sex Glands 110

10.2.8 Fetus, Umbilical Cord, and Fetal Membranes 110

10.2.9 Distal Colon/Rectum/Anus 112

10.3 Special Techniques 112

10.4 Common Artifacts and Postmortem Changes 113

10.5 Common, Classic, and Pathognomonic Lesions 114

11 The Nervous System 115

11.1 Anatomy Review and Species Differences 115

11.2 Organ Examination and Sampling 116

11.2.1 Brain 116

11.2.2 Spinal Cord 120

11.2.3 Peripheral Nerves 121

11.3 Special Techniques 121

11.4 Common Artifacts, Incidental Findings, and Postmortem Changes 121

11.5 Common, Classic, and Pathognomonic Lesions 123

12 The Eye and Ear 124

12.1 Anatomy Review and Species Differences 124

12.1.1 The Eye 124

12.1.2 The Ear 125

12.2 Organ Examination and Sampling 127

12.2.1 The Eye 127

12.2.2 The Ear 128

12.3 Special Techniques 129

12.3.1 The Eye 129

12.3.2 The Ear 130

12.4 Common Artifacts, Incidental Findings, and Postmortem Changes 131

12.5 Common, Classic, or Pathognomonic Lesions 131

13 The Endocrine System 132

13.1 Anatomy Review and Species Differences 132

13.1.1 The Pituitary Gland 132

13.1.2 The Thyroid and Parathyroid Glands 132

13.1.3 The Endocrine Pancreas (Islets of Langerhans) 134

13.1.4 The Adrenal Glands 134

13.2 Organ Examination and Sampling 135

13.2.1 The Pituitary Gland 135

13.2.2 The Thyroid and Parathyroid Glands 135

13.2.3 The Endocrine Pancreas 136

13.2.4 The Adrenal Glands 136

13.3 Special Techniques 137

13.4 Common Artifacts and Postmortem Changes 137

13.5 Common, Classic, and Pathognomonic Lesions 137

14 The Lymphoreticular System 139

14.1 Anatomy Review and Species Differences 139

14.1.1 Thymus 139

14.1.2 Lymph Nodes 139

14.1.3 Spleen 141

14.1.4 Bone Marrow 143

14.1.5 Tonsils 143

14.1.6 Hemal Nodes 143

14.2 Organ Examination and Sampling 143

14.2.1 Thymus 143

14.2.2 Lymph Nodes 144

14.2.3 Spleen 145

14.2.4 Bone Marrow 146

14.2.5 Tonsils 146

14.2.6 Hemal Nodes 147

14.3 Special Techniques 147

14.4 Common Artifacts, Incidental Findings, and Postmortem Changes 147

14.5 Common, Classic, or Pathognomonic Lesions 148

Part III Nonmammalian Necropsies 149

15 Birds 151

15.1 Anatomy Review and Species Differences 151

15.1.1 Integument 151

15.1.2 Musculoskeletal System 153

15.1.3 Cardiovascular System 154

15.1.4 Respiratory Tract 154

15.1.5 Alimentary Tract 155

15.1.6 Hepatobiliary System 156

15.1.7 Urogenital System 157

15.1.8 Nervous System 157

15.1.9 Endocrine System 157

15.1.10 Lymphatic System 158

15.1.11 Special Sense Organs 159

15.2 Safety Considerations 159

15.3 Necropsy Procedure 159

15.3.1 External Examination 159

15.3.2 Skinning the Carcass 159

15.3.3 Opening the Coelomic Cavity 159

15.3.4 Initial Tissue Collection 160

15.3.5 Examination of Organ Systems 160

15.3.6 Brain, Eyes, Joints, Peripheral Nerves, and Bone Marrow 160

15.4 Special Procedures 161

15.5 Common, Classic, and Pathognomonic Lesions 161

16 Reptiles 162

16.1 Anatomy Review and Order Differences 162

16.2 Safety Considerations 166

16.3 Necropsy Procedure 166

16.3.1 External Examination 166

16.3.2 Accessing the Coelom 166

16.3.3 Internal Examination and Organ Removal 168

16.4 Common Artifacts, Incidental Findings, and Postmortem Changes 170

16.5 Common, Classic, and Pathognomonic Lesions 171

17 Amphibians 172

17.1 Anatomy Review and Order Differences 172

17.2 Larval Amphibian Anatomy 176

17.3 Safety Considerations 178

17.4 Necropsy Procedure for Adult Amphibians 178

17.5 Necropsy Procedure for Larval Amphibians 179

17.6 Fixation, Decalcification, and Trimming Considerations 179

17.7 Common Artifacts, Incidental Findings, and Postmortem Changes 180

17.8 Common, Classic, and Pathognomonic Lesions 180

18 Fish 181

18.1 Anatomy Review 181

18.2 Species Differences 182

18.3 Safety Considerations 183

18.4 Necropsy Procedure 184

18.5 Special Techniques 187

18.6 Common Artifacts, Incidental Findings, and Postmortem Changes 187

18.7 Common, Classic, and Pathognomonic Lesions 188

Part IV Additional Testing 189

19 Cytology 191

19.1 Types of Cytology Preparations 191

19.2 Making a Touch Imprint 191

19.3 Making a Bone Marrow Smear 191

19.4 Other Preparations 192

19.5 Staining 192

19.6 Atlas of Normal Tissues 193

20 Histopathology 196

20.1 Necropsy Samples for Histopathology 196

20.2 Fixation 196

20.3 Practical Guidelines to Optimize Fixation 199

21 Infectious Disease Testing 201

21.1 Test Types 201

21.2 Aerobic Culture 201

21.3 Anaerobic Culture 202

21.4 Fungal Culture 203

21.5 Fluorescent Antibody Tests 204

21.6 Pcr 204

21.7 Elisa 204

21.8 Virus Isolation 204

21.9 Fecal Examination 205

21.10 Immunohistochemistry 205

21.11 In Situ Hybridization 205

22 Toxicology Testing 206

23 Packaging and Shipping Samples 210

23.1 Packing Samples to Send to the Lab 211

Part V Special Cases 213

24 Forensic Necropsies 215

24.1 What Is a Forensic Necropsy? 215

24.2 Who Should Perform a Forensic Necropsy? 215

24.3 How Is a Forensic Necropsy Different from a Diagnostic Necropsy? 215

24.4 Before the Necropsy 216

24.5 The Forensic Necropsy Procedure 217

24.6 Forensic Necropsy Report 219

Part VI Appendices 221

Appendix 1 Normal Organ Weights (Percentage Body Weight) 223

Appendix 2 Describing Gross Lesions 233

A2. 1 Location 233

A. 2 Distribution 233

A2. 3 Number/Extent 233

A2. 4 Size/Weight 233

A2. 5 Color 233

A2. 6 Consistency 234

A2. 7 Texture 234

A2. 8 Shape 234

A2. 9 Lesion borders 234

A2. 10 Liquids 234

A2. 11 Odor 234

Appendix 3 Tissue Collection Checklists 235

Standard Set of Tissues for Histopathology 235

Additional Tissues for Histopathology, if History Warrants 235

Samples for Toxicology 236

Samples for Infectious Disease Testing 236

Abscess 236

Respiratory disease 236

Diarrhea 236

Abortion 236

Neurologic disease 236

Appendix 4 Online Resources 237

Index 239