Differential Diagnosis in Small Animal Medicine

About the authors Alex Gough, MA, VetMB, CertSAM, CertVC, PGCert (Neuroimaging), MRCVS Alex is the director of a referral and first opinion practice in Bath, UK, where he sees referrals in small animal medicine, cardiology and neurology. He is a holder of the Royal College of Veterinary Surgeons Certificate of Small Animal Medicine and Veterinary Cardiology and a Postgraduate Certificate in Neuroimaging for Research. He is the author of Breed Predispositions to Disease in Dogs and Cats (with Alison Thomas, Wiley-Blackwell, 2010) and is a frequent contributor to the Veterinary Times. Kate Murphy, BVSc (Hons), DSAM, DipECVIM-CA, MRCVS, PGCert(HE) Kate is the clinical lead in a referral practice in Bristol, UK, where she sees a wide spectrum of medicine cases. Before working in referral practice, Kate was a small animal medicine clinician at the University of Bristol from 2002 to early 2011 where she ran the intensive care and emergency medicine service and also the medicine referral team. She is a diplomate of the European College of Veterinary Internal Medicine. Kate is co-author of Notes on Canine Internal Medicine (with Edward Hall and Peter Darke, Wiley-Blackwell, 2004), has contributed chapters to BSAVA manuals and also has a number of peer-reviewed publications.

"Differential Diagnosis in Small Animal Medicine is not a book, it is a tool – and very useful one." (European Journal of Companion Animal Practice, 1 October 2015)"It will be handy for your clinical rota but I'm certain you will keep it when in practice." (Vet Nurses Today, 1 October 2015)"The second edition of Differential Diagnosis in Small Animal Medicineis an excellent resource for third- and fourth-year veterinary students on clinical rotations and new graduates who are in need of a compact, pocket-friendly reference with a problem-oriented approach to clinical cases." (Journal of the American Veterinary Medical Association, 15 June 2015)"I would say this book allows for peace of mind that every possible avenue has been explored. When dealing with a returning patient, which requires more in-depth examination, the book may well come into its own. The list-like structure makes referencing simple and clear, and explains the varying diagnosis resulting from a huge range of clinical signs and biological data." (Veterinary Record, 2016)

• Introduction 1Part 1: Historical Signs 51.1 General, systemic and metabolic historical signs 51.1.1 Polyuria/polydipsia 51.1.2 Weight loss 71.1.3 Weight gain 91.1.4 Polyphagia 101.1.5 Anorexia/inappetence 111.1.6 Failure to grow 131.1.7 Syncope/collapse 141.1.8 Weakness 181.2 Gastrointestinal/abdominal historical signs 221.2.1 Ptyalism/salivation/hypersalivation 221.2.2 Gagging/retching 241.2.3 Dysphagia 261.2.4 Regurgitation 271.2.5 Vomiting 281.2.6 Diarrhoea 341.2.7 Melaena 401.2.8 Haematemesis 421.2.9 Haematochezia 441.2.10 Constipation/obstipation 461.2.11 Faecal tenesmus/dyschezia 481.2.12 Faecal incontinence 491.2.13 Flatulence/borborygmus 501.3 Cardiorespiratory historical signs 511.3.1 Coughing 511.3.2 Dyspnoea/tachypnoea 521.3.3 Sneezing and nasal discharge 531.3.4 Epistaxis 551.3.5 Haemoptysis 561.3.6 Exercise intolerance 581.4 Dermatological historical signs 591.4.1 Pruritus 591.5 Neurological historical signs 611.5.1 Seizures 611.5.2 Trembling/shivering 651.5.3 Ataxia 671.5.4 Paresis/paralysis 761.5.5 Coma/stupor 801.5.6 Altered behaviour: General changes 821.5.7 Altered behaviour: Specific behavioural problems 841.5.8 Deafness 851.5.9 Multifocal neurological disease 871.6 Ocular historical signs 901.6.1 Blindness/visual impairment 901.6.2 Epiphora/tear overflow 931.7 Musculoskeletal historical signs 951.7.1 Forelimb lameness 951.7.2 Hindlimb lameness 991.7.3 Multiple joint/limb lameness 1031.8 Reproductive historical signs 1041.8.1 Failure to observe oestrus 1041.8.2 Irregular seasons 1061.8.3 Infertility in the female with normal oestrus 1071.8.4 Male infertility 1081.8.5 Vaginal/vulval discharge 1111.8.6 Abortion 1111.8.7 Dystocia 1121.8.8 Neonatal mortality 1141.9 Urological historical signs 1151.9.1 Pollakiuria/dysuria/stranguria 1151.9.2 Polyuria/polydipsia 1151.9.3 Anuria/oliguria 1161.9.4 Haematuria 1171.9.5 Urinary incontinence/inappropriate urination 119Part 2: Physical Signs 1212.1 General/miscellaneous physical signs 1212.1.1 Abnormalities of body temperature – hyperthermia 1212.1.2 Abnormalities of body temperature – hypothermia 1272.1.3 Enlarged lymph nodes 1272.1.4 Diffuse pain 1302.1.5 Peripheral oedema 1302.1.6 Hypertension 1322.1.7 Hypotension 1332.2 Gastrointestinal/abdominal physical signs 1352.2.1 Oral lesions 1352.2.2 Abdominal distension 1372.2.3 Abdominal pain 1382.2.4 Perianal swelling 1412.2.5 Jaundice 1422.2.6 Abnormal liver palpation 1442.3 Cardiorespiratory physical signs 1462.3.1 Dyspnoea/tachypnoea 1462.3.2 Pallor 1512.3.3 Shock 1512.3.4 Cyanosis 1532.3.5 Ascites 1552.3.6 Abnormal respiratory sounds 1552.3.7 Abnormal heart sounds 1562.3.8 Abnormalities in heart rate 1602.3.9 Jugular distension/hepatojugular reflux 1632.3.10 Alterations in arterial pulse 1632.4 Dermatological signs 1642.4.1 Scaling 1642.4.2 Pustules and papules (including miliary dermatitis) 1662.4.3 Nodules 1682.4.4 Pigmentation disorders (coat or skin) 1702.4.5 Alopecia 1722.4.6 Erosive/ulcerative skin disease 1742.4.7 Otitis externa 1762.4.8 Pododermatitis 1782.4.9 Disorders of the claws 1802.4.10 Anal sac/perianal disease 1822.5 Neurological signs 1832.5.1 Abnormal cranial nerve (CN) responses 1832.5.2 Vestibular disease 1862.5.3 Horner’s syndrome 1892.5.4 Hemineglect syndrome (Forebrain dysfunction q.v.) 1902.5.5 Spinal disorders 1902.6 Ocular signs 1922.6.1 Red eye 1922.6.2 Corneal opacification 1972.6.3 Corneal ulceration/erosion 1982.6.4 Lens lesions 2002.6.5 Retinal lesions 2012.6.6 Intraocular haemorrhage/hyphaema 2032.6.7 Abnormal appearance of anterior chamber 2042.7 Musculoskeletal signs 2042.7.1 Muscular atrophy or hypertrophy 2042.7.2 Trismus (‘lockjaw’) 2062.7.3 Weakness 2072.8 Urogenital physical signs 2072.8.1 Kidneys abnormal on palpation 2072.8.2 Bladder abnormalities 2082.8.3 Prostate abnormal on palpation 2102.8.4 Uterus abnormal on palpation 2102.8.5 Testicular abnormalities 2112.8.6 Penis abnormalities 211Part 3: Radiographic and Ultrasonographic Signs 2133.1 Thoracic radiography 2133.1.1 Artefactual causes of increased lung opacity 2133.1.2 Increased bronchial pattern 2133.1.3 Increased alveolar pattern 2143.1.4 Increased interstitial pattern 2173.1.5 Increased vascular pattern 2203.1.6 Decreased vascular pattern 2213.1.7 Cardiac diseases that may be associated with a normal cardiac silhouette 2223.1.8 Increased size of cardiac silhouette 2223.1.9 Decreased size of cardiac silhouette 2233.1.10 Abnormalities of the ribs 2243.1.11 Abnormalities of the oesophagus 2253.1.12 Abnormalities of the trachea 2283.1.13 Pleural effusion 2303.1.14 Pneumothorax 2323.1.15 Abnormalities of the diaphragm 2333.1.16 Mediastinal abnormalities 2343.2 Abdominal radiography 2373.2.1 Liver 2373.2.2 Spleen 2393.2.3 Stomach 2413.2.4 Intestines 2443.2.5 Ureters 2513.2.6 Bladder 2513.2.7 Urethra 2543.2.8 Kidneys 2553.2.9 Loss of intra-abdominal contrast 2583.2.10 Prostate 2603.2.11 Uterus 2613.2.12 Abdominal masses 2613.2.13 Abdominal calcification/mineral density 2623.3 Skeletal radiography 2643.3.1 Fractures 2643.3.2 Altered shape of the long bones 2643.3.3 Dwarfism 2653.3.4 Delayed ossification/growth plate closure 2663.3.5 Increased radiopacity 2663.3.6 Periosteal reactions 2673.3.7 Bony masses 2673.3.8 Osteopenia 2683.3.9 Osteolysis 2703.3.10 Mixed osteolytic/osteogenic lesions 2713.3.11 Joint changes 2713.4 Radiography of the head and neck 2753.4.1 Increased radiopacity/bony proliferation of the maxilla 2753.4.2 Decreased radiopacity of the maxilla 2753.4.3 Increased radiopacity/bony proliferation of the mandible 2763.4.4 Decreased radiopacity of the mandible 2763.4.5 Increased radiopacity of the tympanic bulla 2763.4.6 Decreased radiopacity of the nasal cavity 2773.4.7 Increased radiopacity of the nasal cavity 2773.4.8 Increased radiopacity of the frontal sinuses 2793.4.9 Increased radiopacity of the pharynx 2793.4.10 Thickening of the soft tissues of the head and neck 2803.4.11 Decreased radiopacity of the soft tissues of the head and neck 2813.4.12 Increased radiopacity of the soft tissues of the head and neck 2813.5 Radiography of the spine 2823.5.1 Normal and congenital variation in vertebral shape and size 2823.5.2 Acquired variation in vertebral shape and size 2833.5.3 Changes in vertebral radiopacity 2853.5.4 Abnormalities in the intervertebral space 2863.5.5 Contrast radiography of the spine (myelography) 2873.6 Thoracic ultrasonography 2893.6.1 Pleural effusion 2893.6.2 Mediastinal masses 2903.6.3 Pericardial effusion 2903.6.4 Altered chamber dimensions 2913.6.5 Changes in ejection phase indices of left ventricular performance (fractional shortening, FS%; ejection fraction, EF) 2943.7 Abdominal ultrasonography 2943.7.1 Renal disease 2943.7.2 Hepatobiliary disease 2973.7.3 Splenic disease 3003.7.4 Pancreatic disease 3013.7.5 Adrenal disease 3023.7.6 Urinary bladder disease 3023.7.7 Gastrointestinal disease 3043.7.8 Ovarian and uterine disease 3053.7.9 Prostatic disease 3063.7.10 Ascites 3063.8 Ultrasonography of other regions 3083.8.1 Testes 3083.8.2 Eyes 3093.8.3 Neck 311Part 4: Laboratory Findings 3134.1 Biochemical findings 3134.1.1 Albumin 3134.1.2 Alanine transferase 3154.1.3 Alkaline phosphatase 3164.1.4 Ammonia 3184.1.5 Amylase 3194.1.6 Aspartate aminotransferase 3204.1.7 Bilirubin 3214.1.8 Bile acids/dynamic bile acid test 3224.1.9 C-reactive protein (D) 3224.1.10 Cholesterol 3234.1.11 Creatinine 3244.1.12 Creatine kinase 3244.1.13 Ferritin 3254.1.14 Fibrinogen 3264.1.15 Folate 3264.1.16 Fructosamine 3274.1.17 Gamma-glutamyl transferase 3274.1.18 Gastrin 3284.1.19 Globulins 3294.1.20 Glucose 3304.1.21 Iron 3334.1.22 Lactate dehydrogenase 3334.1.23 Lipase 3354.1.24 Triglycerides 3364.1.25 Troponin 3374.1.26 Trypsin-like immunoreactivity 3384.1.27 Urea 3384.1.28 Vitamin B12 (cobalamin) 3414.1.29 Zinc 3414.2 Haematological findings 3424.2.1 Regenerative anaemia 3424.2.2 Poorly/non-regenerative anaemia 3454.2.3 Polycythaemia 3484.2.4 Thrombocytopenia 3504.2.5 Thrombocytosis 3534.2.6 Neutrophilia 3544.2.7 Neutropenia 3554.2.8 Lymphocytosis 3574.2.9 Lymphopenia 3584.2.10 Monocytosis 3594.2.11 Eosinophilia 3604.2.12 Eosinopenia 3614.2.13 Mastocytemia 3614.2.14 Basophilia 3624.2.15 Increased buccal mucosal bleeding time (disorders of primary haemostasis) 3624.2.16 Increased prothrombin time (disorders of extrinsic and common pathways) 3634.2.17 Increased partial thromboplastin time or activated clotting time (disorders of intrinsic and common pathways) 3634.2.18 Increased fibrin degradation products 3644.2.19 Decreased fibrinogen levels 3644.2.20 Decreased antithrombin III levels 3644.3 Electrolyte and blood gas findings 3654.3.1 Total calcium 3654.3.2 Chloride 3674.3.3 Magnesium 3694.3.4 Potassium 3714.3.5 Phosphate 3734.3.6 Sodium 3754.3.7 pH 3774.3.8 pa02 3794.3.9 Total C02 3814.3.10 Bicarbonate 3814.3.11 Base excess 3814.4 Urinalysis findings 3814.4.1 Alterations in specific gravity 3814.4.2 Abnormalities in urine chemistry 3834.4.3 Abnormalities in urine sediment 3884.4.4 Infectious agents 3904.5 Cytological findings 3924.5.1 Tracheal/bronchoalveolar lavage 3924.5.2 Nasal flush cytology 3944.5.3 Liver cytology 3954.5.4 Kidney cytology 3974.5.5 Skin scrapes/hair plucks/tape impressions 3984.5.6 Cerebrospinal fluid (CSF) analysis 3984.5.7 Fine-needle aspiration of cutaneous/ subcutaneous masses 4004.6 Hormones/endocrine testing 4014.6.1 Thyroxine 4014.6.2 Parathyroid hormone 4034.6.3 Cortisol (baseline or post-ACTH stimulation test) 4044.6.4 Insulin 4054.6.5 Acth 4054.6.6 Vitamin D (1,25-dihydroxycholecalciferol) 4054.6.7 Testosterone 4064.6.8 Progesterone 4064.6.9 Oestradiol 4074.6.10 Pro-BNP 4074.7 Faecal analysis findings 4084.7.1 Faecal blood 4084.7.2 Faecal parasites 4084.7.3 Faecal culture 4094.7.4 Faecal fungal infections 4094.7.5 Undigested food residues 409Part 5: Electrodiagnostic Testing 4105.1 Electrocardiographic findings 4105.1.1 Alterations in P wave 4105.1.2 Alterations in QRS complex 4115.1.3 Alterations in P–R relationship 4135.1.4 Alterations in S–T segment 4145.1.5 Alterations in Q–T interval 4155.1.6 Alterations in T wave 4165.1.7 Alterations in baseline 4165.1.8 Rhythm alterations 4165.1.9 Alterations in rate 4205.2 Electromyographic findings 4225.2.1 Spontaneous activity 4225.2.2 Evoked activity 4235.3 Nerve conduction velocity findings 4235.3.1 Decreased velocity 4235.3.2 Increased velocity 423Index 424