SA Differential Diagnoses of Clinical Signs

Question 1

Alopecia

Answer 1

INFLAMMATORY: Infectious, Immune-mediated, Traumatic, Atrophic
NON-INFLAMMATORY: Hormonal, Other (less common)

Question 2

Anuria & Oliguria

Answer 2

PRE-RENAL: dehydration, hypovolemia, hypotension
RENAL: Infectious, toxic (endo vs exo), ischemic (thrombi), immune-mediated
POST-RENAL: obstruction

Question 3

Constipation

Answer 3

DIETARY
DRUGS
REFUSAL TO DEFECATE: pain in rectum vs orthopedic
BEHAVIOURAL & ENVIRONMENTAL
COLONIC OBSTRUCTION: intra vs extra luminal
COLONIC WEAKNESS:
- Systemic Dz: Hypercalcemia, hypothyroid, hypokalemia
- Local Neuro Dz: Spinal dz, pelvic nerve dz, dysautonomia, chronic stretch and damage
- Other: idiopathic megacolon in cats, severe dehydration

Question 4

Coughing

Answer 4

UPPER: inflammatory, infectious, neoplastic, allergic, other

LOWER: inflammatory, parasitic, neoplastic, cardiovascular, non-cardiovascular pulmonary edema, allergic, other

Question 5

ACUTE Diarrhea

Answer 5

DIET
PARASITES
INFECTIOUS: viral, bacterial, rickettsial
OTHER:
- Gastro: HGE, Intussusception, IBS, Foreign body
- Non- gastro: Toxins, Drugs, Pancreatitis, Hypoadrenocorticism, Peritonitis, Pyometra

Question 6

CHRONIC Diarrhea

Answer 6

SMALL INTESTINAL: Food intolerance, IBD, Neoplasia, Parasitic, EPI, Obstruction/ Intussusception, Liver disease, Endocrine (hypoadreno, hypothyroid, hyperthyroid), Renal disease, Intestinal lymphangiectasia

LARGE INTESTINAL: Food Intolerance, IBD (4 types), Neoplasia, Parasitic

Question 7

Epistaxis

Answer 7

LOCAL: Neoplasia, FB, Infectious (parasite, fungal), Dental dz + fistula, eosinophilic & lymphoplasmacytic rhinitis

SYSTEMIC: thrombocytopenia, thrombocytopathia (1 Vwb dz or 2 Uremia, multiple myeloma, NSAIDs), Coagulation factor deficits, acquired coagulopathies, systemic hypertension, increased capillary fragility

Question 8

Fever of Unknown Origin

Answer 8

INFECTIOUS- bacteria, viral, fungal, rickettsial, protozoal
NEOPLASIA
IMMUNE-MEDIATED
INFLAMMATORY- Hypertrophic osteodystrophy, juvenile cellulitis, pancreatitis, panosteitis, panniculitis
OTHER- hyperthyroidism, certain Ab’s, metabolic bone dz, PSS, Shar-pei fever

Question 9

Head Tilt

Answer 9

PERIPHERAL: otitis interna/ media, middle ear tumor, trauma, aminoglycoside toxicity, feline idiopathic vestibular dz, geriatric canine vestibular dz

CENTRAL: trauma/ hemorrhage, infectious inflammatory fever (RMSF, FIP, bacterial, protozoal, mycotic, rickettsial, distemper), granulomatous meningoencephalitis, neoplasia, vestibular infarct, thiamine deficiency, metronidazole toxicity, toxicity, degenerative dz (storage neuropathies, demyelinating dz), hydrocephalus

Question 10

Horner Syndrome: Apply Phenylephrine eye drops –> No pupillary dilation (assume pre-ganglionic lesion)

Answer 10

FIRST ORDER (Central): Intracranial dz, C1-C3 spinal myelopathy

SECOND ORDER (Pre-ganglionic): T1-T3 spinal cord lesion, Thoracic dz, brachial plexus avulsion, skull based tumour

Question 11

Horner Syndrome: Apply Phenylephrine eye drops –> Pupillary dilation (assume post-ganglionic)

Answer 11

THIRD ORDER (post-ganglionic): FeLV/FIV, otitis media/ interna, otic mass, retrobulbar injury/ mass, idiopathic (most common especially in Goldens)

Question 12

Hyperthermia

Answer 12

FEVER
HEAT STROKE
Exercise hyperthermia- seizures, hypocalcemic tetany
Pathologic etiologies- hyperthyroidism, malignant hyperthermia

Question 13

Icterus (Jaundice)

Answer 13

PRE-HEPATIC (hemolysis): autoimmune, infectious, toxic (drugs/ food), fragmentation, snake/ brown recluse spider, bee venoms

HEPATIC: cholangiohepatitis, cirrhosis, diffuse neoplasia, toxic hepatopathy, hepatic lipidosis, FIP, Parasitic

POST-HEPATIC biliary obstruction: pancreatitis, enteritis/ cholecystitis, trauma, neoplasia, calculus, stricture, mucocele, ruptured bile duct or gallbladder

Question 14

Joint Swelling

Answer 14

TRAUMA
DEGENERATIVE JOINT DZ
NEOPLASIA
INFLAMMATORY INFECTIOUS: bacterial, fungal, lyme, rickettsial, leishmaniasis, anaplasmosis, mycoplasma, viral (calicivirus, canine distemper)
INFLAMMATORY NON-INFECTIOUS:
- Erosive: Rheumatoid arthritis, erosive polyarthritis of Greyhounds, Feline chronic progressive polyarthritis
- Non-Erosive: Immune-mediated polyarthritis, Systemic lupus erythromatosis, breed-specific arthritis syndromes, lymphocytic/ plasmacytic synovitis, Drug reactions (TMS in Doberman), Chronic infection causing secondary immune-mediated polyarthritis

Question 15

Lameness

Answer 15

ORTHOPAEDIC: Trauma, Infectious, Immune-mediated polyarthritis, Degenerative (DJD, cruciate dz, hip dysplasia, elbow dysplasia), developmental (patellar luxation, OCD, panosteitis, HOD, avascular necrosis, ununited anconeal process, bone cysts, radial agenesis), Metabolic (panosteitis, HOD, diabetic neuropathy), Nutritional (Vit D deficiency), Neoplasia

MUSCLES: Trauma (contusion, strain, laceration, rupture, contracture), Inflammatory (polymyositis, dermatomyositis), Infectious (protozoal myositis)

TENDONS/ LIGAMENTS: Sprain/Strain, Hyperextension, Tear, Rupture

note:
strain = muscle-tendon injury
sprain = ligament injury

Question 16

Pallor

Answer 16

ANEMIA:

• Regenerative: IMHA, erythrocyte parasite, fragmentation, oxidative injury, blood loss
• Non-regenerative: anemia of chronic disease, anemia of renal disease, FeLV, Endocrine (mild in hypoadreno and hypothyroid), Bone marrow suppression or toxicity

SHOCK:

• Cardiogenic: ↓ ventricular function, ↓ ventricular filling, outflow obstruction (intrathoracic tumors, stenosis, hypertrophic obstructive cardiomyopathy, heartworm disease, thrombosis, severe arrythmia)
• Non-cardiogenic trauma, hypovolemia, disruption in blood flow (sepsis, endotoxemia, hypotension)

Question 17

Papules

Answer 17

Bacterial pyoderma
Demodicosis
Sarcoptes
Hypersensitivity
Pemphigus
Early-stage neoplasia

Question 18

Pustules

Answer 18

Bacterial pyoderma
Demodicosis
Pemphigus

Question 19

Polyuria/ Polydipsia

Answer 19

Renal Insufficiency or failure
Diabetes mellitus
Hyperadrenocorticism and Hypoadrenocorticism
Lower Urinary Tract Infection
Pyometra
Hypercalcemia
Pyelonephritis
Hypokalemia
Iatrogenic (corticosteroids, diuretics, anti-convulsants, fluid therapy)
Hyperthyroidism
Hepatic Insufficiency
Diabetes insipidus (central vs renal)
Psychogenic drinking
Renal glycosuria

Question 20

Regurgitation

Answer 20

ESOPHAGEAL DISEASE: megaoesophagus, esophagitis, mechanical obstruction
ALIMENTARY DISORDER: pyloric outflow obstruction, GDV, hiatal hernia
NEUROPATHIES: peripheral neuropathies, CNS dz, Dysautonomia
NEUROMUSCULAR JUNCTION DISORDERS: myasthenia gravis, tetanus, botulism, Ach-ase toxicity
IMMUNE-MEDIATED DISORDERS: SLE, polymyositis, dermatomyositis
ENDOCRINE DISEASE: hypothyroidism, hypoadrenocorticism

Question 21

Scaling & Crusting

Answer 21

Bacterial
Fungal
Parasitic
Protozoal: Leishmaniasis
Viral: FeLV
Allergic: Atopic dermatosis, hypersensitivity
Endocrine & Metabolic: hyperadrenocorticism, hypothyroidism
Immune-mediated: pemphigus, DLE, erythema multiforme
Keratinization Defects: secondary seborrhea, Vitamin-A response dermatosis, ear margin dermatosis
Environmental: solar dermatitis
Nutritional: Zinc-responsive, fatty acid deficiency
Other: cutaneous lymphoma, sebaceous adenitis, otitis externa

Question 22

Seizure

Answer 22

INTRACRANIAL: Inflammatory dz, infectious dz, neoplasia, granulomatous meningoencephalitis, hemorrhage/ infarct (due to renal failure, hypothyroid, hyperthyroid, hypertension, septic emboli, neoplasia, coagulopathies, heartworm dz, vasculitis), congenital malformations, necrotizing meningoencephalitis, degenerative dz (metabolic storage diseases, leukodystrophies, hypomyelination disorders, spongy disorders)

EXTRACRANIAL: toxins, metabolic dz, hepatic dz, electrolyte disturbance (hypernatremia), severe uremia, hyperlipoproteinemia, hyperviscosity, hyperosmolarity, heat stroke, hypertension, hyperthyroid (cats), hypothyroid (dogs)

Question 23

Strunguria/ Pollakuria

Answer 23

SMALL BLADDER:
Cystitis
Detrusor hyperspasticity
Urethritis
Urethral mass

LARGE BLADDER:
Lower Urinary Tract Obstruction- Functional vs Mechanical

Question 24

Urinary Retention

Answer 24

Easy Catheterization:

• Normal Neuro Exam: cystic calculi or mass, detrusor areflexia from overdistention, reflex dyssyndergia
• Abnormal Neuro Exam: UMN, LMN, Dysautonomia

Difficult Catheterization:
Urethral spasm, urethral calculi, urethral stricture, urethral neoplasia, TCC, Urethral inflammation, Prostatic dz, mucoid/ crystalline plug (cats)

Question 25

Stomatitis

Answer 25

- INFECTIOUS: FIV, FeLV, Feline calicivirus, Feline herpes, FIP, Bartonellosis, Canine distemper virus, Feline Panleukopenia, Candidiasis - IMMUNOSUPPRESSIVE DZ - FELINE EOSINOPHILIC GRANULOMA COMPLEX - allergies - IDIOPATHIC FELINE GINGIVITIS/ STOMATITIS - IMMUNE-MEDIATED dz: SLE, pemphigus, idiopathic vasculitis, toxic epidermal necrolysis - UREMIC STOMATITIS/ CAUSTIC AGENT - RADIATION-INDUCED

Question 26

Syncope

Answer 26

NORMAL CEREBRAL PERFUSION: Severe hypoxemia, hypoglycemia CEREBRAL HYPOPERFUSION: take blood pressure reading - NORMOTENSIVE: Cerebrovascular dz, cerebral vasoconstriction - SYSTEMIC HYPOTENSION: Decreased cardiac output -- Loss of preload: cardiac tamponade, AV stenosis, hypovolemia, diuretics -- Outflow obstruction: aortic/ subaortic and pulmonic stenosis, pulmonary hypertension, pulmonary thromboembolism, myocardial infarction, hypertrophic & restrictive cardiomyopathy, SAM of mitral valve, heartworm dz, masses -- Arrhythmia: Bradyarrhythmia: SSS, 3rd AV block, persistent atrial standstill, Beta Blockers, Ca channel blockers Tachyarrhythmia: atrial fibrillation, atrial tachycardia, V-tach -- Loss of vascular resistance: Drug therapy: ACE-inhibitors, Beta blockers, Ca channel blockers, hydralazine, nitrates, phenothiazines Reflex syncope: orthostatic, post-exertion, micturition, defecation, cough, emotional distress, pain, carotid sinus hypersensitivity ANS dz: 1 or 2 (DM, amyloidosis, paraneoplastic, chronic renal failure, autoimmune dz) Cyanotic Heart dz: tetralogy of Fallot, reversed shunt

Question 27

Tenesmus & Dyschezia

Answer 27

Intraluminal and Extraluminal Obstruction Pharmaceuticals: opioids, diuretics leading to dehydration Neurogenic: -- Systemic dz: hypercalcemia, hypothyroid, hypokalemia -- Local neuro dz: spiral dz, pelvic nerve dz, dysautonomia, chronic stretch and damage -- Other: idiopathic megacolon in cats, severe dehydration recall: dysautonomia = dysfunction of the autonomic NS, this can happen in any part of the body but may be more apparent if digestive nerves are affected

Question 28

Vision Loss, sudden (Blindness)

Answer 28

Corneal lesions: edema (trauma, glaucoma, immune-mediated keratitis), keratoconjunctivitis sicca, exposure keratitis, superficial keratitis (pannus), corneal melanosis (entropian, ectropian, lagophthalmos, facial nerve paralysis), cellular infiltrate, fibrosis/ scarring Aqueous humor lesions: fibrin (anterior uveitis: many causes), hypopyon (immune-mediated, neoplastic, infectious, hyphema (trauma, blood-clotting deficiencies, hypertension, retinal detachment, neoplasia), lipid (hyperlipidemia with concurrent anterior uveitis Lens lesions: cataracts (genetic, metabolic/ diabetic, nutritional, traumatic, toxic, retinal degeneration, hypocalcemia, electric shock, chronic uveitis, lens luxation) Vitreous humor lesions: hemorrhage (trauma, systemic hypertension, clotting deficiency, neoplasia, retinal detachment), hyalitis (infectious, penetrating injury with cellular infiltrate) Retinal lesions: glaucoma, SARD, progressive retinal atrophy, central progressive retinal atrophy, toxicity (fluoroquinolones in cats), hypertension, retinal detachment Failure to transmit visual message: viral infections, mycoses, neoplasia, traumatic avulsion of optic nerve (traumatic proptosis), granulomatous meningoencephalitis, hydrocephalus, optic nerve hypoplasia, immune-mediated optic neuritis Failure to interpret visual message: distemper, FIP, mycoses, granulomatous meningoencephalitis, trauma, heat stroke, hypoxia, hydrocephalus, hepatoencephalopathy, neoplasia, storage diseases, postictal, meningitis

Question 29

Dysphagia

Answer 29

ORAL LESIONS: fractures, periodontitis, trauma, feline resorptive lesions, osteomyelitis, retrobulbar abscess/ inflammation, temporal-masseter myositis, stomatitis, glossitis, pharyngitis, gingivitis, tonsillitis, sialadenitis (immune-mediated dz, feline viral dz, foreign. bodies or granulomas, tooth root abscess, uremia, caustic chemicals), cleft palate, cricopharyngeal achalasia OBSTRUCTIVE LESIONS: esophageal stricture/ FB, esophagitis, electric cord burns, neoplasia, inflammatory (abscess, polyp, granuloma), lymphadenopathy, eosinophilic granuloma, FB NEUROMUSCULAR DISEASE: myasthenia gravis, acute polyradiculitis, masticatory myositis, tick paralysis, botulism, polymyositis, TMJ dz, rabies, trigeminal nerve paralysis or neuritis, neuropathies of CN 5, 7, 9, 10, 12, brain stem disease, tetanus, hypothyroidism

Question 30

Hematochezia

Answer 30

ANAL DZ: perianal fistulas, anal sacculitis or abscess, stricture, neoplasia, perineal hernia, FB RECTAL and COLONIC DZ: Hemorrhagic gastroenteritis Proctitis Colitis: idiopathic, dietary allergy, IBD, stress, infectious (Campylobacter spp, Clostridial), Histoplasmosis, Pythiosis, Food allergy, trichomoniasis (cats) Parvovirus Parasites: whipworms, hookworms, coccidia Neoplasia Prolapsed rectum Mucosal trauma: FB, pelvic fractures, iatrogenic (thermometers, enemas, fecal loops, rectal palpation) Ileocecal intussusceptions

Question 31

Hematuria

Answer 31

RENAL or LOWER UTD: Inflammation/ infection, urolithiasis, obstruction, trauma, neoplasia, bleeding disorder, heat stroke, renal infarct, granulomatous urethritis, FLUTD, parasitism, drug-induced (cyclophosphamide), renal pelvic hematoma, vascular malformation, idiopathic, Pseudohematuria (myoglobin, hemoglobin, drugs, dyes) EXTRAURINARY Dz: Prostatic dz (infection, tumor, cyst, abscess) Uterine dz (pyometra, proestrus, tumor, subinvolution of placental sites Vaginal (trauma, neoplasia) Estrus Preputial/ penile (trauma, neoplasia)

Question 32

Fecal Incontinence

Answer 32

NON-NEUROLOGIC Dz: Colorectal Disease: IBD, Neoplasia, Constipation Anorectal Dz: Perianal fistula, Neoplasia, Iatrogenic from previous anorectal surgery Miscellaneous: decreased mentation, severe diarrhea, irritable bowel disease, old age NEUROLOGIC Dz: Sacral Spinal Cord Disease: diskospondylitis, neoplasia, degenerative myelopathy, congenital vertebral malformation, sacrococcygeal hypoplasia of Manx cats, sacral fracture, sacrococcygeal subluxation, lumbosacral instability, meningomyelitis Peripheral Neuropathy: trauma, penetrating wounds, repair of perineal hernia, perineal uresthrostomy, hypothyroidism, diabetes mellitus, dysautonomia

Question 33

Urinary Incontinence

Answer 33

BLADDER DISTENDED: Neurogenic: -- LMN bladder: urine dribbling, large flaccid easy to express: S1-S3 or pelvic nerve damage -- UMN bladder: large firm bladder, difficult to express: L1 - L5 or damage to hypogastric nerve ``` Obstructive: Functional obstruction (reflex dyssynergia) Mechanical obstruction (uroliths, tumors, strictures, granulomatous urethritis, urethral inflammation, prostatic disease, mucoid or crystalline plug) ``` BLADDER NOT DISTENDED: Dysuria/ pollakiuria absent: urethral spincter mechanism incompetence (middle to older aged spayed dogs), congenital (ectopic ureters, patent urachus) Dysuria/ pollakiuria present: detrusor hyperreflexia (uroliths, UTI, urethral mass)

Question 34

Melena

Answer 34

INGESTED BLOOD: oral lesions, nasopharyngeal lesions, pulmonary lesions, diet PARASITISM: hookworms, protozoa NEOPLASIA: adenocarcinoma, lymphoma, leiomyoma/sarcoma, mast cell tumor, gastrinoma, nasal or oral tumor UPPER GI INFLAMMATION: gastritis, ulceration/ erosion, hemorrhagic gastroenteritis, IBD, FB, esophagitis INFECTION: campylobacter, clostridium perfringens, salmonella, parvo, neorickettsia helmonthoeca, histoplasma, pythium, helicobacter DRUGS: NSAIDs, glucocorticoids MISCELLANEOUS: pancreatitis, liver failure, renal failure, hypoadrenocorticism, GI ischemia, polyps, coagulopathies (thrombocytopenia, factor deficiencies, rodenticide toxicity, DIC)

Question 35

Nystagmus

Answer 35

PERIPHERAL VESTIBULAR DISEASE: horizontal nystagmus with NO change when head position moved. Fast phase toward normal side -- otitis media/ interna, feline idiopathic vestibular disease, canine geriatric vestibular disease, neoplasia, feline nasopharyngeal polyps in middle ear, granuloma, trauma (iatrogenic to ear cleaning), ototoxic drugs, neuropathy (hypothyroid, CN 8 dz) CENTRAL VESTIBULAR DISEASE: horizontal, vertical or rotary nystagmus, which may change with varying head position -- trauma/ hemorrhage, infectious inflammatory (viral, rickettsial, fungal, toxoplasmosis, neosporosis), granulomatous meningoencephalitis, neoplasia, vascular infarct, thiamine deficiency, metronidazole toxicity, toxic (lead), degenerative disease (storage dz, neuronopathies, demyelinating diseases), hydrocephalus

Question 36

Pruritus

Answer 36

ALLERGY: flea allergy, atopic, food allergy, contact dermatitis, mosquito-bite hypersensitivity, eosinophilic plaque (cats) PARASITES: fleas, mites, lice INFECTIOUS AGENTS: pyoderma, malassezia, dermatophytosis BEHAVIOURAL: acral lick dermatosis, psychogenic alopecia IMMUNE-MEDIATED: pemphigus foliaceus DRUG MISCELLANEOUS: cornification defects, superficial necrolytic dermatitis, tail dock neuroma, rhabditic dermatitis

Question 37

Reverse Sneezing

Answer 37

Nasopharyngeal irritation, purpose is to move secretions and foreign material to the oropharynx to be swallowed - Excitement, foreign bodies, nasal mites, viral infections and epiglottic entrapment of the soft palate

Question 38

Sneezing and Nasal Discharge

Answer 38

Nasal and Upper Resp Disease INFECTIOUS: viral, bacterial, fungal, parasitic INFLAMMATORY: allergic rhinitis, lymphocytic-plasmacytic rhinitis, acquired nasopharyngeal stenosis, polyps NEOPLASIA: adenocarcinoma, SCC, fibrosarcoma, osteosarcoma, chondrosarcoma, lymphoma, TVT FOREIGN BODY CONGENITAL: cleft palate, ciliary dyskinesia, nasopharyngeal stenosis, choanal atresia DENTAL DISEASE: tooth root abscess, oronasal fistula TRAUMA VASCULAR MALFORMATION: Systemic Disease INFECTIOUS: canine distemper virus, kennel cough complex, pneumonia HYPERTENSION: hyperthyroid, hyperadrenocorticism, renal disease, pheochromocytoma, hypothyroid, acromegaly, polycythemia, diabetes COAGULOPATHIES: thrombocytopenia, RMSF, vWd, factor deficiencies, congenital (hemophilia A and B), acquired (Vitamin K rodenticide toxicity, DIC, hepatic failure) VASCULITIS: toxic, inflammatory, immune-mediated (SLE), neoplastic, infectious (ehrlichiosis, FIP, RMSF, leishmaniasis HYPERVISCOSITY: multiple myeloma, lymphoma, IgM macroglobulinemia,

Question 39

Stupor and Coma

Answer 39

INCREASED INTRACRANIAL PRESSURE: encephalitis, meningitis, neoplasia, granulomas, abscess, vascular events (hemorrhage, embolism, ischemia), trauma, underlying metabolic injury (hypertension), developmental (hydrocephalus, storage diseases) SYSTEMIC INFECTIONS: rabies, FIP, canine distemper, fungal, parasitic CEREBRAL EDEMA: vasogenic (brain masses leading to breakdown of BBB), cytotoxic (hypoxia, neuroglycopenia), interstitial (hydrocephalus) HERNIATION OF BRAIN TISSUES EXTRACRANIAL CAUSES: hypoglycemia, hypernatremia, hyponatremia, DKA, uremic encephalopathy, severe hypothyroidism, heat stroke, toxins, hepatic disease, hyperadrenocorticism, erythrocytosis, hyperglobulinemia

Question 40

Vomiting

Answer 40

GASTRIC DISEASE: gastritis, parasites, FB< obstruction, ulceration, neoplasia, GDV. hiatal hernia, motility disorders, pyloric stenosis SMALL INTESTINE DZ: parasites, IBD, FB, bacterial overgrowth/ enteritis, HGE, neoplasia, viral enteritis (parvo, distemper), intussusception LARGE INTESTINE DZ: colitis, obstipation, parasites DIETARY: indiscretion, intolerance, allergy DRUGS: chemo agents, antibiotics (erythromycin, tetracycline), NSAIDs, apomorphine, xylazine, penicillamine EXTRA-GIT: pancreatitis, peritonitis, hepatobiliary dz, neoplasia, uremia, DM or DKA, hypercalcemia, hyperthyroidism, hypoadrenocorticism, hepatic dz, septicemia/ endotoxemia, pyometra, acid-base disorders, electrolyte disorders, hypertriglyceridemia, gastrinoma INTOXICANTS: lots of inorganic, organic, plant toxins etc. NEUROLOGICAL: epilepsy, tumor, meningitis, increased intracranial pressure, dysautonomia