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🩸 COMPLETE BLOOD COUNT (CBC) — VETERINARY CLINICAL GUIDE

Sources: Henry's Clinical Diagnosis & Management by Laboratory Methods | Histology: A Text and Atlas (Pawlina/Ross) | Textbook of Family Medicine 9e | Robbins & Kumar Basic Pathology | Medical Microbiology 9e | Applied veterinary clinical knowledge

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SECTION 1 — WHAT IS A CBC?

• Red blood cells (Erythrocytes) — oxygen-carrying capacity
• White blood cells (Leukocytes) — immune system status
• Platelets (Thrombocytes) — clotting/hemostasis ability

⚠️ Veterinary Note: Reference ranges differ significantly between species. Always use species-specific reference intervals. A "normal" dog value is NOT normal for a cat, horse, or cow.

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SECTION 2 — CBC PARAMETERS (ONE BY ONE)

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🔴 PART A: RED BLOOD CELL (RBC) PARAMETERS

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1. RBC Count (Erythrocyte Count)

• Primary polycythemia (Polycythemia vera) — bone marrow disorder
• Secondary polycythemia — chronic hypoxia (lung disease, high altitude, cardiac disease), erythropoietin-secreting tumor
• Relative polycythemia — dehydration (most common cause in clinical setting — the RBC count looks high because plasma volume decreased)

• Blood loss (trauma, surgery, GI bleeding, parasites)
• Iron / B12 / folate deficiency
• Hemolysis (immune-mediated, toxins, infectious agents — Babesia, Hemobartonella)
• Bone marrow suppression (FeLV in cats, drugs, chronic disease)
• Chronic renal disease (decreased erythropoietin)

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2. Hemoglobin (Hgb / Hb)

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3. Hematocrit / PCV (Packed Cell Volume)

Severity grading (applicable to all species):

• Mild anemia: PCV 25–35% (dog), 20–30% (cat)
• Moderate anemia: PCV 15–25% (dog), 14–20% (cat)
• Severe anemia: PCV < 15% (dog), < 14% (cat)
• Transfusion territory: PCV < 12–15%

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4. MCV — Mean Corpuscular Volume

Key Vet Point: A HIGH MCV in a dog with anemia = REGENERATIVE response → bone marrow is working → GOOD sign. Low MCV in an anemic patient = chronic iron deficiency or portosystemic shunt.

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5. MCH — Mean Corpuscular Hemoglobin

• Low MCH = cells are hypochromic (pale, less Hgb per cell) → iron deficiency
• High MCH = spherocytes or macrocytes with more Hgb content

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6. MCHC — Mean Corpuscular Hemoglobin Concentration

• Low MCHC (Hypochromic): Iron deficiency anemia — cells are pale, not fully packed with Hgb
• High MCHC: Intravascular hemolysis → free Hgb raises the reading artificially; lipemia or Heinz bodies can also cause this
• Normal MCHC: Most anemias (normochromic)

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7. RDW — Red Cell Distribution Width

• Normal: ~11–15%
• High RDW: Iron deficiency anemia, regenerative anemia (mix of large reticulocytes + small old cells), B12 deficiency
• Normal RDW with low MCV: Thalassemia-type or breed variation
• High RDW is an early indicator that anemia is developing — often changes before MCV does

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8. Reticulocyte Count

This is the KEY parameter to classify anemia as Regenerative vs Non-Regenerative.

Species Note: Cats release aggregate reticulocytes and punctate reticulocytes. Only aggregate reticulocytes indicate active regeneration. Dogs release polychromatic cells (visible on smear as bluish large cells).

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⚪ PART B: WHITE BLOOD CELL (WBC/Leukocyte) PARAMETERS

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9. Total WBC Count (Leukocyte Count)

• Infection (bacterial most common)
• Inflammation (any tissue injury — trauma, surgery, burns)
• Stress/corticosteroids (physiologic leukocytosis)
• Excitement (epinephrine release, especially dogs & cats)
• Leukemia (very high counts >100,000/µL = hyperleukocytosis → think neoplasia)

• Overwhelming bacterial sepsis (WBCs consumed faster than produced)
• Viral infections (parvovirus destroys bone marrow precursors!)
• Bone marrow depression (FeLV, drugs, toxins, radiation)
• Autoimmune disease

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10. WBC DIFFERENTIAL — THE MOST IMPORTANT PART

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🔵 A. NEUTROPHILS (Segmented + Bands)

• Bacterial infection — most classic cause
• Acute inflammation / tissue necrosis
• Corticosteroids / stress (no left shift in this case)
• Leukemia (neoplastic)
• Excitement (transient)

• Overwhelming bacterial sepsis (consumed in tissues)
• Viral infection (parvovirus, FeLV, FIV, canine distemper) — virus destroys bone marrow
• Bone marrow failure
• Immune-mediated neutropenia
• Drug toxicity (chemotherapy, estrogen toxicity)

MOST IMPORTANT CONCEPT — LEFT SHIFT: A left shift = presence of BAND neutrophils (immature) in circulation. When infection or severe inflammation is occurring, the bone marrow dumps immature cells (bands) into blood because it can't keep up.

• Regenerative left shift: Total WBC is high + bands present → bone marrow IS coping → bacterial infection, moderate inflammation
• Degenerative left shift: Total WBC is LOW + many bands → more bands than mature neutrophils → bone marrow is OVERWHELMED → severe sepsis, very poor prognosis
• Toxic neutrophils: Cells show toxic granulation, Döhle bodies, vacuolation → severe systemic infection/endotoxemia

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🔴 B. LYMPHOCYTES

• Viral infections (classic! EBV, hepatitis A, CMV in humans; herpesvirus, FIV, FIP in animals)
• Chronic bacterial infections (tuberculosis, brucellosis, pertussis)
• Physiologic lymphocytosis — excitement in cats (epinephrine shifts marginated lymphocytes into circulation — counts can double!)
• Lymphocytic leukemia / lymphoma
• Immune stimulation, vaccination response
• Hypoadrenocorticism (Addison's disease — "reverse stress leukogram": lymphocytosis + eosinophilia)

• Corticosteroids (endogenous stress OR exogenous treatment) — classic! Steroids cause lymphocytes to leave blood
• Viral infections (FIV, FeLV, parvovirus)
• Immunodeficiency diseases
• Loss via lymphatics (lymphangiectasia, chylothorax)
• Radiation / chemotherapy

Key diagnostic clue: Lymphocytosis = think VIRAL. Neutrophilia = think BACTERIAL.

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🟡 C. MONOCYTES

• Chronic bacterial infections (especially intracellular bacteria — Brucella, Mycobacterium)
• Chronic inflammation / tissue necrosis — monocytes clean up debris
• Fungal infections (Histoplasma, Blastomyces)
• Neoplastic disease
• Corticosteroids (part of stress leukogram)
• Recovery from bone marrow suppression

Key rule: Monocytosis = chronic or intracellular infection, or ongoing tissue destruction.

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🟠 D. EOSINOPHILS

• Parasitic infections ← MOST CLASSIC CAUSE (heartworm, hookworm, roundworm, toxoplasmosis, lungworm, Giardia with eosinophilic response)
• Allergic / Hypersensitivity reactions (atopy, flea allergy dermatitis, eosinophilic granuloma complex in cats)
• Skin diseases
• Pulmonary eosinophilia (PIE syndrome in dogs)
• Mast cell tumor, lymphoma, other neoplasia
• Hypereosinophilic syndrome (cats)
• Addison's disease (adrenal insufficiency → eosinophilia is a clue)

• Acute stress (physical stress, trauma, illness)
• Corticosteroids — steroids dramatically decrease eosinophils (classic finding on stress leukogram)
• Cushing's disease (hyperadrenocorticism)

KEY DIAGNOSTIC RULE: Eosinophilia in a pet with GI signs, weight loss, coughing, or skin disease = RULE OUT PARASITES FIRST before anything else!

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⚫ E. BASOPHILS

• Allergic reactions (Type I hypersensitivity)
• Heartworm disease (classic in dogs!)
• Chronic myeloid leukemia
• Mast cell tumor
• Polycythemia vera
• Hypothyroidism

Basophilia alone is rarely dramatic but basophilia + eosinophilia together strongly suggests parasitism or allergic disease.

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🟣 PART C: PLATELET (THROMBOCYTE) PARAMETERS

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11. Platelet Count

Caveat: Cats are prone to platelet clumping in the tube → falsely low count. ALWAYS check blood smear when cat platelet count looks low.

• Iron deficiency anemia (reactive/secondary thrombocytosis)
• Inflammation / chronic infection
• Splenectomy or splenic disease
• Myeloproliferative disease (bone marrow cancer)
• Rebound after thrombocytopenia

• Immune-mediated thrombocytopenia (IMT/ITP) — most common cause in dogs (especially Cocker Spaniels, retrievers)
• Ehrlichia / Anaplasma — tick-borne diseases → classic thrombocytopenia
• Babesia — destroys platelets
• Bone marrow suppression (FeLV, leukemia, estrogen toxicity, drugs)
• Disseminated Intravascular Coagulation (DIC) — platelets consumed → thrombocytopenia + prolonged clotting times
• Increased consumption (sepsis, vasculitis)
• Decreased production (leukemia, lymphoma invading marrow)

Bleeding risk:

• Platelets < 50,000/µL → spontaneous bleeding possible
• Platelets < 20,000/µL → HIGH risk of spontaneous hemorrhage (petechiae, ecchymoses, epistaxis, melena)

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12. MPV — Mean Platelet Volume

• High MPV: Young, large platelets = bone marrow is actively releasing new platelets (regenerative) → seen in IMT, active destruction
• Low MPV: Small platelets → bone marrow failure, Wiskott-Aldrich type syndromes

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SECTION 3 — THE DIAGNOSTIC DECISION TREE: HOW TO READ A CBC IN < 1 MINUTE

STEP 1: Look at WBC total
         ↑ High?          → Infection, inflammation, stress, leukemia
         ↓ Low?           → Viral infection, severe sepsis, bone marrow failure, toxin

STEP 2: Run the Differential
         Neutrophilia + Left shift?  → BACTERIAL infection or severe inflammation
         Lymphocytosis?              → VIRAL infection, excitement (cats), lymphoma, Addison's
         Eosinophilia?               → PARASITES first, then allergy, then neoplasia
         Monocytosis?                → CHRONIC infection/inflammation, intracellular bacteria
         Basophilia + Eosinophilia?  → PARASITES (especially heartworm)

STEP 3: Assess RBC / PCV
         PCV Low?   → Anemia present
           ↓ Check MCV:
             Microcytic?    → Iron deficiency / chronic blood loss / portosystemic shunt
             Normocytic?    → Acute hemorrhage / chronic disease / renal disease
             Macrocytic?    → Regenerative response / B12 deficiency / FeLV (cats)
           ↓ Check Reticulocytes:
             High?  → Regenerative → hemorrhage or hemolysis
             Low?   → Non-regenerative → bone marrow problem

STEP 4: Assess Platelets
         Very low (<50k)?  → Tick disease (Ehrlichia/Anaplasma), IMT, DIC, FeLV
         Very high?        → Reactive (inflammation) or myeloproliferative

STEP 5: Put it all together!

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SECTION 4 — DISEASE PATTERN RECOGNITION TABLE

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SECTION 5 — BLOOD SMEAR INTERPRETATION (Always Do This!)

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SECTION 6 — THE STRESS LEUKOGRAM (Very Important in Vet Practice)

• ↑ Neutrophils (mature, NO left shift)
• ↓ Lymphocytes
• ↓ Eosinophils
• ↑ Monocytes

This pattern is caused by cortisol → redistributes WBCs. This is NOT infection. It is a stress response. You must distinguish this from a true infection pattern. The KEY differentiator: stress leukogram has NO left shift (no band cells), while bacterial infection DOES have a left shift.

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SECTION 7 — REGENERATIVE vs NON-REGENERATIVE ANEMIA

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SECTION 8 — CLINICAL CBC EXAMPLES (Most Common Cases in Pet Hospital)

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📋 CASE 1: Canine Parvovirus (Unvaccinated Puppy, Vomiting + Bloody Diarrhea)

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📋 CASE 2: Pyometra (Intact Female Dog, Lethargy, PU/PD, Vaginal Discharge)

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📋 CASE 3: Feline Heartworm / Eosinophilic Condition (Cat, Chronic Cough)

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📋 CASE 4: Ehrlichiosis (Dog, Tick History, Petechiae on Gums, Lethargy)

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📋 CASE 5: Immune-Mediated Hemolytic Anemia — IMHA (Dog, Yellow Gums, Weakness)

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📋 CASE 6: Chronic GI Parasitism (Young Dog, Weight Loss, Diarrhea, Pot-Belly)

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SECTION 9 — QUICK REFERENCE: WHAT EACH CELL TELLS YOU

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SECTION 10 — PRACTICE QUESTIONS (Test Your Knowledge)

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Answer: Pyometra with bacterial endotoxemia. Left shift (bands >300/µL) indicates bone marrow is releasing immature neutrophils due to overwhelming bacterial demand. Toxic changes confirm endotoxin exposure. Emergency ovariohysterectomy + antibiotics required.

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Answer: Canine Parvoviral Enteritis. Parvovirus specifically targets rapidly dividing cells, including bone marrow neutrophil precursors → profound leukopenia and neutropenia. This is a hallmark finding. Thrombocytopenia contributes to bloody diarrhea (hemorrhagic gastroenteritis). Supportive care + isolation mandatory.

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Answer: (1) Feline heartworm disease (Dirofilaria immitis — antigen + antibody test), (2) Lungworm / Aelurostrongylus abstrusus (Baermann fecal test), (3) Feline allergic bronchitis/asthma (thoracic radiograph + bronchoscopy/BAL). Eosinophilia + basophilia = parasite or allergy. Basophilia is rare in cats and should strongly prompt parasite workup.

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Answer: Ehrlichia canis (Canine Monocytic Ehrlichiosis). Morulae in monocytes = pathognomonic. Severe thrombocytopenia causes hemorrhagic signs. Mild pancytopenia typical in acute/chronic phase. Treatment: Doxycycline 10 mg/kg/day PO for 28 days. Supportive care ± transfusion if PCV critical.

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Answer: Immune-Mediated Hemolytic Anemia (IMHA). Spherocytes are pathognomonic — they form when macrophages partially phagocytose antibody-coated RBCs, removing part of the membrane, leaving a small dense sphere without central pallor. Concurrent thrombocytopenia = Evans Syndrome. Treatment: Prednisolone + azathioprine/mycophenolate, possible transfusion.

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Answer: This is a Stress Leukogram (not infection). Key features: neutrophilia WITHOUT left shift, lymphopenia, eosinopenia, monocytosis. Caused by endogenous cortisol release due to pain/surgery/hospitalization stress. No band cells = no new infection. No treatment needed — treat the underlying cause (pain management, recovery).

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QUICK DIAGNOSTIC CHEAT SHEET — BACTERIA vs VIRAL vs PARASITIC vs STRESS

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Sources: Henry's Clinical Diagnosis & Management by Laboratory Methods (Elsevier); Histology: A Text and Atlas — Pawlina/Ross (Wolters Kluwer); Textbook of Family Medicine 9e (Elsevier); Robbins & Kumar Basic Pathology (Elsevier); Medical Microbiology 9e (Elsevier). Applied to veterinary species-specific reference ranges per standard veterinary clinical hematology.

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🔊 ULTRASONOGRAPHY IN VETERINARY PRACTICE

A Complete Clinical Guide for the Veterinary Professional

Sources: Goldman-Cecil Medicine 2-Vol Set | Textbook of Clinical Echocardiography | Yamada's Textbook of Gastroenterology | Sleisenger & Fordtran's GI and Liver Disease | Histology: A Text and Atlas (Pawlina/Ross) | Harrison's Principles of Internal Medicine 22e | Applied Veterinary Clinical Knowledge

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SECTION 1 — WHAT IS ULTRASONOGRAPHY?

How Does It Work? (The Physics — Made Simple)

1. Emits high-frequency sound waves into the body
2. Receives the echoes (sound waves bounced back) from tissues
3. Converts echo data into a grayscale image on screen

Frequency Selection — The Most Important Machine Setting

HIGH FREQUENCY (7.5 – 15 MHz)
→ Excellent resolution, POOR penetration
→ Use for: Small animals (cats, small dogs, rabbits)
         Superficial structures (lymph nodes, skin, eyes, testicles)
         Guided biopsy needles (you can see the needle clearly)

MEDIUM FREQUENCY (5 – 7.5 MHz)
→ Good balance of resolution and penetration
→ Use for: Medium-sized dogs (abdominal organs)
         Most routine small animal work

LOW FREQUENCY (2 – 5 MHz)
→ Poor resolution, EXCELLENT penetration
→ Use for: Large animals (horses, cattle, large-breed dogs)
         Deep abdominal structures
         Cardiac imaging (echocardiography)

Simple Rule: Small animal, shallow structure = HIGH frequency. Large animal, deep structure = LOW frequency.

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SECTION 2 — ULTRASOUND TERMINOLOGY (THE ECHO SCALE)

The Most Important Echogenicity Rule:

• Black (Anechoic) = FLUID
• White (Hyperechoic) = DENSE STRUCTURE (stone, bone, fat, calcification)
• Gray (Hypoechoic) = SOFT TISSUE
• Dirty/Speckled (Heterogeneous) = PATHOLOGY

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SECTION 3 — ULTRASOUND MODES (What the Machine Can Do)

For daily vet hospital use: B-Mode is what you'll use 90% of the time. Doppler modes are used for cardiac work.

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SECTION 4 — TRANSDUCER (PROBE) TYPES

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SECTION 5 — PATIENT PREPARATION FOR ULTRASOUND

Clipping the Hair (Mandatory for Good Images)

• Abdominal scan: Clip from xiphoid to pubis, both flanks
• Cardiac scan: Clip both right and left parasternal windows (where ribs meet sternum), subxiphoid area
• Neck (thyroid, lymph nodes): Clip ventral cervical region
• Bladder / reproductive: Clip inguinal and caudal abdominal area

Coupling Gel

Fasting (for Abdominal Ultrasound)

• Ideal: Fast 6–12 hours before scanning (dogs), 4–6 hours (cats)
• Reason: Food and gas in GI tract causes acoustic shadowing that obscures deeper organs (especially pancreas, mesenteric lymph nodes)
• Emergency scans are done without fasting — just accept degraded image quality

Sedation / Restraint

• Most cats and calm dogs: Manual restraint only
• Anxious, aggressive, or painful patients: Mild sedation (butorphanol, dexmedetomidine)
• Heavy sedation (propofol/alfaxalone): For Doppler cardiac work requiring motionless patient
• NEVER use general anesthesia for routine abdominal USG unless necessary

Patient Positioning

• Dorsal recumbency (lying on back): Best for abdominal scanning — organs fall away from spine, bladder is easily visualized, gravity helps orient organs
• Left lateral recumbency: Liver, right kidney (scan from right side)
• Right lateral recumbency: Spleen, left kidney
• Standing: Large animals (horses, cattle) — scan from flank
• Sternal: Cardiac work in cats (some prefer this)

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SECTION 6 — UNDERSTANDING THE ULTRASOUND SCREEN

• Top of image = closest to probe (skin surface)
• Bottom of image = deepest structures
• Left side = depends on probe orientation marker (usually cranial or medial)
• Depth marker on the side = distance in centimeters from probe surface
• Gain = overall brightness of image (increase if too dark, decrease if too bright)
• Focus depth = the point where beam is narrowest = clearest image (set this at the organ of interest)
• Freeze button = captures image for measurement and documentation

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SECTION 7 — ARTIFACTS (What Fools You on Ultrasound)

Clean shadow = Stone/Mineral. Dirty shadow = Gas.

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SECTION 8 — ORGAN-BY-ORGAN ULTRASONOGRAPHY

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🟤 A. LIVER

Normal Liver Ultrasound Appearance:

• Echogenicity: Moderately hyperechoic (slightly brighter than renal cortex, slightly less bright than spleen in dogs; In cats: liver ≈ spleen echogenicity)
• Texture: Homogeneous (uniform, fine granular pattern)
• Margins: Smooth, sharp edges
• Portal veins: Visible as anechoic tubular structures with hyperechoic (bright) walls — wall is bright because it's connective tissue
• Hepatic veins: Anechoic tubular structures WITHOUT bright walls — no connective tissue sheath
• Bile ducts: Should be barely visible (if visible = dilated = pathological)
• Size: Should fit within costal arch (not extend beyond last rib in dog)

Liver Pathology — What to Look For:

Most Important Rule: Compare liver echogenicity to the right renal cortex (kidney cortex). In a normal dog, liver should be slightly brighter than kidney cortex. If liver is much brighter → fatty liver (lipidosis). If liver is darker → congestion or lymphoma.

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🫁 B. GALLBLADDER & BILE DUCTS

• Anechoic (black) interior — filled with bile (pure fluid)
• Thin, smooth walls (< 3 mm in dogs, < 1 mm in cats)
• Posterior acoustic enhancement behind it (fluid enhances)
• Small amount of bile sludge (echogenic material that moves when patient position changes) can be normal, especially in fasted animals

Gallbladder Pathology:

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🫘 C. KIDNEYS (RENAL ULTRASONOGRAPHY)

Normal Kidney Appearance:

• Shape: Bean-shaped; smooth capsular margin
• Cortex: Outer layer — hypoechoic (darker gray), homogeneous
• Medulla (Renal Pyramids): Inner layer — even more hypoechoic (darker than cortex) — triangular/wedge shapes visible in cross section
• Pelvis: Central hyperechoic (bright) line = renal sinus fat + collecting system = "renal crest"
• Corticomedullary differentiation (CMD): Healthy kidneys show a clear difference between cortex and medulla. Loss of CMD = renal disease.

Normal Kidney Size (Approximate):

Kidney Pathology:

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🫀 D. SPLEEN

• Echogenicity: Most hyperechoic (brightest) of all parenchymal organs — this is your reference! Spleen is brightest → then liver → then renal cortex (most hypoechoic of the three)
• Texture: Extremely homogeneous, fine-grained "sandy" appearance
• Margins: Smooth, sharp, well-defined capsule
• Location: Left cranial abdomen, just caudal to stomach

Reference rule for echogenicity: Spleen > Liver > Kidney cortex in brightness (dogs and cats)

Splenic Pathology:

The "Meatball" Appearance: Large, round, mixed-echogenicity nodules in the spleen of a middle-aged to old German Shepherd or Golden Retriever = think Splenic Hemangiosarcoma until proven otherwise. This is an oncological emergency.

Important: In dogs given acepromazine sedation, the spleen dramatically enlarges. This is a pharmacologic effect, not disease.

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🫁 E. URINARY BLADDER

• Anechoic interior (urine = pure fluid = black)
• Thin, smooth wall (2–4 mm when full)
• Posterior acoustic enhancement behind bladder
• Triangular or oval shape depending on fullness

Bladder Pathology:

TCC (Transitional Cell Carcinoma) Tip: In dogs, the most common location is the trigone (where ureters enter bladder). Biopsy via cytocentesis is contraindicated (risk of seeding). Use urine cytology or traumatic catheter lavage instead.

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🫁 F. PANCREAS

• Sits retroperitoneally between stomach and duodenum
• Gas-filled duodenum frequently obscures the right limb
• Very similar echogenicity to surrounding mesenteric fat

Pancreatic Pathology:

Clinical note for cats: Triaditis — simultaneous pancreatitis + cholangitis + IBD is common in cats. USG showing thickened small intestine + abnormal pancreas + dilated bile duct in a cat = triaditis until proven otherwise.

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🐕 G. GASTROINTESTINAL TRACT

From outside → inside:
1. Serosa        → Hyperechoic (bright)
2. Muscularis    → Hypoechoic (dark)
3. Submucosa     → Hyperechoic (bright) ← Thickest bright layer
4. Mucosa        → Hypoechoic (dark)
5. Mucosal surface → Hyperechoic (bright)

• Stomach: 3–5 mm
• Small intestine (dog): 2–5 mm
• Small intestine (cat): 2–4 mm (duodenum up to 5 mm)
• Large intestine: 2–4 mm

GI Pathology:

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🐾 H. ADRENAL GLANDS

• Right adrenal: Craniomedial to right kidney, between caudal vena cava and kidney
• Left adrenal: Craniomedial to left kidney, medial to aorta

• Small, peanut/comma-shaped, hypoechoic structures
• Dog: Length < 3 cm, width < 7.4 mm
• Cat: Smaller, 3–6 mm width
• Hyperechoic cortex with hypoechoic medulla — in ideal images

Adrenal Pathology:

Normal adrenal width > 7.4 mm in dogs = adrenomegaly. Measure at the widest point.

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💗 I. ECHOCARDIOGRAPHY (CARDIAC ULTRASOUND)

• Heart is surrounded by ribs and lungs → acoustic windows are limited
• Patient must be still — cardiac motion is rapid
• Acoustic windows: Right parasternal, left parasternal, subcostal, apical

1. 2D B-Mode: Anatomy, chamber size, wall thickness, valves
2. M-Mode: Precisely measures wall thickness and chamber dimensions over time
3. Color Doppler: Valve regurgitation (backflow) and stenosis (narrow flow)
4. Pulsed Wave Doppler: Measures blood flow velocities (mitral E/A wave, aortic outflow)
5. Continuous Wave Doppler: Measures high-velocity flows through stenotic valves

Standard Views in Veterinary Echocardiography:

Key Measurements (M-Mode, Right Parasternal Short Axis):

Common Cardiac Diseases on Echo:

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🐾 J. REPRODUCTIVE ULTRASONOGRAPHY

Female — Uterus and Ovaries

Male — Testes and Prostate

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👁️ K. OCULAR ULTRASONOGRAPHY

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🦷 L. LYMPH NODE ULTRASONOGRAPHY

• Oval or elongated
• Hypoechoic cortex, hyperechoic hilum (central bright line = fat + vessels)
• Long:Short axis ratio > 2:1 (elongated = normal)

• Submandibular: Caudal to mandible, medial side
• Prescapular: Cranial to shoulder
• Axillary: Medial axilla
• Inguinal: Inguinal canal
• Popliteal: Caudal stifle
• Mesenteric/Sublumbar: Deep abdominal (requires high penetration)

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SECTION 9 — ABDOMINAL FLUID (FREE FLUID / EFFUSION)

• Between the liver and right kidney (hepatorenal recess)
• Between the spleen and left kidney (splenorenal recess)
• Around the bladder
• Between intestinal loops
• In the falciform ligament area

FAST Exam (Focused Assessment with Sonography for Trauma): A rapid 4-quadrant scan to detect free fluid in emergencies:

1. DH (Diaphragmaticohepatic) — right side, liver + right kidney
2. SS (Splenorenal) — left side, spleen + left kidney
3. UR (Urinary Bladder) — caudal midline
4. HG (Hepatogastric) — cranial midline

Any anechoic fluid in these windows in a trauma patient = emergency abdominal exploration.

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SECTION 10 — ULTRASOUND-GUIDED PROCEDURES

Fine Needle Aspirate (FNA) / Core Biopsy:

• Use high-frequency linear probe
• Visualize needle tip entering the lesion in real time
• Freehand technique: Probe in one hand, needle in other hand
• Needle guide: Bracket attachment on probe for guided biopsy
• Avoid: Vessels (use color Doppler to check before needle entry), major ducts, gas-filled bowel

What Can Be Aspirated / Biopsied Under USG:

• Liver (diffuse disease FNA, focal mass)
• Spleen (lymphoma, mast cell tumor)
• Kidney (cortex biopsy for CKD classification)
• Lymph nodes (reactive vs. neoplastic)
• Masses anywhere
• Cysts (drainage)
• Joint fluid (guided arthrocentesis)
• Thoracic fluid (guided thoracocentesis)
• Abdominal fluid (guided abdominocentesis/paracentesis)

Cystocentesis (Bladder Urine Sampling):

• Visualize full bladder
• Insert needle directly through ventral abdominal wall into bladder center
• Aspirate 1–5 mL urine into sterile syringe
• Avoids contamination — gold standard for urine culture

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SECTION 11 — AGE-RELATED ULTRASONOGRAPHIC FINDINGS

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SECTION 12 — ARTIFACTS AND MISTAKES TO AVOID

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SECTION 13 — DOCUMENTATION AND REPORTING

1. Patient info: Name, species, breed, age, sex, weight, date
2. Clinical indication: Why was USG done?
3. Machine settings: MHz used, mode (B/M/Doppler)
4. Patient prep: Fasted or not? Sedated? Clipped?
5. Organ-by-organ systematic findings: Even if normal — document "normal" for each organ
6. Measurements: Size of organs, masses, lymph nodes, wall thickness
7. Images captured: Save representative images for each organ
8. Interpretation: Summary of findings
9. Recommendations: Further tests, guided procedures, follow-up

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SECTION 14 — PRACTICE QUESTIONS

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Answer: Severely distended uterine horns bilaterally, filled with anechoic to mildly echogenic fluid (pus). The horns are visible as large tortuous fluid-filled tubular structures caudal to the kidneys and around/caudal to the bladder. Wall may be thickened. Free abdominal fluid may be present if uterus has ruptured. Diagnosis: Open-cervix pyometra. Emergency ovariohysterectomy required.

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Answer: Hepatic Lipidosis (Fatty Liver Syndrome). The extreme hyperechogenicity is due to fat accumulation in hepatocytes. This is an emergency in cats — prolonged anorexia triggers rapid fat mobilization into liver. Next steps: FNA of liver (confirms hepatic lipidosis on cytology — large hepatocytes stuffed with lipid vacuoles), CBC/biochemistry (ALT, bilirubin ↑), and start aggressive nutritional support (esophagostomy tube or NE tube feeding immediately).

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Answer: Splenic Hemangiosarcoma with hemoabdomen. The heterogeneous mass with cavitated (blood-filled) areas is classic for hemangiosarcoma in a Golden Retriever. The echogenic free abdominal fluid = blood (hemoperitoneum). Emergency stabilization (IV fluids, blood transfusion if needed) + emergency splenectomy. Poor prognosis — mean survival with surgery + chemotherapy ~4–6 months. Cardiac USG also recommended (concurrent cardiac hemangiosarcoma in right atrium is common).

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Answer: Polycystic Kidney Disease (PKD). Autosomal dominant — one copy of mutant PKD1 gene causes the disease. Cysts gradually enlarge and replace functional renal tissue → eventually causing CKD. All Persian cats and Persian-derived breeds (Exotic Shorthair, British Shorthair) should be screened by USG at ≥10 months of age. At this age, sensitivity is >90%. Genetic testing (DNA test for PKD1 mutation) is also available and more sensitive. Affected cats should not be bred.

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Answer: Transitional Cell Carcinoma (TCC) of the urinary bladder. The trigone location is the most common site for TCC in dogs. No shadow differentiates this from a stone. Diagnostic approach: Urine cytology (free-catch or traumatic catheter lavage — NOT cystocentesis, as needle aspiration risks needle-track seeding of tumor cells into the abdominal wall). A urine BRAF mutation test (VetMAX) is now available for non-invasive molecular diagnosis. Cystoscopic biopsy with histopathology is confirmatory if needed. Treatment: Piroxicam (NSAID — anti-tumor effect) ± mitoxantrone chemotherapy.

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Answer: Pre-clinical Dilated Cardiomyopathy (Occult DCM). The enlarged LVIDd + decreased fractional shortening indicates systolic dysfunction with ventricular dilation before clinical signs develop. This is Stage B DCM in a Doberman. The dog is not symptomatic yet but is heading towards CHF. Recommend: Holter monitoring to detect occult ventricular premature contractions (VPCs) — Dobermans with occult DCM often have arrhythmias first. Treatment: Recent evidence supports starting pimobendan in pre-clinical DCM when LVIDd exceeds body-size-corrected threshold. Recheck echo every 6 months. Advise against breeding.

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QUICK REFERENCE — AT-A-GLANCE ORGAN ECHOGENICITY

ECHOGENICITY BRIGHTNESS SCALE (Bright → Dark):

BRIGHTEST:  Fat/Peritoneal fat, Bone cortex, Stones, Calcifications, Air interface
            ↓
            Spleen  ← MOST HYPERECHOIC solid organ
            ↓
            Liver   ← Should be slightly brighter than kidney cortex
            ↓
            Renal Cortex ← Should be slightly darker than liver
            ↓
            Renal Medulla ← Darker than cortex
            ↓
            Muscle ← Hypoechoic
            ↓
DARKEST:    Urine, Bile, Cyst fluid ← ANECHOIC (pure black)

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QUICK REFERENCE — ACOUSTIC SHADOW CHART

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Sources: Goldman-Cecil Medicine 22e; Textbook of Clinical Echocardiography (Otto, 5e); Yamada's Textbook of Gastroenterology 7e; Harrison's Principles of Internal Medicine 22e; Sleisenger and Fordtran's GI and Liver Disease; Histology: A Text and Atlas (Pawlina/Ross); Applied veterinary clinical knowledge for species-specific interpretation.

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☢️ RADIOGRAPHY (X-RAY) IN VETERINARY PRACTICE

A Complete Clinical Guide for the Veterinary Professional

Sources: Goldman-Cecil Medicine 2-Vol Set | Grainger & Allison's Diagnostic Radiology | Murray & Nadel's Textbook of Respiratory Medicine | Rosen's Emergency Medicine | Fishman's Pulmonary Diseases | Roberts & Hedges' Clinical Procedures in Emergency Medicine | Harriet Lane Handbook | Applied Veterinary Clinical Knowledge

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SECTION 1 — WHAT IS RADIOGRAPHY?

Why X-ray is Different from Ultrasound

Golden Rule: X-ray = bones, chest, air, foreign bodies. Ultrasound = soft tissue, fluid, organs.

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SECTION 2 — PHYSICS OF X-RAY (MADE SIMPLE)

How X-rays Work

1. An X-ray tube produces a beam of high-energy photons (X-rays)
2. X-rays pass through the patient's body
3. Different tissues absorb (attenuate) X-rays differently
4. The remaining X-rays hit a detector (digital plate or film)
5. Areas where more X-rays were absorbed = white (opaque) on image
6. Areas where fewer X-rays were absorbed = black (lucent) on image

The 5 Radiographic Densities — The Foundation of X-ray Reading

WHITE ←————————————————————————————→ BLACK
Metal  Bone  Soft Tissue  Fat  Air/Gas
(most)                              (least)
absorbs                         absorbs
X-rays                          X-rays

The most important rule: Air is BLACK. Fluid is GRAY. Bone is WHITE. Metal is BRILLIANT WHITE.

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SECTION 3 — TERMINOLOGY YOU MUST KNOW

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SECTION 4 — RADIOGRAPHIC VIEWS / POSITIONS (Very Important!)

Standard Views in Small Animal Radiography

Why two views for every case? Always take a minimum of 2 views (lateral + VD/DV) for any body region. A mass visible only on one view may be real or may be summation artifact. Two views = 2D confirmation.

Large Animal Radiography Positions

• Standing lateral: Horse, cow — X-ray machine brought to the animal
• Portable unit: Used for limbs and head
• Horizontal beam: For thorax, abdomen in standing large animals

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SECTION 5 — X-RAY MACHINE SETTINGS

The Three Exposure Factors (The Exposure Triangle)

• Thick body part → Increase mAs
• Dense structure (bone) → Need higher kVp
• Motion blur → Reduce exposure time (increase mA, reduce seconds)
• Obese patient → Significantly increase mAs

Image Quality Terms

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SECTION 6 — PATIENT PREPARATION FOR X-RAY

Positioning and Restraint

• Patient must be positioned accurately — a rotated or tilted view is uninterpretable
• Sedation: Often needed for proper positioning (especially lateral thoracic views)
• Manual restraint: Only when absolutely necessary — radiation protection for staff
• Foam wedges and sandbags: Used to prop the patient in position without hands in beam

Radiation Safety (CRITICAL — Every Vet Must Follow)

• Never hold a patient in the beam without lead protection — professional standard
• Lead apron, thyroid collar, and lead gloves are mandatory when near beam
• 2 meter rule: Move at least 2 meters from primary beam when possible
• Dosimetry badge: All staff working with X-rays must wear a radiation monitoring badge
• Minimize repeat exposures: Correct positioning first time — don't just "take another quick one"
• Pregnancy: Pregnant staff should NOT handle X-ray patients (even with lead protection, by policy)
• Age limit: Young animals are more radiosensitive (rapidly dividing cells) — minimize exposures

Contrast Media (For Special Studies)

• Barium sulfate: Oral or enema, shows GI tract (thick white in lumen)
• Iohexol (Omnipaque): Iodine-based water-soluble contrast — used for myelography, fistulography, cystourethrography, AngioX-ray
• DO NOT use barium if perforation suspected — use water-soluble contrast instead

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SECTION 7 — HOW TO READ ANY X-RAY SYSTEMATICALLY

The ABCDE System for Chest X-ray:

A — Airway: Trachea midline? Tracheal deviation? Tracheal narrowing?
B — Bones: Rib fractures? Vertebral lesions? Scapula?
C — Cardiac silhouette: Size, shape, borders
D — Diaphragm: Both visible? Blunted angles? Elevated?
E — Everything else: Mediastinum, soft tissue, extra-thoracic structures

The ABCDE System for Abdominal X-ray:

A — Air pattern: Normal gas? Dilated loops? Free air?
B — Bones: Spine, pelvis, ribs — any lesions?
C — Contrast/Organs: Liver, spleen, kidneys visible? Normal size/position?
D — Density abnormalities: Calcifications, stones, mineral opacities?
E — Everything else: Foreign bodies, masses, extra-abdominal structures

Always complete the whole system before reporting!

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SECTION 8 — THORACIC (CHEST) RADIOGRAPHY

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📸 NORMAL CHEST X-RAY

• Lungs: Black (air-filled) with faint white vascular markings spreading from hilum to periphery
• Cardiac silhouette: White/gray, clear sharp borders
• Trachea: Midline dark tubular structure
• Diaphragm: White curved lines at lung bases, both visible
• Costophrenic angles: Sharp, acute angles where diaphragm meets chest wall
• Ribs: White curved structures, symmetric
• Spine: White vertebral column in midline

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🫀 CARDIAC SILHOUETTE

Vertebral Heart Scale (VHS) — The Standard Method for Dogs and Cats

1. Measure the long axis of the heart from the carina to the apex
2. Measure the short axis at the widest point perpendicular to long axis
3. Both measurements are expressed in thoracic vertebral body lengths starting from T4

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Cardiomegaly — Enlarged Heart on X-ray

• Heart shadow wider than normal
• Cardiothoracic ratio > 0.5 (heart takes up more than 50% of chest width)
• Cardiac borders pushed against thoracic wall
• Loss of clear cardiac-lung interface

• Dilated Cardiomyopathy (DCM) — all chambers dilated → large globular heart (Dobermans, Great Danes)
• Hypertrophic Cardiomyopathy (HCM) — walls thickened (cats) → less dramatic X-ray change
• Pericardial effusion — fluid around heart → round "basketball" shape
• Valvular disease → specific chamber enlargement
• Congestive Heart Failure — combined cardiomegaly + pulmonary changes

Left Atrial Enlargement (LAE)

• On lateral view: Dorsal elevation of left mainstem bronchus
• On VD view: Bulging at 2–3 o'clock position of heart shadow
• Classic sign in dogs with Mitral Valve Disease (MMVD) — Cavalier CKCS, other small breeds

Right Heart Enlargement

• Reverse D shape (D-shaped heart on VD with flat left side)
• Seen with pulmonary hypertension, tricuspid valve disease, heartworm disease

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🫁 LUNG FIELD PATTERNS

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PATTERN 1: ALVEOLAR PATTERN (Consolidation)

• Bacterial Pneumonia — most common cause of lobar consolidation
• Pulmonary edema (cardiogenic — from heart failure)
• Pulmonary hemorrhage
• Lung neoplasia
• Aspiration pneumonia (common in dogs — "megaesophagus" patients)
• Contusion (trauma to lung)

• Lobar consolidation (one whole lobe) → bacterial pneumonia, aspiration
• Bilateral perihilar (near hilum) → cardiogenic pulmonary edema
• Ventral distribution → aspiration pneumonia (gravity-dependent)
• Diffuse bilateral → viral pneumonia, ARDS, severe pulmonary edema

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PATTERN 2: INTERSTITIAL PATTERN

• Cardiogenic pulmonary edema — most common in veterinary patients! Left heart failure → fluid backs up into interstitium
• Non-cardiogenic pulmonary edema — toxins, near-drowning, head trauma
• Viral pneumonia
• Feline Infectious Peritonitis (FIP) — interstitial lung involvement
• Chronic interstitial disease / fibrosis
• Lungworm (Aelurostrongylus in cats, Oslerus osleri in dogs)
• Early bacterial pneumonia before alveolar filling

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PATTERN 3: BRONCHIAL PATTERN

• Feline Asthma / Allergic Bronchitis — the classic cause in cats → bronchial pattern is THE most characteristic X-ray finding
• Chronic Bronchitis in dogs (especially small breeds)
• Bronchopneumonia
• Lungworm (peribronchial inflammation)

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PATTERN 4: VASCULAR PATTERN

• Enlarged, tortuous right caudal lobar artery — pathognomonic
• Right heart enlargement
• Perivascular haziness (eosinophilic infiltrate)
• Interstitial pattern
• "Reverse D" right heart silhouette in severe cases

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PATTERN 5: MIXED PATTERN

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💧 PLEURAL EFFUSION

• Blunting of the costophrenic angles (normally sharp V-shaped corners) — earliest sign
• "Meniscus sign" — curved upper fluid border
• Homogeneous white opacity at lung bases
• Fissure lines (fluid tracking along interlobar fissures)
• With large effusion: mediastinal shift away from effusion (pushed by fluid)
• Lung appears smaller/compressed

On DV view, cats with CHF often show bilateral effusion + the heart is hidden within the fluid. The heart may look "small" because it's surrounded by white fluid — this is a trap!

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💨 PNEUMOTHORAX

• Visceral pleural line — the key sign: a thin white line parallel to the chest wall, with no lung markings peripheral to it (just black air space)
• Lung looks smaller/collapsed (retracted toward hilum)
• If severe: Mediastinal shift TOWARD collapsed lung (lung pulls mediastinum to it)

• Trauma (hit by car, bite wounds, rib fractures) — most common
• Spontaneous bullae rupture (dogs with emphysema, giant breeds)
• Pulmonary abscess rupture
• Penetrating wound
• Post-surgical (thoracic surgery complication)
• Rib fracture lacerating lung

• Mediastinal shift AWAY from the pneumothorax side
• Collapsed lung on one side + opposite lung over-expanded
• This is life-threatening — air enters but can't exit → compresses both lungs and heart
• Emergency decompression (needle thoracocentesis) immediately

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📊 MEDIASTINAL CHANGES

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🐘 DIAPHRAGM

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SECTION 9 — ABDOMINAL RADIOGRAPHY

What X-ray Sees in the Abdomen

• Gas in GI tract (black)
• Fat (slightly darker than soft tissue)
• Mineral/calcification (bright white)
• Organ size and position (subtle gray differences)

Normal Abdominal X-ray Features

Retroperitoneal fat stripe:

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🫁 GASTRIC DILATION-VOLVULUS (GDV) — THE MOST IMPORTANT ABDOMINAL EMERGENCY

• Massively gas-distended stomach
• The stomach is rotated (volvulus) — creates a compartmentalized appearance with a soft tissue band dividing the gas shadow
• The pylorus flips to the LEFT side (normally it's on the right)
• "Popeye arm" or "C-shaped" gas pattern — classic finding

Emergency surgery required within 1–2 hours. X-ray confirms diagnosis → immediate surgical intervention.

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🌀 INTESTINAL OBSTRUCTION

• Normal small intestine diameter in dogs: Should not exceed width of a rib body (roughly 1.5× the rib)
• Loops > 2–3× rib width = significant dilation = obstruction until proven otherwise
• Valvulae conniventes: The "stack of coins" pattern = small intestinal loops (seen as laddered lines across the loop width)
• Haustra: The bubble-like gas segments = large intestine (seen as bubbles separated by soft tissue folds)

• Dilated small intestine + no colon gas → small intestinal obstruction
• Dilated large intestine → colonic obstruction, megacolon

• Foreign body (bones, toys, corn cobs, fabric — dogs)
• Intussusception (telescoping of bowel) — mainly young animals, post-parvoviral enteritis
• Volvulus
• Mass/adhesion
• Mesenteric hernia

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🟡 ABDOMINAL CALCIFICATIONS / UROLITHIASIS

Radiolucent stones (urate, cystine, matrix) are NOT visible on plain X-ray. Need contrast study or ultrasound.

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🫁 FREE ABDOMINAL AIR (PNEUMOPERITONEUM)

• On standing lateral or VD with horizontal beam: Air rises to the top (subphrenic = under diaphragm)
• Air seen between liver and diaphragm (normally they're the same gray and touch = no visible interface)
• Air under diaphragm appears as black crescent

• Gastrointestinal perforation (perforated ulcer, intestinal rupture, perforating foreign body) — most serious
• Post-surgical (normal for 2–3 weeks after abdominal surgery)
• Penetrating abdominal wound
• Rectal perforation (e.g., from bite wound, thermometer)

Free air in the abdomen in a non-surgical patient = perforation until proven otherwise → emergency surgery.

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📐 ORGAN SIZE CHANGES

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SECTION 10 — MUSCULOSKELETAL (BONE) RADIOGRAPHY

Normal Bone Anatomy on X-ray

Epiphysis  ← Bone end (joint surface) — contains growth plate in young animals
   |
Growth plate (physis) ← Dark line in growing bones — closes with maturity
   |
Metaphysis ← Flared zone between growth plate and diaphysis
   |
Diaphysis  ← Shaft of bone — dense cortex + hollow medullary canal
   |
Cortex     ← Outer hard white shell
   |
Medullary canal ← Inner darker channel (contains bone marrow)
   |
Trabeculae ← Internal spongy bone pattern
   |
Periosteum ← Outer membrane (not visible unless reacting)

Reading a Bone X-ray — What to Check:

1. Cortex: Intact? Disrupted? Thinned? Thickened?
2. Medullary canal: Normal density? Lucent lesion? Sclerotic?
3. Periosteal reaction: Any new bone forming on outside?
4. Joint space: Normal? Narrowed? Widened? Debris?
5. Bone density: Normal white? Too white (sclerotic)? Too dark (osteoporosis)?
6. Alignment: Fragments aligned? Displaced? Angulated?

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🦴 FRACTURES

Fracture Classification (What to Report on X-ray)

Physeal (Growth Plate) Fractures in Young Animals

• Very important in puppies/kittens
• Salter-Harris classification:
  • Type I: Slip through growth plate (whole epiphysis separates)
  • Type II: Through growth plate + into metaphysis (most common)
  • Type III: Through growth plate + into epiphysis (joint involved)
  • Type IV: Through metaphysis + growth plate + epiphysis
  • Type V: Crush of growth plate (worst — causes growth stunting)

Fracture Healing — Radiographic Stages

If no callus is forming at 3–4 weeks = delayed union. If fracture site remains mobile and no union by 4+ months = non-union → surgical intervention needed.

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🦴 BONE LESIONS (Lytic vs. Proliferative)

• Typically affects metaphysis of long bones in large/giant breeds
• Distal radius, proximal humerus, distal femur, proximal tibia most common locations
• X-ray: Aggressive bone destruction (lytic) + sunburst periosteal reaction + soft tissue swelling
• May see Codman's triangle (elevation of periosteum at edge of tumor)
• Virtually no normal periosteal reaction = very aggressive = poor prognosis

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🐾 JOINT RADIOGRAPHY

• OFA (Orthopedic Foundation for Animals) extended hip view
• Evaluated at 2 years of age for certification
• Signs: Shallow acetabulum, femoral head subluxation, DJD, remodeling of femoral head
• PennHIP method: Distraction index (DI) measured — the gold standard for predicting HD development

• Fragmented medial coronoid process (FCP), OCD of humeral condyle, ununited anconeal process (UAP)
• X-ray: Elbow OA (osteophytes at anconeal process area), widened humeroradial joint space, sclerosis

• X-ray findings: Cranial tibial thrust, stifle effusion (loss of fat pad, widened joint space), periarticular osteophytes (chronic)
• X-ray does not show the ligament itself — diagnosis is clinical/arthroscopic

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🦷 DENTAL / SKULL RADIOGRAPHY

• Intraoral technique — plates placed inside mouth
• Show tooth roots, periodontal ligament space, alveolar bone
• Essential for: Tooth root abscesses, feline tooth resorption, periodontal disease grading

• DV (dorsoventral) — nasal cavities, frontal sinuses, skull
• Lateral — skull profile, teeth, tympanic bullae
• Rostrocaudal (open mouth) — tympanic bullae (otitis media/interna cases)
• VD oblique — temporomandibular joint

• Chronic otitis externa → otitis media → fluid/thickening in bulla
• X-ray: Increased opacity (white) in bulla = fluid or thickening. Loss of sharp outline = aggressive disease

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SECTION 11 — SPINAL RADIOGRAPHY

Views:

• Lateral: Intervertebral disc spaces, vertebral body alignment, osteophytes
• VD: Disc spaces, vertebral width, narrowing

What to Look For:

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SECTION 12 — CONTRAST RADIOGRAPHY

Common Contrast Studies in Veterinary Practice

• Megaesophagus: Massively dilated esophagus filled with barium
• Esophageal foreign body: Filling defect (where barium can't flow = object is there)
• Hiatal hernia: Stomach herniating through diaphragm

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SECTION 13 — AGE-SPECIFIC RADIOGRAPHIC FINDINGS

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SECTION 14 — RADIOGRAPHIC SIGNS SUMMARY TABLE

Chest X-ray Signs

Abdominal X-ray Signs

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SECTION 15 — PRACTICE QUESTIONS

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Answer: Take right lateral AND VD views immediately (before more deterioration). Expected findings: Massively gas-distended stomach with compartmentalization (soft tissue band dividing the gas = the pyloric/duodenal wall rotated across the gas shadow). On lateral: gas-filled stomach with "double bubble" compartment. On VD: stomach extends across entire cranial abdomen. Small intestinal gas-distension (secondary ileus). Spleen may be displaced. Diagnosis = GDV. Do NOT delay for more views. Emergency surgery within 1 hour after stabilization (IV fluids + decompression). If left untreated → gastric necrosis, shock, death.

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Answer: Lateral and VD thoracolumbar spine X-rays. Expected findings: Calcified intervertebral disc material in multiple disc spaces (characteristic of chondrodystrophic breeds — Dachshunds calcify their nucleus pulposus). Look for narrowed disc space at the level correlating with the neurological deficits. May see extruded calcified disc material in the spinal canal (ventral floor of canal appearing white). However, X-ray alone cannot rule out disc herniation — myelogram or CT/MRI is required to confirm and localize. This is Hansen Type I IVDD — emergency decompressive surgery (hemilaminectomy) if deep pain is absent or rapidly deteriorating.

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Answer: Congestive Heart Failure (CHF) secondary to Myxomatous Mitral Valve Disease (MMVD). The enlarged cardiac silhouette = cardiomegaly. The 2–3 o'clock bulge on VD = left atrial enlargement (pathognomonic for MMVD in Cavaliers). Perihilar haze = early pulmonary edema (cardiogenic — left heart failure → backup of fluid into pulmonary interstitium). Treatment: Furosemide (diuretic) + pimobendan + ACE inhibitor. Confirm with echocardiography (mitral regurgitation, LA:Ao ratio, FS%). VHS would be >10.5 vertebral lengths.

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Answer: Bilateral pleural effusion + cardiomegaly → most likely CHF from HCM (hypertrophic cardiomyopathy) OR chylothorax or FIP in a young cat. First priority: Do NOT stress the cat more — DV view was correct choice (less stressful than VD for dyspneic cats). Immediate treatment: Bilateral thoracocentesis (remove pleural fluid → cat can breathe) BEFORE any further diagnostics. After stabilization: Echocardiogram (assess HCM), fluid analysis (chylothorax vs. transudate vs. FIP exudate). If young cat with bilateral effusion = consider FIP (coronavirus) — check for globulins, A:G ratio.

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Answer: Left-sided tension pneumothorax. The pleural line = air in pleural space collapsing the left lung. The rightward mediastinal shift = air under pressure pushing everything to the right = tension pneumothorax (most dangerous form). Immediate emergency needle decompression: Insert 18G butterfly catheter/needle in the dorsal 7th–9th intercostal space (high up — air rises) of the left side. Release the pressure. Follow with chest drain placement. The patient may arrest without immediate decompression. Do NOT delay for more X-rays. After decompression: reassess with follow-up X-ray, look for underlying rib fractures, lung contusions, diaphragmatic hernia.

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QUICK REFERENCE CARD — WHAT TO LOOK FOR ON EACH X-RAY

Chest X-ray Checklist

☐ Trachea: midline? deviated? narrowed?
☐ Cardiac silhouette: size (VHS)? shape? borders sharp?
☐ Left atrium: tracheal elevation? 2-3 o'clock bulge?
☐ Pulmonary vessels: normal? enlarged? asymmetric?
☐ Lung fields: any opacity? which pattern? (alveolar/interstitial/bronchial/vascular)
☐ Pleural space: costophrenic angles sharp? any effusion? any pleural line?
☐ Diaphragm: both crura visible? elevated? interrupted (hernia)?
☐ Mediastinum: width normal? any mass? pneumomediastinum?
☐ Bones: rib fractures? vertebral lesions? scapular fracture?
☐ Extra-thoracic: any subcutaneous gas? foreign material?

Abdominal X-ray Checklist

☐ Serosal detail: sharp (normal)? hazy (fluid)? absent (serious)?
☐ Liver size: within costal arch? extended caudally?
☐ Spleen: visible? enlarged?
☐ Kidneys: visible? size? position? calcification?
☐ Bladder: visible? size? any calcification?
☐ Stomach: gas? normal position? compartmentalized (GDV)?
☐ Small intestine: diameter vs. rib? dilated loops? air-fluid levels?
☐ Large intestine: diameter? obstruction? megacolon?
☐ Free air: subphrenic? outlining organs?
☐ Calcifications: location? size? shape?
☐ Bones: spine alignment? vertebral lesions? pelvic fractures?
☐ Uterus: visible? enlarged (pyometra/pregnancy)?

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Sources: Grainger & Allison's Diagnostic Radiology (Elsevier); Murray & Nadel's Textbook of Respiratory Medicine (Elsevier); Rosen's Emergency Medicine (Elsevier); Fishman's Pulmonary Diseases and Disorders (McGraw-Hill); Roberts & Hedges' Clinical Procedures in Emergency Medicine (Elsevier); Goldman-Cecil Medicine International Edition; The Harriet Lane Handbook 23e; Applied veterinary species-specific radiographic knowledge.

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🧪 LFT + RFT + COMPLETE HEALTH CHECK IN PETS

The Most Detailed Clinical Guide for Veterinary Practice

Sources: Henry's Clinical Diagnosis & Management by Laboratory Methods | Washington Manual of Medical Therapeutics | Robbins & Kumar Basic Pathology | Quick Compendium of Clinical Pathology 5e | Tietz Textbook of Laboratory Medicine 7e | Barash Clinical Anesthesia 9e | Morgan & Mikhail's Clinical Anesthesiology 7e | Brenner & Rector's The Kidney | Applied Veterinary Clinical Knowledge

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UNDERSTANDING THE BLOOD BIOCHEMISTRY PANEL

• LFT (Liver Function Tests) — Checks if the liver is healthy
• RFT (Renal Function Tests) — Checks if the kidneys are healthy

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PART 1 — LFT: LIVER FUNCTION TESTS

═══════════════════════════════════

Why the Liver Matters

• Breaks down fats, carbohydrates, proteins
• Produces bile (for fat digestion)
• Detoxifies drugs, toxins, ammonia
• Makes blood clotting factors (prothrombin, fibrinogen)
• Makes albumin (the main blood protein)
• Stores glycogen (energy reserve)
• Converts bilirubin for excretion

If the liver fails → the whole body fails. LFTs tell you HOW the liver is failing and WHY.

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LFT TEST 1: ALT — Alanine Aminotransferase

Species note: ALT is most useful in dogs and cats. In horses and ruminants (cows, goats, sheep), ALT is not as liver-specific.

• Hepatitis (bacterial, viral, autoimmune — copper-associated hepatitis in Bedlington Terriers, Labradors)
• Toxins: Xylitol (dogs — found in sugar-free gum, peanut butter!), aflatoxin (contaminated food), mushrooms (Amanita), blue-green algae
• Acetaminophen (Paracetamol): Deadly in cats — causes hepatic necrosis + methemoglobinemia. Never give paracetamol to cats!
• Corticosteroids (dogs only) → steroid hepatopathy → vacuolar change → ALT 3–10× — important to know because many dogs are on steroids
• Diabetes mellitus → hepatic lipidosis secondary to insulin deficiency
• Hyperthyroidism (cats) → liver enzyme elevation common
• Pancreatitis → adjacent inflammation raises ALT
• Hypothyroidism (dogs) → hepatic lipid accumulation
• Cushing's disease (hyperadrenocorticism) → steroid hepatopathy → very high ALT
• Portosystemic shunt (PSS) → liver not getting adequate blood flow → enzyme changes

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LFT TEST 2: AST — Aspartate Aminotransferase

• Liver damage (hepatocellular — same as ALT)
• Muscle damage (rhabdomyolysis, trauma, myositis, excessive exercise, IM injections)
• Hemolysis (RBC contain AST → broken RBCs release it)
• Cardiac muscle damage (myocarditis)
• Sample artifact — hemolyzed sample falsely elevates AST

Practical tip: If AST is high but ALT is normal → check creatine kinase (CK) to confirm muscle damage.

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LFT TEST 3: ALP — Alkaline Phosphatase (SAP — Serum Alkaline Phosphatase)

• Dog: ALP elevation is very common due to steroid-induced enzyme. Always check if dog is receiving ANY steroid (prednisone, dexamethasone, even topical ear drops!)
• Cat: ALP elevation is MORE concerning in cats because cats DON'T have the steroid-induced isoenzyme. A high ALP in a cat usually means significant liver disease or cholestasis. Even 2× normal in a cat = worth investigating.

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LFT TEST 4: GGT — Gamma Glutamyl Transferase (Gamma GT)

• Biliary obstruction (extra or intrahepatic cholestasis) — THE most sensitive marker
• Cholangiohepatitis in cats — GGT is elevated more often than ALP in cats with hepatic lipidosis
• Corticosteroids in dogs (same as ALP)
• Pancreatic disease
• Bile duct hyperplasia

• In cats: GGT is the better biliary marker than ALP
• In cats with hepatic lipidosis: ALP is usually very high but GGT is often normal or only mildly elevated — this pattern (high ALP + normal/low GGT in a cat) is strongly suggestive of hepatic lipidosis
• If both ALP and GGT are high → true biliary disease or cholangiohepatitis

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LFT TEST 5: BILIRUBIN (Total, Direct/Conjugated, Indirect/Unconjugated)

Bilirubin Pathway (Simplified):

Old RBC destroyed
       ↓
Hemoglobin → Heme → Unconjugated (Indirect) Bilirubin
       ↓ (travels in blood bound to albumin)
Liver picks it up
       ↓
Liver adds glucuronide → Conjugated (Direct) Bilirubin
       ↓
Secreted into bile → goes to intestines → excreted in feces (gives stool its brown color)
                    → some converted to urobilinogen → goes to urine (yellow color)

The Three Types of Jaundice — Most Important Clinical Tool:

TYPE 1: PRE-HEPATIC JAUNDICE (Hemolytic)

• Cause: Too many RBCs being destroyed → too much bilirubin produced → overwhelms liver
• Bilirubin pattern: Mainly UNCONJUGATED (indirect) elevated
• Urine: Normal (no bilirubin in urine — unconjugated bilirubin bound to albumin, can't pass through kidney)
• Urobilinogen: Increased (more bilirubin reaching gut)
• Liver enzymes: Normal or mildly elevated (liver is fine)
• RBC: Low — anemia present
• Examples: IMHA (immune-mediated hemolytic anemia), Babesia, Hemobartonella, severe hemolysis

TYPE 2: HEPATIC JAUNDICE (Liver Disease)

• Cause: Liver cannot process bilirubin properly
• Bilirubin pattern: BOTH conjugated AND unconjugated elevated
• Urine bilirubin: Present (conjugated bilirubin can pass through kidney)
• Urobilinogen: Variable
• Liver enzymes: HIGH (ALT, ALP, GGT elevated)
• Examples: Acute hepatitis, cirrhosis, hepatic lipidosis in cats, leptospirosis, hepatic lymphoma

TYPE 3: POST-HEPATIC JAUNDICE (Obstructive)

• Cause: Bile cannot flow out of liver/bile duct → bilirubin backs up
• Bilirubin pattern: Mainly CONJUGATED (direct) elevated
• Urine bilirubin: Present (dark brown "tea-colored" urine)
• Urobilinogen: ABSENT or very low (bile not reaching gut)
• Feces: Pale/acholic (no bilirubin in stool → stool turns pale/white)
• Liver enzymes: ALP and GGT especially elevated
• Examples: Pancreatitis compressing bile duct, gallbladder mucocele (dogs), cholelith, bile duct carcinoma, duodenal mass

Icterus Quick Recognition Chart:

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LFT TEST 6: BILE ACIDS (Fasting and Post-Prandial)

1. Take blood sample after 12-hour fast → Fasting bile acids
2. Feed a small meal
3. Take blood sample again 2 hours later → Post-prandial bile acids

• Portosystemic Shunt (PSS) — the #1 most common cause in young animals. Blood bypasses the liver → bile acids not cleared → very high levels. This is the BEST diagnostic test for PSS.
• Chronic liver disease (cirrhosis, hepatitis)
• Hepatic lipidosis (cats)
• Any cause of reduced hepatic function

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LFT TEST 7: ALBUMIN

• Peripheral edema (fluid accumulates under skin — especially limbs, face, ventral body)
• Ascites (fluid in abdomen)
• Pleural effusion (fluid in chest)
• Caveat: Signs usually appear when albumin < 1.5–2.0 g/dL

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LFT TEST 8: TOTAL PROTEIN and GLOBULINS

• Chronic infection/inflammation — body producing lots of antibodies
• FIP in cats — very high globulins (often >5 g/dL), low albumin → A:G ratio < 0.8 = very suspicious for FIP
• Multiple myeloma (plasma cell cancer) — monoclonal spike on protein electrophoresis
• Ehrlichiosis — tick-borne disease, chronic → very high globulins
• Leishmaniasis — endemic in Mediterranean regions, dogs
• Brucellosis — chronic infection

• Immunodeficiency
• Neonatal animals who haven't received colostrum (failure of passive transfer)
• Protein-losing enteropathy (all proteins lost equally)

• Normal: 0.8 – 2.0
• A:G < 0.5 in a cat with ascites/effusion = FIP until proven otherwise (the most important use of this ratio)

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LFT TEST 9: PROTHROMBIN TIME (PT) and aPTT

• PT (Prothrombin Time): Tests extrinsic clotting pathway (factors I, II, V, VII, X)
• aPTT: Tests intrinsic pathway (factors I, II, V, VIII, IX, X, XI, XII)

• Severe liver failure — liver not making clotting factors → spontaneous bleeding
• Rodenticide toxicity (anticoagulant rat poison) — warfarin/brodifacoum → inhibits Vitamin K-dependent clotting factors (II, VII, IX, X) → PT prolonged first (VII has shortest half-life)
• DIC (Disseminated Intravascular Coagulation) — both PT and aPTT prolonged + thrombocytopenia
• Vitamin K deficiency — fat malabsorption (obstructive jaundice)
• Inherited coagulopathy (von Willebrand disease, hemophilia A/B)

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LFT TEST 10: AMMONIA

• Seizures, disorientation, circling, head pressing, ptyalism (drooling), stupor, coma
• Classic in dogs with portosystemic shunts (PSS) — especially after a protein meal
• In cats: hyperactivity, aggression, then depression
• Also elevated in severe acute liver failure

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LFT TEST 11: CHOLESTEROL

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LFT TEST 12: GLUCOSE

• Diabetes mellitus — most common cause
• Stress (cats especially — can be 300+ mg/dL from stress alone)
• Pancreatitis (destroys insulin-producing cells)
• Glucocorticoids (steroid treatment or Cushing's)
• Glucagonoma (rare)

• Insulinoma — insulin-producing pancreatic tumor (Boxers, Labrador Retrievers, Irish Setters)
• Neonatal/juvenile hypoglycemia — toy breeds, puppies not eating
• Addison's disease (hypoadrenocorticism)
• Septic shock (bacteria consuming glucose)
• Hepatic failure (liver can't maintain glucose stores)
• Hunting dog hypoglycemia — extreme exercise in poorly fed dog
• Xylitol toxicity (dogs) — xylitol triggers massive insulin release → severe hypoglycemia

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COMPLETE LFT SUMMARY TABLE

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PART 2 — RFT: RENAL FUNCTION TESTS

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Why Kidneys Matter

• Filter blood 60× per day → remove waste products (urea, creatinine, toxins)
• Regulate water balance (concentrated or dilute urine)
• Control blood pressure (renin-angiotensin system)
• Maintain electrolyte balance (Na, K, Ca, Phosphorus)
• Produce erythropoietin (stimulates RBC production)
• Activate Vitamin D

Kidneys have HUGE reserve capacity — by the time BUN and creatinine become abnormal, 75% of kidney function is already lost. This is why early detection tests like SDMA are so important.

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RFT TEST 1: BUN — Blood Urea Nitrogen

• Dehydration (most common!) — concentrated blood → high BUN → called "prerenal azotemia"
• Acute or Chronic Kidney Disease (AKD/CKD)
• Urinary obstruction (cat urethral blockage, urolithiasis)
• High protein diet
• GI hemorrhage — blood in gut = protein source → elevated BUN (without proportional creatinine rise)
• Fever, hypercatabolism
• Corticosteroids (protein catabolism)

• Severe liver failure (liver can't convert ammonia to urea)
• Portosystemic shunt (blood bypasses liver)
• Low protein diet or malnutrition
• Overhydration/polyuria (urea diluted)

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RFT TEST 2: CREATININE

• A very muscular (large, fit) dog may have creatinine at upper normal = normal for them
• A very thin, cachexic, or muscle-wasting cat may have LOW normal creatinine even with significant kidney disease — this makes creatinine UNDERESTIMATE kidney disease in emaciated patients

• Acute Kidney Injury (AKI) — sudden kidney damage (toxins, hypotension, leptospirosis, NSAID overdose, lily toxicity in cats)
• Chronic Kidney Disease (CKD) — progressive loss of nephrons
• Urinary obstruction (post-renal)
• Dehydration (less common for creatinine to rise as much as BUN)

This staging system is critical in veterinary nephrology. Once you stage the patient, you also sub-stage by proteinuria (UPC ratio) and blood pressure.

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RFT TEST 3: SDMA — Symmetric Dimethylarginine

• Not affected by muscle mass (creatinine is!) → more accurate in thin, cachexic, or elderly patients
• Rises earlier than creatinine
• Correlates better with GFR than BUN

• SDMA 14–17 µg/dL + creatinine normal → Stage 1 CKD (diagnose early!)
• SDMA ≥18 µg/dL → Stage 2+ CKD

For senior wellness screening, always run SDMA. This is the game-changer for early CKD detection, especially in cats.

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RFT TEST 4: PHOSPHORUS

• CKD — most common cause in cats and dogs. Phosphorus cannot be excreted → accumulates
• Young animals post-meal (physiologic)
• Hypoparathyroidism
• Vitamin D toxicosis
• Urinary obstruction

• Calcium × Phosphorus product → if too high → calcium phosphate precipitates in soft tissues (kidneys, blood vessels, lungs)
• Promotes further kidney damage
• Causes parathyroid hyperplasia → renal secondary hyperparathyroidism → bone demineralization → "rubber jaw" in dogs

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RFT TEST 5: CALCIUM

Corrected Ca (mg/dL) = Measured Ca - Albumin (g/dL) + 3.5

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RFT TEST 6: ELECTROLYTES

Sodium (Na)

Potassium (K)

• Cardiac effects: Bradycardia, tall T waves, wide QRS, sine wave pattern on ECG → ventricular fibrillation → cardiac arrest
• Emergency treatment: Calcium gluconate (stabilize heart), insulin + glucose (drive K into cells), sodium bicarbonate (acidosis correction), IVF, relieve obstruction

Chloride (Cl)

• Detecting metabolic acidosis/alkalosis
• Evaluating vomiting (hypochloremic metabolic alkalosis from vomiting gastric HCl)
• Addison's disease (↓ Cl follows ↓ Na)

Bicarbonate (HCO₃) / Total CO₂

• ↓ Low (Metabolic Acidosis): CKD, DKA, severe diarrhea, ethylene glycol toxicity, lactic acidosis (shock)
• ↑ High (Metabolic Alkalosis): Vomiting of gastric contents, diuretics, hyperaldosteronism

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RFT TEST 7: URINALYSIS (UA) — The MOST Underused but Most Important Renal Test

How to Collect Urine (Properly!)

Urinalysis — Component by Component:

A. COLOR

B. CLARITY / TURBIDITY

• Clear: Normal
• Cloudy: Cells (WBCs, RBCs), bacteria, crystals, lipid droplets (normal in cats)
• Flocculent: Casts, mucus, debris

C. SPECIFIC GRAVITY (USG) — The MOST Important Single Urine Test

Key rule: A dehydrated animal MUST have concentrated urine (USG > 1.030 dog, > 1.035 cat) to prove kidneys are working. If a dehydrated animal has USG 1.010 → kidneys are NOT responding to dehydration → renal failure.

D. pH (Urine Acidity/Alkalinity)

E. PROTEIN (Proteinuria)

The Urine Protein:Creatinine Ratio (UPC) is the most accurate test for proteinuria.

• Pre-renal: Overflow proteinuria — Bence Jones proteins (myeloma), hemoglobin (hemolysis), myoglobin (muscle damage)
• Renal:
  • Glomerular proteinuria → protein leaking through damaged filter (glomerulonephritis, amyloidosis, diabetic nephropathy)
  • Tubular proteinuria → tubules can't reabsorb small proteins
• Post-renal: Lower urinary tract inflammation/bleeding (UTI, cystitis, prostatitis) — protein from WBCs, RBCs

F. GLUCOSE (Glucosuria)

G. KETONES

• Diabetic Ketoacidosis (DKA) — life-threatening. Insulin-deficient diabetic → fat breakdown → ketone bodies → urine
• Starvation/prolonged anorexia
• Low carbohydrate diet
• Nursing kittens/puppies

Ketonuria in a known diabetic = DKA emergency. Requires hospitalization, IV fluids, insulin, electrolyte monitoring.

H. BILIRUBIN in Urine

• ↑ Bilirubinuria in cats → always significant → liver disease or hemolysis
• ↑ Bilirubinuria in dogs (beyond trace) → hepatic or post-hepatic disease

I. UROBILINOGEN

• Present in normal urine (from bile degradation in gut → reabsorbed → excreted in urine)
• Absent → biliary obstruction (bile not reaching gut)
• Elevated → hemolysis or hepatocellular disease

J. NITRITE

• Indicates bacterial infection (gram-negative bacteria convert nitrate to nitrite)
• Used as screening test for UTI
• False negative: Gram-positive organisms (Staph, Enterococcus) don't produce nitrite

K. LEUKOCYTE ESTERASE

• Indicates white blood cells in urine = pyuria = inflammation/infection
• Must confirm with sediment examination

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Urine Sediment Examination — Microscopic

RED BLOOD CELLS (RBCs) in Urine

• > 5 RBC/HPF = Hematuria
• Causes: Cystitis, urolithiasis, trauma, TCC, coagulopathy, renal disease, prostatitis
• Dysmorphic RBCs (misshapen, acanthocytic) = glomerular hematuria (squeezed through glomerular membrane)
• Normal round RBCs = lower urinary tract source

WHITE BLOOD CELLS (WBCs) in Urine

• > 5 WBC/HPF = Pyuria
• Causes: UTI, cystitis, pyelonephritis, urethritis, prostatitis
• Pyuria + bacteriuria + clinical signs = active UTI → culture + sensitivity + antibiotic treatment

CASTS — Very Important for CKD Diagnosis

Any cellular casts = ACTIVE renal disease happening right now. Waxy/broad casts = chronic advanced disease.

BACTERIA

• Normal urine (cystocentesis sample) = STERILE = no bacteria
• Bacteria in cystocentesis sample = urinary tract infection → culture + sensitivity
• Rods usually = gram-negative (E. coli, Proteus, Pseudomonas)
• Cocci usually = gram-positive (Staphylococcus, Streptococcus, Enterococcus)

CRYSTALS

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RFT TEST 8: UPC RATIO — Urine Protein:Creatinine Ratio

• Non-proteinuric: UPC < 0.2
• Borderline: 0.2–0.5
• Proteinuric: > 0.5 (worse prognosis, start RAAS inhibitor — enalapril or benazepril)

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RFT TEST 9: BLOOD PRESSURE

• Dog: Systolic 100–160 mmHg
• Cat: Systolic 100–150 mmHg

• CKD (most common cause in cats)
• Hyperthyroidism (cats)
• Hyperadrenocorticism (dogs)
• Pheochromocytoma (adrenal tumor)
• Diabetes mellitus
• Primary (idiopathic) hypertension

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COMPLETE RFT SUMMARY TABLE

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PART 3 — COMPLETE HEALTH CHECK (WELLNESS PANEL)

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WELLNESS CHECK — COMPLETE PANEL

1. PHYSICAL EXAMINATION PARAMETERS

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2. CBC (Complete Blood Count) — Already Covered in Full Previously

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3. COMPLETE BIOCHEMISTRY PANEL (LFT + RFT + More)

THYROID HORMONE — T4 (Thyroxine)

• Most common endocrine disease in cats > 8 years old
• Signs: Weight loss despite good appetite, vomiting, hyperactivity, unkempt coat, PU/PD, tachycardia, heart murmur
• Often causes: High ALT, ALP, elevated BP, left ventricular hypertrophy on echo
• Treatment: Methimazole, radioactive iodine, thyroidectomy, iodine-restricted diet (Hill's Y/D)

• Most common endocrine disease in middle-aged dogs (Golden Retrievers, Labrador Retrievers, Dobermans, Boxers)
• Signs: Weight gain, lethargy, cold intolerance, bilateral symmetrical hair loss (truncal alopecia), thickening of skin (myxedema), bradycardia, high cholesterol, high triglycerides
• False low T4: Sick euthyroid syndrome (any non-thyroid illness lowers T4 → misdiagnosis)
• Better test: Free T4 by equilibrium dialysis + cTSH (canine TSH)

Important: Hypothyroid dogs have: HIGH cholesterol + HIGH triglycerides + LOW T4 + HIGH cTSH (elevated because pituitary releasing more TSH to stimulate an underperforming thyroid)

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CORTISOL — Adrenal Function Tests

• Administer dexamethasone → measure cortisol at 4 and 8 hours
• Normal: Cortisol suppressed to < 1.0 µg/dL
• Cushing's: Fails to suppress → cortisol remains high

• Inject synthetic ACTH → measure cortisol at 0 and 1 hour
• Addison's: Basal low + fails to stimulate (cortisol < 2 µg/dL at both times)
• Cushing's: Exaggerated response (> 22 µg/dL post-ACTH)
• Iatrogenic Cushing's: Basal and post-ACTH both LOW (exogenous steroids suppress adrenal)

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PANCREATIC TESTS

• Gold standard blood test for pancreatitis in dogs and cats
• Normal Spec cPL: < 200 µg/L (dog)
• Normal Spec fPL: < 3.5 µg/L (cat)
• Elevated in pancreatitis, pancreatic neoplasia

• Less specific than lipase (also made by intestine, salivary glands)
• Still used as supporting test: elevated in pancreatitis, intestinal disease, renal failure (reduced clearance)
• Normal dog: 200–2000 U/L

• The gold standard test for Exocrine Pancreatic Insufficiency (EPI)
• Normal dog: 5–35 µg/L
• EPI: TLI < 2.5 µg/L — pancreas not making digestive enzymes → maldigestion, voluminous pale greasy feces, weight loss despite ravenous appetite
• Common in German Shepherds (genetic), also young Rough Collies

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COBALAMIN (Vitamin B12) and FOLATE

• Low B12 + High Folate = bacterial overgrowth (bacteria consume B12, produce excess folate)
• Low B12 + Low Folate = diffuse intestinal disease, severe IBD, lymphoma
• Low B12 alone = ileal disease, EPI (ileum absorbs B12)
• Low Folate alone = proximal small intestinal disease (IBD, lymphoma in duodenum/jejunum)

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URINE CULTURE AND SENSITIVITY (C&S)

• Bacterial colony counts
• Organism identification
• MIC (Minimum Inhibitory Concentration) for multiple antibiotics

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FECAL EXAMINATION

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4. HEARTWORM TEST

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5. BLOOD PRESSURE MEASUREMENT

• Every visit for cats > 7 years old
• Every visit for dogs with CKD, Cushing's, diabetes, cardiac disease
• Annual check for all dogs > 7 years

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6. SENIOR WELLNESS PANEL — AGE-BY-AGE GUIDE

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7. VACCINATION STATUS CHECK

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8. DEWORMING AND PARASITE CONTROL

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9. NUTRITIONAL ASSESSMENT

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COMPLETE HEALTH CHECK — SUMMARY SHEET

FULL HEALTH CHECK = ALL OF THE FOLLOWING:
━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━
PHYSICAL EXAM:
☐ Temperature, HR, RR, weight, BCS, MCS
☐ MM color, CRT, hydration
☐ Lymph node palpation
☐ Auscultation (heart murmur? arrhythmia? lung sounds?)
☐ Abdominal palpation (organ size? masses? pain?)
☐ Ophthalmic + ear + skin + oral exam
☐ Orthopedic assessment (joint pain? gait abnormalities?)
━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━
BLOODWORK:
CBC:  WBC differential, RBC, PCV, Hgb, MCV, MCH, MCHC, Platelets, Reticulocytes
LFT:  ALT, AST, ALP, GGT, Total Bilirubin (Direct + Indirect), Bile Acids (fast + post-prandial), Albumin, Total Protein, Globulins, Cholesterol, Glucose, PT/aPTT (if needed), Ammonia (if encephalopathy suspected)
RFT:  BUN, Creatinine, SDMA, Phosphorus, Calcium, Sodium, Potassium, Chloride, Bicarbonate
ADDITIONAL: T4, Spec cPL/fPL (if GI signs), TLI (if EPI suspected), Cortisol/LDDS/ACTH (if endocrine disease suspected), Cobalamin + Folate (if chronic GI disease)
━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━
URINALYSIS:
☐ Color, Clarity
☐ USG, pH, Protein (+ UPC if proteinuric), Glucose, Ketones, Bilirubin, Urobilinogen, Nitrite, Leukocyte Esterase
☐ Sediment: RBCs, WBCs, Casts, Bacteria, Crystals, Epithelial cells
☐ Culture + Sensitivity if pyuria/bacteriuria present
━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━
FECAL:
☐ Flotation, direct smear, Giardia ELISA (routine)
☐ Baermann (if lungworm suspected)
☐ PCR panel (if diarrhea or systemic illness)
━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━
IMAGING (AS INDICATED):
☐ Thoracic radiographs (cardiac disease, respiratory signs)
☐ Abdominal USG (liver, spleen, kidneys, adrenals, bladder, GIT)
☐ Echocardiography (heart murmur, cardiomegaly on X-ray)
━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━
PREVENTIVE:
☐ Vaccination status review + update
☐ Heartworm test + prevention status
☐ Flea/tick prevention status
☐ Deworming schedule
☐ Blood pressure (all cats > 7y, senior dogs, CKD/hypertension patients)
☐ Dental assessment (periodontal disease grading)
☐ Nutritional counseling (BCS, diet review)
━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━

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QUICK CLINICAL DECISION GUIDE

When you see HIGH ALT in a dog:

When you see HIGH ALP in a cat:

When you see HIGH BUN but NORMAL Creatinine:

When you see HIGH BUN AND HIGH Creatinine together:

When USG is fixed at 1.010 in a sick pet:

Cat with weight loss + polyphagia + tachycardia:

Dog with PU/PD + pot belly + thin skin + muscle wasting + hair loss:

Dog with PU/PD + low Na + high K + Na:K < 27:1 + Low BCS:

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Sources: Henry's Clinical Diagnosis & Management by Laboratory Methods | Washington Manual of Medical Therapeutics | Robbins & Kumar Basic Pathology | Quick Compendium of Clinical Pathology 5e | Tietz Textbook of Laboratory Medicine 7e | Barash Clinical Anesthesia 9e | Morgan & Mikhail's Clinical Anesthesiology 7e | Brenner & Rector's The Kidney | Applied Veterinary Clinical Knowledge (species-specific reference ranges and interpretations)