Canine Medicine

---
name: canine-medicine
description: Canine-specific clinical medicine covering breed predispositions, common disease presentations, normal physiologic parameters, and species-specific diagnostic and treatment approaches for dogs.
---

# Canine Medicine

## Overview

Canine-specific clinical medicine covering breed predispositions, common disease presentations, normal physiologic parameters, and species-specific diagnostic and treatment approaches for dogs. Dogs are the most commonly treated veterinary species with the deepest evidence base, but significant breed variation means "canine medicine" is not monolithic.

## When to Use

- Patient is a dog of any breed, age, or size
- User asks about canine-specific disease presentations, diagnostics, or treatments
- User asks about breed-specific considerations in dogs
- Keywords: dog, canine, puppy, breed, K9

## Clinical Reference Values (Adult Dog)

| Parameter | Normal Range |
| --- | --- |
| Temperature | 100.5-102.5°F (38.1-39.2°C) |
| Heart rate | 60-140 bpm (size-dependent: large dogs lower, small dogs higher) |
| Respiratory rate | 10-30 bpm |
| CRT (capillary refill time) | < 2 seconds |
| Systolic blood pressure | 110-160 mmHg |
| PCV | 37-55% |
| Total protein | 5.0-7.5 g/dL |
| Blood glucose | 74-143 mg/dL |
| BUN | 7-27 mg/dL |
| Creatinine | 0.5-1.8 mg/dL (sighthounds: up to 2.2 mg/dL normal) |

## Key Canine-Specific Considerations

- **Breed diversity creates enormous clinical variation.** A 2 kg Chihuahua and a 70 kg Great Dane are the same species but have dramatically different disease profiles, drug dosing, anesthetic risk, and life expectancy (5-7 years for giant breeds vs. 14-16 years for small breeds).
- **Sighthound normals differ:** Greyhounds and related breeds have lower WBC, platelet counts, and T4, higher PCV (55-65%), and higher creatinine (up to 2.2 mg/dL). These are physiologic, not pathologic.
- **MDR1 mutation:** Primarily affects herding breeds (Collie, Australian Shepherd, Shetland Sheepdog, Old English Sheepdog, and crosses). Causes sensitivity to ivermectin (high dose), loperamide, acepromazine, and some chemotherapy agents. Test before prescribing P-glycoprotein substrates.
- **Brachycephalic breeds** (Bulldogs, Pugs, French Bulldogs): Brachycephalic obstructive airway syndrome (BOAS), higher anesthesia risk, corneal ulceration, spinal malformations, heat stroke susceptibility.
- **Large/Giant breeds:** Higher incidence of orthopedic disease (hip/elbow dysplasia, OCD), osteosarcoma, DCM, GDV. Shorter life expectancy. Prophylactic gastropexy may be recommended for GDV-prone breeds.

## Common Canine Diseases (No Feline Equivalent)

- **GDV (gastric dilatation-volvulus):** Surgical emergency. Deep-chested breeds (Great Dane, German Shepherd, Standard Poodle, Weimaraner). Mortality 10-45% even with treatment.
- **CCL rupture (cranial cruciate ligament):** Most common orthopedic surgery in dogs. Breeds: Labrador, Rottweiler, Newfoundland. TPLO is gold standard surgical correction.
- **Canine cognitive dysfunction (CCD):** Age-related dementia. Prevalence >50% in dogs over 11 years. Disorientation, altered sleep cycles, loss of housetraining.
- **Idiopathic epilepsy:** Breed-dependent prevalence (Border Collie, Belgian Tervuren, Labrador, Golden Retriever). Onset typically 1-5 years. First-line: phenobarbital or levetiracetam.

## Canine-Specific Diagnostics

| Test | Purpose | Notes |
| --- | --- | --- |
| 4Dx SNAP | Heartworm + tick-borne disease (Ehrlichia, Anaplasma, Lyme) | Annual screening in endemic areas |
| cPLI / Spec cPL | Canine pancreatitis | More specific than lipase/amylase |
| NT-proBNP | Cardiac biomarker | Screening for occult heart disease |
| SDMA | Early renal disease | Rises before creatinine in CKD |
| Thyroxine (T4) | Hypothyroidism screening | Common in middle-aged large breeds |
| Cortisol (LDDS/ACTH stim) | Cushing's disease | Common in older small breeds |

## Drug Safety Notes

- Dogs tolerate acetaminophen (with caution, 10 mg/kg PO q12h) but cats cannot.
- Chocolate (theobromine) toxicity: dogs metabolize theobromine slowly (~17.5 hour half-life). Dose-dependent: mild GI at 20 mg/kg, cardiac at 40 mg/kg, seizures/death at 60+ mg/kg.
- Xylitol: Profoundly hypoglycemic in dogs (0.1 g/kg), hepatotoxic at higher doses.
- Grape/raisin toxicity: Idiosyncratic nephrotoxicity. No established safe dose. Treat all exposures as potentially lethal.
- NSAIDs: Carprofen, meloxicam, deracoxib, firocoxib all FDA-approved for canine use. Always check renal function and avoid concurrent corticosteroid use.

## Workflow

1. Identify breed, age, sex, reproductive status, and weight.
2. Apply breed-specific disease predispositions to differential ranking.
3. Use canine-specific reference ranges for lab interpretation. Note sighthound exceptions.
4. Check MDR1 status for herding breeds before prescribing P-glycoprotein substrates.
5. Select canine-approved drugs at species-appropriate doses.
6. Consider size-category differences (toy, small, medium, large, giant) for drug dosing, anesthetic protocols, and disease risk.

## Limitations

- Canine medicine is the best-evidenced area of veterinary medicine, but many conditions still lack RCT-level evidence.
- Mixed breed dogs may carry predispositions from any contributing breed. DNA testing (Embark, Wisdom Panel) can help but is not comprehensive.
- Regional disease prevalence varies significantly (heartworm, tick-borne diseases, Valley Fever, blastomycosis, leptospirosis).
- Breed-specific reference ranges are only well-established for sighthounds; other breeds may have uncharacterized normals.